Efficient and Low-Complexity Surveillance Video Compression Using Backward-Channel Aware Wyner-Ziv Video Coding

Video surveillance has been widely used in recent years to enhance public safety and privacy protection. A video surveillance system that deals with content analysis and activity monitoring needs efficient transmission and storage of the surveillance video data. Video compression techniques can be used to achieve this goal by reducing the size of the video with no or small quality loss. State-of-the-art video compression methods such as H.264/AVC often lead to high computational complexity at the encoder, which is generally implemented in a video camera in a surveillance system. This can significantly increase the cost of a surveillance system, especially when a mass deployment of end cameras is needed. In this paper, we discuss the specific considerations for surveillance video compression. We present a surveillance video compression system with low-complexity encoder based on Wyner-Ziv coding principles to address the tradeoff between computational complexity and coding efficiency. In addition, we propose a backward-channel aware Wyner-Ziv (BCAWZ) video coding approach to improve the coding efficiency while maintaining low complexity at the encoder. The experimental results show that for surveillance video contents, BCAWZ can achieve significantly higher coding efficiency than H.264/AVC intra coding as well as existing Wyner-Ziv video coding methods and is close to H.264/AVC inter coding, while maintaining similar coding complexity with intra coding. This shows that the low motion characteristics of many surveillance video contents and the low-complexity encoding requirement make our scheme a particularly suitable candidate for surveillance video compression. We further propose an error resilience scheme for BCAWZ to address the concern of reliable transmission in the backward-channel, which is essential to the quality of video data for real-time and reliable object detection and event analysis.

I. Introduction

Video surveillance is an important tool to enhance public safety and privacy protection. It has long been deployed in places of homeland security interests such as airports, train and subway stations, city centers, and major sports events. Surveillance cameras in London provided key photos of the men who bombed the underground system in July 2005. The latest terrorist attack in London was foiled in 2007, partly thanks to the millions of surveillance cameras that London authorities have installed across the city. According to a recent Reuters report, France will triple the number of surveillance cameras by 2009 as part of the fight against terrorism and street crimes. Video surveillance is also used in commercial locations such as banks, automated teller machines (ATMs), supermarkets, and parking areas to prevent and track criminal activities. Consumer adoptions of video surveillance also have soared in recent years due to the increasing concern on privacy protection.