A novel approach to color image compression using 3-d Discrete Cosine Transform (DCT)

Most of the color image compression schemes transforms the highly correlated RGB color space into a decorrelated color space like YUV, YCrCb etc. in order to reduce the redundancies between the color components, then the decorrelated color components are coded individually by monochrome image compression schemes. In this paper, we present a novel approach to color image compression scheme using 3-Dimensional Discrete Cosine Transform (3-D DCT). We use 3-D DCT to reduce the intercolor redundancy. In the proposed scheme the 3-D block DCT is directly applied on the highly correlated RGB color components and the coefficients are quantized and entropy coded. We also propose a wavelet structure for 3-D block DCT coefficients. We use Lagrange multiplier method for optimal bit allocation between the different slices of 3-D DCT coefficients. Our proposed coder gains competitive results comparing to the performance of JPEG baseline and JPEG2000 standard. Experimental results shows that the proposed coder performs close to the JPEG2000 standard in terms of R-D performance and outperforms the JPEG baseline standard by a large margin.