Учет свойств нормального спектрального разложения матрицы контейнера при обеспечении надежности восприятия стегосообщения

В работе разработан новый подход к проблеме обеспечения надежности восприятия стегосообщения, основой которого является использование некоторых особенностей спектрального разложения матрицы, а реализация сводится к анализу возмущений собственных векторов и собственных значений матрицы контейнера при его стегопреобразовании. Приводятся результаты вычислительного эксперимента.In the article the new approach to a problem of maintenance in perception reliability of covert message is developed, which basis is use of some features of spectral matrix decomposition, and the realization is reduced to the indignation analysis of eigenvectors and eigenvalues of a matrix container at it stegotransformations. The results of computing experiment are presented

New Watermarking Scheme for Security and Transmission of Medical Images for PocketNeuro Project

We describe a new Watermarking system of medical information security and terminal mobile phone adaptation for PocketNeuro project. The later term refers to a Project created for the service of neurological diseases. It consists of transmitting information about patients \"Desk of Patients\" to a doctor\'s mobile phone when he is visiting or examining his patient. This system is capable of embedding medical information inside diagnostic images for security purposes. Our system applies JPEG Compression to Watermarked images to adapt them to the doctor\'s mobile phone. Experiments performed on a database of 30-256x256 pixel-sized neuronal images show that our Watermarking scheme for image security is robust against JPEG Compression. For the purpose of increasing the image Watermarking robustness against attacks for an image transmission and to perform a large data payload, we encode with Turbo-Code image-embedded bits information. Fidelity is improved by incorporation of the Relative Peak Signal-to-Noise Ratio (RPSNR) as a perceptual metric to measure image degradation

A Digital Watermarking Approach Based on DCT Domain Combining QR Code and Chaotic Theory

This paper proposes a robust watermarking approach based on Discrete Cosine Transform domain that combines Quick Response Code and chaotic system.Comment: 7 pages, 6 figure

Quality Assessment for CRT and LCD Color Reproduction Using a Blind Metric

This paper deals with image quality assessment that is capturing the focus of several research teams from academic and industrial parts. This field has an important role in various applications related to image from acquisition to projection. A large numbers of objective image quality metrics have been developed during the last decade. These metrics are more or less correlated to end-user feedback and can be separated in three categories: 1) Full Reference (FR) trying to evaluate the impairment in comparison to the reference image, 2) Reduced Reference (RR) using some features extracted from an image to represent it and compare it with the distorted one and 3) No Reference (NR) measures known as distortions such as blockiness, blurriness,. . .without the use of a reference. Unfortunately, the quality assessment community have not achieved a universal image quality model and only empiricalmodels established on psychophysical experimentation are generally used. In this paper, we focus only on the third category to evaluate the quality of CRT (Cathode Ray Tube) and LCD (Liquid Crystal Display) color reproduction where a blind metric is, based on modeling a part of the human visual system behavior. The objective results are validated by single-media and cross-media subjective tests. This allows to study the ability of simulating displays on a reference one

A Wavelet Visible Difference Predictor

In this paper, we describe a model of the human visual system (HVS) based on the wavelet transform. This model is largely based on a previously proposed model, but has a number of modifications that make it more amenable to potential integration into a wavelet based image compression scheme. These modifications include the use of a separable wavelet transform instead of the cortex transform, the application of a wavelet contrast sensitivity function (CSF), and a simplified definition of subband contrast that allows us to predict noise visibility directly from wavelet coefficients. Initially, we outline the luminance, frequency, and masking sensitivities of the HVS and discuss how these can be incorporated into the wavelet transform. We then outline a number of limitations of the wavelet transform as a model of the HVS, namely the lack of translational invariance and poor orientation sensitivity. In order to investigate the efficacy of this wavelet based model, a wavelet visible difference predictor (WVDP) is described. The WVDP is then used to predict visible differences between an original and compressed (or noisy) image. Results are presented to emphasize the limitations of commonly used measures of image quality and to demonstrate the performance of the WVDP. The paper concludes with suggestions on how the WVDP can be used to determine a visually optimal quantization strategy for wavelet coefficients and produce a quantitative measure of image quality

