Modeling and evaluation of image quality in wireless surveillance networks

This paper studies the security image quality attained in streaming video over wireless networks under different packet error models. Wireless video sensor networks are becoming common place due to increasing crime rates and growing terrorist activities. A crucial requirement for video surveillance technology especially for real-time monitoring is that the video quality must not fall below a certain threshold so that objects and events in these videos could be identified and properly interpreted by viewers. However, the time varying transmission characteristics of the wireless channel and limited throughput can lead to poor performance of multimedia traffic over wireless networks. As a result, the end user may perceive jerky motions, frame freezes, and missing segments which may affect their ability to recognize objects and effectively analyze the scenes. An experimental set-up required for wireless network surveillance using IEEE 802. is described. The authors adopt subjective user tests to study the degree of identification of objects and events in security videos generated from camera security systems and subjected to wireless channel packet loss conditions to benchmark identification in the degraded sequences. Packet loss conditions were introduced into the sequences using NS-2 network simulator.