3D DFT-based video watermarking using perceptual models

Fast unbiased finite impulse response (UFIR) filtering of polynomial signals can be provided in the discrete Fourier transform (DFT) domain employing fast Fourier transform (FFT). We show that the computation time can further be reduced by utilizing properties of UFIR filters in the DFT domain. The transforms have been found and investigated in detail for low-degree FIRs most widely used in practice. As a special result, we address an explicit unbiasedness condition uniquely featured to UFIR filters in DFT domain. The noise power gain and estimation error bound have also been discussed. An application is given for state estimation in a crystal clock employing the Global Positioning System based measurement of time errors provided each second. Based upon it, it is shown that filtering in the time domain takes about 1 second, which is unacceptable for real-time applications. The Kalman-like algorithm reduces the computation time by the factor of about 8, the FFT-based algorithm by about 18, and FFT with the UFIR filter DFT properties by about 20.

In this paper the problem of restoring an image distorted by a linear space-invariant (LST) point-spread function (PSF) which is not exactly known is solved using a maximum-a posteriori (MAP) formulation. Using the diagonalization properties of the discrete Fourier transform (DFT) for circulant matrices, the MAP estimate is computed in the DFT domain. The similarities between the MAP and the regularized constrained total least-squares (RCTLS) estimates are reported and their equivalence under certain conditions is discussed. A perturbation analysis of the MAP estimate is performed to obtain its mean-squared error (MSE) in a closed form, for small PSF errors. Numerical experiments for different PSF errors are performed to test the MAP estimator for this problem. Objective MSE-based and visual comparisons with the modified linear minimum mean-squared error (LMMSE) filter are presented that verify the superiority of the MAP estimator for higher PSF errors. >

Content for mobile devices, unlike content for PCs, need to be optimized for the features of the mobile device.In recent years, with the progress in mobile telecom technology including Wibro and 3G, various types of mobile devices have become widely available, such as PMP, PDA, or UMPC.This has drawn attention to interactive multimedia services such as IPTV, DMB broadcasting, mobile portals and mobile TVs.However, in order to provide appropriate services for the mobile environment, the process of converting MPEG-4 BIFS to LASeR is required.This paper proposed optimized watermarking scheme for mobile device.Proposed watermarking algorithm uses z-axis location information of MPEG-4 BIFS and original model is not needed in extraction procedure.This proposed watermarking algorithm has good imperceptibility and robustness against the geometrical attacks such as noise addition, simplification and cropping.And it is proved that this proposed algorithm is good for access control capability by the experiment.

This paper proposes a novel preprocessing technique in order to improve the performance of a Face Recognition (FR) system. The proposed Edge-based Scale Normalization (ESN) process involves the use of scale normalization along with edge detection as a preprocessing technique in order to eliminate unwanted background details in face images. Feature extraction is performed on the preprocessed image using Discrete Fourier Transform (DFT). The DFT spectrums of these images extract the low frequency coefficients required for face recognition. These important features are selected through a rhombus-shaped mask around the center of the DFT spectrum. Further optimization in feature selection is achieved through Binary Particle Swarm Optimization (BPSO) technique. Experimental results, obtained by applying the proposed algorithm on Cambridge ORL and Extended YaleB face databases, show that the proposed system outperforms other FR systems. A significant increase in the recognition rate and a substantial reduction in the number of features is observed. Significant dimensionality reduction by more than 98.5% and improved recognition rate of 98% are achieved for both datasets. ∗Corresponding author, E-mail: kmanikantan@msrit.edu †E-mail: ramachandr@gmail.com DFT domain Feature Extraction using Edge-based Scale Normalization for Enhanced Face Recognition 135

Discrete Fourier transforms (DFTs) over finite fields have widespread applications in various communication and storage systems. Hence reducing the computational complexities of DFTs is of great significance. Recently proposed cyclo-tomic fast Fourier transforms (CFFTs) are promising due to their low multiplicative complexities. Unfortunately, they have very high additive complexities. Techniques such as common subexpression elimination (CSE) can be used to reduce the additive complexities of CFFTs, but their effectiveness for long DFTs is limited by their complexities. In this paper, we propose prime factor cyclotomic Fourier transforms (PFCFTs), which use CFFTs as sub-DFTs via the prime factor algorithm. When the length has co-prime factors, the short lengths of the sub-DFTs allow us to use CSE to significantly reduce their additive complexities. In comparison to previously proposed fast Fourier transforms, our PFCFTs achieve reduced overall complexities when the lengths of DFTs are at least 255, and the improvement significantly increases as the length grows. This approach enables us to propose the first efficient DFTs with very long length (e.g., 4095-point) in the literature. Finally, our PFCFTs are also advantageous for hardware implementation due to their regular structure.

