1. An apparatus, comprising: an infrared (IR) pixel array in which an n by n sub-array of the pixels is organized as four different, m by m groups of pixels in which only a single, particular pixel is a member of all four groups, m being one less than n, and each pixel within any group of pixels receiving a clock signal whose phase is different than any other pixel within a same group; an image signal processor having four depth calculation units associated with each n by n sub-array of the pixels, the four depth calculation units to calculate a respective time of flight depth value for different pixel array locations associated with the four different, m by m groups of pixels, each of the one or more depth calculation units to receive a same response signal from a pixel the IR pixel array so that said four depth calculation units are able to calculate multiple depth values for said different pixel array locations of said IR pixel array from the different groups of pixels in said pixel array of which said pixel is a member.