Direct Di erential Range Estimation Using Optical Masks

We describe a novel formulation of the range recovery problem, based on computation of the di erential variation in image intensities with respect to changes in camera position. The method uses a single stationary camera and a pair of calibrated optical masks to directly measure this di erential quantity. The subsequent computation of the range image is simple and should be suitable for real-time implementation. We also describe a variant of this technique, based on direct measurement of the di erential change in image intensities with respect to aperture size. These methods are comparable in accuracy to other single-lens ranging techniques. We demonstrate the potential of our approach with a simple example.