Discrete Wavelet Transform Domain Research Articles

Performance Evaluation of Block based Video Watermarking after Attacks

In today’s era use of digital media is most popular way of communication. Digital media covers images, videos and animations available online. The easy methods of accessing, copying and editing digital media have made them more popular. With several advantages these easy methods of copying and editing data have created some big issues like ownership identification. This increases the demand of protecting online digital media. Watermarking is solution of such problem. In this work, a block-based method has been proposed for video watermarking that uses a key at the time of embedding and extraction. Some frames are selected from the video according to a key. Watermark is embedded on the selected frames after dividing into parts called blocks. Each part of the watermark is embedded in one selected frame of the video. This method increases the security of the system as the complete watermark cannot be extracted without knowing the positions of watermarked frames and the position of the block in that frame. Watermarking is performed in the Discrete Wavelet Transform domain after scaling of watermark data. To show the authenticity of proposed scheme various attacks are applied on different watermarked video frames and extracted watermark results are shown under different tables.

Security of 3D-HEVC transmission based on fusion and watermarking techniques

This paper presents two robust hybrid watermarking techniques for efficiently securing the transmission of the Three-Dimensional High Efficiency Video Coding (3D-HEVC). The first watermarking technique is the homomorphic-transform-based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. The second technique is the three-level Discrete Stationary Wavelet Transform (DSWT) in Discrete Cosine Transform (DCT) domain. The objective of the two proposed hybrid watermarking techniques is to increase the immunity of the watermarked 3D-HEVC to attacks and achieve adequate perceptual quality. Also, we propose a wavelet-based fusion technique to combine multiple depth watermark frames into one fused depth watermark frame. Then, the resultant fused depth watermark is embedded in the 3D-HEVC color frames using the two proposed watermarking techniques to produce the watermarked 3D-HEVC streams. The proposed techniques reduce the required bit rate for transmitting the color-plus-depth 3D-HEVC data. The performances of the two proposed watermarking techniques are compared with those of the state-of-the-art watermarking techniques. The comparisons depend on both subjective visual results and objective results: the Peak Signal-to-Noise Ratios (PSNRs) of the watermarked frames and the Normalized Correlation (NC) of the extracted watermark frames. Extensive simulation experiments on different standard 3D video sequences have been conducted in the presence of attacks. The obtained results confirm that the proposed watermarking techniques achieve not only very good perceptual quality, appreciated PSNR values, and saving of the transmission bit rate, but also high correlation coefficients, and high robustness in the presence of attacks. Furthermore, the proposed techniques improve both the capacity of the embedded information and the robustness without affecting the perceptual quality of the original 3D-HEVC frames. Indeed, the extraction of the fused and multiple primary and secondary depth watermark frames is possible in the presence of different attacks.

The visual color QR code algorithm (DWT-QR) based on wavelet transform and human vision system

A novel visual Quick Response (QR) code algorithm based on Wavelet transform and Human Visual System (HVS) approach is presented in this study and named DWT-QR. Unlike other QR codes are generally embedded in the spatial domain, the composite coefficients using global and local characteristics of the host image are considered in the discrete wavelet transform (DWT) domain for the visual QR codes. In order to get the best perceptual embedding capability of visual QR codes, the collaboration of the perceptual model of contrast-sensitive function (CSF) with the noise reduction of the visibility thresholds for HVS in DWT domain, achieves the goal of fine tuning of the perceptual weights according to the basis function amplitudes for the best quality of perceptual visibility. In addition, the computation of Noise Visibility Function (NVF) characterizes the local image properties to determine the optimal QR code strength during the QR codes embedding stage. After the detection pattern embedded for the visual QR codes, different distortion attacks have been performed for the proposed method. The experimental results demonstrate that the proposed DWT-QR approach outperforms the known techniques and not only improves the visual quality of the images but also the robustness against various attacks.

