Performance information

• Focusing of airborne ultrasound emitted by a flexurally vibrating plate using a transmission mask with spatially designed holes
  Keisuke Hasegawa; Masaya Fujimori; Masaya Takasaki
  Journal of Applied Physics, Volume：137, Number：12, Mar. 2025, [Reviewed], [Lead, Corresponding]
  We propose a focusing method of intense midair ultrasound out of ultrasonic emission from a single flexurally vibrating plate partially covered with a purposely designed amplitude mask. Many applications relying on nonlinear acoustic effects, such as radiation force employed in acoustic levitation, have been devised. For those applications, focused intense airborne ultrasound is conventionally formed using phased arrays of transducers or sound sources with specific fabricated shapes. However, the former strategies are costly, and the latter may require minute three-dimensional fabrication processes, which both hinder their utilization, especially in constructing a large ultrasound-emitting aperture. Our method offers a possible solution for this, where the amplitude masks are designed depending on the positions of nodes and antinodes of the vibrating plate. We experimentally demonstrate the successful formation of midair ultrasound focus at a desired position, which is localized in a region whose diameter is less than a few wavelengths. Our method only requires a monolithic plate, a driving transducer under the plate, and an amplitude mask fabricated out of laser machining of an acrylic plate. Magnification of the spatial scale of ultrasound apertures based on our method is much more readily and affordably achieved than conventional methods, leading to new midair ultrasound applications with the whole-room workspace.
  AIP Publishing, Scientific journal
  DOI：https://doi.org/10.1063/5.0247366
  DOI ID：10.1063/5.0247366, ISSN：0021-8979, eISSN：1089-7550
• Spatially variable parametric sound image presentation with sparsely arranged ultrasonic sources with controlled emission direction　　　　　　　　　　　　　　　
  Takeru Momoki; Masaya Takasaki; Keisuke Hasegawa
  Applied Acoustics, Volume：231, Mar. 2025, [Reviewed], [Last, Corresponding]
  This paper proposes a new method for personalized sound image presentation using parametric arrays with controllable azimuthal direction. Despite a long research history of parametric arrays, few preceding studies handle the issue of subjectively perceived sound source direction. In addition, the control of such virtual parametric sound source directions in practical system configuration remains little practical. To this issue, we propose a solution with much better feasibility, where only several small-sized parametric loudspeakers are supposed to be sparsely arranged with their emission angles controlled depending on the position and attitude of a listener. To this end, we experimentally determined the prediction model of the perceived sound image direction as a function of the sound source position and the direction of ultrasound emission, which was proven to be described as a linear function of those parameters. This paper also discusses how the interaural time difference and interaural level difference influence the sound image position based on acoustic measurement. It was demonstrated that the parametric sound images could be presented reproducibly with our strategy, indicating that our achievement will contribute considerably to the practical possibility of constructing a personalized device-free spatial audio system.
  Scientific journal
  DOI：https://doi.org/10.1016/j.apacoust.2025.110547
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  DOI ID：10.1016/j.apacoust.2025.110547, ISSN：0003-682X, eISSN：1872-910X, SCOPUS ID：85215940474
• Frequency shift of parametric sound by face-to-face pair of sources in relative motion　　　　　　　　　　　　　　　
  Shun Kotoku; Reita Maeno; Keisuke Hasegawa
  Journal of the Acoustical Society of America, Volume：155, Number：5, First page：3447, Last page：3460, May 2024, [Reviewed], [Last, Corresponding]
  This paper reports an acoustic phenomenon regarding a parametric sound source (also referred to as a parametric array): a secondary sound wave is generated from the nonlinear interaction of multiple primary sound waves with varied frequency components, particularly when two relatively moving sound sources face each other. It was found that the frequency of the secondary wave fluctuated according to the source movement and provided a theoretical explanation for this phenomenon. It is experimentally demonstrated that this frequency shift was approximately proportional to the velocity of the moving source toward the fixed source and to the driving frequency of the moving source. This phenomenon has much in common with the Doppler's effect, but its unique property is that the frequency shift depends on neither the observation position nor the source velocity toward the observer. These sound generation principles enable measurement of the velocity of slowly moving sound sources while maintaining a low-modulation frequency band and a short measurement time. This phenomenon can potentially be applied to an alternative approach for acoustic noncontact velocimetry of moving objects.
  Scientific journal
  DOI：https://doi.org/10.1121/10.0026135
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  DOI ID：10.1121/10.0026135, ISSN：0001-4966, eISSN：1520-8524, PubMed ID：38780197, SCOPUS ID：85194026469
• Suppression of short-range exposure to infectious aerosols using multiple paths of midair ultrasound acoustic streaming　　　　　　　　　　　　　　　
  Kouta Nagata; Keisuke Hasegawa
  Aerosol Science and Technology, Volume：58, Number：7, First page：796, Last page：811, Apr. 2024, [Reviewed], [Last, Corresponding]
  One of the major infectious routes of respiratory diseases, such as COVID-19, is exposure to viral aerosols transmitted from an infected person over a short distance. Conventionally, plastic shields or personalized ventilation methods utilizing fans or jets to generate airflows between two facing users have been used to combat such short-range infection. Nevertheless, these methods entail several drawbacks: bulky apparatus hindering users’ cooperative activities must be placed between them, the shields need frequent cleaning and block conversation voices, and the jet- or fan-based methods yield uncomfortably strong airflows hitting the user’s face. Here, a new airflow-based strategy for suppressing aerosol exposure, which overcomes all the above inconveniences, was proposed. In this strategy, ultrasound-driven localized airflows called acoustic streaming, whose positions and traveling directions can be electronically controlled, was used. A prototype system composed of a group of phased arrays of airborne ultrasound transducers was created, and they were set behind the users to redirect paths of aerosols emitted from the user’s mouth toward their upper and back sides. It is experimentally confirmed that the proposed system could reduce exposure to aerosols whose diameters are the same as ones emitted from people by 89.95% under a certain setup. By controlling the position and direction of the streaming, the proposed method can maintain its performance when users move their heads or bodies. The proposed system can virtually produce or delete programmable partitions in the air as desired, and can be integrated with other conventional methods for infection control.
  Scientific journal
  DOI：https://doi.org/10.1080/02786826.2024.2345156
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  DOI ID：10.1080/02786826.2024.2345156, ISSN：0278-6826, eISSN：1521-7388, SCOPUS ID：85192358939
• Airborne ultrasound focusing aperture with binary amplitude mask over planar ultrasound emissions　　　　　　　　　　　　　　　
  Masatake Kitano; Keisuke Hasegawa
  Journal of Applied Physics, Volume：133, Number：14, Apr. 2023, [Reviewed], [Last, Corresponding]
  Phased arrays of airborne ultrasound transducers are widely utilized as a key technology to achieve mid-air convergence of intense ultrasound, which is applied to a variety of systems, such as contactless tactile presentation, acoustic levitation and its application, mid-air-flow acceleration, etc. However, it requires considerably precise phase control with temporally severe synchronization between elements, which leads to difficulty in scaling up the entire system beyond the tabletop size as most of the current application systems. Here, we propose a much simpler and easier scaling-up method of airborne ultrasound convergence, where a binary amplitude mask that serves as a Fresnel Zone Plate (FZP) is placed on the planar in-phase ultrasound sources. We experimentally demonstrate that the FZP-based ultrasound focusing achieved a spatial resolution that is comparable to conventional methods, based on the use of phase-controlled transducers. The ultrasound foci created using FZPs are sufficiently intense for most application scenarios that are currently in practical use. We also determine favorable side effects of our method suppressing grating lobes, which is inevitable with the conventional phase-controlling method. The FZPs and planar ultrasound sources are both readily implemented with inexpensive ingredients and components. The result of our study contributes to upsizing dimensions in which a mid-air convergent ultrasound field is successfully generated. Accordingly, unprecedented application scenarios that target the entire room as the workspace will be possible.
  Scientific journal
  DOI：https://doi.org/10.1063/5.0140604
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  DOI ID：10.1063/5.0140604, ISSN：0021-8979, eISSN：1089-7550, SCOPUS ID：85153677445
• Self-localization of monaural microphone using dipole sound sources　　　　　　　　　　　　　　　
  Kazuyuki Arikawa; Keisuke Hasegawa; Takaaki Nara
  The Journal of the Acoustical Society of America, Volume：153, Number：1, First page：105, Last page：118, Jan. 2023, [Reviewed]
  This paper introduces a method for indoor self-localization of a monaural microphone, which is required for various location-based services. By generating two pairs of dipole sound fields, localization is performed on each device, irrespective of the number of devices, based on orthogonal detection of observed signals and some simple operations that are feasible with limited computational resources. A method using multiple source frequencies for enhancing robustness against the effects of reflection and scattering is also proposed. The effectiveness of this method was evaluated by numerical simulations and experiments in an anechoic chamber and indoor environment, and the average errors for the azimuth and zenith angles were 4.8 and 1.9 deg, respectively, in the anechoic chamber and 21 and 11 deg, respectively, in the indoor environment.
  Acoustical Society of America (ASA), Scientific journal
  DOI：https://doi.org/10.1121/10.0016812
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  DOI ID：10.1121/10.0016812, ISSN：0001-4966, eISSN：1520-8524, PubMed ID：36732260, SCOPUS ID：85145875853
• A Method for Electrical Property Tomography Based on a Three-Dimensional Integral Representation of the Electric Field　　　　　　　　　　　　　　　
  Naohiro Eda; Motofumi Fushimi; Keisuke Hasegawa; Takaaki Nara
  IEEE Transactions on Medical Imaging, Volume：41, Number：6, First page：1400, Last page：1409, Jun. 2022, [Reviewed]
  Magnetic resonance electrical properties tomography (MREPT) noninvasively reconstructs high-resolution electrical property (EP) maps using MRI scanners and is useful for diagnosing cancerous tissues. However, conventional MREPT methods have limitations: sensitivity to noise in the numerical Laplacian operation, difficulty in reconstructing three-dimensional (3D) EPs and convergence not guaranteed in the iterative process. We propose a novel, iterative 3D reconstruction MREPT method without a numerical Laplacian operation. We derive an integral representation of the electric field using its Helmholtz decomposition with Maxwell's equations, under the assumption that the EPs are known on the boundary of the region of interest with the approximation that the unmeasurable magnetic field components are zero. Then, we solve the simultaneous equations composed of the integral representation and Ampere's law using a convex projection algorithm whose convergence is theoretically guaranteed. The efficacy of the proposed method was validated through numerical simulations and a phantom experiment. The results showed that this method is effective in reconstructing 3D EPs and is robust to noise. It was also shown that our proposed method with the unmeasurable component $H^{-}$ enhances the accuracy of the EPs in a background and that with all the components of the magnetic field reduces the artifacts at the center of the slices except when all the components of the electric field are close to zero.
