From the Rendering Equation to Stratified Light Transport Inversion

摘要

Recent advances in fast light transport acquisition have motivated new applications for forward and inverse light transport. While forward light transport enables image relighting, inverse light transport provides new possibilities for analyzing and cancelling interreflections, to enable applications like projector radiometric compensation and light bounce separation. With known scene geometry and diffuse reflectance, inverse light transport can be easily derived in closed form. However, with unknown scene geometry and reflectance properties, we must acquire and invert the scene’s light transport matrix to undo the effects of global illumination. For many photometric setups such as that of a projector-camera system, the light transport matrix often has a size of 105×105 or larger. Direct matrix inversion is accurate but impractical computationally at these resolutions.