PILC Projector: Image Projection With Pixel-Level Infrared Light Communication

Invisible-light communication between a projector and multiple devices on the projection plane enables human-computer interaction applications such as movable displays and pointing devices. In this paper, we propose a pixel-level infrared light communication (PILC) projector that can project rich, invisible position-dependent information on high-contrast, full-color visible images. Although previous methods for such communication sacrificed the image quality, the amount of information, or other features, our method meets all the requirements by adding an infrared light source to a full-color DLP projector. This system alternately projects visible images and invisible data sequences with visible and infrared light, respectively. As proof of concept, we built a functional prototype and confirmed that its image contrast is more than 60 times that of a previous method while maintaining pixel-level position accuracy. In addition, we investigated flicker-perception rates in response to different amounts of embedded information and discovered that we could send rich information (up to approximately 2 kbps) with imperceptible flicker. Finally, we built a tabletop application with the proposed system, in which users can simultaneously see both an aerial photograph and a map through movable displays.