  Institute of Electrical and Electronics Engineers (IEEE), Scientific journal
  DOI：https://doi.org/10.1109/tmi.2021.3139455
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  DOI ID：10.1109/tmi.2021.3139455, ISSN：0278-0062, eISSN：1558-254X, PubMed ID：34968176, SCOPUS ID：85122597661
• Sequential structured volumetric ultrasound holography for self-positioning using monaural recording　　　　　　　　　　　　　　　
  Honoka Mukai; Keisuke Hasegawa; Takaaki Nara
  The Journal of the Acoustical Society of America, Volume：150, Number：6, First page：4178, Last page：4190, Dec. 2021, [Reviewed], [Corresponding]
  In this article, a structured acoustic holography technique in the self-positioning method of a single microphone from the monaurally recorded signals is proposed. A series of three-dimensional ultrasonic holograms, designed for positioning in a workspace, are sequentially projected. As a result, the microphone receives a position-dependent sequence of amplitude signals encoded with information on the observation position. Subsequently, the microphone position is determined by obtaining the peak position of the cross-correlation function between the received signal and the reference signal. Experiments were conducted using a custom-made phased array of 40-kHz ultrasound transducers to evaluate the positioning accuracy. It is demonstrated that when applied to a 100×100×50 mm3 workspace, the measurement error was less than 1 mm at all observation points in the numerical experiment, which was maintained for more than 96% of the points in the real-environment experiments. The proposed method is advantageous in that it does not use the phase information of the recorded signals, thus requiring no multiple synchronized recordings as the microphone-array-based methods. In addition, this scheme does not directly use the absolute value of the received amplitude as a positioning clue, which means that no amplitude-to-voltage calibration is required.
  Acoustical Society of America (ASA), Scientific journal
  DOI：https://doi.org/10.1121/10.0007464
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  DOI ID：10.1121/10.0007464, ISSN：0001-4966, eISSN：1520-8524, PubMed ID：34972280, SCOPUS ID：85121098343
• Spatiotemporal Pinpoint Cooling Sensation Produced by Ultrasound-Driven Mist Vaporization on Skin　　　　　　　　　　　　　　　
  Mitsuru Nakajima; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  IEEE Transactions on Haptics, Volume：14, Number：4, First page：874, Last page：884, 2021, [Reviewed]
  In this study, we achieved a noncontact tactile display that presents a pinpoint and instantaneous cooling sensation on the skin surface with no devices directly in contact with the user's body. We employed ultrasound phased arrays to generate a focused ultrasound, which locally and instantaneously expedites the vaporization of room-temperature water mist floating near the surface of the user's skin, offering a sudden pinpoint cooling sensation. In this article, we describe the physical configuration of the proposed method and show the measurement results, demonstrating how the user's skin surface was cooled. During the experiments, we discovered that a part of the skin exposed to a focused ultrasound within the floating mist was selectively cooled with negligible delay. Our prototype system offers a cooling spot of approximately 15 mm in diameter, which causes a temperature decrease of 4.6 K in 1 s and 3.3 K in the first 0.5 s on a hand situated 500 mm away from the device. Additionally, the ultrasound-driven cooling spot can be controlled on the skin surface, which is felt as a cool moving spot. Such a position-free cooling system with a high spatiotemporal resolution will open the door to unprecedented practical tactile applications.
  Scientific journal
  DOI：https://doi.org/10.1109/TOH.2021.3086516
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  DOI ID：10.1109/TOH.2021.3086516, ISSN：1939-1412, eISSN：2329-4051, PubMed ID：34086577, SCOPUS ID：85107365586
• Volumetric acoustic holography and its application to self-positioning by single channel measurement
  Keisuke Hasegawa; Hiroyuki Shinoda; Takaaki Nara
  Journal of Applied Physics, Volume：127, Number：24, First page：244904, Last page：244904, Jun. 2020, [Reviewed], [Lead, Corresponding]
  We generated dense mid-air volumetric acoustic holography using a newly developed computation algorithm and experimentally verified its utility for three-dimensional self-positioning via monaural amplitude measurements. We computed the holography by solving an inverse problem where complex amplitudes of ultrasound emissions are to be determined so that the given acoustic amplitude field at a finite set of control points in the workspace could be generated as faithfully as possible. With a one-directional gradient pattern of a 40 kHz ultrasonic field that stretched uniformly toward the depth direction, numerical simulations showed that positioning with an average error less than 3 mm is ideally possible in a 100 mm-sided cubic workspace. We experimentally verified that this error was approximately 8 mm with our custom-made phased array. Our work shows the first example of information systems, where a position-dependent information field is embedded in the environment as a form of holographic wave field that can be sensed by standalone mobile devices.
  AIP Publishing, Scientific journal
  DOI：https://doi.org/10.1063/5.0007706
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  DOI ID：10.1063/5.0007706, ISSN：0021-8979, eISSN：1089-7550, SCOPUS ID：85088012785
• Tactile Stimulation by Repetitive Lateral Movement of Midair Ultrasound Focus　　　　　　　　　　　　　　　
  Ryoko Takahashi; Keisuke Hasegawa; Hiroyuki Shinoda
  IEEE Transactions on Haptics, Volume：13, Number：2, First page：334, Last page：342, Apr. 2020, [Reviewed], [Corresponding]
  CCBY We report a new vibrotactile modulation method of midair ultrasound focus namely, lateral modulation (LM), in which the focus quickly moves along a small cyclic trajectory and provides stronger and clearer vibrotactile stimuli than those by the conventional amplitude modulation (AM) method. Midair ultrasound haptics has an essential technical advantage of offering remote, non-contact, and pinpoint tactile stimuli on device-free bare skin. On the other hand, lack of clarity in the presented vibrotactile sensation has often been pointed out, and until now, an AM focus has been valid only on glabrous skin. Our main scientific contribution of the study is to verify the LM method, with the following experimental findings newly obtained. We confirmed that with the same maximum output amplitude of the ultrasound phased arrays, LM stimuli with circular focal trajectories were sensed stronger than AM stimuli by glabrous skin and hairy skin in a modulation frequency of 10-200 Hz. We also found that the detection threshold in glabrous skin mainly depended on the focal speed, whereas the tendency in hairy skin was different from that. With these results, we discuss a basis of perceptional mechanism that responds to LM stimuli, along with practical aspects of potential applications.
  Scientific journal
  DOI：https://doi.org/10.1109/TOH.2019.2946136
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  DOI ID：10.1109/TOH.2019.2946136, ISSN：1939-1412, eISSN：2329-4051, PubMed ID：31634143, SCOPUS ID：85073752903
• Midair Haptic Pursuit　　　　　　　　　　　　　　　
  Azuma Yoshimoto; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  IEEE Transactions on Haptics, Volume：12, Number：4, First page：652, Last page：657, Oct. 2019, [Reviewed]
  © 2019 IEEE. In human vision, smooth pursuit eye movement is the basic ability to visually follow a moving object by keeping it at the sight center. In this study, we validate that a human hand has a similar ability to track a midair haptic stimulus, i.e., a human palm exposed to a point vibration by a noncontact ultrasound tactile display can follow the continuous movement of the stimulation point. The experimental results show that the trackable velocity limit is 10 cm/s for motion parallel to the palm, when the initial velocity is zero. This ability of motion tracking by hand can be applied to haptic guidance for visually impaired people or for evacuation navigation, where no devices are needed to be equipped by users.
  Scientific journal
  DOI：https://doi.org/10.1109/TOH.2019.2906163
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  DOI ID：10.1109/TOH.2019.2906163, ISSN：1939-1412, eISSN：2329-4051, PubMed ID：30908263, SCOPUS ID：85072783185
• Curved acceleration path of ultrasound-driven air flow
  Keisuke Hasegawa; Hiroki Yuki; Hiroyuki Shinoda
  Journal of Applied Physics, Volume：125, Number：5, Feb. 2019, [Reviewed], [Lead, Corresponding]
  © 2019 Author(s). We established a method for generating an ultrasound beam that propagates along a narrow, isolated curved path and is accompanied by an arc-shaped airflow, and experimentally confirmed the actual generation of such a beam. The method employs a two-dimensional orthogonal phased array of ultrasound transducers, whose individual columns correspond to a line segment in a given beam trajectory. Each column of transducers yields a “ring” in which acoustic energy is concentrated. A cluster of these ultrasound rings arranged at sufficiently small spatial intervals interfere with adjacent rings, consequently forming a fine curved path of propagating ultrasound accompanied by an ultrasound-driven air flow. The positions of these rings can be electronically controlled and so can the position of the resulting beam path. We obtained isolated sharp arc-shaped airflows propagating over nearly 1 m in open space. Such airflows have never been reported and are extremely difficult to generate by the superposition of ordinary jet-driven airflows. Our achievement will lead to the ability to generate airflows along an arbitrarily designed three-dimensional arc-shaped path. This technique will be utilized in such unprecedented applications as midair transportation of gaseous substance or control of heat in the air while circumventing obstacles, which are intuitive, yet hard to achieve by other methods.
  Scientific journal
  DOI：https://doi.org/10.1063/1.5052423
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  DOI ID：10.1063/1.5052423, ISSN：0021-8979, eISSN：1089-7550, SCOPUS ID：85061314715
• Three-Dimensional Manipulation of a Spherical Object Using Ultrasound Plane Waves　　　　　　　　　　　　　　　
  Takuro Furumoto; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  IEEE Robotics and Automation Letters, Volume：4, Number：1, First page：81, Last page：88, Jan. 2019, [Reviewed]
  © 2016 IEEE. In this letter, we demonstrate a new robotic framework where a lightweight balloon with no onboard actuators or batteries acts as a mid-air robot that travels three-dimensionally within a workspace. The workspace contains five sparsely arranged ultrasound transducer arrays emitting steerable plane waves that cause acoustic radiation forces on the balloon and actuate it. The fabricated system performs a dynamic PID control of the movement of the balloon based on visual feedback. For practical operation of the system, we experimentally modeled the acoustic radiation force applied on a sphere. Based on the model, we developed the system dynamics model and a control law. We constructed a prototype system and demonstrated meter-scale three-dimensional manipulation of a 200 mm-diameter spherical object. Our proposed methodology is beneficial for long-term mid-air robotic applications, such as 24-h indoor surveillance system with no blind spots caused by battery limitation.
  Scientific journal
  DOI：https://doi.org/10.1109/LRA.2018.2880330
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  DOI ID：10.1109/LRA.2018.2880330, eISSN：2377-3766, SCOPUS ID：85063310130
• Aerial Vibrotactile Display Based on Multiunit Ultrasound Phased Array
  Keisuke Hasegawa; Hiroyuki Shinoda
  IEEE Transactions on Haptics, Volume：11, Number：3, First page：367, Last page：377, Jul. 2018, [Reviewed], [Lead, Corresponding]
  © 2008-2011 IEEE. In this paper, we report on an airborne vibrotactile display with a multiunit ultrasound phased array synthetic aperture. The system generates an ultrasound field with a location-tunable focus in the air, which exerts time-variant acoustic radiation pressure on the users skin, resulting in perceivable localized vibrotactile stimuli. The paper contains three major new contributions from previous related works. The first is an experimental validation of large-aperture focusing with improved synchronization offering an enlarged workspace in which sufficient acoustic power concentration is guaranteed. From the experiments, it is expected that perceivable vibrotactile focus can be generated 1 m away from a four-unit array system. The second is an experimental evaluation of the presented pressure for producing a broad variety of tactile perception, which shows that the generated ultrasound focus can serve as an vibrotactile actuator that has flat frequency characteristics in the domain of perceptual stimuli. The third is a psychophysical result of the detection threshold curve for sinusoidal stimuli offered by the system. The obtained curve shows similarity with conventionally known results, which have minimum values at approximately 200 Hz.
