Improving image quality for JPEG compression

Abstract

JPEG is a well-known method for digital image compression. The drawback of JPEG is distortion to image quality by truncation errors from quantizing the DCT coefficients. Another problem is the damage on the extracted watermarks from JPEG compression for the spatial-domain watermarks. In this paper, we proposed an improved method to enhance the quality of the decompressed image. The purpose of our proposed method is to adjust the reconstructed DCT coefficients closed as their original values. The coefficient adjustment blocks are used to guide the decompression operation during the coefficient reconstruction. Experimental results show that the proposed method has indeed made the image quality improvement as comparing to the images in the traditional method. © Springer-Verlag Berlin Heidelberg 2005.