COHERENSi: A new full-reference IQA index using error spectrum chaos

We introduce a new family of quality indices that are based on the reported findings that biological visual systems exhibit interference in spatial harmonic distortion, and that local phase distortion is more perceived than global phase distortion. This paper specifically addresses a full-reference version of the proposed indices. The proposed quality index has three components: harmonic chaos analysis, phase chaos analysis, and pooling. The first two parts produce two maps that are weighted and summed to produce a single map. Then, we use the mean of the logarithmically scaled combined map as the quality index. We further propose a multi-scale variation of the index. Experimental evaluations were conducted on more than 1,300 images from the TID2 013 image database. We specifically test the quality index on three distortion categories: Simple, Actual, and Noise. Then, we cross-validate the results with the LIVE database. The results show that the proposed index outperforms all known indices based on correlation with subjective evaluation.