A subjective refraction-based assessment of image quality metrics

Tools for quantifying image quality should be bench-marked against subjective human assessment. It is expected that image quality metrics (IQMs) that are based on a human visual system should closely correlate with an observer's perception of vision quality. Performances of a range of popular IQMs were evaluated using subjective and objective measures of optimal refraction from 120 eyes. An optimization algorithm was devised in which objective refraction corresponding to the peak of a given IQM was sought. That optimized objective refraction was then correlated with the corresponding subjective refraction. The results show that although most IQMs result in a similar performance for defocus, those which only use the second order statistical information do not correlate well with a subjective assessment of image quality.