Robust DT-CWT watermarking for DIBR 3D images and videos

Abstract

The popularity of 3D content is on the rise because it provides an immersive experience to viewers. In this situation, DIBR 3D content has taken on an important role in 3D technology due to its low bandwidth cost, ease of depth configuration, and numerous applications exploiting depth maps. Noting that a viewer could record provided center view or synthesized views for illegal distribution, it is clear that copyright protection must be taken into account for the DIBR 3D content, including the possibility that one single view could be illegally distributed as 2D content. In this dissertation, we propose a robust watermarking scheme for DIBR 3D images and videos by quantization on dual-tree complex wavelet transform (DT-CWT) coefficients in consideration of watermark imperceptibility. To make the proposed scheme robust to a depth-image-based rendering (DIBR) process, two characteristics of DT-CWT are employed: approximate shift invariance and directional selectivity. In order to robustly embed watermarks in a single DIBR 3D image, we select certain coefficient sub-blocks of the DT-CWT and group the coefficient sub-bands based on the properties of the DIBR system. On the extraction side, thresholds are carefully chosen with a low false positive rate. The simulation results show that the embedded watermark is stably extracted from the center view and the synthesized left and right views. In addition, even if the synthesized left and right views are distorted by general attacks, the watermark is successfully extracted. Furthermore, the proposed scheme is robust to pre-processing of depth maps and baseline configuration, which are common processing on the DIBR system for better quality of 3D views. For DIBR 3D videos, temporal axis, which is a main difference characteristic between a image and a video, is exploited by dividing all frames into several groups. To reduce process time of both embedding and extraction processes, three algorithms are added ...