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Showing papers on "Multiresolution analysis published in 2014"


Book
12 Mar 2014
TL;DR: In this article, a 2D Transform based on Lifting is presented, where the Haar Transform is used for denoising and the Discrete Wavelet Transform via Lifting.
Abstract: 1. Introduction.- 1.1 Prerequisites.- 1.2 Guide to the Book.- 1.3 Background Information.- 2. A First Example.- 2.1 The Example.- 2.2 Generalizations.- Exercises.- 3. The Discrete Wavelet Transform via Lifting.- 3.1 The First Example Again.- 3.2 Definition of Lifting.- 3.3 A Second Example.- 3.4 Lifting in General.- 3.5 DWT in General.- 3.6 Further Examples.- Exercises.- 4. Analysis of Synthetic Signals.- 4.1 The Haar Transform.- 4.2 The CDF(2,2) Transform.- Exercises.- 5. Interpretation.- 5.1 The First Example.- 5.2 Further Results on the Haar Transform.- 5.3 Interpretation of General DWT.- Exercises.- 6. Two Dimensional Transforms.- 6.1 One Scale DWT in Two Dimensions.- 6.2 Interpretation and Examples.- 6.3 A 2D Transform Based on Lifting.- Exercises.- 7. Lifting and Filters I.- 7.1 Fourier Series and the z-Transform.- 7.2 Lifting in the z-Transform Representation.- 7.3 Two Channel Filter Banks.- 7.4 Orthonormal and Biorthogonal Bases.- 7.5 Two Channel Filter Banks in the Time Domain.- 7.6 Summary of Results on Lifting and Filters.- 7.7 Properties of Orthogonal Filters.- 7.8 Some Examples.- Exercises.- 8. Wavelet Packets.- 8.1 From Wavelets to Wavelet Packets.- 8.2 Choice of Basis.- 8.3 Cost Functions.- Exercises.- 9. The Time-Frequency Plane.- 9.1 Sampling and Frequency Contents.- 9.2 Definition of the Time-Frequency Plane.- 9.3 Wavelet Packets and Frequency Contents.- 9.4 More about Time-Frequency Planes.- 9.5 More Fourier Analysis. The Spectrogram.- Exercises.- 10. Finite Signals.- 10.1 The Extent of the Boundary Problem.- 10.2 DWT in Matrix Form.- 10.3 Gram-Schmidt Boundary Filters.- 10.4 Periodization.- 10.5 Moment Preserving Boundary Filters.- Exercises.- 11. Implementation.- 11.1 Introduction to Software.- 11.2 Implementing the Haar Transform Through Lifting.- 11.3 Implementing the DWT Through Lifting.- 11.4 The Real Time Method.- 11.5 Filter Bank Implementation.- 11.6 Construction of Boundary Filters.- 11.7 Wavelet Packet Decomposition.- 11.8 Wavelet Packet Bases.- 11.9 Cost Functions.- Exercises.- 12. Lifting and Filters II.- 12.1 The Three Basic Representations.- 12.2 From Matrix to Equation Form.- 12.3 From Equation to Filter Form.- 12.4 From Filters to Lifting Steps.- 12.5 Factoring Daubechies 4 into Lifting Steps.- 12.6 Factorizing Coiflet 12 into Lifting Steps.- Exercises.- 13. Wavelets in Matlab.- 13.1 Multiresolution Analysis.- 13.2 Frequency Properties of the Wavelet Transform.- 13.3 Wavelet Packets Used for Denoising.- 13.4 Best Basis Algorithm.- 13.5 Some Commands in Uvi_Wave.- Exercises.- 14. Applications and Outlook.- 14.1 Applications.- 14.2 Outlook.- 14.3 Some Web Sites.- References.

341 citations


Journal ArticleDOI
TL;DR: A fault detection and classification method for medium voltage DC (MVDC) shipboard power systems (SPSs) by integrating wavelet transform (WT) multiresolution analysis (MRA) technique with artificial neural networks (ANNs) is proposed.
Abstract: This paper proposes a fault detection and classification method for medium voltage DC (MVDC) shipboard power systems (SPSs) by integrating wavelet transform (WT) multiresolution analysis (MRA) technique with artificial neural networks (ANNs). The MVDC system under consideration for future all-electric ships presents a range of new challenges, in particular the fault detection and classification issues addressed in this paper. The WT-MRA and Parseval's theorem are employed in this paper to extract the features of different faults. The energy variation of the fault signals at different resolution levels are chosen as the feature vectors. As a result of analysis and comparisons, the Daubechies 10 (db10) wavelet and scale 9 are the chosen wavelet function and decomposition level. Then, ANN is adopted to automatically classify the fault types according to the extracted features. Different fault types, such as short circuit faults on both dc bus and ac side, as well as ground fault, are analyzed and tested to verify the effectiveness of the proposed method. These faults are simulated in real time with a digital simulator and the data are then initially analyzed with MATLAB. The case study is a notional MVDC SPS model, and promising classification accuracy can be obtained according to simulation results. Finally, the proposed fault detection algorithm is implemented and tested on a real-time platform, which enables it for future practical use.

