Abstract
In many JPEG image splicing forgeries, the tampered image patch has been JPEG-compressed twice with different block alignments. Such phenomenon in JPEG image forgeries is called the shifted double JPEG (SDJPEG) compression effect. Detection of SDJPEG-compressed patches could help in detecting and locating the tampered region. However, the current SDJPEG detection methods do not provide satisfactory results especially when the tampered region is small. In this paper, we propose a new SDJPEG detection method based on an adaptive discrete cosine transform (DCT) coefficient model. DCT coefficient distributions for SDJPEG and non-SDJPEG patches have been analyzed and a discriminative feature has been proposed to perform the two-class classification. An adaptive approach is employed to select the most discriminative DCT modes for SDJPEG detection. The experimental results show that the proposed approach can achieve much better results compared with some existing approaches in SDJPEG patch detection especially when the patch size is small.
Highlights
With the rapid development of image processing tools, manipulating a digital image without leaving obvious visual traces is becoming easier and easier
The major contributions of our work lie in the following: (i) we perform a rigorous theoretic analysis of the discrete cosine transform (DCT) coefficient variations caused by shifted double JPEG (SDJPEG) and derive from it a rigorous statistical model for the DCT coefficients of SDJPEG patches, which provides a more accurate estimation of the quantization noise introduced by the shifted JPEG quantization compared with that in [13,14]; (ii) based on the analysis, we propose an effective discriminative feature to detect SDJPEG patches; and (iii) we propose an adaptive DCT component selection method to select the most discriminative DCT components
It can be observed that (i) the coefficient variations caused by rounding errors and shifted JPEG compression follow Gaussian distributions and hSmD;nðf Þ can be approximated by (7); (ii) the AC DCT coefficient distribution of the SSJPEG patch (shown in Figure 5 (c2 and c3)) follows the Laplacian distribution, which is similar to that of uncompressed images [22], and is very different from that of the SDJPEG patches shown in Figure 5 (a2 and b2)
Summary
With the rapid development of image processing tools, manipulating a digital image without leaving obvious visual traces is becoming easier and easier. Huang et al [18] proposed an aligned double JPEG detection algorithm that applied to the case where both the original and final images have the same quantization matrix Their approach cannot provide accurate detection results for small image patch. The tampered region can be located by searching for all the aligned patches where the cues left by shifted compression exist Such cues vary greatly with image content and the quality factor of the inserted patch, and it is difficult to find a robust and discriminative feature for all situations. According to [19], the DCT coefficients of block A and
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