  Scientific journal
  DOI：https://doi.org/10.1109/TOH.2018.2799220
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  DOI ID：10.1109/TOH.2018.2799220, ISSN：1939-1412, eISSN：2329-4051, SCOPUS ID：85041391710
• Midair ultrasound fragrance rendering
  Keisuke Hasegawa; Liwei Qiu; Hiroyuki Shinoda
  IEEE Transactions on Visualization and Computer Graphics, Volume：24, Number：4, First page：1477, Last page：1485, Apr. 2018, [Reviewed], [Lead]
  © 2018 IEEE Computer Society. All rights reserved. We propose a system that controls the spatial distribution of odors in an environment by generating electronically steerable ultrasound-driven narrow air flows. The proposed system is designed not only to remotely present a preset fragrance to a user, but also to provide applications that would be conventionally inconceivable, such as: 1) fetching the odor of a generic object placed at a location remote from the user and guiding it to his or her nostrils, or 2) nullifying the odor of an object near a user by carrying it away before it reaches his or her nostrils (Fig. 1). These are all accomplished with an ultrasound-driven air stream serving as an airborne carrier of fragrant substances. The flow originates from a point in midair located away from the ultrasound source and travels while accelerating and maintaining its narrow cross-sectional area. These properties differentiate the flow from conventional jet- or fan-driven flows and contribute to achieving a midair flow. In our system, we employed a phased array of ultrasound transducers so that the traveling direction of the flow could be electronically and instantaneously controlled. In this paper, we describe the physical principle of odor control, the system construction, and experiments conducted to evaluate remote fragrance presentation and fragrance tracking.
  Scientific journal
  DOI：https://doi.org/10.1109/TVCG.2018.2794118
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  DOI ID：10.1109/TVCG.2018.2794118, ISSN：1077-2626, SCOPUS ID：85041649999
• Electronically steerable ultrasound-driven long narrow air stream　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Liwei Qiu; Akihito Noda; Seki Inoue; Hiroyuki Shinoda
  Applied Physics Letters, Volume：111, Number：6, Aug. 2017, [Reviewed], [Lead, Corresponding]
  © 2017 Author(s). Acoustic streaming, which is the unidirectional movement of a medium driven by its internal intense acoustic vibrations, has been known for more than a century. Despite the long history of research, there have been no scientific reports on the creation of long stretching steerable airflows in an open space, generated by ultrasound. Here, we demonstrated the creation of a narrow, straight flow in air to a distance of 400 mm from an ultrasound phased array emitting a Bessel beam. We also demonstrated that the direction of the flow could be controlled by appropriately tuning the wavefronts of the emission from the phased array. Unlike conventional airflows such as those generated by jets or fans, which decelerate and spread out as they travel farther, the flow that we created proceeded while being accelerated by the kinetic energy supplied from the ultrasound beam and keeping the diameter as small as the wavelength. A flow of 3 m/s with a 10 mm diameter extended for several hundreds of millimeters in a room that was large enough to be regarded as an open-boundary environment. These properties of the generated flow will enable fine and rapid control of three-dimensional airflow distributions.
  AMER INST PHYSICS, English, Scientific journal
  DOI：https://doi.org/10.1063/1.4985159
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  DOI ID：10.1063/1.4985159, ISSN：0003-6951, eISSN：1077-3118, SCOPUS ID：85027316476, Web of Science ID：WOS:000407696500062
• Character Reading via Stylus Reproducing Normal Handwriting Motion　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Tatsuma Sakurai; Yasutoshi Makino; Hiroyuki Shinoda
  IEEE Transactions on Haptics, Volume：9, Number：1, First page：13, Last page：19, Jan. 2016, [Lead]
  In this paper, we report a method of intuitively transmitting symbolic information to untrained users via only their hands, without using any visual or auditory cues. In this simple concept, three-dimensional letter trajectories are presented to the user's hand via a stylus which is mechanically manipulated. In experiments, participants were able to read 14 mm-high lower-case letters displayed at a rate of one letter per second with an accuracy rate of 71.9 percent in their first trials, which improved to 91.3 percent after a 5-minute training period. These results showed small individual differences among participants (standard deviation of 12.7 percent in the first trials and 6.7 percent after training). We also found that this accuracy was still retained to a high level (85.1 percent, with SD of 8.2 percent) even when the letters were reduced to a height of 7 mm. Thus, we revealed that sighted adults potentially possess the ability to read small letters accurately at normal writing speed using their hands.
  IEEE COMPUTER SOC, English, Scientific journal
  DOI：https://doi.org/10.1109/TOH.2016.2517625
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84964318404&origin=inward
  DOI ID：10.1109/TOH.2016.2517625, ISSN：1939-1412, eISSN：2329-4051, SCOPUS ID：84964318404, Web of Science ID：WOS:000372996700003
• High-speed Dynamic Information Environment with Airborne Ultrasound Tactile Display-Camera System and The Calibration Method(Mixed Reality)　　　　　　　　　　　　　　　
  Sueishi Tomohiro; Hasegawa Keisuke; Okumura Kohei; Oku Hiromasa; Shinoda Hiroyuki; Ishikawa Masatoshi
  Transactions of the Virtual Reality Society of Japan, Volume：19, Number：2, First page：173, Last page：183, 2014, [Reviewed]
  In this paper, we propose an image and tactile presentation system for quickly moving objects, high-speed dynamic information environment, and a calibration method between a camera and Airborne Ultrasound Tactile Display(AUTD), which can present tactile sensation noncontactly as focused ultrasound. We realize one example of high-speed dynamic information environment that even if an object is moving, we can use the object as a tool for human interfaces without delay by combining a high-speed gaze controller by rotational mirrors. An accuracy of position, however, is not sufficient against difference threshold between images and tactile sensation because of mainly error of position between AUTD and camera. We calibrate the AUTD-camera system by visualizing the invisible focal position using Frustrated Total Internal Reflection(FTIR). Experimental results show that estimation accuracy is better than the threshold.
  THE VIRTUAL REALITY SOCIETY OF JAPAN, Japanese
  DOI：https://doi.org/10.18974/tvrsj.19.2_173
  DOI ID：10.18974/tvrsj.19.2_173, ISSN：1344-011X, CiNii Articles ID：110009830241, CiNii Books ID：AA11448578

• Remotely Estimating Strategy for Direction of Emitting Source of Gaseous Substance Using Angular Scanning of Ultrasound-Driven Straight Airflow　　　　　　　　　　　　　　　
  Taihei Suda; Masaya Takasaki; Keisuke Hasegawa
  2024 SICE Festival with Annual Conference, SICE FES 2024, First page：414, Last page：419, 2024
  We propose a method for remotely estimating the direction of indoor gaseous sources based on the use of electronically steerable ultrasound-driven narrow airflows that create midair gas transportation paths to a spatially fixed sensor. Localization of gas sources have been investigated for several decades, where use of mobile robots equipped with sensors is a current dominant method. However, there are difficult cases to apply the moving robots, where workers are present or footing condition for the robots is bad, for example. Our proposed method employs narrow airflow paths that conveys the gas on the path to the sensor, hereby is free from those problems. In this paper, we experimentally assessed the possibility of the direction-estimation principle, where the sensor output is temporally related to the scanning angle of the ultrasound-driven airflows. It was confirmed that the sensor responded significantly when ultrasound-driven acoustic flow passed near the gaseous substance source. At the same time, significant sensor response was also observed occasionally for the case where the flow path was not close to the source. We give a brief discussion on the possible causes for this and propose several solutions.
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216403226&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85216403226&origin=inward
  SCOPUS ID：85216403226
• A Designing Method of Multi-Channel Ultrasound Source Signals for Presenting Private Sound Field with Parametric Mixing in Air　　　　　　　　　　　　　　　
  Tatsuya Ito; Mayasa Takasaki; Kesisuke Hasegawa
  IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium, UFFC-JS 2024 - Proceedings, 2024
  We aim to generate a private and personalized audible sound field spot in an intersection region of two parametric sound beams. We design driving waveforms of the parametric sound sources so that the secondary sound source waveform produced by self-demodulation after nonlinear mixing in the intersection region is as close as possible to the desired one, whereas the produced secondary sound is indistinct outside this region. Unlike conventional parametric-array-based methods, our method aims to achieve the three-dimensional spatial selectivity of comprehensible audio presentation. In this study, we propose two different design method of driving signals of the sources. We qualitatively assessed the auditory qualities of the presented audible sound with our method by primitive subjective observations.
  DOI：https://doi.org/10.1109/UFFC-JS60046.2024.10793781
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216456130&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85216456130&origin=inward
  DOI ID：10.1109/UFFC-JS60046.2024.10793781, SCOPUS ID：85216456130
• Strategy for Overhead Redirection of Exhaled Infectious Aerosols using Upward Upright Acoustic Streaming by Floor-Reflected Ultrasonic Beam　　　　　　　　　　　　　　　
  Hiromu Hashimoto; Masaya Takasaki; Keisuke Hasegawa
  IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium, UFFC-JS 2024 - Proceedings, 2024
  Diseases caused by exposure to airborne infectious aerosols such as COVID-19 are serious threats to humanity. Recently, besides using masks and physical partitions, ultrasound-driven airflow technically known as the acoustic streaming was employed for the purpose of suppressing direct exposure to aerosols exhaled by a facing person. Although this method was proven to be effective, it can only be applied to a situation where two people face each other. To overcome this restriction, we propose and experimentally demonstrate a technique for redirecting the aerosols emitted from people toward the ceiling of the room by vertical upward acoustic streaming. We place phased arrays of airborne ultrasound transducers on the ceiling and emit ultrasound beams that is reflected on the desk or floor surface, which result in an upward ultrasound beam causing the acoustic streaming toward the ceiling. In this study, we experimentally show that our method is expected to simultaneously suppress the short-range exposure to aerosols and expedite discharge of the aerosols from the room by ventilation systems commonly installed in the ceiling.
