業績情報

• Top-down effects on translucency perception in relation to shape cues　　　　　　　　　　　　　　　
  Takehiro Nagai; Hiroaki Kiyokawa; Juno Kim
  PLOS ONE, 巻：20, 号：2, 2025年02月, ［査読有り］
  It is well established that object shape perception significantly influences the perception of translucency. However, how object shape cues such as motion and binocular disparity affect the perception of translucency in rich environments, like virtual reality or real visual environments, remains unclear. This study aims to psychophysically measure the extent to which multiple object shape cues influence the perception of translucency. Additionally, we examined whether top-down factors, such as changes in cognitive attitude caused by the sequence of experiments, affect translucency perception. The results revealed that while motion and binocular disparity enhance translucency perception, this effect is confined to situations where shape cues are poor. Moreover, the effect became particularly pronounced when the experiments began with weak specular reflection stimuli, followed by the experiments using stimuli with specular reflection. In the case of translucent objects without specular reflection, strong shape information cannot be derived solely from shading patterns. These findings thus suggest that top-down factors related to shape modulate the influence of shape cues on translucency perception.
  PUBLIC LIBRARY SCIENCE, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1371/journal.pone.0314439
  DOI ID：10.1371/journal.pone.0314439, ISSN：1932-6203, Web of Science ID：WOS:001425429000021
• Commonalities and variations in emotion representation across modalities and brain regions.　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Ryusuke Hayashi
  Scientific reports, 巻：14, 号：1, 開始ページ：20992, 終了ページ：20992, 2024年09月, ［査読有り］, ［筆頭著者］, ［国際誌］
  Humans express emotions through various modalities such as facial expressions and natural language. However, the relationships between emotions expressed through different modalities and their correlations with neural activities remain uncertain. Here, we aimed to unveil some of these uncertainties by investigating the similarity of emotion representations across modalities and brain regions. First, we represented various emotion categories as multi-dimensional vectors derived from visual (face), linguistic, and visio-linguistic data, and used representational similarity analysis to compare these modalities. Second, we examined the linear transferability of emotion representation from other modalities to the visual modality. Third, we compared the representational structure derived in the first step with those from brain activities across 360 regions. Our findings revealed that emotion representations share commonalities across modalities with modality-type dependent variations, and they can be linearly mapped from other modalities to the visual modality. Additionally, emotion representations in uni-modalities showed relatively higher similarity with specific brain regions, while multi-modal emotion representation was most similar to representations across the entire brain region. These findings suggest that emotional experiences are represented differently across various brain regions with varying degrees of similarity to different modality types, and that they may be multi-modally conveyable in visual and linguistic domains.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/s41598-024-71690-y
  DOI ID：10.1038/s41598-024-71690-y, PubMed ID：39251743, PubMed Central ID：PMC11385795
• The perception of translucency from surface gloss.　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Takehiro Nagai; Yasuki Yamauchi; Juno Kim
  Vision research, 巻：205, 開始ページ：108140, 終了ページ：108140, 2023年04月, ［査読有り］, ［筆頭著者］, ［国際誌］
  Translucent objects (like fruit and wax) reflect and transmit incident light to generate complex retinal image structure. Understanding how we visually perceive translucency from these images is challenging, but previous studies have demonstrated that perceived shape and shading is important for perceiving translucency. We considered the possibility that perceived translucency might also depend on 3D shape inferred from surface gloss (i.e., shape from specular highlights). Here, we performed experiments to test whether interactions between specular and non-specular image properties generated by different 3D shape information influences perceived translucency. Results revealed that perceived translucency could be explained by incongruence in 3D shape used to generate specular and non-specular image components. We proposed a new computational model based on measurable image features informative of shading relative to specular highlights that accounted for 59% of the variability in judgments of perceived translucency from the result of 10-fold cross validation. This model was found to outperform other models based on explicit subjective measures of perceived surface shape, suggesting it implicitly taps much of the relevant geometric information necessary for predicting observer judgments of translucency for glossy materials. These results provide new insight into how the visual system might infer translucency from the structure of specular and non-specular shading generated by glossy semi-opaque materials.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.visres.2022.108140
  DOI ID：10.1016/j.visres.2022.108140, ISSN：0042-6989, eISSN：1878-5646, PubMed ID：36336645, Web of Science ID：WOS:000954904300001
• Effects of specular roughness on the perception of color and opacity.　　　　　　　　　　　　　　　
