Slant edge method for point spread function estimation

The traditional edge method (TEM) is applicable only in areas whose knife edges are horizontal or vertical. The slant edge method (SEM) requires using the approximate function in the edge spread function (ESF) fitting. The ESF sample is uneven and therefore affects the accuracy of the estimated point spread function (PSF). This study proposes a novel slant edge method (NSEM), including a knife-edge area extraction algorithm that ensures the evenness of the ESF sample and a PSF estimation algorithm that directly fits the line spread function, to improve the accuracy of the estimated PSF. The validity and applicability of the NSEM have been proven in theory and practice, respectively. Compared with the TEM and SEM, the NSEM exhibits a clear improvement in accuracy and stability across the three experiments conducted in this study. (C) 2015 Optical Society of America.