  DOI：https://doi.org/10.1109/UFFC-JS60046.2024.10793706
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216472987&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85216472987&origin=inward
  DOI ID：10.1109/UFFC-JS60046.2024.10793706, SCOPUS ID：85216472987
• Non-Contact Mode-Selective Excitation of Liquid Motion in a Container using Acoustic Radiation Force of Airborne Convergent Ultrasound　　　　　　　　　　　　　　　
  Shunsuke Hijikata; Mayasa Takasaki; Kesisuke Hasegawa
  IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium, UFFC-JS 2024 - Proceedings, 2024
  We demonstrate a non-contact method for mode-selective excitation of liquid in a container with its spatial tract of several tens of millimeters by focusing airborne ultrasound on the antinodes of the liquid surface in a spatiotemporally synchronized manner. The key technology in our method is pinpoint acoustic radiation force exerted on the liquid surface by converged ultrasound, which has been used to manipulate a various kind of objects. However, the target objects have been limited to extremely lightweight ones due to the very weak net force exerted to the objects. In this study, we utilized the resonance of the target system and succeeded in liquid motion excitation with an amplitude that has not been realized in previous midair radiation-force related studies. In addition, we experimentally verified that rotational liquid motions that resulted in non-contact liquid agitation was also possible with our method. Our achievements will lead to a new approach of noncontact liquid handling with an improved degree of freedom, requiring no mechanical components that might be eroded during contact with the liquid.
  DOI：https://doi.org/10.1109/UFFC-JS60046.2024.10794163
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216477620&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85216477620&origin=inward
  DOI ID：10.1109/UFFC-JS60046.2024.10794163, SCOPUS ID：85216477620
• Study on Non-Contact Rotation Mechanism Using Single Ultrasonic Transducer : 2nd Report : Installation of Reflector　　　　　　　　　　　　　　　
  Toshikazu Hagio; Keisuke Hasegawa; Yuji Lshino; Takeshi Mizuno; Masaya Takasaki
  IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium, UFFC-JS 2024 - Proceedings, 2024
  Ultrasonic motors are known as actuators that use ultrasonic vibration. Actuation force is induced though friction, which causes wear and damage on sliding parts, resulting in a shortened lifetime. Previously, an airborne non-contact rotation mechanism using ultrasonic vibration was proposed. In this mechanism, an ultrasonic transducer is fixed with its vibration surface facing upward, and a rotor with geometrically designed holes was placed on the surface. The rotor is levitated and rotated with ultrasonic vibration. Since this rotating mechanism is non-contact, a longer lifetime of the actuator can be expected. Non-contact rotation was observed, and the effect of the shape of the rotor holes on rotation was examined. In this report, a new mechanism using reflected ultrasonic wave was proposed, and the effect of the reflected wave on rotation was evaluated in expectation of improving stability and rotational performance.
  DOI：https://doi.org/10.1109/UFFC-JS60046.2024.10793972
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216484007&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85216484007&origin=inward
  DOI ID：10.1109/UFFC-JS60046.2024.10793972, SCOPUS ID：85216484007
• Acoustic field measurement by midair scanning of an acoustically levitated microphone　　　　　　　　　　　　　　　
  Tasuku Mizuno; Keisuke Hasegawa
  IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium, UFFC-JS 2024 - Proceedings, 2024
  Acoustic levitation is widely utilized to grasp objects in air that are sufficiently smaller than the wavelength. Recent development of phase engineering technique of airborne ultrasound transducers (airborne ultrasound phased arrays) has realized rotation and translation of levitated objects in an electronic manner. Based on this technological progress, this paper focuses on direct measurement of acoustic fields in a space through aerial manipulation of a small and lightweight levitation sensor system that we call a wired sensor unit. Our method is free from inconveniences with conventional methods such as robotic-arm-based sensor scanning that they can be dangerous when operated around human or that they lack in the flexibility of the operating range determined in advance. In this paper, the principle of acoustic levitation sensing is verified through an experimental demonstration of acoustic field measurement in a table-top workspace.
  DOI：https://doi.org/10.1109/UFFC-JS60046.2024.10794137
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85216495208&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85216495208&origin=inward
  DOI ID：10.1109/UFFC-JS60046.2024.10794137, SCOPUS ID：85216495208
• Two-Dimensional Visualization of Intense Ultrasound Field using Confined Particle Movement Caused by Radiation Pressure Field　　　　　　　　　　　　　　　
  Keisuke Hasegawa
  IEEE International Ultrasonics Symposium, IUS, 2023
  This paper presents an easy-to-use visualization apparatus for high intensity midair ultrasound field. In many applications of such high-power ultrasound that have been devised so far, construction of minutely designed ultrasound field is crucially important for their performance to the degree of practical use. However, adjustment of generated ultrasound fields has been not an easy task because ultrasound is invisible, and visualization of such fields usually requires scanning of microphones. My proposed method just utilizes passive mechanical component that consists of lightweight polystyrene beads confined between two layers of acoustically translucent membranes. This paper describes how ultrasound fields are visualized with my method and gives theoretical insights for the observed phenomenon.
  DOI：https://doi.org/10.1109/IUS51837.2023.10306357
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85178561420&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85178561420&origin=inward
  DOI ID：10.1109/IUS51837.2023.10306357, ISSN：1948-5719, eISSN：1948-5727, SCOPUS ID：85178561420
• Spatial Calibration of Airborne Ultrasonic Phased Arrays with Two-Dimensional Visualization of Ultrasound Emissions　　　　　　　　　　　　　　　
  Masato Nakagawa; Keisuke Hasegawa
  IEEE International Ultrasonics Symposium, IUS, 2023
  In order to expand the applications of electronically controllable intense mid-air ultrasonic fields generated with airborne ultrasonic phased arrays (AUPA), a precise spatial calibration method between multiple AUPAs is in great demand. However, the conventional methods, such as manual fine-tuning and acoustic beam scanning, take a long time to complete. Here, we propose a quicker calibration method using thermal imaging. By placing an acoustically translucent screen in the AUPAs' sound field containing narrow and straight sound beams, acoustic energy in the field is converted into a two-dimensional heat map. By shooting several images with a thermal camera changing the beam position, information about the relative spatial information between the screen and the AUPAs is promptly visualized. We developed the algorithm to estimate the postures of AUPAs from the obtained image. We conducted a preliminary experiment about thermal imaging and a numerical simulation of the AUPA posture estimation algorithm and verified the effectiveness of our proposed method.
  DOI：https://doi.org/10.1109/IUS51837.2023.10307129
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85178591525&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85178591525&origin=inward
  DOI ID：10.1109/IUS51837.2023.10307129, ISSN：1948-5719, eISSN：1948-5727, SCOPUS ID：85178591525
• Numerical Verification of Generation of Ultrasound-Driven Bent Flow by Centripetal and Tangential Body Force Field　　　　　　　　　　　　　　　
  Kenta Matsuuchi; Keisuke Hasegawa
  IEEE International Ultrasonics Symposium, IUS, 2023
  We propose a method of generating midair acoustic streaming traveling along a curve by combining a central acceleration field with a tangential one by ultrasound emissions from multiple phased arrays of ultrasound transducers. Via numerical experiments, we confirmed, using a hypothetical acceleration field, that a centripetal force contributed to the steady formation of a narrow curved flow. We also demonstrated that a curved flow (0.4 m radius semicircle) could be generated by the phased arrays emitting both centripetal and tangential acceleration field in their possible arrangements, both numerically and experimentally. Half of the arrays generated tangential force field parallel to the given beam trajectory and the others generated centripetal force field that penetrated the center of the array. Although currently generated flows being short in spatial range, such curved flows can potentially increase the spatial flexibility of applications, by circumventing obstacles in the environment, for example.
  DOI：https://doi.org/10.1109/IUS51837.2023.10307809
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85178645523&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85178645523&origin=inward
  DOI ID：10.1109/IUS51837.2023.10307809, ISSN：1948-5719, eISSN：1948-5727, SCOPUS ID：85178645523
• A Spatial Calibration Strategy of Multiple Airborne Ultrasonic Phased Arrays based on Acoustic Beam Steering　　　　　　　　　　　　　　　
  Masato Nakagawa; Keisuke Hasegawa
  Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics, Volume：2022-October, First page：311, Last page：316, 2022
  In application use of electronically controllable ultrasound fields, spatial calibration of multiple airborne ultrasonic phased arrays forming a synthetic aperture must be completed with subwavelength accuracy for extending workspaces. However, manually completing the calibration requires a lot of time and effort, and there has been no established automatic method for this problem. Here we propose an acoustic calibration method using spatiotemporal structured ultrasound field sequentially generated by each array and a single microphone for acoustic measurement. We form a point cloud of microphone positions by the measurement and then register them into Gaussian model in the global coordinate system common across all arrays. We apply likelihood maximization approach to estimate the positions and postures of all arrays that minimizes the discrepancy of global microphone positions retrieved from local observations. We conducted numerical experiments to find that the calibration with no error was achieved with no measurement errors in microphone position, whereas mean estimation errors of less than a quarter of the wavelength in position and one degree in posture were observed when assuming a possible magnitude of measurement errors estimated in previous works.
  DOI：https://doi.org/10.1109/SMC53654.2022.9945557
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85142758623&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85142758623&origin=inward
  DOI ID：10.1109/SMC53654.2022.9945557, ISSN：1062-922X, SCOPUS ID：85142758623
• Single microphone positioning based on Angular scanning of acoustic Bessel beam from symmetric ultrasound emission　　　　　　　　　　　　　　　
  Keisuke Hasegawa
  Measurement: Sensors, Volume：18, Dec. 2021
  We propose a three-dimensional self-positioning method of the single microphone situated in the acoustic field containing the steered Bessel beams generated by a two-dimensional planar ultrasound phased array. The presented method is a modified version of the previously proposed one that suffered from considerable positioning errors. In this paper, we report that this error is caused from asymmetric emission of the phased array that results in distorted beam shape. To overcome this problem, we divided the array aperture in two sub-apertures that separately formed two scanning beams. As a result, the estimation error is tremendously reduced. We also demonstrate that this error can be even reduced to several millimeters by performing coarse-to-fine two stage estimation as a post processing.
  DOI：https://doi.org/10.1016/j.measen.2021.100247
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85122756463&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85122756463&origin=inward
  DOI ID：10.1016/j.measen.2021.100247, eISSN：2665-9174, SCOPUS ID：85122756463
• Self-Localization of Single Microphone from Ultrasound Field Generated by Sources with Subwavelength Displacement　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Takaaki Nara
  IEEE International Ultrasonics Symposium, IUS, Volume：2019-October, First page：2496, Last page：2499, Oct. 2019
  We propose a self-localization method of a single microphone based on measured phase gradient of wave field created by sources with sub-wavelength movements. Unlike most of conventional localization methods based on time-of-arrival (TOA) of time-difference-of-arrival (TDOA) from impulsive wave packets emitted from sources, we employ spatial information of wave field that is entirely derived from the wave equation containing a point source. Instead of impulsive emissions, continuous sinusoidal wave from a point source is utilized in our technique. We describe a localization strategy that integrates multiple measurements for a stable and robust performance. We verified the validity of our method via numerical and realenvironment experiments.
  DOI：https://doi.org/10.1109/ULTSYM.2019.8926256
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85077539209&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85077539209&origin=inward
  DOI ID：10.1109/ULTSYM.2019.8926256, ISSN：1948-5719, eISSN：1948-5727, SCOPUS ID：85077539209
• Indoor Self Localization of a Single Microphone based on Asynchronous Scanning of Modulated Bessel Beams　　　　　　　　　　　　　　　
  Keisuke Hasegawa
  2019 58th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2019, First page：142, Last page：147, Sep. 2019, [Reviewed]
  © 2019 The Society of Instrument and Control Engineers - SICE. The paper introduces an indoor self-localization method that employs an ultrasound phased array for generating electronically steerable ultrasound Bessel beams. By scanning the beams with their direction information embedded in the received waveform, the microphone yields a 2D map of amplitude according to the beam direction. Because the maximum amplitude in the map corresponds to the beam direction, multiple beams with different root position offers three-dimensional microphone localization. By numerical examples, the validity of the method is assessed and the advantages and drawbacks of the method are accordingly discussed.