Classification of focal and non-focal EEG signals in VMD-DWT domain using ensemble stacking

Classification of focal and non-focal Electroencephalogram (EEG) signals is an important problem especially for the identification of epileptogenic sites in the brain. However, the number of research works reported in the literature is limited and most of them suffer from validation on a limited scale and moderate accuracy. In this paper, focal and non-focal EEG signals are analyzed in variational mode decomposition (VMD) and discrete wavelet transform (DWT) domain and features such as refined composite multiscale dispersion entropy, refined composite multiscale fuzzy entropy, and autoregressive model (AR) coefficients are extracted in VMD, DWT and VMD-DWT domain. Statistical analysis of the features is carried out by one way ANOVA to demonstrate their discriminating ability by means of p-values and visual inspection of the box plots of the features. A feature reduction algorithm based on neighborhood component analysis is used to reduce the model complexity and select the features with the highest discriminating abilities. An ensemble stacking classification approach is adopted to improve the accuracy of classification. The performance of the proposed method is studied using a publicly available benchmark database that contains 3750 pairs of focal and 3750 pairs of non-focal EEG signals. It is shown that the stacking configuration improves the accuracy significantly compared to a standalone classifier. It gives high values of sensitivity (96.1%), Specificity (94.4%), Accuracy (95.2%) and area under curve (0.989). Comparison with various existing methods reveals that the proposed method outperforms the others in accuracy. It may help researchers in developing a computer-aided system to identify epileptogenic sites in the brain.

Sleep stage classification using single-channel EOG

Sleep stage classification is an important task for the timely diagnosis of sleep disorders and sleep-related studies. In this paper, automatic scoring of sleep stages using Electrooculogram (EOG) is presented. Single channel EOG signals are analyzed in Discrete Wavelet Transform (DWT) domain employing various statistical features such as Spectral Entropy, Moment-based Measures, Refined Composite Multiscale Dispersion Entropy (RCMDE) and Autoregressive (AR) Model Coefficients. The discriminating ability of the features is studied using the One Way Analysis of Variance (ANOVA) and box plots. A feature reduction algorithm based on Neighborhood Component Analysis is used to reduce the model complexity and select the features with highest discriminating abilities. Random Under-Sampling Boosting (RUSBoost), Random Forest (RF) and Support Vector Machine (SVM) are employed to classify various sleep stages for 2–6 stage classification problem. Performance of the proposed method is studied using three publicly available databases, the Sleep-EDF, Sleep-EDFX and ISRUC-Sleep databases consisting of 8, 20 and 10 subjects respectively. The proposed method outperforms the state-of-the-art EOG based techniques in accuracy. In addition, its performance is shown to be on par or better than those of various single channel EEG based methods. An important limitation of existing sleep detection methods is the low accuracy of the S1 sleep stage classification for which the proposed method using the RUSBoost classifier gives a superior accuracy as compared to those of EOG and EEG based techniques.

Mean Square Error Optimization to Authenticate Multi-Modality Medical Images in Wavelet Domain

Medical image watermarking which hides patient’s information in the medical image ensures its imperceptibility and at the same time provides robustness to the information that is embedded. Current research scenario embeds the authenticated message as watermark in the frequency domain to get watermarked image which has most of its values as real numbers. Since pixel intensity values must be represented as integers, the watermarked image is converted into spatial domain where the rounding error problem occurs and the embedded message cannot be extracted to prove its authenticity. In proposed work, a new watermarking scheme in Discrete Wavelet Transform (DWT) domain based on Genetic Algorithm (GA) is implemented to ensure correct retrieval of embedded watermark by optimizing Mean Square Error (MSE) measure.

