Integrated Evaluation of Temporal and Spatial Distortions for Low Bit-rate Videos
Most distortion/artifacts in low bit-rate compressed videos are strong and obvious to human eyes, and may even change the spatio-temporal structure of visual objects. Therefore it is important to evaluate the compound perceptual impact of spatial and temporal changes. Recent neurophysiological researches have found that the high-level spatial information (shape and depth, etc.) and temporal information (motion, etc.) are processed separately in two visual pathways in human brains. In this paper, spatial and temporal distortions are evaluated separately in two modules, and are then combined in an integration module. Two subjective viewing experiments are performed. One experiment is to evaluate the subjective quality on temporal distortion only, and second experiment is to evaluate the low bit-rate videos with both spatial and temporal distortions. Experimental results and the associated analysis show that the proposed visual quality metric is in good alignment with human perception