225 citations


Journal ArticleDOI
TL;DR: A new edge/texture-preserving image denoising using twin support vector machines (TSVMs) is proposed in this paper, which can preserve edges and textures very well while removing noise.

80 citations


Journal ArticleDOI
TL;DR: It is shown that the hyperspectral image can be restored using a few sparse components and that WSRRR not only effectively removes noise but also maintains more fine features compared to other methods used.
Abstract: In this paper, a method called wavelet-based sparse reduced-rank regression (WSRRR) is proposed for hyperspectral image restoration. The method is based on minimizing a sparse regularization problem subject to an orthogonality constraint. A cyclic descent-type algorithm is derived for solving the minimization problem. For selecting the tuning parameters, we propose a method based on Stein's unbiased risk estimation. It is shown that the hyperspectral image can be restored using a few sparse components. The method is evaluated using signal-to-noise ratio and spectral angle distance for a simulated noisy data set and by classification accuracies for a real data set. Two different classifiers, namely, support vector machines and random forest, are used in this paper. The method is compared to other restoration methods, and it is shown that WSRRR outperforms them for the simulated noisy data set. It is also shown in the experiments on a real data set that WSRRR not only effectively removes noise but also maintains more fine features compared to other methods used. WSRRR also gives higher classification accuracies.

78 citations


Journal ArticleDOI
TL;DR: In this paper, an efficient numerical method based on unorm Haar wavelet for the numerical solutions of two parameter singularly perturbed boundary value problems was proposed, where an extensive amount of error analysis has been carried out to obtain the convergence of the method.
Abstract: In this paper, we proposed an efficient numerical method based on un iform Haar wavelet for the numerical solutions of two parameter singularly perturbed boundary value problems. Such type of problems arise in various field of science and engineering, such as heat transfer problem with large Peclet numbers, Navier-Stokes flows with large Reynolds numbers, transport phenomena in chemistry and biology, chemical reactor theory, aerodynamics, reaction-diffusion process, quantum mechanics, optimal control theory etc. In present study more accurate solutions have been obtained by wavelet decomposition with multiresolution analysis. An extensive amount of error analysis has been carried out to obtain the convergence of the method. Four test problems are considered to check the efficiency and accuracy of the proposed method. The numerical res ults are found in good agreement with exact and existing solutions in literature.

39 citations


Journal ArticleDOI
TL;DR: A wavelet transform is used to represent remote sensing big data that are large scale in the space domain, correlated in the spectral domain, and continuous in the time domain and it is found that the scale features of different textures for the big data set are obviously reflected in the probability density function and GMM parameters of the wavelet coefficients.
Abstract: Since it is difficult to deal with big data using traditional models and algorithms, predicting and estimating the characteristics of big data is very important. Remote sensing big data consist of many large-scale images that are extremely complex in terms of their structural, spectral, and textual features. Based on multiresolution analysis theory, most of the natural images are sparse and have obvious clustering and persistence characters when they are transformed into another domain by a group of basic special functions. In this paper, we use a wavelet transform to represent remote sensing big data that are large scale in the space domain, correlated in the spectral domain, and continuous in the time domain. We decompose the big data set into approximate multiscale detail coefficients based on a wavelet transform. In order to determine whether the density function of wavelet coefficients in a big data set are peaky at zero and have a heavy tailed shape, a two-component Gaussian mixture model (GMM) is employed. For the first time, we use the expectation-maximization likelihood method to estimate the model parameters for the remote sensing big data set in the wavelet domain. The variance of the GMM with changing of bands, time, and scale are comprehensively analyzed. The statistical characteristics of different textures are also compared. We find that the cluster characteristics of the wavelet coefficients are still obvious in the remote sensing big data set for different bands and different scales. However, it is not always precise when we model the long-term sequence data set using the GMM. We also found that the scale features of different textures for the big data set are obviously reflected in the probability density function and GMM parameters of the wavelet coefficients.

28 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented a numerical scheme using uniform Haar wavelet approximation and quasilinearization process for solving some nonlinear oscillator equations, which is applied on three types of oscillators namely, Duffing, Van der Pol, and Duffing-van der Pol.

25 citations


Journal ArticleDOI
TL;DR: It turns out that the greedy algorithm RFMP yields sparse approximations by combining different types of trial functions in a (particular) optimal way, where the sparsity can essentially be increased by a-priori choosing the dictionary appropriately.
Abstract: We show the applicability of a modified version of the recently developed Regularized Functional Matching Pursuit (RFMP) to the approximation of functions on the sphere from grid-based data. We elaborate the mathematical details of the choice of trial functions and the specifics of the algorithm. Moreover, we show numerical examples for some benchmarks. The dictionary of trial functions contains orthogonal polynomials (spherical harmonics) as well as spherical scaling functions and wavelets. It turns out that the greedy algorithm RFMP yields sparse approximations by combining different types of trial functions in a (particular) optimal way, where the sparsity can essentially be increased by a-priori choosing the dictionary appropriately. Moreover, the result of the RFMP can be used for a multiresolution analysis of the investigated function.

