JPEG image quality improvement

This paper proposes a method to enhance the quality of the decompressed JPEG images. A so-called Modified Coefficient Adjustment Block is used to record the round off situation while the DCT coefficients in a block are quantized according to a given quantization block. During decompression, the information recorded in the Modified Coefficient Adjustment Block is then used to adjust the de-quantized DCT coefficients before the Inverse DCT transformation. The experimental results show our method provides significantly better results than the method proposed by Chang et al.