Rate-Distortion based Video Watermarking for storing Privacy Information using H263 Codec

To protect the privacy of individuals in surveillance video, the images of selected individuals need to be erased, blurred or re-rendered. Such video modifications, however, destroy the authenticity of the surveillance video. In this proposal, we describe a new rate-distortion based compression domain video watermarking algorithm for the purpose of storing privacy information. Using this algorithm, we can safeguard the original video so that we can reverse the modification process if proper authorization can be established. Existing privacy data preservation schemes such as those described in [1] and [2] mandates a specific type of video modification, namely scrambling. Watermarking focuses solely on the data preservation problem and is thus far more flexible as any modification algorithm can be used. Watermarking algorithm proposed in the previous work provides excellent watermarked video quality at the expense of the output bit rate[3]. This is due to the fact that it does not take the compression technique used for storing the video into consideration. Our proposed rate distortion algorithm minimizes both the output distortion and the output bit rate by exploiting the features of compression technique used. Moreover by analyzing the Lagrangian cost of embedding the watermark in various locations of the image, this algorithm provides a control to tradeoff between rate and distortion based on the requirement. Our initial experiments has demonstrated encouraging results.