Discrete Fractional Cosine Transform Research Articles

Efficient hybrid passive method for the detection and localization of copy-move and spliced images

Digital passive image forgery methods are extensively used to verify the authenticity and integrity of images.Splicing and copy-move are the most common types of passive digital image forgeries. Several approaches have beenproposed to detect these forgeries separately, but very few approaches are available that can detect them simultaneously.However, a more e?icient method is still in demand to meet the day-to-day challenges to detect these forgeries at thesame time. So, a passive hybrid approach based on discrete fractional cosine transform (DFrCT) and local binarypattern (LBP) is proposed to detect copy-move and splicing forgeries simultaneously. The extra parameter i.e. fractionalparameter of DFrCT is utilized to enhance the accuracy and LBP is used to highlight the tampering artifacts effectively.Then, a support vector machine (SVM) is employed to categorize the images into authentic, copy-move, and splicedimages. Next, localization is performed on both the copy-move and spliced images to localize the duplicated areas inthe image. Experiments on six benchmark datasets, namely, CASIA v1.0, GRIP, CASIA v2.0, IMD, COVERAGE,and Columbia, attain accuracy rates of 99.67%, 99.23%, 99.76%, 98.81%, 95%, and 98.17%, respectively. To validatethe effectiveness of the proposed method, comparative analysis has been performed with existing methods in terms ofROC, precision, recall,F1score,F2score, and accuracy. Moreover, the robustness of the proposed work is tested underrotation attack and better results are attained in comparison to the existing techniques.

Anti-forensic approach for JPEG compressed images with enhanced image quality and forensic undetectability

Most of the detectors employed in digital image forensics are based on JPEG compression. To determine the capability of these forensic detectors, proficient anti-forensic techniques that challenge and help in the upgradation of forensic techniques are required. This paper proposes an anti-forensic technique based on the shifted block Discrete Fractional Cosine Transform (DFrCT) approach. Afterwards, Total variation (TV) -based deblocking operation is used in order to remove the compression blocking artifacts. Due to the shifted block approach, the proposed method performs histogram smoothing without adding any dithering signal, which means that it is capable of applying dithering by itself. Further, to remove blocking artifacts which are left during the JPEG compression TV-based deblocking is used. The DFrCT approach provides an additional fractional parameter to improve the accuracy of the proposed approach. The proposed scheme is evaluated based on the UCID dataset images by considering the scalar based and machine learning-based forensic detectors. It is observed from the experimental results that the proposed approach provides improved performance in terms of PSNR, SSIM, and forensic undetectability when compared to existing techniques. The analysis performed in this paper challenges the security and robustness of JPEG compression forensic techniques.

A Proposed Orthogonal Chirp Division Multiplexing (OCDM) Multicarrier Transceiver Based on the Discrete Fractional Cosine Transform

Doppler spread is a phenomenon caused by rapid changes in the channel response due to the movement of the transmitter/receiver through a multipath environment, which is also known as a doubly selective channel response. In doubly selective fading channel where the channel frequency response is regarded as rapidly time-varying, the inter carrier interference (ICI) occurs mainly because the traditional multicarrier transceivers are incapable to diagonalize the channel matrix. The proposed scenario is for an Orthogonal Chirp Division Multiplexing (OCDM) multicarrier system derived from Discrete Fractional Cosine Transform (DFrCT). The proposed DFrCT-OCDM multicarrier system is proofed to be less signal processing complexity and easier to implement, compared to the traditional Fast Fourier Transform (FFT). Simulation results reveal that the DFrCT provides superior performance reflected the significant improvement in the BitError Rate which reaches to 10 dB, better spectrum efficiency and better energy concentration properties than the conventional FFT. Finally, several equlizers are applied and they all show that the proposed DFrCT-OCDM over performs the other systems with all these equlizers.

Peak-to-Average Power Ratio Performance Analysis for Orthogonal Chirp Division Multiplexing Multicarrier Systems Based on Discrete Fractional Cosine Transform

In doubly selective fading channels, the orthogonal frequency division multiplexing (OFDM) multicarrier system may fail. Chirp like basis (fractional Fourier transform-fractional cosine transform) may be used instead of complex exponential basis in this case to improve the system performance. However, in multicarrier transmission, the high peak to average power ratio (PAPR) of the transmitted signal is one of the difficult problems that face both the chirp and the exponential basis. In this paper, an evaluation for the PAPR performance of a multicarrier system based on the fractional cosine transform (FrCT) is introduced and then compared with DFrFT and FFT. Moreover, applying the SLAM technique over these systems is provided to understand the behaviour of these systems when applying SLAM. Simulations verify that this system obtains a better PAPR performance. Moreover, further PAPR reduction can be gained using the well-known PAPR reduction methods. Moreover, applying SLAM technique improves the performance of (dB) by 4 dB to 5 dB and all systems become as competitive to each other when SLAM is applied. Finally, BER performance comparison among OFDM, Discrete Cosine Transform MCM (DCT- MCM), Discrete Hartley Transform MCM (DHT-MCM), DFrFT-OCDM and DFrCT- OCDM MCM systems was done by means of simulation over 100,000 multicarrier blocks for each one and showed that our proposed scenario gave the best performance.