This paper reviews the video watermarking schemes resistance against tampering attacks. There are several transform methods which are used for Video Watermarking including Discrete Fourier Transform (DFT), Discrete Cosine Transform (DCT), Discrete wavelet transform (DWT) and are discussed and compared in this paper. The results are presented in a table with a summary of their advantages.

A robust content-based digital image watermarking scheme

A novel method is proposed which deals with secure extraction of data by utilizing transform based image watermarking techniques. The image is embedded with a watermark using a combination of Discrete Cosine Transform (DCT), Discrete Fourier Transform (DFT) and Discrete Wavelet Transform (DWT) in this scheme. The conventional transforms are applied in an optimized mode in these schemes in different spatial regions of the image to embed a watermark. The scheme is subjected to Signal processing attacks and Geometric attack to test against the robustness of the image. The watermarking of image is made secure by testing against unauthorized detection techniques employed by attackers. This is realized by a correlation based detector applied to the scheme. Experimental results show that the watermarked image is robust and secure against Signal Processing attacks, Geometric attacks and unauthorized Detection attacks.

A blind dual color images watermarking based on singular value decomposition

The paper analyzes the effect of harmonics and wideband noise on the accuracy of the phasor estimator provided by the Discrete Fourier Transform (DFT) at off-nominal frequency when a decaying dc offset component is either absent or present in the acquired signal. The analysis, performed through both computer simulations and experimental results, shows the high sensitivity to transient conditions of the DFT-based phasor estimator algorithm.

Digital video watermarking has attracted a great deal of research interest in the past few years in applications such as digital fingerprinting and owner identification. The H.264/AVC (advanced video coding) standard is the latest and most advanced video coding standard, but to this date, very few watermarking schemes have been designed for it. This is mainly due to its complexity and compression efficiency, which present a major challenge for any video watermarking approach. We developed a new, quantization-based video watermarking scheme that is designed to work with H.264/AVC. We propose a locally adaptive, rate-distortion optimized watermark that is inserted in the transform coefficients of the macro blocks. We use a unique perceptual mask in order to control the levels of spatial and temporal distortion. Our scheme is designed with a built-in bit allocation mechanism that ensures optimum distribution of watermark bits between different macro blocks. Our watermark offers constant robustness to H.264 video compression at different bit rates, without significantly affecting the overall bit rate and quality of the video stream. Experimental results show that our scheme outperforms existing watermarking methods under compression, transcoding, filtering, scaling, rotation, and collusion attacks.

Nowadays Digital Watermarking is widely used in the health care centers to secure the patient's records.In India, nowadays the hospitals are adapting the telemedicine technology where it is providing facility for the patients and doctors to transmit the reports and as well as to access it easily as and when it is required to do so.In order to protect the privacy, authenticity and the integrity of the Electronic Health Record (EHR), some measure has to be employed.In this regard Digital watermarking (DWM) plays a major role.Digital watermarking is implemented in mainly two domains: one at the pixel level usually called as the spatial domain and the other is at the frequency components of the information called as the frequency domain.Of the two methods, second method is most commonly adapted by most of the researchers.It includes the transforms like Discrete Cosine Transform (DCT), Discrete Fourier Transform (DFT), Discrete Wavelet Transform (DWT) and the variations of DWT viz.Lifting Wavelet Transform (LWT) and Integer Wavelet Transform (IWT).In this paper DWM for the medical scanned images and the medical video is implemented using DWT.The watermark is patient information which will be converted to quick response (QR) code using the built in function.A simple key is used at the embedding part of the DWM technique and the same key is used at the decoder side to retrieve the information which enhances the security of both medical images/videos and the patient details.

