image: In shadowless projection mapping (right), the projected text (the green word “chocolate” at the center) remains visible even when occlusion occurs. We found that this property contributes to the perception of the projection as a change in the object itself, rather than as overlaid imagery.
Credit: Daisuke Iwai
Osaka, Japan – Projection mapping is widely known as a lighting technique that overlays images onto buildings or objects to create visual effects. In fields such as extended reality (XR) and vision science, however, researchers have suggested that projection could go beyond simple overlays, potentially allowing the color, pattern, or even the perceived material properties of an object to appear as though they have physically changed.
In practice, this effect is difficult to achieve. Most projection mapping results are perceived not as changes in the object itself but as projected imagery layered on top of it. Visual cues such as shadows caused by a user’s body or directional lighting often reveal that the appearance is created by projection.
A research team led by Professor Daisuke Iwai of The University of Osaka Graduate School of Engineering Science, including master’s student Takahiro Okamoto and doctoral student Masaki Takeuchi, in collaboration with Associate Professor Masataka Sawayama of Hokkaido University, investigated how eliminating these cues might change human perception.
The researchers focused on a key difference between projected imagery and the physical appearance of real objects. Projected images can easily be blocked by a user’s body, creating shadows, whereas the color and texture of real objects do not disappear when illumination from one direction is obstructed.
In the future, the researchers envision that this system will be valuable for applications beyond entertainment, such as industrial design support, remote collaboration, and information presentation in medical environments.
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This research is to be presented as an oral presentation at the IEEE Conference on Virtual Reality and 3D User Interfaces, and it received Best Paper Award.
The article, “Shadowless Projection Mapping for Tabletop Workspaces with Synthetic Aperture Projector,” is to be published in IEEE Transactions on Visualization and Computer Graphics at DOI: https://doi.org/10.48550/arXiv.2603.11551
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Movie: https://youtu.be/DEDGYcM5H84
Caption: Project video
License：Original content
Usage restriction: No restrictions.
Credit: Daisuke Iwai
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About The University of Osaka
The University of Osaka was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world. Now, The University of Osaka is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.
Website: https://resou.osaka-u.ac.jp/en
Journal
IEEE Transactions on Visualization and Computer Graphics
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Shadowless Projection Mapping for Tabletop Workspaces with Synthetic Aperture Projector
Article Publication Date
12-Mar-2026