Abstract Recently, forensic tools have been presented for detecting the forged image and illegal image manipulations. This paper presents an efficient and simple image contents verifying approach acting as a forensic technique. The presented approach mechanism is built by adding a hidden mark in a secret images, this mark achieves image integrity verification and detecting the tampering or forgery in the secret/authentic images. The secret/authentic/authentic image is divided to two main partitions, each portion is segmented to small blocks. These blocks in one partition are used to mark the blocks of the second partition using data transform technique. Firstly, the sensitive image is marked according to a self-embedding method. Then, a transform domain is utilized in order to embed a block-based signature into another block of the same image. Common discrete transform domains like DWT, DCT, and DFT are examined individually. Different analyses and comparison measurements are employed. The DCT is proved to be the most suitable and efficient transform domain to be used with the proposed scheme. At the receiver side, the reverse process is performed to verify image integrity. As proved from the experiments, this mark-algorithm is not visible or observable and robust against various attacks.

The high efficiency video coding (HEVC) partial encryption (PE) technique depends on encrypting the highly sensitive data on the video bit stream. The HEVC PE technique should keep the video format compliance, should be of the same bit rate, and ensure real-time constraints. The paper suggests an effective RC6 HEVC PE technique which encrypts sensible video data bits with low complexity overhead, fast encoding time for real-time applications, and fixed HEVC bitrate. These features result from using the low computational complexity RC6 block cipher for encrypting the selective video bins. The proposed RC6 HEVC PE encrypts the discrete cosine transform (DCT) coefficients sign bit, the DCT remaining absolute values suffixes that are binarized by Exp-Golomb (EGk) order zero, the motion vector difference (MVD) sign bits, and MVD absolute values suffixes that are binarized by EGk order one. Also, this paper introduces experimental results that compare between the proposed RC6 HEVC PE and HEVC PE algorithms that use the Advanced Encryption Standard in different operation modes. This paper presents more details about the security analysis of RC6 HEVC PE including encryption quality test, key space test, statistical analysis such as histogram and correlation coefficient analysis, and sensitivity analysis such as the key sensitivity analysis. The achieved test results ensured and confirmed the security, reliability, and robustness of RC6 HEVC PE technique.

This paper presents an efficient technique for sharpening of Misrsat-1 data using superresolution (SR) methods and fusion methods. Due to the difference in spectral characteristics between bands 1 and 3 and the panchromatic (PAN) band of Misrsat-1, we implement SR on high details of these bands and use the resulting image to sharpen the bands of the multispectral (MS) image. Several SR methods are tested and compared in this paper for this purpose. The first class of methods uses spatial-domain SR, in which SR is performed on the high-pass details extracted from bands 1 and 3 and the PAN band. The superresolved high-pass details are used after that to enhance the spatial resolution of the MS data using the high-pass filter fusion method. The second class of methods depends on the interpolation of coefficients in the high-frequency subbands of a multiscale representation of bands 1 and 3 and the PAN band and an additive fusion method to add the high-frequency subband coefficients to different bands of the MS image. A comparison study between different SR methods belonging to the aforementioned classes such as nonuniform interpolation (NUI), projection onto convex sets (POCS), iterative back projection (IBP), structure-adaptive normalized convolution (SANC), and adaptive steering kernel regression (ASKR) is presented. The simulation results show that iterative SR methods such as IBP and POCS produce more noise than interpolation methods such as NUI, SANC, and ASKR. The results also reveal that combining the ASKR with a multiscale decomposition enhances the signal-to-noise ratio.