  Yuyang Cai; Hiroaki Kiyokawa; Takehiro Nagai; Leyla Haghzare; Matthew Arnison; Juno Kim
  Journal of the Optical Society of America. A, Optics, image science, and vision, 巻：40, 号：3, 開始ページ：A220-A229, 2023年03月, ［査読有り］, ［国際誌］
  Previous studies have shown that information concerning object shape is important for the perception of translucency. This study aims to explore how the perception of semi-opaque objects is influenced by surface gloss. We varied specular roughness, specular amplitude, and the simulated direction of a light source used to illuminate a globally convex bumpy object. We found that perceived lightness and roughness increased as specular roughness was increased. Declines in perceived saturation were observed but were far smaller in magnitude with these increases in specular roughness. There were inverse correlations found between perceived gloss and perceived lightness, perceived transmittance and perceived saturation, and between perceived roughness and perceived gloss. Positive correlations were found between perceived transmittance and glossiness, and between perceived roughness and perceived lightness. These findings suggest that specular reflections influence the perception of transmittance and color attributes, and not just perceived gloss. We also performed follow-up modeling of image data to find that perceived saturation and lightness could be explained by the reliance on different image regions with greater chroma and lower lightness, respectively. We also found systematic effects of lighting direction on perceived transmittance that indicate there are complex perceptual interactions that require further consideration.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1364/JOSAA.479972
  DOI ID：10.1364/JOSAA.479972, PubMed ID：37133045
• Spatial Frequency Effective for Increasing Perceived Glossiness by Contrast Enhancement.　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Tomonori Tashiro; Yasuki Yamauchi; Takehiro Nagai
  Frontiers in psychology, 巻：12, 開始ページ：625135, 終了ページ：625135, 2021年02月, ［査読有り］, ［筆頭著者］, ［国際誌］
  It has been suggested that luminance edges in retinal images are potential cues for glossiness perception, particularly when the perception relies on low-luminance specular regions. However, a previous study has shown only statistical correlations between luminance edges and perceived glossiness, not their causal relations. Additionally, although specular components should be embedded at various spatial frequencies depending on the micro-roughness on the object surface, it is not well understood what spatial frequencies are essential for glossiness perception on objects with different micro-roughness. To address these issues, we examined the impact of a sub-band contrast enhancement on the perceived glossiness in the two conditions of stimuli: the Full condition where the stimulus had natural specular components and the Dark condition where it had specular components only in dark regions. Object images with various degrees of surface roughness were generated as stimuli, and their contrast was increased in various spatial-frequency sub-bands. The results indicate that the enhancement of the sub-band contrast can significantly increase perceived glossiness as expected. Furthermore, the effectiveness of each spatial frequency band depends on the surface roughness in the Full condition. However, effective spatial frequencies are constant at a middle spatial frequency regardless of the stimulus surface roughness in the Dark condition. These results suggest that, for glossiness perception, our visual system depends on specular-related information embedded in high spatial frequency components but may change the dependency on spatial frequency based on the surface luminance to be judged.
  FRONTIERS MEDIA SA, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3389/fpsyg.2021.625135
  DOI ID：10.3389/fpsyg.2021.625135, ISSN：1664-1078, PubMed ID：33613400, PubMed Central ID：PMC7892470, Web of Science ID：WOS:000619274000001
• Luminance edge is a cue for glossiness perception based on low-luminance specular components　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Tomonori Tashiro; Yasuki Yamauchi; Takehiro Nagai
  JOURNAL OF VISION, 巻：19, 号：12, 2019年10月, ［査読有り］, ［筆頭著者］
  The visual system is considered to employ various image cues from an object image to perceive its glossiness. It has been reported that, surprisingly, even for object images without specular highlights we can perceive glossiness by relying on low-luminance specular components (Kim, Marlow, & Anderson, 2012). This type of perceptual glossiness is referred to as dark gloss. However, it is still unclear whether dark gloss is observed commonly across various objects, and what image features are cues for dark gloss. To address these issues, we performed several psychophysical experiments. First, we measured perceived glossiness for a number of computer-graphics object images with natural specular reflection components (Full condition) and for those without high-luminance components of specular reflections (Dark condition). The results showed that dark gloss (glossiness perception in the Dark condition) was generally observed on almost all object images, while its intensity was rather different across the images. Then we psychologically or computationally measured several image features for the stimulus images, such as luminance edge number, recognizability of reflection images, and some highlight-related features, to examine their relations to perceived glossiness with a multiple regression analysis. The results demonstrated that luminance edge number was most strongly related to glossiness scores among the measured features only for object images with potent dark gloss. These results suggest that luminance edges are an effective cue for dark gloss under certain stimulus conditions.
  ASSOC RESEARCH VISION OPHTHALMOLOGY INC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1167/19.12.5
  DOI ID：10.1167/19.12.5, ISSN：1534-7362, Web of Science ID：WOS:000492307500005
• 能動的課題遂行による視覚的質感判断への知覚学習　　　　　　　　　　　　　　　
  清川 宏暁; 川島 祐貴; 山内 泰樹; 永井 岳大
  日本感性工学会論文誌, 巻：17, 号：2, 開始ページ：309, 終了ページ：319, 2018年04月, ［査読有り］, ［筆頭著者］
  There have been growing interests in clarifying perceptual mechanisms for different material features such as glossiness and transparency in recent years. In this study, we examined whether perceptual learning effects can be observed for material perceptions, and whether active conduct of material judgment tasks is important for the learning effects. The observers were divided into two groups; the glossiness group and the transparency group. The former observers repeated a glossiness discrimination task, while the latter observers repeated a transparency discrimination task for 10 days. We measured changes in correct response ratios and reaction times for discriminations of learned and unlearned material features between before and after the learning. In the results, in both learning groups, the reaction times for the learned material features were significantly shortened after the learning. These results suggest that the human visual system can increase glossiness and transparency discrimination performances by actively repeating material discrimination tasks.
