Efficient color image reconstruction by color-multiplexing and vector quantization in the wavelet domain

Color images are usually represented by three-color planes. For high fidelity low bit rate image storage or transmission, redundancy of information on theses color planes can be further reduced when combined with other image coding techniques. Instead of generating three codebooks for three color planes individually when vector quantization (VQ) is applied, as is regularly done incolor image compression with VQ, our new approach is to reduce three color planes into one multiplexed plane using a spatial color-multiplexing technique, achieving a 3:1 compression before quantization. Wavelet transform is then applied on the multiplexed plane. Vector quantization of the wavelet coefficients is performed by using an adaptive fuzzy leader clustering (AFLC) approach. Inverse wavelet transform and demultiplexing at the decoder side are required to recover the color image in the spatial domain. Our experiment shows that this new scheme yields high fidelity reconstruction at a considerably lower bit rate than the bit rate achievable without color multiplexing.