In this paper, a novel watermarking method for depth-image-based rendering methods employed in free viewpoint television systems is proposed. The proposed method uses a correlation-based approach; where a watermark pattern is warped for each different view of the multi-view source video, and embedded to the texture maps of those views in spatial domain. First, the projection matrix of the 2D rendered image is estimated; then, using this matrix, a rendered watermark is formed by warping the original watermark pattern. Finally, Symmetric Phase Only Matched Filtering is used to find the correlation between the rendered image and the rendered watermark. Extended simulations with various attacks show the applicability of the proposed solution.