Slope Disparity Gating: System and Applications

Active illumination systems which have the ability to selectively image photons that arrive from a specified surface geometry some distance away have several applications in robotics, autonomous vehicles, and surveillance. In this paper, we present a new technique for sloped disparity gating utilizing a synchronized projector-camera system consisting of a raster scanning laser projector and a rolling shutter camera. This system enables disparity-based triangulation of light from specific sloped planar surfaces in the imaging volume. We demonstrate how to control the slope and thickness of these planar surfaces using hardware parameters of pixel clock, synchronization delay, and exposure. Using our system, we present a new decomposition of the light transport matrix in a scene as a function of disparity. We perform applications including real-time image masking and imaging and relighting in scattering media. We also demonstrate applications of the proposed light transport probing technique like novel disparity-dependent relighting, light transport-aware foreground/background separation and green screening, and improved visualization and relighting in scattering media.