A Discrete Fractional Cosine Transform Based Speech Enhancement System Through Adaptive Kalman Filter Combined with Perceptual Weighting Filter with Pitch Synchronous Analysis

The speech enhancement plays a vital role commonly used in noisy environment to develop the performance of speech identification in mobile phones or in car navigation system. Thus the quality of the performance of the speech recognition is becoming worse due to the presence of noises in the surrounding. The objective is to increase the evident quality of the speech and to develop the transparency. Signal representation and enhancement in cosine transformation is observed to provide significant results. As an alternative of using DCT, a combination of conventional Discrete Cosine Transform (DCT) and Discrete Fourier Transform (DFT) which forms the another transform called as the Discrete Fractional Cosine Transform (DFrCT). The DFrCT have a free parameter, its fraction. In order to deal with the issue of frame to frame deviations of the Cosine Transformations, DFrCT is integrated with Pitch Synchronous Analysis (PSA). Also Pitch Synchronous OverLap and Add (PSOLA) method are used to enhance the performance of PSA. Moreover, in order to improve the noise minimization of the system, Improved Iterative Wiener Filtering approach called Adaptive Kalman Filter Combined with Perceptual Weighting Filter is used in this approach. This filter is used to eliminate the matrix operations, reduces both the calculation time and complexity. Thus, a novel DFrCT based speech enhancement using improved iterative filtering algorithm integrated with PSA is used in this approach

Video Compression-Encryption using Three Dimensional Discrete Fractional Transforms

The temporal correlation between consecutive frames is exploited. The proposed algorithm is based on video compression-encryption using 3 Dimensional (3-D) discrete fractional transforms, which makes full use of the additional degree of freedom provided by the fractional orders to achieve an optimum domain in the compression and encryption. We first used Discrete Fractional Fourier Transform (DFrFT) to compress the adjacent difference frame of video and thereafter the obtained compressed difference frame was encrypted using Discrete Fractional cosine Transform (DFrCT) with fractional keys. The worth of the reconstructed video was measured with Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR). Noteworthy improvement in results using our method from that of current existing methods is the efficacy of this study.

Image Encryption Algorithm Based on Image Element and DFRCT

A discrete fractional cosine transform with arbitrary period is proposed, which is a linear combination of discrete fractional cosine transform (DFRCT). We propose a new image encryption algorithm based on the discrete fractional cosine transform with arbitrary period, and set up some experiments by the different image block methods. The specific steps of encryption and decryption are given, and this encryption algorithm in items of many evaluation indexes is analyzed. The results of the detailed analysis demonstrate that the encryption algorithm effectiveness, efficiency and ability to resist brute-force attack are satisfying.

Color Image Encryption Based on the Multiple-Order Discrete Fractional Cosine Transform and Chaos in YCbCr Space

Based on the theory that a color image can be decomposed into three primary components and each one can be seen as a gray image, we propose a color image encryption method with multiple-order discrete fractional cosine transform (MODFrCT), which is a kind of encryption with the secrecy of pixel value and pixel position simultaneously. The complex number mode that has a real part and an imaginary one is used in this encryption method to save the transmission channel. Human vision is more sensitive to the Y component than to other two components in YCbCr color space and this color format is used for encrypting the color image. Chaos is introduced to scramble the image phases both in spatial and transformation domains. The numerical simulations demonstrate the validity and efficiency of this scheme and the robustness of the method against occlusion attack is examined.

Tridiagonal Commuting Matrices and Fractionalizations of DCT and DST Matrices of Types I, IV, V, and VIII

In this paper, we first establish new relationships in matrix forms among discrete Fourier transform (DFT), generalized DFT (GDFT), and various types of discrete cosine transform (DCT) and discrete sine transform (DST) matrices. Two new independent tridiagonal commuting matrices for each of DCT and DST matrices of types I, IV, V, and VIII are then derived from the existing commuting matrices of DFT and GDFT. With these new commuting matrices, the orthonormal sets of Hermite-like eigenvectors for DCT and DST matrices can be determined and the discrete fractional cosine transform (DFRCT) and the discrete fractional sine transform (DFRST) are defined. The relationships among the discrete fractional Fourier transform (DFRFT), fractional GDFT, and various types of DFRCT and DFRST are developed to reduce computations for DFRFT and fractional GDFT.

The discrete fractional cosine and sine transforms

This paper is concerned with the definitions of the discrete fractional cosine transform (DFRCT) and the discrete fractional sine transform (DFRST). The definitions of DFRCT and DFRST are based on the eigen decomposition of DCT and DST kernels. This is the same idea as that of the discrete fractional Fourier transform (DFRFT); the eigenvalue and eigenvector relationships between the DFRCT, DFRST, and DFRFT can be established. The computations of DFRFT for even or odd signals can be planted into the half-size DFRCT and DFRST calculations. This will reduce the computational load of the DFRFT by about one half.