Optical Flow Approximation of Sub-Pixel Accurate Block Matching for Video Coding
Yu M. Chi, Trac Duy Tran, Ralph Etienne‐Cummings · 2007
Video compression algorithms almost universally rely on block matching algorithms (BMA) to exploit the temporal redundancy in image sequences. However block matching is extremely computationally intensive, especially if sub-pixel accuracy is desired. We propose a fundamentally different approach to obtaining motion vectors using the principles from gradient based optical flow but in a form fully compatible with any macro-block based video compression scheme. Experimental results show that in many cases, the gradient approximation to block matching results in videos within 0.3 dB PSNR to BMA at sub-pixel resolution while being potentially much more computationally efficient and easier to implement at the hardware level.