Efficient multi-level security for robust 3D color-plus-depth HEVC

This paper presents two robust hybrid watermarking techniques for securing the Three-Dimensional High Efficiency Video Coding (3D-HEVC). The first watermarking technique is the homomorphic-transform-based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. The second watermarking technique is the three-level Discrete Stationary Wavelet Transform (DSWT) in Discrete Cosine Transform (DCT) domain. The objective of the two proposed hybrid watermarking techniques is to increase the immunity of the watermarked 3D-HEVC streams to attacks. Also, we propose a wavelet-based fusion technique to combine two depth watermark frames into one fused depth watermark frame. Then, the resultant fused depth watermark is encrypted using chaotic Baker map to increase the level of security. After that, the resultant chaotic encrypted fused depth watermark is embedded in the 3D-HEVC color frames using the proposed hybrid watermarking techniques to produce the watermarked 3D-HEVC streams. In addition to achieving multi-level security in the transmitted 3D-HEVC streams, the proposed hybrid techniques reduce the required bit rate for transmitting the color-plus-depth 3D-HEVC data over limited-bandwidth networks. The performance of the proposed hybrid techniques is compared with those of the state-of-the-art techniques. Extensive simulation results on standard 3D video sequences have been conducted in the presence of attacks. The obtained results confirm that the proposed hybrid fusion-encryption-watermarking techniques achieve not only a good perceptual quality with high Peak Signal-to-Noise Ratio (PSNR) values and less bit rate, but also high correlation coefficient values between the original and extracted watermarks in the presence of attacks. Furthermore, the proposed hybrid techniques improve the capacity of information embedding and the robustness without affecting the perceptual quality of the original 3D-HEVC frames. Indeed, the extraction of the encrypted, fused, primary, and secondary depth watermark frames is possible in the presence of attacks.

Efficient facial expression recognition using histogram of oriented gradients in wavelet domain

Facial expression recognition plays a significant role in human behavior detection. In this study, we present an efficient and fast facial expression recognition system. We introduce a new feature called W_HOG where W indicates discrete wavelet transform and HOG indicates histogram of oriented gradients feature. The proposed framework comprises of four stages: (i) Face processing, (ii) Domain transformation, (iii) Feature extraction and (iv) Expression recognition. Face processing is composed of face detection, cropping and normalization steps. In domain transformation, spatial domain features are transformed into the frequency domain by applying discrete wavelet transform (DWT). Feature extraction is performed by retrieving Histogram of Oriented Gradients (HOG) feature in DWT domain which is termed as W_HOG feature. For expression recognition, W_HOG feature is supplied to a well-designed tree based multiclass support vector machine (SVM) classifier with one-versus-all architecture. The proposed system is trained and tested with benchmark CK+, JAFFE and Yale facial expression datasets. Experimental results of the proposed method are effective towards facial expression recognition and outperforms existing methods.

Key‐dependent audio fingerprinting technique based on a quantisation minimum‐distance hash extractor in the DWT domain

A novel key-dependent audio fingerprinting technique is proposed by introducing the quantisation minimum distance (QMD) as a hash extractor in the discrete wavelet transform (DWT) domain. The quantiser dithers of the QMD are generated using a chaotic map whose initial value is used as a secret key for fingerprint extraction. Experimental results show that the proposed audio fingerprinting technique achieves with a small fingerprint size an excellent discrimination between audio signals of different contents and outperforms the existing Philips robust hash based techniques in terms of the robustness.

Robust watermarking in DWT domain using SVD and opposition and dimensional based modified firefly algorithm

The process of authenticating a digital image by embedding a watermark into it is called digital image watermarking, which protects the image from copyright infringement. This paper proposes an optimized watermarking scheme in the discrete wavelet transform (DWT) domain based on the singular value decomposition (SVD) using opposition and dimensional based modified firefly algorithm (ODFA).The host image is segmented into 8 × 8 non-overlapping blocks and the most suitable embedding blocks are selected for embedding. The selected blocks are then transformed into DWT domain and SVD is applied on LL1 sub-bands. Finally, the process of embedding the watermarked bits is optimized using ODFA, which applies the combination of imperceptibility and robustness as the objective function. The embedding algorithm possesses good similarity between the host and the watermarked images as well as the strong robustness against various image processing operations and attacks. Experimental results reveal that the proposed scheme has a higher degree of imperceptibility and robustness compare to related existing schemes.

