Abstract: JPEG compression algorithm based on DCT transform produces the diamonds effect when working at low bit rate transform, and it influences the vision effect of decoding image badly. The main reason is the DCT transform lose too many high frequency information, so this article tries to improve it. And the main methods is to replace the DCT module in JPEG arithmetic with wave transform, moreover simulates and analyzes it with MATLAB language, and obtaines a better vision effect.

Key words: wavelet transforms, JPEG, DCT coding