Seam carving is an outstanding content-aware image resizing technique. When the resizing ratio is relatively lower, seam carving can achieve image resizing without leaving any visual obvious artifacts. However, it may also be used for malicious purposes, such as changing image semantic content by object removal. Seam caving changes the relationship between neighboring pixels, thus seam carved images should be different from natural ones. Inspired by this, an end-to-end seam carving detection network, namely SCDNet, is proposed to detect seam carved images. To highlight seam carving artifacts, a pre-processing layer, namely the subtractive pixel adjacency module, is designed as the first layer of SCDNet. Then, 16 residual blocks with shortcut learn features from the input, and a spatial pyramid pooling module is embedded at the end of the residual block to generate fixed-length features, which can eliminate the requirement of fixed-resolution input images for existing deep models. Finally, the features are fed into the fully-connected layer for final classification. In addition, to expose seam carved images with a small carving ratio, a transfer learning strategy is exploited to gradually clarify the artifacts. Extensive experiments demonstrate that SCDNet obtains better detection accuracy than state-of-the-art methods, especially for seam carving with small scaling ratios.
Read full abstract