Multidimensional Enhanced Hadamard Error Correcting Code In Comparison with Reed-Solomon Code in Video-Watermarking Applications

Watermarking technology.play a central role in the digital right management for multimedia data. Especially a video watermarking is a real challenge, because of very high compression ratio (about 1:200). Normally the watermarks can barely survive such massive attacks, despite very sophisticated embedding strategies. It can only work with a sufficient error correcting code method. In this paper, the authors introduce a new developed Enhanced Multidimensional Hadamard Error Correcting Code (EMHC), which is based on well known Hadamard Code, and compare his performance with Reed-Solomon Code regarding its ability to preserve watermarks in the embedded video. The main idea of this new developed multidimensional Enhanced Hadamard Error Correcting Code is to map the 2D basis images into a collection of one-dimensional rows and to apply a 1D Hadamard decoding procedure on them. After this, the image is reassembled, and the 2D decoding procedure can be applied more efficiently. With this approach, it is possible to overcome the theoretical limit of error correcting capability of (d-1)/2 bits, where d is a minimum Hamming distance. Even better results could be achieved by expanding the 2D to 3D EMHC. A full description is given of encoding and decoding procedure of such Hadamard Cubes and their implementation into video watermarking procedure.To prove the efficiency and practicability of this new Enhanced Hadamard Code, the method was applied to a video Watermarking Coding Scheme. The Video Watermarking Embedding procedure decomposes the initial video through Multi-Level Interframe Wavelet Transform. The low pass filtered part of the video stream is used for embedding the watermarks, which are protected respectively by Enhanced Hadamard or ReedSolomon Correcting Code. The experimental results show that EHC performs much better than RS Code and seems to be very robust against strong MPEG compression. Key-Words: Hadamard Error Correcting Code, ECC, Hadamard Transform, , Watermarking, DWT, MPEG