An automatic scheme for stereoscopic video object-based watermarking using qualified significant wavelet trees

A fully automatic system for embedding visually recognizable watermark patterns to video objects is proposed. The architecture consists of 3 main modules. In the first module, unsupervised video object extraction is performed, by analyzing stereoscopic pairs of frames. Then each video object is decomposed into three levels with ten subbands, using the discrete wavelet transform (DWT) and three pairs of subbands are formed (HL₃, HL₂), (LH₃, LH₂) and (HH₃, HH₂). Next qualified significant wavelet trees (QSWTs) are estimated for the specific pair of subbands that contains the highest energy content compared to the other two pairs. QSWTs are derived from the embedded zerotree wavelet (EZW) algorithm and they are high-energy coefficient paths within the selected pair of subbands. Finally, in the third module, visually recognizable watermark patterns are redundantly embedded to the coefficients of the highest energy QSWTs and the inverse DWT is applied to provide the watermarked video object. The performance of the proposed video object watermarking system is tested under various signal distortions such as JPEG lossy compression, sharpening, blurring and adding different types of noise. Experimental results on real life stereoscopic images are presented to indicate the efficiency and robustness of the proposed scheme.