Watermarking for Image-Based Rendering via Homography-Based Virtual Camera Location Estimation
The recent advances in image based rendering (IBR) have pioneered freely determining the viewing position and angle in a scene from multi-view video. Remembering that a person could 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 IBR applications, as well. In our recent work (Alper Koz, 2006), we propose a watermarking method, which embeds the watermark pattern into every frame of multi-view video and extracts this watermark from a rendered image, generated by the nearest-interpolation based light-field rendering (LFR) and watermark detection is achieved for the cases in which the virtual camera could be arbitrarily located on the camera plane only. This paper presents an extension to the previous formulation for the rendered images, which are generated by using bilinear interpolation, namely the most attractive and promising interpolation method in LFR-based applications. Moreover, the location of the virtual camera could be completely arbitrary in this new formulation. The results show that the watermark could be extracted successfully for LFR via bilinear interpolation for any imagery camera location and rotation, as long as the visual quality of the rendered image is preserved.