Qualitative and quantitative image quality assessment of vector quantization, JPEG, and JPEG2000 compressed images

The main objective of this work is to determine a numerical measure that can judge block-based compressed images, namely vector quantization (VQ), JPEG, and JPEG2000 encoded images. Various objective measures are investigated and new measures are developed, then all measures are classified into groups. The analysis of normalized versions of the measures within each group has led to the design of a new measure, denoted as the normalized perceptual image quality measure (NPIQM), that better matches the psychophysical evaluation of the image quality than using the peak signal-to-noise ratio (PSNR) criterion. NPIQM can also be plotted graphically in a radar-fashion form, which gives the ability to compare different images at different bit rates, and give a detailed judgment based on the proposed graphical interpretation. A perceptual examination is carried out and proves the superiority of the NPIQM measure over PSNR. (C) 2003 SPIE and IST.