Keypoints-Based Image Passive Forensics Method for Copy-Move Attacks

A novel image passive forensics method for copy-move forgery detection is proposed. The proposed method combines block matching technology and feature point matching technology, and breaks away from the general framework of the visual feature-based approach that used local visual feature such as SIFT and followed by a clustering procedure to group feature points that are spatially close. In our work, image keypoints are extracted using Harris detector, and the statistical features of keypoint neighborhoods are used to generate forensics features. Then we proposed a new forensics features matching approach, in which, a region growth technology and a mismatch checking approach are developed to reduce mismatched keypoints and improve detected accuracy. We also develop a duplicate region detection method based on the distance frequency of corresponding keypoint pairs. The proposed method can detect duplicate regions for high resolution images. It has higher detection accuracy and computation efficiency. Experimental results show that the proposed method is robust for content-preserving manipulations such as JPEG compression, gamma adjustment, filtering, luminance enhancement, blurring, etc.

Genomic Duplication, Fractionation and the Origin of Regulatory Novelty

Having diverged 50 MYA, rice remained diploid while the maize lineage became tetraploid and then fractionated by losing genes from one or the other duplicate region. We sequenced and annotated 13 maize genes (counting the duplicate gene as one gene) on one or the other of the pair of homeologous maize regions; 12 genes were present in one cluster in rice. Excellent maize-rice synteny was evident, but only after the fractionated maize regions were condensed onto a finished rice map. Excluding the gene we used to define homeologs, we found zero retention. Once retained, fractionation (loss of functioning DNA sequence) could occur within cis-acting gene space. We chose a retained duplicate basic leucine zipper transcription factor gene because it was well marked with big, exact phylogenetic footprints (CNSs). Detailed alignments of lg2 and retained duplicate lrs1 to their rice ortholog found that fractionation of conserved noncoding sequences (CNSs) was rare, as expected. Of 30 CNSs, 27 were conserved. The 3 unexpected, missing CNSs and a large insertion support subfunctionalization as a reflection of fractionation of cis-acting gene space and the recent evolution of lg2’s novel maize leaf and shoot developmental functions. In general, the principles of fractionation and consolidation work well in making sense of maize gene and genomic sequence data.