Wavelet transforms in a JPEG-like image coder

The discrete wavelet transform (DWT) is incorporated into the JPEG baseline system for image coding. The discrete cosine transform (DCT) is replaced by an association of two-channel filter banks connected hierarchically. JPEG block-scanning and quantization schemes are adopted while we use JPEG’s entropy coder. The changes in scanning can be incorporated into the transform block in such a way that the only part that needs to be changed in a JPEG framework is to replace the DCT by the DWT. Objective results and reconstructed images are presented demonstrating that the proposed coder outperforms JPEG and approaches the performance of more sophisticated and complex wavelet coders. However, it does not require full-image buffering nor imposes a large complexity increase.