Correlation Between Viewer's Dynamic Visual Acuity and Subjective Evaluation of Moving Picture Sharpness

摘要

A short, but finite, exposure aperture time is necessary for an imager to photoelectrically accumulate converted electrons in a temporal sample. As the output is the electrical signal averaged over the exposure time, motion blur in images of moving objects can occur. In current assessments of the quality of television images, the observer's static visual acuity (SVA) must be screened before the subjective evaluation. However, in the subjective evaluation of moving image sharpness, an observer's evaluation may not be correlated with their SVA but instead with their dynamic visual acuity (DVA). In the present work, we show that the evaluation of moving-picture sharpness was not correlated with SVA but instead with DVA for a visual target with a spatial frequency corresponding to a decimal-scale SVA of 0.8 (DVA 0.8). Our results show that viewers with good DVA tend to provide a harsher assessment (i.e., a lower score) of the sharpness of images of moving objects, suggesting that DVA screening is essential before assessment of the sharpness of television images. We also propose an SVA screening threshold value of 0.8, because the maximum DVA is almost equal to SVA when the viewed object is not in motion.