  DOI：https://doi.org/10.23919/SICE.2019.8859852
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85073878410&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85073878410&origin=inward
  DOI ID：10.23919/SICE.2019.8859852, SCOPUS ID：85073878410
• Remotely Displaying Cooling Sensation Using Ultrasound Mist Beam
  Mitsuru Nakajima; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, Volume：535, First page：85, Last page：87, 01 Jan. 2019
  © 2019, Springer Nature Singapore Pte Ltd. This study describes a midair haptic display that provides a cooling sensation using ultrasound-driven cold air flow cooled by mist vaporization. Non-contact thermal display using ultrasound-driven cold air flow has been reported, but the system uses dry ice as the cold-air source, which limits the range of practical applications. In this study, we propose a method using mist vaporization instead of dry ice to extend the application. Using this system, we demonstrate transporting cold air to a localized spot on a user’s skin.
  DOI：https://doi.org/10.1007/978-981-13-3194-7_18
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85065979500&origin=inward
  DOI ID：10.1007/978-981-13-3194-7_18, ISSN：1876-1100, eISSN：1876-1119, SCOPUS ID：85065979500
• Circular Lateral Modulation in Airborne Ultrasound Tactile Display
  Ryoko Takahashi; Saya Mizutani; Keisuke Hasegawa; Masahiro Fujiwara; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, Volume：535, First page：92, Last page：94, 01 Jan. 2019
  © 2019, Springer Nature Singapore Pte Ltd. Airborne Ultrasound Tactile Display (AUTD) can present tactile stimulus on the skin, but the generated pressure is too small in many cases to be perceived on the hairy part. In a previous paper, we proposed a lateral modulation (LM) method where the ultrasound focus was reciprocated along the skin surface instead of amplitude modulation (AM). LM provided clear vibrotactile stimuli even on the hairy skin. In this research, we examine a new modulation named LMc where the ultrasound focus follows a circumference on the skin. In this method, the frequency of the pressure received by each skin receptor is constant regardless of the position. The conference participants experience the difference among AM, LM, and LMc.
  DOI：https://doi.org/10.1007/978-981-13-3194-7_20
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85065996768&origin=inward
  DOI ID：10.1007/978-981-13-3194-7_20, ISSN：1876-1100, eISSN：1876-1119, SCOPUS ID：85065996768
• Midair Haptic Display to Human Upper Body　　　　　　　　　　　　　　　
  Shun Suzuki; Ryoko Takahashi; Mitsuru Nakajima; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  2018 57th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2018, First page：848, Last page：853, 15 Oct. 2018, [Reviewed]
  © 2018 The Society of Instrument and Control Enginners - SICE. In this paper, we present a calibration method for multi-unit midair haptic display that can cover a workspace larger than one-meter cube. In typical previous midair haptic displays, the workspace was smaller than a 30-cm cube, where the display target was limited to a hand and fingers. To achieve a large workspace covering a human upper body, we develop a system where arbitrarily located multiple display units with sensors can determine the relative positions and postures by a simple calibration process. In a prototype system using two units of 45 cm by 57 cm phased arrays, we examine the ultrasound convergence from the multiple units. We also show that the midair haptic stimulation is perceivable through clothes on the upper body.
  DOI：https://doi.org/10.23919/SICE.2018.8492582
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85056701825&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85056701825&origin=inward
  DOI ID：10.23919/SICE.2018.8492582, SCOPUS ID：85056701825
• Remotely displaying cooling sensation via ultrasound-driven air flow　　　　　　　　　　　　　　　
  Mitsuru Nakajima; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  IEEE Haptics Symposium, HAPTICS, Volume：2018-March, First page：340, Last page：343, 09 May 2018, [Reviewed]
  © 2018 IEEE. A midair haptic display that provides a cooling sensation is developed in this study. Although a noncontact heat display using infrared rays has been reported, such an infrared display cannot cool the skin surface. In this study, we generate and control a straight, thin, long, air flow driven by an ultrasound-phased array and transport cold air to a localized spot on the users' skin. Since the air flow position and direction is electronically steerable, the display area can be controlled freely. A prototype of the proposed display was developed and the cooling performance was evaluated. We confirm that a small cool spot is created and shifted on a user's forearm based on our observations of the temporal changes in the skin temperature distribution using thermography.
  DOI：https://doi.org/10.1109/HAPTICS.2018.8357198
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85047931444&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85047931444&origin=inward
  DOI ID：10.1109/HAPTICS.2018.8357198, ISSN：2324-7347, eISSN：2324-7355, SCOPUS ID：85047931444
• Manual Character Transmission by Presenting Trajectories of 7mm-high Letters in One Second　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Tatsuma Sakurai; Yasutoshi Makino; Hiroyuki Shinoda
  24 Mar. 2015
  In this paper, we report a method of intuitively transmitting symbolic
  information to untrained users via only their hands without using any visual or
  auditory cues. Our simple concept is presenting three-dimensional letter
  trajectories to the user's hand via a stylus which is mechanically manipulated.
  By this simple method, in our experiments, participants were able to read 14
  mm-high lower-case letters displayed at a rate of one letter per second with an
  accuracy rate of 71.9% in their first trials, which was improved to 91.3% after
  a five-minute training period. These results showed small individual
  differences among participants (standard deviation of 12.7% in the first trials
  and 6.7% after training). We also found that this accuracy was still retained
  to a high level (85.1% with SD of 8.2%) even when the letters were reduced to a
  height of 7 mm. Thus, we revealed that sighted adults potentially possess the
  ability to read small letters accurately at normal writing speed using their
  hands.
  DOI：https://doi.org/10.1109/TOH.2016.2517625
  DOI ID：10.1109/TOH.2016.2517625, arXiv ID：arXiv:1503.07401

• Ultrasound Mid-Air Haptics for Touchless Interfaces　　　　　　　　　　　　　　　
  K. Hasegawa; H. Shinoda, [Contributor], Modulation Methods for Ultrasound Midair Haptics
  Springer, Sep. 2022
  DOI：https://doi.org/10.1007/978-3-031-04043-6_9
  DOI ID：10.1007/978-3-031-04043-6_9, ISBN：9783031040436, 共同研究・競争的資金等ID：27897715

• Research on airborne non-contact rotation mechanism using ultrasonic transducers and rotating block-2nd Report: application of reflected wave-　　　　　　　　　　　　　　　
  萩生駿壱; 石野裕二; 水野毅; 長谷川圭介; 高崎正也
  電磁力関連のダイナミクスシンポジウム講演論文集, 2024
  2024 - 2024
• Evaluation of cutting efficiency of ultrasonic dental scaler: Third report: Influence of tip pressing angle　　　　　　　　　　　　　　　
  三浦蓮太郎; 水野毅; 石野裕二; 長谷川圭介; 高崎正也
  電磁力関連のダイナミクスシンポジウム講演論文集, 2024
  2024 - 2024
• Characteristics of magnetic suspension system with rotational flux-path control mechanism　　　　　　　　　　　　　　　
  後山翔; 水野毅; 長谷川圭介; 石野裕二; 高崎正也
  電磁力関連のダイナミクスシンポジウム講演論文集, 2024
  2024 - 2024
• Application of pumps with the ultrasonic transducer and opposing block to liquid~Second report: Investigation of performance improvement by new block shapes~　　　　　　　　　　　　　　　
  石田慎義; 長谷川圭介; 石野裕二; 水野毅; 高崎正也
  電磁力関連のダイナミクスシンポジウム講演論文集, 2024
  2024 - 2024
• Fabrication of ultrasonic transducer usable in high magnetic field and driving tests　　　　　　　　　　　　　　　
  多田良知; 高崎正也; 水野毅; 石野裕二; 長谷川圭介; 原正之; 大西秀明; 大鶴直史; 児玉直樹; 櫻井典子
  日本機械学会ロボティクス・メカトロニクス講演会講演論文集(CD-ROM), 2024
  2024 - 2024
• Design of Multi-Channel Ultrasound Source Signals for Presenting Personal Sound Field with Parametric Mixing in Air　　　　　　　　　　　　　　　
  伊藤辰弥; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Investigations on Suppression of Exposure to Infectious Aerosols using Upward Upright Acoustic Flow by Floor-Reflected Ultrasonic Beam　　　　　　　　　　　　　　　
  橋本拓武; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Experimental investigation of the influence of ultrasound emission field on perceived parametric sound image direction　　　　　　　　　　　　　　　
  百木健; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Remote and non-contact liquid rocking using focused ultrasound and system resonance　　　　　　　　　　　　　　　
  土方駿佑; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Designing multimodal haptic display by simultaneously presenting non-contact tactile and thermal sensation　　　　　　　　　　　　　　　
  細川龍生; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Virtual Push Button with Pre-contact Midair Tactile Feedback using Focused Ultrasound　　　　　　　　　　　　　　　
  菅原景哉; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Forming Airborne Ultrasonic Focus by Controlling Radiation Amplitude Distribution of a Diaphragm with Flexural Vibration Mode　　　　　　　　　　　　　　　
  藤森正也; 高崎正也; 長谷川圭介
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), 2023
  2023 - 2023
• Remotely Displaying Cooling Sensation Using Ultrasound Mist Beam　　　　　　　　　　　　　　　
  Mitsuru Nakajima; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2019
  2019 - 2019
  © 2019, Springer Nature Singapore Pte Ltd. This study describes a midair haptic display that provides a cooling sensation using ultrasound-driven cold air flow cooled by mist vaporization. Non-contact thermal display using ultrasound-driven cold air flow has been reported, but the system uses dry ice as the cold-air source, which limits the range of practical applications. In this study, we propose a method using mist vaporization instead of dry ice to extend the application. Using this system, we demonstrate transporting cold air to a localized spot on a user’s skin.
• Circular Lateral Modulation in Airborne Ultrasound Tactile Display　　　　　　　　　　　　　　　
  Ryoko Takahashi; Saya Mizutani; Keisuke Hasegawa; Masahiro Fujiwara; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2019
  2019 - 2019
  © 2019, Springer Nature Singapore Pte Ltd. Airborne Ultrasound Tactile Display (AUTD) can present tactile stimulus on the skin, but the generated pressure is too small in many cases to be perceived on the hairy part. In a previous paper, we proposed a lateral modulation (LM) method where the ultrasound focus was reciprocated along the skin surface instead of amplitude modulation (AM). LM provided clear vibrotactile stimuli even on the hairy skin. In this research, we examine a new modulation named LMc where the ultrasound focus follows a circumference on the skin. In this method, the frequency of the pressure received by each skin receptor is constant regardless of the position. The conference participants experience the difference among AM, LM, and LMc.
