Interactive display of image details using a camera-coupled mobile projector

A mobile projector can be used to enhance a small region of a large projected image. We use a camera attached to the mobile projector to locate a frame-shaped marker embedded in the large image, providing sufficient geometric information to identify the position of the mobile projector in space. The image displayed by this projector can then be warped to fit correctly into the large image, within the frame. Pointing at distant areas of the screen is also possible. The region illuminated by the mobile projector image represents a miniature of the entire projected image. Our software detects shadows in this region in camera images, and locates the position of the user´s fingertip, which is interpreted as a pointer. Depth information can also be acquired by measuring the penumbra of the shadow. A prototype system is presented and user reactions are reported.