Robust hybrid watermarking techniques for different color imaging systems

Digital watermarking is an efficient and promising mechanism for protecting the copyright of the transmitted multimedia information. Thus, this paper presents two robust hybrid color image watermarking techniques. The objective of the proposed watermarking techniques is to increase the immunity of the watermarked color images against attacks and to achieve adequate perceptual quality. The first proposed hybrid technique is the homomorphic transform based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. Firstly, the DWT is employed to divide an image into non-overlapping bands. Then, the reflectance components of the LL sub-bands are extracted using the homomorphic transform of each of the RGB (Red, Green, and Blue) color image components. After that, the watermark is embedded by applying the SVD on these reflectance components. The second proposed hybrid technique is the three-level Discrete Stationary Wavelet Transform (DSWT) in Discrete Cosine Transform (DCT) domain. In this technique, the RGB components of the host color image are separated, and then the DCT is applied on each separated color component. The three-level DSWT is employed to divide the DCT components into four sub-bands. These sub-bands are the A, H, V, and D matrices, which have the same host image size. The watermark image is then embedded into the determined matrix A. The two proposed hybrid watermarking techniques are compared with the current state-of-the-art techniques. This paper also presents a comparative study of the proposed techniques for different color imaging systems to determine their robustness and stability. The comparisons are based on the subjective visual results to detect any degradation in the watermarked image in addition to the objective results of the Peak Signal-to-Noise Ratio (PSNR) of the watermarked image, and the Normalized Correlation (NC) of the extracted watermark to test and evaluate the performance efficiency of the proposed watermarking techniques. Extensive experimental results show that the proposed hybrid watermarking techniques are both robust and have adequate immunity against different types of attacks compared to the traditional watermarking techniques. They achieve not only very good perceptual quality with appreciated PSNR values, but also high correlation coefficient values in the presence of different multimedia attacks.

A color image steganography in hybrid FRT–DWT domain

In this paper, a color image steganography technique based on Finite Ridgelet Transform (FRT) and Discrete Wavelet Transform (DWT) is proposed. The FRT is applied on the cover color image to get Ridgelet coefficients of each color channel of cover color image and a single level DWT is applied to get different wavelet coefficients, which are further modified by encrypted channel values of secret color image to get stego color image. In the proposed method, Arnold scrambling is used to encrypt channels of secret color image. The proposed technique is tested for its effectiveness on various types of standard color images and the results showed improved imperceptibility of the stego image compared to the existing technique. Further, the embedding capacity of the proposed technique is high.

Spatial and Transform Domain based Steganography Using Chaotic Maps for Color Images

We propose an efficient and robust steganography scheme for color images based on combined spatial and transform domains using chaos theory. The Discrete Wavelet Transform (DWT) domain is used as a transform domain for both secret and cover image to increase imperceptibility and robustness. In order to further improve security chaotic maps are used for scrambling the secret color image before hiding and for selecting randomly the embedding locations in the cover image. After scrambling and embedding the two images are merged in a single image and IDWT is applied to form the stego image. In the extraction process, the secret image can be extracted from the stego image without needing the original cover image. The simulation results of Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR) and correlation show that the proposed steganography scheme has better invisibility, stronger robustness, higher security and reliability against common image processing attacks, such as filtering and noise attacks, for any kind of image data than pervious approaches. Simulation results show maximum PSNR values of 76.8 dB and correlations of 99.99% for the stego image and of 55.4 dB and 100% for the extracted secret image.

