No-reference image blur assessment using multiscale gradient

The increasing number of demanding consumer video applications, as exemplified by cell phone and other low-cost digital cameras, has boosted interest in no-reference objective image and video quality assessment (QA). In this paper, we focus on no-reference image and video blur assessment. There already exist a number of no-reference blur metrics, but most are based on evaluating the widths of intensity edges, which may not reflect real image quality in many circumstances. Instead, we consider natural scenes statistics and adopt multi-resolution decomposition methods to extract reliable features for QA. First, a probabilistic support vector machine (SVM) is applied as a rough image quality evaluator; then the detail image is used to refine and form the final blur metric. The algorithm is tested on the LIVE Image Quality Database; the results show the algorithm has high correlation with human judgment in assessing blur distortion of images.