SYMLET AND GABOR WAVELET PREDICTION OF PRINT DEFECTS

Recent studies have been done to create models that predict the response of the human visual system (HVS) based on how the HVS processes an image. The most widely known of these models is the Gabor model, since the Gabor patterns closely resemble the receptive filters in the human eye. The work of this thesis examines the use of Symlets to represent the HVS, since Symlets provide the benefit of orthogonality. One major problem with Symlets is that the energy is not stable in respective Symlet channels when the image patterns are translated spatially. This thesis addresses this problem by up sampling Symlets instead of down sampling, and thus creating shift invariant Symlets. This thesis then compares the representation of Gabor versus Symlet approach in predicting the response of the HVS to detecting print defect patterns such as banding and graining. In summary we noticed that Symlet prediction outperforms the Gabor prediction thus Symlets would be a good choice for HVS response prediction. We also concluded that for banding defect periodicity and size are important factors that affect the response of the HVS to the patterns. For graining defects we noticed that size does not greatly affect the response of the HVS to the defect patterns. We introduced our results using two set of performance metrics, the mean and median

WAVELET AND SINE BASED ANALYSIS OF PRINT QUALITY EVALUATIONS

Recent advances in imaging technology have resulted in a proliferation of images across different media. Before it reaches the end user, these signals undergo several transformations, which may introduce defects/artifacts that affect the perceived image quality. In order to design and evaluate these imaging systems, perceived image quality must be measured. This work focuses on analysis of print image defects and characterization of printer artifacts such as banding and graininess by using a human visual system (HVS) based framework. Specifically the work addresses the prediction of visibility of print defects (banding and graininess) by representing the print defects in terms of the orthogonal wavelet and sinusoidal basis functions and combining the detection probabilities of each basis functions to predict the response of the human visual system (HVS). The detection probabilities for basis function components and the simulated print defects are obtained from separate subjective tests. The prediction performance from both the wavelet based and sine based approaches is compared with the subjective testing results .The wavelet based prediction performs better than the sinusoidal based approach and can be a useful technique in developing measures and methods for print quality evaluations based on HVS

Perceptual Image Quality Of Launch Vehicle Imaging Telescopes

A large fleet (in the hundreds) of high quality telescopes are used for tracking and imaging of launch vehicles during ascent from Cape Canaveral Air Force Station and Kennedy Space Center. A maintenance tool has been development for use with these telescopes. The tool requires rankings of telescope condition in terms of the ability to generate useful imagery. It is thus a case of ranking telescope conditions on the basis of the perceptual image quality of their imagery. Perceptual image quality metrics that are well-correlated to observer opinions of image quality have been available for several decades. However, these are quite limited in their applications, not being designed to compare various optical systems. The perceptual correlation of the metrics implies that a constant image quality curve (such as the boundary between two qualitative categories labeled as excellent and good) would have a constant value of the metric. This is not the case if the optical system parameters (such as object distance or aperture diameter) are varied. No published data on such direct variation is available and this dissertation presents an investigation made into the perceptual metric responses as system parameters are varied. This investigation leads to some non-intuitive conclusions. The perceptual metrics are reviewed as well as more common metrics and their inability to perform in the necessary manner for the research of interest. Perceptual test methods are also reviewed, as is the human visual system. iv Image formation theory is presented in a non-traditional form, yielding the surprising result that perceptual image quality is invariant under changes in focal length if the final displayed image remains constant. Experimental results are presented of changes in perceived image quality as aperture diameter is varied. Results are analyzed and shortcomings in the process and metrics are discussed. Using the test results, predictions are made about the form of the metric response to object distance variations, and subsequent testing was conducted to validate the predictions. The utility of the results, limitations of applicability, and the immediate ability to further generalize the results is presented

Performance and Microarchitectural Analysis for Image Quality Assessment

This thesis presents performance analysis for five matured Image Quality Assessment algorithms: VSNR, MAD, MSSIM, BLIINDS, and VIF, using the VTune ... from Intel. The main performance parameter considered is execution time. First, we conduct Hotspot Analysis to find the most time consuming sections for the five algorithms. Second, we perform Microarchitecural Analysis to analyze the behavior of the algorithms for Intel's Sandy Bridge microarchitecture to find architectural bottlenecks. Existing research for improving the performance of IQA algorithms is based on advanced signal processing techniques. Our research focuses on the interaction of IQA algorithms with the underlying hardware and architectural resources. We propose techniques to improve performance using coding techniques that exploit the hardware resources and consequently improve the execution time and computational performance. Along with software tuning methods, we also propose a generic custom IQA hardware engine based on the microarchitectural analysis and the behavior of these five IQA algorithms with the underlying microarchitectural resources.School of Electrical & Computer Engineerin