Efficient watermarking system with increased reliability for video authentication

The widespread adoption of digital video techniques has generated a requirement for authenticity verification in applications such as criminal evidence, insurance claims and commercial databases. This paper extends our previous work and improves the watermark estimation procedure of a spatial digital video watermarking system designed to detect and characterize time-base attacks. Most watermark extraction processes utilize the noise masking levels of the image. These levels change during transmission, especially when the host signal is compressed at low bit-rates. The blocking artifacts that are introduced by this process modify the noise masking levels and influence the ability to form a good estimate of the embedded watermark. This paper describes a novel filter procedure to eliminate these artifacts from the noise masking levels. The efficiency is compared with the standard MPEG-4 deblocking and deringing filters. Extracting the watermark from only the encoded Macroblocks, excluding the skipped Macroblocks improves the performance significantly without an increase in computational complexity. The functionality of this system within an MPEG-4 implementation is demonstrated with a receiver operating characteristic