A Coefficient Density Adaptive Quantization Approach for Lossless Color Image Compression

  • Dr.P.Suresh Babu et al.

Abstract

Lossless color image compression is considered to be the efficient compression scheme as it primarily preserves the image sharpness without the loss of vital elements. In our previous works, we have introduced MHPCA for encoding the chrominance images Cu and Cv and MHPBLI for encoding the luminance channel Y. Then the Context adaptive arithmetic coding is applied to achieve efficient lossless image compression. In the MHPBLI coding scheme, a division of 8×8 non overlapping blocks is made in the luminance channel Y. After that blocks are classified into black, white and gray blocks and then are quantized and encoded.  The performance of this approach can further be improved by applying a suitable transform to the blocks before quantization. In this paper, Coefficient Density Adaptive Quantization (CDAQ) approach is introduced to improve the image quantization for achieving lossless color image compression. In this work, the Discrete Cosine Transform (DCT) is applied to improve the performance of image compression performance. For efficient division of the image into 8×8 chunks, DCT is applied in JPEG-LS based compression schemes. Then the blocks are categorized and the density functions of DCT coefficients for the gray and black blocks are determined globally and also locally from which the magnitude of each DCT coefficient is determined. By determining the magnitude of the density of coefficients, the images are adaptively quantized which preserves the quality of the image pixels. Result of the CDAQ shows that it provides better performance than earlier works and can enhance the image compression efficiency.

Published
2019-12-21
How to Cite
et al., D. B. (2019). A Coefficient Density Adaptive Quantization Approach for Lossless Color Image Compression. International Journal of Advanced Science and Technology, 28(17), 234 - 245. Retrieved from http://sersc.org/journals/index.php/IJAST/article/view/2249