Enhancing Contrast of Compressed Images: Reducing Block Artifacts Adaptively

Block artifacts in DCT-based compression are a significant problem. A small reduction in block artifacts could easily improve the quality of the resultant image. For this purpose, in the present work, we propose a novel approach that adaptively enhances the DCT coefficients relying on their band importance. The proposed technique is designed to enhance the contrast in DCT domain and moreover preserves edges and details. Since the image enhancement is performed in DCT domain, therefore, the compressibility of the original image is not affected. Experimental results on standard images validate the concept of adaptively modifying different bands.