Equalized Structural Similarity Index for image quality assessment

A novel version of the popular SSIM image quality assessment technique, specifically designed to yield uniform MOS prediction in presence of different types of image distortions is presented. Response equalization is obtained through the polynomial combination of a basic SSIM metric with an auxiliary metric characterized by a diverse sensitivity. Accuracy and consistency of this composite index, called E-SSIM, are demonstrated with experiments conducted on two independent archives annotated with MOS values.