• 空中超音波LM触覚刺激における刺激点移動パターンと知覚強度の関係　　　　　　　　　　　　　　　
  高橋諒子; 水谷沙耶; 藤原正浩; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2018
  Dec. 2018 - Dec. 2018, Japanese
• 超音波ミストビームによる遠隔冷覚提示　　　　　　　　　　　　　　　
  中島允; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2018
  Dec. 2018 - Dec. 2018, Japanese
• 超音波走査による匂いディスプレイ　　　　　　　　　　　　　　　
  中島允; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2018
  Sep. 2018 - Sep. 2018, Japanese
• Sensing Odor Using Ultrasound Phased Array　　　　　　　　　　　　　　　
  中島 允; 長谷川 圭介; 牧野 泰才; 篠田 裕之
  センシングフォーラム資料, Aug. 2018, 計測自動制御学会計測部門
  Aug. 2018 - Aug. 2018, Japanese
• Visuo-tactile interaction with virtual objects that yields kinetic effects on real objects　　　　　　　　　　　　　　　
  Kyosuke Yamazaki; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2018
  2018 - 2018
  © Springer Nature Singapore Pte Ltd. 2018. In this presentation, we describe an HMD-based immersive VR environment which allow us to touch virtual objects and to apply actual kinetic effects on corresponding objects in real world. We utilize foci of airborne ultrasound for generating tactile feedback to users’ hands and applying kinetic force to the real objects. Our system offers a new tele-operation system, where bare-handed users can manipulate real objects located away from them with tactile feedback.
• An immersive Visuo-Haptic VR environment with pseudo-haptic effects on perceived stiffness　　　　　　　　　　　　　　　
  Daichi Matsumoto; Ya Zhu; Yuya Tanaka; Kyosuke Yamazaki; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2018
  2018 - 2018
  © Springer Nature Singapore Pte Ltd. 2018. In this presentation, we describe an immersive visuo-tactile VR system which presents tunable subjective hardness of virtual objects by employing the pseudo-haptic effects. Our system supposes that users put on an HMD and a glove which contains a mechanical structure that presents constraining force to his or her fingers in pinching virtual objects. The system visually displays a re-rendered virtual hand pinching deformed objects with its finger flexion magnified or suppressed graphically, for arousing the pseudo-haptic effect. We expect this method to be effective in creating mobile wearable tactile systems that are correlated to personal VR systems in home applications.
• Character recognition by flick movements presented on fingers　　　　　　　　　　　　　　　
  Kentaro Yoshida; Koji Tanaka; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2018
  2018 - 2018
  © Springer Nature Singapore Pte Ltd. 2018. It is general to recognize informations of languages visually or audibly. But, the recognition of such informations by haptics can be a good way according to the surrounding environment. Moreover, people who lose visual and auditory senses need a character reading method without using such senses. Though the braille is given as an example for character recognition by haptics, learning braille requires a much time and the number of its users who can read braille enough is few. Then, this report proposes a device presenting flick movements onto the fingers for character recognition.
• Haptoclonear (Haptic-optical clone with augmented reality) for mutual interactions with midair 3D floating image and superimposed 2D display　　　　　　　　　　　　　　　
  Kentaro Yoshida; Takaaki Kamigaki; Seki Inoue; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2018
  2018 - 2018
  © Springer Nature Singapore Pte Ltd. 2018. In the previous study, a new interactive system called HaptoClone was proposed. In HaptoClone system, a user can interact with optically copied objects from the adjacent workspace with haptic feedback. In this study, we propose an improved version of the HaptoClone system called HaptoCloneAR, which superimposes a virtual 2D screen on the copied objects by using half-mirrors. The system can display 2 different images independently to each workspace. In this paper, we show a basic configuration of the HaptoCloneAR system. We demonstrate a feasibility of the proposed system with our prototype.
• Haptic tracing of midair linear trajectories presented by ultrasound bessel beams　　　　　　　　　　　　　　　
  Shun Suzuki; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2018
  2018 - 2018
  © Springer International Publishing AG, part of Springer Nature 2018. This paper verifies the ability of human subjects with no audiovisual clues to trace their hands along an invisible vibrotactile line in three-dimensional space created by an ultrasound Bessel beam. A narrow, long, and stationary Bessel beam that passes through a target position is generated. The beam produces midair vibrotactile stimuli on the subjects’ hands. The subjects are required to perceive the beam location and direction actively to trace the presented linear trajectory. With our method, no real-time hand tracking is necessary, which guarantees no latency in presenting the vibrotactile stimuli. We experimentally verified that the subjects were able to trace the beam over 50 cm in its stretching direction with their hands. The average deviation from the beam center was less than 6 cm. Unlike conventional wearable-based motion guidance, the proposed technique requires no devices to be worn by the users in practical situations.
• Lateral Modulation of Midair Ultrasound Focus for Intensified Vibrotactile Stimuli　　　　　　　　　　　　　　　
  Ryoko Takahashi; Keisuke Hasegawa; Hiroyuki Shinoda
  Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2018
  2018 - 2018
  © Springer International Publishing AG, part of Springer Nature 2018. In this paper, we propose a new modulation method of midair ultrasound focus named Lateral Modulation (LM), which provides significantly stronger vibrotactile stimuli on the skin surface compared to that provided by conventional Amplitude Modulation (AM) in the realm of midair ultrasound haptics. We experimentally validated the effectiveness of the LM method by showing that it significantly lowered the vibrotactile detection threshold compared with the AM method, for a wide range of modulation frequencies. The method was found to be valid both on the glabrous and hairy skins, and is expected to be applied to whole-body midair haptics. We demonstrate that the LM method relies on the characteristics of human perception of moving stimuli on the skin surface.
• 超音波駆動音響流による匂い環境制御　　　　　　　　　　　　　　　
  長谷川圭介; QIU Liwei; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2017
  Dec. 2017 - Dec. 2017, Japanese
• 音響ビームによる任意方向への冷気の誘導に基づく遠隔冷覚提示　　　　　　　　　　　　　　　
  中島允; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2017
  Dec. 2017 - Dec. 2017, Japanese
• 空中平面超音波による浮遊物体の動的位置制御　　　　　　　　　　　　　　　
  古本拓朗; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2017
  Dec. 2017 - Dec. 2017, Japanese
• Interactive midair odor control via ultrasound-driven air flow　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Liwei Qiu; Hiroyuki Shinoda
  SIGGRAPH Asia 2017 Emerging Technologies, SA 2017, Nov. 2017
  Nov. 2017 - Nov. 2017
• 空中超音波による浮遊物体の運動制御　　　　　　　　　　　　　　　
  古本拓朗; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2017
  Sep. 2017 - Sep. 2017, Japanese
• 音響流ベッセルビームを用いた遠隔冷覚提示　　　　　　　　　　　　　　　
  中島允; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2017
  Sep. 2017 - Sep. 2017, Japanese
• Displaying variable stiffness by passive nonlinear spring using visuo-haptic interaction　　　　　　　　　　　　　　　
  Daichi Matsumoto; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  2017 IEEE World Haptics Conference, WHC 2017, Jul. 2017, Institute of Electrical and Electronics Engineers Inc.
  Jul. 2017 - Jul. 2017, English
  This paper proposes an immersive visuo-haptic display system composed of an easy-to-carry and light-weight passive haptic device and an HMD. We employ visuo-haptic interaction to control a wide range of perceived stiffness without using mechanical actuators that would inevitably make the device bulky and power-consuming. Via an HMD a user sees his or her own rendered hand with its finger flexion that is appropriately modified in relation to presented virtual stiffness. We experimentally verified that the proposed system could display both a pinchable elastic ball and a rigid undeformable one.
• 反発力提示機構を用いた没入型視触覚VR環境における擬似力覚的硬さ提示　　　　　　　　　　　　　　　
  松本大知; ZHU Ya; 田中雄也; 山崎喬輔; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2016
  Dec. 2016 - Dec. 2016, Japanese
• 空中匂い分布制御に向けた音響流の数値シミュレーション　　　　　　　　　　　　　　　
  仇力維; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2016
  2016 - 2016, Japanese
• 実物体への力学的作用を伴う視触覚VR環境　　　　　　　　　　　　　　　
  山崎喬輔; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2016
  2016 - 2016, Japanese
• 指のフリック動作提示による文字認識　　　　　　　　　　　　　　　
  吉田健太郎; 田中宏治; 長谷川圭介; 牧野泰才; 牧野泰才; 篠田裕之; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2016
  2016 - 2016, Japanese
• Estimation of Fingers' Position with a Data Glove using Cameras and Orientation Sensors　　　　　　　　　　　　　　　
  TAKANO Akihiro; HASEGAWA Keisuke; NODA Akihito; MAKINO Yasutoshi; SHINODA Hiroyuki
  The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec), 2016, The Japan Society of Mechanical Engineers
  2016 - 2016, Japanese
  <p>We propose a method that enables a data glove to estimate the positions of the wearer's fingers out of the two different measurements, a vision-based marker tracking and an orientation estimation with 9-axis sensors. Since these measurements have inherently different temporal scales, we integrate them using the complementary filtering techniques. In derivation of the proposed estimation algorithm, we introduce a simplified model of finger movements in order to associate the output of 9-axis sensor with the finger positions. We experimentally evaluated the validity of the proposed method. Our method requires only several tiny sensors and electronic components equipped on the glove, which allows the glove to avoid being bulky.</p>
• Handheld Haptic Alphabet Display Presenting Letter Trajectories to Fingers　　　　　　　　　　　　　　　
  TANAKA Koji; HASEGAWA Kesuke; MAKINO Yasutoshi; SHINODA Hiroyuki
  The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec), 2016, The Japan Society of Mechanical Engineers
  2016 - 2016, Japanese
  <p>This paper proposes a pocket-size device that enables users with no prior long-time trainings to intuitively read text letters using only their haptic sense. The device forces the user's finger-tip to trace trajectories of alphabet characters. Vibrotactile stimuli are superposed on fingers so that users can distinguish writing strokes from transient movements of fingers between strokes. The device structure, displayed motions, and experimental results of character reading are shown. The results suggest that the access to symbolic information via haptic modalities would turn into practical applications for people with late blindness or even people with normal vision.</p>
• Motion Guidance to Target Area Using Airborne Ultrasound　　　　　　　　　　　　　　　
  YOSHIMOTO Azuma; HASEGAWA Keisuke; MAKINO Yasutoshi; SHINODA Hiroyuki
  The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec), 2016, The Japan Society of Mechanical Engineers
  2016 - 2016, Japanese
  <p>In this study, we examine a method for guiding the users' hands to a specific region in the air, by utilizing Airborne Ultrasound Tactile Display (AUTD). The AUTD is a device that creates focused airborne ultrasound on the surface of human skin resulting in perceivable vibrotactile stimuli. Measuring the position of a hand in real time, the fabricated system allows users to tactually feel a virtual wall out of focused ultrasound that is accordingly generated. The AUTD is placed on the left side of the workspace yielding rightward radiation force onto the palm of the user. In this paper we particularly discuss the human performance of locating horizontal position displayed by the system, in terms of its accuracy.</p>
• A Pocket-Size Alphabet Display with Letter Trajectories Presented to Fingers　　　　　　　　　　　　　　　
  Koji Tanaka; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  HAPTICS: PERCEPTION, DEVICES, CONTROL, AND APPLICATIONS, EUROHAPTICS 2016, PT I, 2016, SPRINGER INT PUBLISHING AG
  2016 - 2016, English
  We propose a pocket-size device that enables users with no prior long-time trainings to intuitively read text letters using only their haptic sense. The device forces the user's finger-tip to trace trajectories of lowercase roman alphabet characters. In displaying multistroke characters, vibrotactile stimuli are accordingly superposed on fingers so that users can distinguish writing strokes from transient movements of fingers between strokes. Our experiments showed that participants could recognize all alphabet characters. They were able to identify them with an accuracy rate of approximately 80% when presented at an average rate of 1.4 s/letter. We also showed that the accuracy rate varied slightly depending on holding orientation of the device, and that these identification performances could be obtained after only five-minute training. These results suggest that the access to symbolic information via haptic modalities, which were conventionally considered to be of limited use among people with early blindness, would turn into practical mobile applications for people with late blindness or even people with normal vision.