Efficient Hybrid Watermarking Scheme for Security and Transmission Bit Rate Enhancement of 3D Color-Plus-Depth Video Communication

Three-Dimensional Video-plus-Depth (3DV + D) comprises diverse video streams captured by different cameras around an object. Therefore, there is a great need to fulfill efficient compression to transmit and store the 3DV + D content in compressed form to attain future resource bounds whilst preserving a decisive reception quality. Also, the security of the transmitted 3DV + D is a critical issue for protecting its copyright content. This paper proposes an efficient hybrid watermarking scheme for securing the 3DV + D transmission, which is the homomorphic transform based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. The objective of the proposed watermarking scheme is to increase the immunity of the watermarked 3DV + D to attacks and achieve adequate perceptual quality. Moreover, the proposed watermarking scheme reduces the transmission-bandwidth requirements for transmitting the color-plus-depth 3DV over limited-bandwidth wireless networks through embedding the depth frames into the color frames of the transmitted 3DV + D. Thus, it saves the transmission bit rate and subsequently it enhances the channel bandwidth-efficiency. The performance of the proposed watermarking scheme is compared with those of the state-of-the-art hybrid watermarking schemes. The comparisons depend on both the subjective visual results and the objective results; the Peak Signal-to-Noise Ratio (PSNR) of the watermarked frames and the Normalized Correlation (NC) of the extracted watermark frames. Extensive simulation results on standard 3DV + D sequences have been conducted in the presence of attacks. The obtained results confirm that the proposed hybrid watermarking scheme is robust in the presence of attacks. It achieves not only very good perceptual quality with appreciated PSNR values and saving in the transmission bit rate, but also high correlation coefficient values in the presence of attacks compared to the existing hybrid watermarking schemes.

Enhanced high capacity image steganography using discrete wavelet transform and the Laplacian pyramid

This paper introduces a high capacity image hiding scheme with enhanced stego image quality. This new hiding scheme utilizes a multiscale Laplacian pyramid of the cover image in the Discrete Wavelet Transform (DWT) domain. Previous work either enhanced capacity at the expense of stego quality or improved stego quality albeit at lower capacities. The proposed scheme will utilize the high-frequency bands of the DWT of the cover image for increased hiding capacity while further extending the payload capacity by hiding in the lowest level Laplacian pyramid of the DWT low-frequency band using a curve-fitting adaptive region approach in the spectral magnitude discrete cosine transform domain. The proposed scheme results in enhanced visual fidelity as well as high capacities as compared to competing methods. Comparative experimental results will show that the proposed scheme outperforms recent methods in terms of payload capacity as well as various image quality measures. Resistance to data-loss and noise tampering, geometric distortions and Checkmark attacks, and steganalysis detection attacks will further demonstrate the robustness of the proposed scheme.

A Novel DWT Domain Watermarking Scheme Based On a Discrete-Time Chaotic System

Abstract In this paper, we present a novel watermarking scheme in the Discrete Wavelet Transform (DWT) domain based on a discrete-time chaotic system. A modified Henon map and a discrete step-by-step observer are, respectively, considered as transmitter and receiver of the chaotic transmission scheme, leading to an exact synchronization and therefore an exact recovery of the system states. The secret keys of the transmission scheme are the transmitter parameters. The said modified Henon map is used to encrypt an image, inserted by inclusion method in the chaotic discrete-time system’s dynamics, to then use the resulting cyphered image as a watermark to a host image. This host image is watermarked by a DWT domain watermarking function. After the extraction process, the recovered watermark is then sent through the previous chaotic channel to decrypt it. Simulation results are presented to highlight the feasibility and robustness of the proposed method.

