A video signal coding and decoding apparatus with an adaptive edge enhancement filter

摘要

Discrete cosine transform (DCT) is a popular coding technique for high compression ratio bandwidth reduction of digital video signal. Basically, DCT converts statistically dependent picture elements into independent coefficients. The resultant coefficients are usually energy concentrated in only a few of the coefficients containing the main part of the picture information which can then be quantized and run-length encoded efficiently. However, when this method is applied to a block of pixel which represents an edge boundary of the object in the picture, ringing effect will appear around the edge of the decoded picture. By detecting the decoded block for edge block, an adaptive edge enhancement filter can be applied to reduce such ringing effect, thereby giving a much less distorted edge. <IMAGE>