Adaptive video-blocking artifact removal in discrete Hadamard transform domain

We present a novel postprocessing algorithm for blocking artifact removal in the discrete Hadamard transform (DHT) domain, which does not require prior knowledge of quantization parameters and features low computational complexity. All block-based video coding methods suffer annoying blocking artifacts at low bit rates. We first acquire edge information for the frame, then calculate block activities from DHT coefficients so as to classify smooth and coarse regions adaptively. Blocking artifacts are adaptively filtered in the DHT domain according to block activities. Experimental results show that the proposed method is able to remove blocking artifacts effectively while preserving image details and object edges well, and that it achieves better visual quality compared with other methods.