Subjective liver ultrasound video quality assessment of internet based videophone services for real-time telesonography

In conventional telesonography, the ultrasound video is encoded at a constant bit rate and transmitted to the expert side for diagnosis, this is highly bandwidth demanding and less adaptable to the varying network conditions. In contrary, Internet based videophone applications adapt to the network conditions with variable bit rate encoding and error concealment algorithms. Since portable ultrasound scanners are coming with Internet connectivity, this motivated us to evaluate the viability of using existing Internet based videophone services for real-time telesonography. Popular videophone services like Skype, Facebook and WebRTC is chosen for this purpose. The performance of these services is analyzed by varying network parameters like bandwidth, packet loss, delay and packet error in a controlled set up. Liver ultrasound video is considered for the study. A total of 273 different network settings is analyzed for evaluating the performance of each videophone service, constituting a total of 819 instances for evaluating three services. Three medical experts were participated in the subjective study. From an extensive analysis, an inference is made that the Internet based videophone services are reliable enough for telesonography provided a network with minimum bandwidth of 1600 kHz, delay up to 200 ms, packet loss up to 3% and packet error up to 3%.