Multiscale Contrast Enhancement for Compressed Digital Images with Block Artifacts Consideration
A simple and efficient algorithm is presented for contrast enhancement, of JPEG compressed images, in the Discrete Cosine Transform (DCT) domain. The algorithm enhances the DCT coefficients in accordance with their band importance. Since uniformly modifying all the frequency bands causes block artifacts, therefore, the low frequency bands are dealt with differently than the rest of the frequency bands. As the enhancement is done in the decompression stage, compressibility of the original image is not affected. Subjective and objective tests performed on various images validate the concept of multiscale contrast enhancement.
KeywordsContrast Enhancement Digital Image Enhancement Discrete Cosine Transform (DCT) and JPEG Compression.
Unable to display preview. Download preview PDF.
- R. Gonzalez and P. Wintz, “Digital Image Processing”, MA: Addison-Wesley, 1987Google Scholar
- S.S. Agaian, K. Panetta, and A. M. Grigoryan, “Transform-based image enhancement algorithms with performance measure,” IEEE Trans. Image Processing, vol. 10, pp. 37-382, Mar. 2001.Google Scholar
- Z.Wang, A.C. Bovic and H.R. Sheikh, “Image Quality Assessment: From Error Visibility to Structural Similarity”, IEEE Transactions on Image Processing, Vol. 13, No.4, April 2004.Google Scholar