Blocking artifacts reduction for image compression algorithms

In this paper, a new algorithm is proposed to improve the performance of the existing JPEG image compression algorithm. The algorithm proposes a recursive pruned discrete cosine transform (DCT) to reduce the bit rate and two different methods to reduce the image artifacts arising at these lower bit rates. The recursive algorithm computes the pruned DCT using a structure that allows the generation of higher order pruned DCT from two identical, lower order pruned DCT´s. A variance dependent pruning method determines the pruning based on the statistical properties of the image block. A linear filtering method performs low pass filtering on the block boundaries for smoothing the discontinuities