Free-View Watermarking for Free-View Television
The recent advances in image based rendering (IBR) has pioneered a new technology, free-view television, in which TV-viewers select freely the viewing position and angle by the application of IBR on the transmitted multi-view video. Noting that the TV-viewer might also record a personal video for this arbitrarily selected view and misuse this content, it is apparent that copyright and copy protection problems also exist and should be solved for free-view TV. In this paper, we focus on this problem by proposing a watermarking method for free-view video. The watermark is embedded into every frame of multiple views by exploiting the spatial masking properties of the human visual system (HVS). Assuming that the position and rotation for the imagery view is known, the proposed method extracts the watermark successfully from an arbitrarily generated image. In order to extend the method for the case of an unknown imagery camera position and rotation, the modifications on the watermark pattern due to image based rendering operations are also analyzed. Based on this analysis, a camera position and homography estimation method is proposed considering the operations in image based rendering. The results show that the watermark detection is achieved successfully for the cases in which the imagery camera is arbitrarily located on the camera plane.