No-reference image quality assessment metric by combining free energy theory and structural degradation model

In the research of image quality assessment (IQA), no-reference approaches are usually thought of as a big challenge since none of original image information is available. To tackle this problem, we propose a new no-reference image quality metric through combining two recently proposed reduced-reference IQA models, namely the free energy based distortion metric (FEDM) and the structural degradation model (SDM). In this work, it will be shown that there exists an approximate linear relationship between the original image information of the free energy feature and the structural degradation information. Based on this observation and the application of support vector machine (SVM) that is widely used in the current study of IQA, our newly developed No-reference Free energy and Structural degradation based Distortion Metric (NFSDM) is found to alleviate the dependance of original images, and has achieved remarkably well prediction accuracy, outperforming the most two full-reference IQA approaches PSNR/SSIM and several mainstream no-reference image quality metrics.