the paper proposes a tool, VisiMark1_0, as assistance for evaluating the robustness of video watermarking algorithms as evaluation of a video watermarking algorithm for robustness with available tools is a tedious task. It is our belief that for researchers of robust video watermarking, a tool needs to be designed that will assist in the evaluation procedure irrespective of the design algorithm. This tool provides a test bed of various attacks. The input to this tool will be a watermarked video whereas the outputs will be attacked videos, evaluated parameters PSNR, MSE, MSAD and DELTA, graphical comparisons of the attacked and watermarked videos with all parameters needed by researchers, and the attacks report. Provision for comparison of any two videos is an additional facility provided in the tool. The attacks implemented in VisiMark1_0 are categorized mainly in three. Firstly, Video attacks: Frame dropping, Frame averaging, Frame swapping, Changing the sequence of the scenes, Changing Frame rate, Fade and dissolve, Contrast stretching, Motion blurring, Chroma sampling, Inter frame averaging are some of the novel offerings in video frame attacks category. Secondly, Geometrical attacks: Apart from the traditional Rotation, Scaling and Cropping attacks for images, VisiMark1_0 contributed towards Sharpening, Shearing, Flipping, Up/down sampling and Dithering attacks for a video and signal processing attacks like Conventional Noising, Denoising and Filtering attacks for images are incorporated for video along with Pixel removal attack as a novel contribution. VisiMark1_0 is an endeavor to design a tool for evaluating a raw video (an .avi file currently) incorporating various attacks having a prospect for numerous video formats in near future.

In this paper, a new robust and secure video watermarking scheme based on discrete Wavelet Transform (DWT), singular value decomposition (SVD), and Laplacian pyramid is proposed for copyright protection applications. The main contributions of this work are: 1) Increasing watermark robustness towards common signal processing attacks by separating the watermark image into a high-frequency image and a low-frequency image using laplacian pyramid. Then, the singular values of each of the low-frequency watermark image and the high-frequency watermark image are hidden in two different DWT subbands of the original video frame. Separating the watermark and hiding its two parts in two different subbands of the DWT of the video frame makes it robust towards noise, filtering, and compression attacks. 2) Improving the quality of the extracted watermarks via correcting the received watermarked videos using SURF points when those videos are geometrically attacked, mainly by rotation, scaling, and shear attacks. 3) Increasing security and avoiding false positive problems (FPP) associated with SVD by using perceptual image hashing in the proposed scheme. Through experimental results and comparisons to other techniques, the proposed scheme has shown very high imperceptibility for the tested watermarked videos in terms of peak signal to noise ratio (PSNR). Also, the proposed scheme has demonstrated high watermark robustness towards various types of attacks, and an improvement in the quality of the extracted watermarks from 4 to 20 dB compared to other techniques.

Watermarking is an important technique used for copyright protection, authentication, tamper detection and hiding secret information in multimedia contents. In this article a new digital watermarking scheme is proposed based on multiple parameter discrete fractional Fourier transform and using least significant bit (LSB) technique. The multiple parameter discrete fractional Fourier transform (MPDFRFT) is the generalization of the discrete fractional Fourier transform (DFRFT) in terms of its different nature of its fractional orders. The MPDFRFT can converge to DFRFT when all of its fractional order parameters having a similar value. The multiple parameter discrete fractional transforms shows it’s superiority over DFRFT because of that it benefitted us with an extra degree of freedom that is provided by its multiple fractional orders. The LSB technique is more preferable because of its lesser effect on the image characteristics. During the implementation of proposed scheme cover image is subdivided and MPDFRFT is applied to each subdivided image to transformed coefficients and watermark images are embedded by using LSB technique. Similarly during watermark extraction process the reverse order of MPDFRFT is applied for reconstruction of original images along with LSB extraction mechanism. The MPDFRFT fractional order parameters are used as secret key to improve the robustness of the system. The robustness of the watermark image is tested under different attacks such as additive noise, cropping, rotation and Gaussian low-pass filtering is analyzed and the results demonstrate that the embedding scheme has good performance of robustness. The imperceptibility of the proposed scheme against the hostile person is also verified by simulations results.