• Simulation of Acoustic Streaming for Odorant Display Controlled by Airborne Ultrasound　　　　　　　　　　　　　　　
  Liwei Qiu; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  2016 55TH ANNUAL CONFERENCE OF THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS OF JAPAN (SICE), 2016, IEEE
  2016 - 2016, English
  The paper presents a method to control odorant material distribution in the air utilizing acoustic streaming produced by an ultrasonic phased array. By controlling the three-dimensional acoustic energy distribution, we can virtually locate airflow sources in the 3D space, which creates and controls the airflow paths in the workspace. As a special case, this paper shows the simulation result of a thin and long airflow produced by a Bessel beam created by an ultrasonic phased array.
• 空中超音波による無線給電とその応用　　　　　　　　　　　　　　　
  MA Shaoxiang; 吉本東雲; 井上碩; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2015
  Dec. 2015 - Dec. 2015, Japanese
• 空中超音波によるリアルタイム行動誘導　　　　　　　　　　　　　　　
  吉本東天; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2015
  Dec. 2015 - Dec. 2015, Japanese
• 倍率可変視触覚クローン　　　　　　　　　　　　　　　
  新井綾太; 古山佳和; 井上碩; 長谷川圭介; 牧野泰才; 篠田裕之
  計測自動制御学会システムインテグレーション部門講演会(CD-ROM), Dec. 2015
  Dec. 2015 - Dec. 2015, Japanese
• 柔軟センサグローブのリアルタイム自己姿勢推定法　　　　　　　　　　　　　　　
  長谷川圭介; 野田聡人; 牧野泰才; 篠田裕之
  センシングフォーラム資料(CD-ROM), Sep. 2015
  Sep. 2015 - Sep. 2015, Japanese
• Midair touch display　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Yasuaki Monnai; Seki Inoue; Yoshikazu Furuyama; Yasutoshi Makino; Hiroyuki Shinoda
  ACM SIGGRAPH 2015 Emerging Technologies, SIGGRAPH 2015, Jul. 2015, Association for Computing Machinery, Inc
  Jul. 2015 - Jul. 2015, English
  We demonstrate a system which enables users with bare hands and naked eyes to tactually interact with midair three-dimensional objects. The displayed midair images are three-dimensional and can be seen and touched from multiple angles. By creating neatly controlled and designed ultrasound fields, our system can create rich tactile textures added onto them with no devices to be worn by the users, all of which are programmable.
• Transmitting Full Set of Alphabet Letters to Human Hand via Writing Motion with 5-minute Training.　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Tatsuma Sakurai; Yasutoshi Makino; Hiroyuki Shinoda
  CoRR, 2015
  2015 - 2015
• Demo hour.　　　　　　　　　　　　　　　
  Max Rheiner; Thomas Tobler; Fabian Troxler; Seki Inoue; Keisuke Hasegawa; Yasuaki Monnai; Yasutoshi Makino; Hiroyuki Shinoda,Array,Norbert Schnell,Riccardo Borghesi; Frédéric Bevilacqua; Tuncay Cakmak; Holger Hager
  Interactions, 2015
  2015 - 2015
• 音響ベッセルビームによる匂いの空間分布制御の基礎的検討　　　　　　　　　　　　　　　
  長谷川圭介; 牧野泰才; 牧野泰才; 篠田裕之; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2015
  2015 - 2015, Japanese
• 文字軌跡上の追従運動による手指への文書提示　　　　　　　　　　　　　　　
  田中宏治; 長谷川圭介; 牧野泰才; 牧野泰才; 篠田裕之; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2015
  2015 - 2015, Japanese
• 空中超音波触覚ディスプレイによる行動誘導　　　　　　　　　　　　　　　
  吉本東天; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2015
  2015 - 2015, Japanese
• リアルタイム擬ホログラフィによる接触感を伴う対面コミュニケーション　　　　　　　　　　　　　　　
  古山佳和; 松林篤; 新井綾太; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), 2015
  2015 - 2015, Japanese
• Generating vibrotactile images on the human palms　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2015, Springer Verlag
  2015 - 2015, English
  We have created a system that generates vibrotactile images on the surface of bare human palms. It simultaneously projects visible images by a video projector and produces non-contact vibrotactile stimuli using focused airborne ultrasound on the users’ skin. The vibrotactile images can be moved smoothly owing to the ultrasound phased array technique employed in the system. The vibrational texture can be tuned with amplitude modulation of ultrasound at the focal point. Our proposed system does not postulate that users wear specific devices for sensing tactile stimuli, which allows users to be free from any physical constraints.
• Adding texture to aerial images using ultrasounds　　　　　　　　　　　　　　　
  Yasuaki Monnai; Keisuke Hasegawa; Masahiro Fujiwara; Kazuma Yoshino; Seki Inoue; Hiroyuki Shinoda
  Lecture Notes in Electrical Engineering, 2015, Springer Verlag
  2015 - 2015, English
  We present a method to add textures to aerial images using ultrasounds. The superposition of an acoustic radiation pressure on an aerial image allows users to feel a tactile texture of a virtual object floating in midair. Tactile textures can be altered by modulating the waveform of the ultrasounds. The tactile feedback is presented selectively on the user’s fingertip using an infrared sensor without an extra marker. The proposed method provides a rich visuo–tactile experience all in free space.
• HaptoMime　　　　　　　　　　　　　　　
  Yasuaki Monnai; Keisuke Hasegawa; Masahiro Fujiwara; Kazuma Yoshino; Seki Inoue; Hiroyuki Shinoda
  Proceedings of the 27th annual ACM symposium on User interface software and technology, Oct. 2014, ACM
  Oct. 2014 - Oct. 2014
• HaptoMime: Mid-air haptic interaction with a floating virtual screen　　　　　　　　　　　　　　　
  Yasuaki Monnai; Keisuke Hasegawa; Masahiro Fujiwara; Kazuma Yoshino; Seki Inoue; Hiroyuki Shinoda
  UIST 2014 - Proceedings of the 27th Annual ACM Symposium on User Interface Software and Technology, Oct. 2014, Association for Computing Machinery, Inc
  Oct. 2014 - Oct. 2014, English
  We present HaptoMime, a mid-air interaction system that allows users to touch a floating virtual screen with hands-free tactile feedback. Floating images formed by tailored light beams are inherently lacking in tactile feedback. Here we propose a method to superpose hands-free tactile feedback on such a floating image using ultrasound. By tracking a fingertip with an electronically steerable ultrasonic beam, the fingertip encounters a mechanical force consistent with the floating image. We demonstrate and characterize the proposed transmission scheme and discuss promising applications with an emphasis that it helps us 'pantomime' in mid-air.
• 空中収束超音波による振動触覚提示のための触感記録装置　　　　　　　　　　　　　　　
  長谷川圭介; 熊谷壮一郎; 牧野泰才; 篠田裕之
  センシングフォーラム資料(CD-ROM), Sep. 2014
  Sep. 2014 - Sep. 2014, Japanese
• 動荷重計測に基づいた空中超音波振動触感提示　　　　　　　　　　　　　　　
  熊谷壮一郎; 長谷川圭介; 牧野泰才; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2014
  Sep. 2014 - Sep. 2014, Japanese
• HORN: The hapt-optic reconstruction　　　　　　　　　　　　　　　
  Seki Inoue; Koseki J. Kobayashi-Kirschvink; Yasuaki Monnai; Keisuke Hasegawa; Yasutoshi Makino; Hiroyuki Shinoda
  ACM SIGGRAPH 2014 Emerging Technologies, SIGGRAPH 2014, 2014, Association for Computing Machinery
  2014 - 2014, English
  In this paper we propose a system that superposes a haptic sensa- tion on a mid-air floating image based on ultrasonic standing waves. Conventional approaches of using airborne traveling ultrasounds could only apply weak pressure to the finger surface from a cer- tain angle and thus a limited haptic sensation. Also, the ultrasounds generated air flow as a side-effect [Hoshi et al. 2009]. © 2014 held by the Owner/Author.
• 運動する人体上に高速追従する映像投影への空中超音波触覚の重畳　　　　　　　　　　　　　　　
  長谷川圭介; 末石智大; 奥村光平; 奥寛雅; 石川正俊; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2013
  Sep. 2013 - Sep. 2013, Japanese
• 駆動鏡面式高速視線制御を用いたステレオトラッキングによる動的対象への視触覚提示システム　　　　　　　　　　　　　　　
  末石智大; 長谷川圭介; 奥村光平; 奥寛雅; 篠田裕之; 石川正俊
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2013
  Sep. 2013 - Sep. 2013, Japanese
• 1A1-E05 Generation of Remote Tactile Sensation with Controlled Spatial Distribution of Airborne Ultrasound Amplitude(Haptic Interface (1))　　　　　　　　　　　　　　　
  HASEGAWA Keisuke; SHINODA Hiroyuki
  The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec), 2013, 一般社団法人 日本機械学会
  2013 - 2013, Japanese
  In this paper we propose a method for calculating ultrasound phase and amplitude of transducers in an array which accomplishes the desirable spatial distribution of resulting ultrasound amplitude for generating tactile sensation on human bodies in a remote and non-contact way. Based on the principle of acoustic radiation pressure, a region where the sound pressure is high enough, pushes the surfaces of objects located in it. A three-dimensional ultrasound amplitude distribution can be designed with our calculation method and thus three-dimensionally expanding remote tactile stimuli can be generated. We operated a few numerical simulations to verify the validity of our proposal method.
