Image quality assessment based on theil inequality coefficient and discrete 2-D wavelet transform

Based on the characteristics of wavelet coefficients of images and Theil inequality coefficient, a novel image quality assessment is proposed in this paper. Firstly, the reference image and the distorted images are decomposed into several levels by means of wavelet transform respectively. Secondly, the approximation and detail coefficients of reference image are the reference sequences and the approximation and detail coefficients of the distorted images are the comparative sequences respectively. And the included angle cosine values are calculated between the reference sequences and the comparative sequences respectively. Moreover, image quality assessment matrix of every distorted image can be constructed based on the Theil inequality coefficient values and image quality can be assessed. The algorithm makes full use of perfect integral comparison mechanism of Theil inequality coefficient and the well matching of discrete wavelet transform with multichannel model of human visual system. Experimental results show that the proposed algorithm can not only evaluate the integral and detail quality of image fidelity accurately but also bears more consistency with the human visual system than the traditional method PSNR.