Shadow cameras: Reciprocal views from illumination masks

Scene appearance from the point of view of a light source is called a reciprocal or dual view. Since there exists a large diversity in illumination, these virtual views may be non- perspective and multi-viewpoint in nature. In this paper, we demonstrate the use of occluding masks to recover these dual views, which we term shadow cameras. We first show how to render a single reciprocal scene view by swapping the camera and light source positions. We extend this tech- nique for multiple views by building a virtual shadow cam- era array with static masks and a moving source. We also capture non-perspective views such as orthographic, cross- slit and a pushbroom variant, while introducing novel ap- plications such as converting between camera projections and removing refractive and catadioptric distortions. Fi- nally, since a shadow camera is artificial, we can manip- ulate any of its intrinsic parameters, such as camera skew, to create perspective distortions.

• Type: Conference
• Year: 2009
• Where: ICCV
• Authors: Sanjeev J. Koppal and Srinivasa G. Narasimhan
• Keywords: Computer Vision, ICCV 2009, Shadow Cameras