ENHANCEMENT OF LOW BIT-RATE CODED IMAGES USING EDGE-DETECTION AND ESTIMATION

Low bit-rate image coding results in artifacts at reconstruction whose characteristics depend on the form of the coding/decoding algorithm used. A very common and visually objectionable effect of most coding methods is distortion of edges. Classical spatially-invariant filtering techniques are of little use in removing this signal-dependent reconstruction error. We present an algorithm for enhancement of edge quality through nonstationary filtering based on estimates of edge locations. Edge detection and enhancement are performed by a sequence of simple one-dimensional processes. The algorithm yields appreciable improvement when applied to images coded by pixel-domain methods. © 1991.