Continuous assessment of image quality

This paper addresses the question of whether subjects are able to assess the perceived time-varying quality of video sequences continuously. To this end, a method is used in which subjects continuously indicate the perceived image quality by moving a slider along a graphical scale. The slider's position on this scale is sampled at a constant rate of typically 1/sec. The temporal variations of the assessed quality of one particular sequence are compared with the results of another experiment in which the image quality of very short palindromically presented fragments of the video sequence was Fated separately on a graphical scale. The results show that subjects can monitor image-quality variations almost instantaneously.