Subjective MPEG2 compressed video quality assessment: Application to Tele-surgery

The digital revolution in medical environment speeds up development of remote Robotic-Assisted Surgery and consequently the transmission of medical numerical data such as pictures or videos becomes possible. However, medical video transmission requires significant bandwidth and high compression ratios, only accessible with lossy compression. Therefore research effort has been focussed on video compression algorithms such as MPEG-2. In this paper, we are interested in determining compression thresholds and associated bit-rates which are acceptable with respect to the quality required in the field of medical video transmission. To evaluate MPEG-2 compressed medical video quality, we performed a subjective assessment test with a panel of human observers (experienced surgeons) using a DSCQS (Double-Stimuli Continuous Quality Scale) protocol derived from the International Telecommunication Union recommendations (ITU-R BT-500-11). Promising results estimate that 3 Mbits/s could be sufficient (compression ratio around threshold compression level around 90:1 compared to the original 270 Mbits/s) as far as perceived quality is concerned.