• A Method for Distribution Control of Aerial Ultrasound Radiation Pressure for Remote Vibrotactile Display　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Hiroyuki Shinoda
  2013 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE), 2013, IEEE
  2013 - 2013, English
  We propose a calculation method for phase and amplitude of ultrasound transducers in arrays, which are supposed to generate proper spatial distribution of radiation pressure on users' skin corresponding to vibrotactile sensation conveyed to users. The phased array technique has been applied for ultrasound transducer array and converged energy in a focus of magnified amplitude in the air has been successfully generated as well as vibrotactile stimulation in a point. In this paper we expand that phasing scheme for a single focus to arbitrary three-dimensional distribution amplitude with transducers located in three-dimensional disposition. We verify the validity of our method with numerical experiments.
• Aerial Display of Vibrotactile Sensation with High Spatial-Temporal Resolution using Large-Aperture Airborne Ultrasound Phased Array　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Hiroyuki Shinoda
  2013 WORLD HAPTICS CONFERENCE (WHC), 2013, IEEE
  2013 - 2013, English
  We fabricated a tactile display which can generate vibrotactile sensation on human skin on which no equipment is mounted. It utilizes focused airborne ultrasound radiation pressure for stimulation. The workspace of our new tactile display is widened to a cube of 1m x 1m x 1m, which allows users free motions in it. In order to widen the workspace, our new prototype integrates multiple ultrasound transducer units and achieves a large aperture airborne ultrasound phased array. As the workspace is widened, it has become possible to stimulate arbitrary regions all over a human body.
  The amplitude of imposed radiation pressure can be time-variant. The profiles of generated vibrotactile stimuli can be designed with a temporal resolution of 0.5 ms and 320-level quantization of radiation pressure amplitude. It is easy to choose a recorded waveform and reproduce it as vibrotactile stimuli at an arbitrary spatial point. This paper introduces how our new tactile display works and reports its performance evaluation.
• Visuo‐Tactile Projector:映像と触覚の同時投影装置の提案　　　　　　　　　　　　　　　
  長谷川圭介; 吉野数馬; 藤原正浩; 中妻啓; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2012
  Sep. 2012 - Sep. 2012, Japanese
• Dynamic Range Enhancement of Airborne Ultrasound Tactile Display　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Hiroyuki Shinoda
  2012 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE), 2012, SOC INSTRUMENT CONTROL ENGINEERS JAPAN
  2012 - 2012, English
  In this paper we propose a method for enhancement of dynamic range of tactile stimulation amplitude generated remotely with Airborne Ultrasound Tactile Display (AUTD). We attribute the importance of this issue to the improvement of generated force intensity and widened workspace due to the harmonic multi-unit AUTD scheme. The proposed method utilizes the weighted mean strategy among two different discrete output amplitudes. A numerical experiment was carried out to verify the validity of our method, which has shown the drastic reduction of relative errors from desired focal pressures. The influence of spatial focusing violation with our method is discussed as well.
• Measuring Visio-Tactile threshold for Visio-Tactile Projector　　　　　　　　　　　　　　　
  Kazuma Yoshino; Keisuke Hasegawa; Hiroyuki Shinoda
  2012 PROCEEDINGS OF SICE ANNUAL CONFERENCE (SICE), 2012, SOC INSTRUMENT CONTROL ENGINEERS JAPAN
  2012 - 2012, English
  This paper proposes a new device, Visio-Tactile Projector (VT Projector). VT Projector is a projector which can project both visual image and tactile stimulation on human skin at the same time. For the design or applications of VT Projector, we measured Visio-Tactile threshold (VTT) in three movement patterns and two vibration frequencies by constant method. VTT is the distance on the skin that is required for people to recognize the difference of two stimulated points between projected visual point image and a tactile stimulation. The results showed the VTT is about 10 to 13 mm regardless of the stimulate pattern.
• 把持物体への空中超音波照射による触覚提示　　　　　　　　　　　　　　　
  長谷川圭介; 篠田裕之
  日本バーチャルリアリティ学会大会論文集(CD-ROM), Sep. 2011
  Sep. 2011 - Sep. 2011, Japanese
• 信頼度重みづけを考慮した非同期録音のブラインドアラインメント　　　　　　　　　　　　　　　
  長谷川圭介; 小野順貴; 宮部滋樹; 嵯峨山茂樹
  日本音響学会研究発表会講演論文集(CD-ROM), Sep. 2010
  Sep. 2010 - Sep. 2010, Japanese
• 分散型マイクロホンアレーによる非同期録音信号のブラインドアラインメントの実環境評価　　　　　　　　　　　　　　　
  長谷川圭介; 宮部滋樹; 小野順貴; 嵯峨山茂樹
  電子情報通信学会大会講演論文集, Mar. 2010, The Institute of Electronics, Information and Communication Engineers
  Mar. 2010 - Mar. 2010, Japanese
• Blind Estimation of Locations and Time Offsets for Distributed Recording Devices　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Nobutaka Ono; Shigeki Miyabe; Shigeki Sagayama
  LATENT VARIABLE ANALYSIS AND SIGNAL SEPARATION, 2010, SPRINGER-VERLAG BERLIN
  2010 - 2010, English
  This paper presents a blind technique to estimate locations and recording time offsets of distributed recording devices from asynchronously recorded signals. In our method, locations of sound sources and recording devices, and the recording time offsets are estimated from observed time differences of arrivals (TDOAs) by decreasing the mean squared errors. The auxiliary-function-based updates guarantee the monotonic decrease of the objective function at each iteration. The TDOAs are estimated by the generalized cross correlation technique. The validity of our approach is shown by experiments in real environment, where locations of seven sound sources and eight microphones and eight time offsets were estimated from signals recorded by four stereo IC recorders in reverberant rooms.
• Algebraic computation of the stability radius of a multilinear polynomial　　　　　　　　　　　　　　　
  Keisuke Hasegawa; Masaaki Kanno; Shinji Hara
  ICCAS-SICE 2009 - ICROS-SICE International Joint Conference 2009, Proceedings, Dec. 2009
  Dec. 2009 - Dec. 2009
  This paper proposes an algebraic algorithm for the computation of the stability radius of a multilinear polynomial. Two algebraic conditions are used to characterize the stability radius and they are exploited to calculate the stability radius. Two numerical examples are provided for demonstration purposes. © 2009 SICE.

• 2024
• 2024

• Development of ultrasound field generator with large apertures embedded in indoor environment by electronic control of emission amplitude distribution　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory), 30 Jun. 2023 - 31 Mar. 2026
  Saitama University
  Grant amount(Total)：6370000, Direct funding：4900000, Indirect funding：1470000
  Grant number：23K18488
• 収束空中超音波の局所非線形効果を活用したピンポイント非接触屋内環境計測の研究　　　　　　　　　　　　　　　
  01 Apr. 2023 - 31 Mar. 2026
  Grant amount(Total)：19240000, Direct funding：14800000, Indirect funding：4440000
  Grant number：23H03473
• 屋内空気の遠隔制御による感染症対応型情報環境の構築　　　　　　　　　　　　　　　
  2021 - 2024
  Principal investigator
• Search for victims in rubble using rotating magnetic and acoustic dipoles　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory), Grant-in-Aid for Challenging Research (Exploratory), 30 Jul. 2020 - 31 Mar. 2023
  The University of Tokyo
  Grant amount(Total)：6110000, Direct funding：4700000, Indirect funding：1410000
  Grant number：20K21051
• Midair Flow Control with High Spatiotemporal Resolution based on Ultrasound-Driven Streaming　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), 01 Apr. 2018 - 31 Mar. 2022
  Hasegawa Keisuke, The University of Tokyo
  Grant amount(Total)：15990000, Direct funding：12300000, Indirect funding：3690000
  The main results of this research are summarized into the three following topics. (1) A construction method of acoustic intensity field that corresponds to acoustic streaming field to generate is established by means of continuous optimization of amplitude distribution with a proper regularization. (2) An arc-shaped intense ultrasound beam is generated by creating series of congregative ultrasound foci that forms the beam. It is verified that the acceleration of air is done in direction of the beam tangent at each line segment of the beam. (3) Binary M-sequence pattern of ultrasound amplitude is generated in the workspace to enable a single monoaural microphone to estimate its self-position. In this framework, the amplitude pattern is spatially scanned so that the microphone position can be retrieved using amplitude signal received by the microphone as a position-dependent positional clue.
  Grant number：18H01458
• Parsonal Olfactory Environment by Controlled Acoustic Streamings　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A), Grant-in-Aid for Young Scientists (A), 01 Apr. 2015 - 31 Mar. 2018
  Hasegawa Keisuke, The University of Tokyo
  Grant amount(Total)：18460000, Direct funding：14200000, Indirect funding：4260000
  We succeeded in generating a narrow, straight and steerable airflow that is accompanied with ultrasound Bessel beam emitted from a phased array of ultrasound transducers. The cross-sectional area of the flow was observed to be almost comparable to several times of the ultrasound wavelength. Based on this technique, we achieved remote fragrance presentation to a specific user in a personalized fashion, where the scent was transported from the scent source to the user’s nostril via the ultrasound-driven airflows. We also demonstrated that selective transportation of a specific kind of scent out of several sources located close to one another was also possible by our technique. We created a system that offered face-tracking scent that targeted freely moving users wearing no devices.
  Grant number：15H05316
• Transmission of Symbolic Information via Forced Handwriting　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research, Grant-in-Aid for Challenging Exploratory Research, 01 Apr. 2015 - 31 Mar. 2017
  Hasegawa Keisuke, The University of Tokyo
  Grant amount(Total)：2990000, Direct funding：2300000, Indirect funding：690000
  This study aimed at conveying symbolic information to human via only haptic modalities based on the “write to read” approach where the users’ hand and fingers were guided along the letter trajectories by external force applied by the mechanical device that we fabricated. As a result, users were able to identify the lower-case alphabets presented by a fabricated desktop system at an accuracy rate of more than 90% without any prior long-time trainings. We also implemented its hand-held version supposed to be used in practical situations, which successfully conveyed the letter trajectories to untrained users. We demonstrated that this method is superior to the conventional ones in the context of intuitiveness.
  Grant number：15K12073
• Basic Study on Super Haptics　　　　　　　　　　　　　　　
  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), 01 Apr. 2013 - 31 Mar. 2016
  Shinoda Hiroyuki; MAKINO Yasutoshi; HOSHI Takayuki; MONNAI Yasuaki; HASEGAWA Keisuke, The University of Tokyo
  Grant amount(Total)：47190000, Direct funding：36300000, Indirect funding：10890000
  Super haptics is haptic human support free from the problems and constraints ascribed to the mechanical contact between the human and haptic stimulators. First in this study, the elementary technology to stimulate a human skin using airborne ultrasound was established. We also developed a sensing technology for remotely measuring the generated force of a human hand. Based on those technologies, we realized novel interface systems: Aerial touch panel in which we can operate floating images with haptic feedback, Haptic-optical clone system that realizes symmetric mutual telexistence in which we can remotely touch each other through realistic 3D images, and a motion navigation system where a hand is navigated by noncontact ultrasound stimulation.
  Grant number：25240032
  書籍等出版物ID：48093729
• 空中超音波フェーズドアレーによる非接触触覚インタフェースの研究　　　　　　　　　　　　　　　
  2012 - 2013
  Grant amount(Total)：1800000, Direct funding：1800000
  Grant number：12J09694