Detecting and Extracting the Photo Composites Using Planar Homography and Graph Cut

With the advancement of photo and video editing tools, it has become fairly easy to tamper with photos and videos. One common way is to insert visually plausible composites into target images and videos. In this paper, we propose an automatic fake region detection method based on the planar homography constraint, and an automatic extraction method using graph cut with online feature/parameter selection. Two steps are taken in our method: 1) the targeting step, and 2) the segmentation step. First, the fake region is located roughly by enforcing the planar homography constraint. Second, the fake object is segmented via graph cut with the initialization given by the targeting step. To achieve an automatic segmentation, the optimal features and parameters for graph cut are dynamically selected via the proposed online feature/parameter selection. Performance of this method is evaluated on both semisimulated and real images. Our method works efficiently on images as long as there are regions satisfying the planar homography constraint, including image pairs captured by the approximately cocentered cameras, image pairs photographing planar or distant scenes, and a single image with duplications.