Perceived sharpness in complex moving images

This paper is concerned with the combined influence of image motion and image resolution on (perceived) sharpness. We examined these effects for both a fixation and a pursuit condition: only in the latter case was it possible to follow the object in motion. In the fixation condition we presented various resolution levels, and image velocities up to 5.3 deg/s. We found that sharpness decreases with object velocity, especially for images with maximum resolution. In the pursuit condition we used the same set of resolution levels, but the object velocities ranged up to 35 deg/s. There we found only a small decrease with velocity for maximum resolution images, whereas a considerable increase in sharpness was found for images having a lower resolution. The effects observed are discussed in terms of both their possible origins and their implications for video encoding.