A Novel Image Authentication with Tamper Localization and Self-Recovery in Encrypted Domain Based on Compressive Sensing

This paper proposes a novel tamper detection, localization, and recovery scheme for encrypted images with Discrete Wavelet Transformation (DWT) and Compressive Sensing (CS). The original image is first transformed into DWT domain and divided into important part, that is, low-frequency part, and unimportant part, that is, high-frequency part. For low-frequency part contains the main information of image, traditional chaotic encryption is employed. Then, high-frequency part is encrypted with CS to vacate space for watermark. The scheme takes the processed original image content as watermark, from which the characteristic digest values are generated. Comparing with the existing image authentication algorithms, the proposed scheme can realize not only tamper detection and localization but also tamper recovery. Moreover, tamper recovery is based on block division and the recovery accuracy varies with the contents that are possibly tampered. If either the watermark or low-frequency part is tampered, the recovery accuracy is 100%. The experimental results show that the scheme can not only distinguish the type of tamper and find the tampered blocks but also recover the main information of the original image. With great robustness and security, the scheme can adequately meet the need of secure image transmission under unreliable conditions.

An Efficient Digital Watermarking Technique for Color Images Using Directional Transforms

This paper is concerned with a digital watermarking technique for color images based on directional transforms. Different from the traditional watermarking schemes which embed the watermarks into the spatial domain or frequency domain of the Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT), this paper investigates the performance of the watermarking schemes using the Fast Discrete Curvelet Transforms (FDCT) and Contourlet Transform (CT). We evaluate the performance of the watermarking schemes using the directional transforms on a standard database of color images in terms of invisibility and robustness. The performance metrics are measured by Peak Signal-to-Noise Ratio (PSNR), Normalized Correlation (NC), Structural SIMilarity (SSIM) and required time for extracting and embedding process. The experimental results reveal that watermarking schemes in the directional transform domains outperform the other schemes in DWT domains.

Evaluvation of Multiresolution Watermarking Algorithm

Now-a-days watermarking plays a pivotal role in most of the industries for providing security to their own as well as hired or leased data. This paper its main aim is to study the multiresolution watermarking algorithms and also choosing the effective and efficient one for improving the resistance in data compression. Computational savings from such a multiresolution watermarking framework is obvious. The multiresolutional property makes our watermarking scheme robust to image/video down sampling operation by a power of two in either space or time. There is no common framework for multiresolutional digital watermarking of both images and video. A multiresolution watermarking based on the wavelet transformation is selected in each frequency band of the Discrete Wavelet Transform (DWT) domain and therefore it can resist the destruction of image processing. The rapid development of Internet introduces a new set of challenging problems regarding security. One of the most significant problems is to prevent unauthorized copying of digital production from distribution. Digital watermarking has provided a powerful way to claim intellectual protection. We proposed an idea for enhancing the robustness of extracted watermarks. Watermark can be treated as a transmitted signal, while the destruction from attackers is regarded as a noisy distortion in channel. For the implementation, we have used minimum nine coordinate positions. The watermarking algorithms to be taken for this study are Corvi algorithm and Wang algorithm. In all graph, we have plotted X axis as peak signal to noise ratio (PSNR) and y axis as Correlation with original watermark. The threshold value ά is set to 5. The result is smaller than the threshold value then it is feasible, otherwise it is not.

A novel hybrid of DCT and SVD in DWT domain for robust and invisible blind image watermarking with optimal embedding strength

To optimize the tradeoff between imperceptibility and robustness properties, this paper proposes a robust and invisible blind image watermarking scheme based on a new combination of discrete cosine transform (DCT) and singular value decomposition (SVD) in discrete wavelet transform (DWT) domain using least-square curve fitting and logistic chaotic map. Firstly cover image is decomposed into four subbands using DWT and the low frequency subband LL is partitioned into non-overlapping blocks. Then DCT is applied to each block and several particular middle frequency DCT coefficients are extracted to form a modulation matrix, which is used to embed watermark signal by modifying its largest singular values in SVD domain. Optimal embedding strength for a specific cover image is obtained from an estimation based on least-square curve fitting and provides a good compromise between transparency and robustness of watermarking scheme. The security of the watermarking scheme is ensured by logistic chaotic map. Experimental results demonstrate the better effectiveness of the proposed watermarking scheme in the perceptual quality and the ability of resisting to conventional signal processing and geometric attacks, in comparison with the related existing methods.