  日本感性工学会, 英語
  DOI：https://doi.org/10.5057/jjske.tjske-d-18-00019
  DOI ID：10.5057/jjske.tjske-d-18-00019, eISSN：1884-5258, CiNii Articles ID：130006728097

• Skewness adaptation induced an asymmetric effect in glossiness perception but not in translucency.　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Keigo Yoshida; Ichiro Kuriki
  巻：24, 開始ページ：526, 終了ページ：526, 2024年10月, ［査読有り］
  英語
• Manipulation of glossiness perception by contrast enhancement of high spatial frequency components　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Tomonori Tashiro; Yasuki Yamauchi; Takehiro Nagai
  巻：20, 開始ページ：364, 終了ページ：364, 2020年06月, ［査読有り］
  英語
• Perceived Glossiness Based on Low-Luminance Specular Components Can Be Increased by Enhancing Luminance Edge Contrasts　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Tomonori Tashiro; Yasuki Yamauchi; Takehiro Nagai
  巻：10, 開始ページ：160, 終了ページ：160, 2019年09月, ［査読有り］
  英語
• Image cues for glossiness perception obtained from low luminance specular reflection components.　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa; Tomonori Tashiro; Yasuki Yamauchi; Takehiro Nagai
  巻：48, 開始ページ：143, 終了ページ：143, 2018年08月, ［査読有り］
  英語
• Glossiness perception not depending on specular highlights -impacts of luminance edges-　　　　　　　　　　　　　　　
  Hiroaki Kiyokawa, Tomonori Tashiro, Yasuki Yamauchi, Takehiro Nagai
  巻：8, 開始ページ：48, 終了ページ：49, 2017年07月, ［査読有り］
  英語

• 脳活動および知覚の個人差に基づく脳内色情報表現の研究　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 基盤研究(A), 2024年04月 - 2028年03月
  栗木 一郎; 山口真美; 金沢 創; 金子沙永; 永井岳大; 楊 嘉楽; 上野賢一; 清川宏暁, 埼玉大学
  配分額（総額）：47710000, 配分額（直接経費）：36700000, 配分額（間接経費）：11010000
  課題番号：24H00702
• 視覚情報工学アプローチによる感性的質感知覚メカニズムの解明　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 若手研究, 2023年04月01日 - 2026年03月31日
  清川 宏暁, 埼玉大学
  配分額（総額）：3380000, 配分額（直接経費）：2600000, 配分額（間接経費）：780000
  該当年度は，物性的質感が物体カテゴリ分類に寄与しているのかについて，物体認識を学習した深層学習モデルの内部に光沢感という物性的質感の知覚に寄与する画像特徴が獲得されているのか，という視点から検討した．また，それらの画像特徴がモデル内のどのレベルの階層で表現されているのかを検討した．実験では，モデルの各階層で表現される画像特徴を画像間で転写する技術であるスタイル変換を用いて，光沢物体画像の特徴を光沢のない物体に転写した．この際，モデル内に５段階ある階層のうち，1つの階層の画像特徴のみを除外してスタイル変換を行う除外条件と，1つの階層の特徴のみを利用してそれ以外を排除する保存条件でスタイル変換を適用した．これにより得られたスタイル変換画像の光沢感をヒト観察者に評定させた．その結果，除外条件では第２層の特徴を除外した場合に有意な光沢感の低下が生じた．また，保存条件では第2, 3, 4層の特徴をそれぞれ保存した際に，光沢感が有意にそれ以外の条件よりも増加した．これらの結果は中間レベルの層で光沢感に関連する画像特徴が表現されていることを示唆している．
  また，光沢感と半透明感という異なる質感の知覚には相互作用があることが知られているが，視覚系の情報処理のどのレベルで相互作用が発生しているのかは未解明であった．この問題に対処するため，低レベルの特徴と高レベルの特徴への順応実験を行い，順応効果の転移を検討した．実験では，光沢感の知覚と関連する輝度ヒストグラムの統計量に対する順応(低レベル順応条件)と光沢感や半透明感を持つ物体画像(高レベル順応条件)に対する順応実験を行った．その結果，高レベル順応条件でのみ順応効果の転移が確認できた．これらの結果は，相互作用は高レベルの情報処理過程で発生していることを示唆している．
  課題番号：23K16985