Projection mapping ‘magic trick’ makes shadows disappear

A team at Osaka University, Japan has developed a projection mapping system that makes shadows vanish for interactive mapping applications.

The system was inspired by a surgical light system that does not cast shadows on patients’ bodies, the Sato Lab team, a special optical system of vertical mirrors were used to shed light on the projection surface from various directions.

The Shadowless Projector system consists of a projector, micro-mirror array plate (MMAP) and a pair of mirror-symmetric objects: a dummy and target.

When the dummy and target are placed plane-symmetrically with respect to the MMAP, textures are projected onto the dummy are copied onto the target.

This allows the MMAP to act as a large aperture lens, preventing the illuminated textures on the target from disappearing unless the entire MMAP is occluded, even when touched [pictured below].

Daisuke Iwai, an associate professor in the research group, said: “In this new system, visibility of projected imagery is not inhibited even when one touches the projection surface, so it will be used for effective projection mapping advertisements and exhibitions that allow for human interaction. Since guidance images can be projected on the operative area of the patient’s body without any loss of information due to occlusion of the images, this system can be also used as a tool to support operations.”

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