Due to our memory management, all pixel data within a win-dow is available and therefore no speed penalty is incurred byusing it (Fig. 4). It also improves the accuracy since we usea larger number of pixels in the matching process. We use theCensus Transform descriptor with Hamming Distance instead ofthe SAD as it achieves illumination invariant matching withoutan additional pre-processing step [Sobel filter Fig. 1(b)].