AN OBJECTIVE MEASUREMENT TOOL FOR MPEG VIDEO QUALITY

A two-stage objective measurement model for MPEG-coded video is propos ed. The first stage weights the coded video distortion according to th e human visual system's response. It computes the frame-by-frame perce ptual impairment in the decoded picture with respect to a reference pi cture; this includes low-pass spatial filtering, a Sobel operation to derive masking coefficients, and spatial masking on the raw error betw een reference and compressed pictures. The second stage, a cognitive e mulator, provides a simulation of human high-level processing of visua l information. This includes the very low temporal response of human v iewers to image quality changes, and asymmetric behaviour in respect o f picture quality changes from bad to good, and vice versa. With this model, we have been able to mimic quite accurately the temporally vary ing subjective picture quality of video sequences as recorded by the I TU-R SSCQE method. (C) 1998 Elsevier Science B.V. All rights reserved.