Perceptual-quality significance map (PQSM) and its application on video quality distortion metrics
The paper presents a new and general concept, PQSM (perceptual quality significance map), to be used in measuring visual distortion. It makes use of the mechanism that the HVS (human visual system) pays more attention to certain areas of visual signals due to one or more of the following factors: salient features in image/video; cues from domain knowledge; association of other media (e.g., speech or audio). PQSM is a 3D/4D array whose elements represent the relative perceptual-quality significance levels for the corresponding pixels/regions for images or video. Due to its generality, PQSM can be incorporated into any visual distortion metrics; it can improve effectiveness or/and efficiency of perceptual metrics or even enhance a PSNR-based metric. A three-stage PQSM generation method is also proposed, with an implementation of motion, luminance, skin-color and face mapping. Experimental results show that the scheme can significantly improve the performance of current image/video distortion metrics.