Abstract: A range or distance estimating apparatus and method estimates the range to various points within a scene by imaging the scene through an optical mask and a lens onto a CCD, and then digitally processing the light intensity values stored in the CCD. The optical mask is designed such that the optical system transformation matrix is rank deficient for a particular set of object ranges. In this way, linear functions can be found to annihilate given sampled image data at a plurality of ranges, independent of the intensity of the light received from the object. A statistical detector is used to determine the closest associated range to the actual range of the point within the scene.