ShadowlessProjector is a projection mapping system in which a shadow (more specifically, umbra) does not suffer the projected result. In a typical projection mapping system, a shadow casts on a projection surface when an occluder such as a user’s hand blocks projected image. The proposed system applied a transmissive mirror as a large aperture lens of the projector. We place a projection surface (Target) under the mirror and another surface whose shape is mirror-symmetrical (Dummy) at the symmetrical position with respect to the plane of the mirror. Then, we project textures onto the Dummy from a normal projector. As a result, the textures on the Dummy is optically copied to the Target. Because the mirror is much larger than a human hand, only a part of projected light from the mirror is occluded by the hand. Consequently, only penumbra is caused, which leads to a shadow-less projection.
Shadowless Projector allows a projection mapping system that is less influenced by occlusion. Conventional projectors apply small lenses; thus, shadows can easily be caused by occluders such as hands. In contrast, we apply a transmissive mirror, which is widely used for displaying floating images, as a large aperture lens to reduce the amount of shadow (more specifically, umbra) in projection mapping systems. We offer a mysterious experience where visitors see a surface is shining itself.