24 citations


Book ChapterDOI
01 Jan 2014
TL;DR: In this paper, it was shown that for many practical purposes of signal processing, a tight frame is almost as good as an orthonormal basis for data compression, which is performed by removing all wavelet expansion coefficients below a fixed threshhold.
Abstract: As we have seen in Section 12.5, the discretization of the CWT leads, among other things, to the theory of frames. For many practical purposes of signal processing, a tight frame is almost as good as an orthonormal basis. Actually, if one stays with the standard wavelets, as we have done so far, one cannot do better, since these wavelets do not generate any orthonormal basis (like the usual coherent states). There are cases, however, in which an orthonormal basis is really required. A typical example is data compression, which is performed (in the simplest case) by removing all wavelet expansion coefficients below a fixed threshhold. In order to not introduce any bias in this operation, the coefficients have to be as decorrelated as possible, and, of course, an orthonormal basis is ideal in this respect.

24 citations


Proceedings ArticleDOI
03 Apr 2014
TL;DR: Experimental results show that the proposed pixel-level image fusion scheme using multiresolution steerable pyramid wavelet transform improves fusion quality by reducing loss of relevant information present in individual images.
Abstract: The objective of image fusion is to combine relevant information from two or more images of the same scene into a single composite image which is suitable for human and machine perception. Spatial domain based methods produce spatial distortions in the fused image which can be well handled by the use of wavelet transform based methods. In this paper, we proposed a pixel-level image fusion scheme using multiresolution steerable pyramid wavelet transform. Wavelet coefficients at different decomposition levels are fused using absolute maximum fusion rule. Two important properties shift invariance and self-reversibility of steerable pyramid wavelet transform are advantageous for image fusion because they are capable to preserve edge information and hence reducing the distortion in the fused image. Experimental results show that the proposed method improves fusion quality by reducing loss of relevant information present in individual images. For quantitative evaluation, we have used fusion metrics as fusion factor, fusion symmetry, entropy and standard deviation.

21 citations


Journal ArticleDOI
TL;DR: A novel selection algorithm of wavelet- based transformer differential current features is proposed, where the minimum description length with entropy criteria are employed for an initial selection of the mother wavelet and the resolution level, whereas stepwise regression is applied for obtaining the most statistically significant features.
Abstract: In this paper, a novel selection algorithm of wavelet- based transformer differential current features is proposed. The minimum description length with entropy criteria are employed for an initial selection of the mother wavelet and the resolution level, respectively; whereas stepwise regression is applied for obtaining the most statistically significant features. Dimensionality reduction is accordingly achieved, with an acceptable accuracy maintained for classification. The validity of the proposed algorithm is tested through a neuro-wavelet- based classifier of transformer inrush and internal fault differential currents. The proposed algorithm highlights the potential of utilizing synergism of integrating multiple feature selection techniques as opposed to an individual technique, which ensures optimal selection of the features.

Journal ArticleDOI
19 May 2014-Entropy
TL;DR: In this study, features of financial returns of PSI20 index, related to market efficiency, are captured using wavelet and entropy based techniques that enhance the capacity to identify the occurrence of financial crashes.
Abstract: In this study, features of the financial returns of the PSI20index, related to market efficiency, are captured using wavelet- and entropy-based techniques. This characterization includes the following points. First, the detection of long memory, associated with low frequencies, and a global measure of the time series: the Hurst exponent estimated by several methods, including wavelets. Second, the degree of roughness, or regularity variation, associated with the H¨older exponent, fractal dimension and estimation based on the multifractal spectrum. Finally, the degree of the unpredictability of the series, estimated by approximate entropy. These aspects may also be studied through the concepts of non-extensive entropy and distribution using, for instance, the Tsallis q-triplet. They allow one to study the existence of efficiency in the financial market. On the other hand, the study of local roughness is performed by considering wavelet leader-based entropy. In fact, the wavelet coefficients are computed from a multiresolution analysis, and the wavelet leaders are defined by the local suprema of these coefficients, near the point that we are considering. The resulting entropy is more accurate in that detection than the H¨older exponent. These procedures enhance the capacity to identify the occurrence of financial crashes.

Journal ArticleDOI
TL;DR: This paper has considered one dimensional and two dimensional Burger’s equation with Dirichlet and periodic boundary conditions and observed that the proposed method takes lesser CPU time.
Abstract: A fast adaptive diffusion wavelet method is developed for solving the Burger’s equation. The diffusion wavelet is developed in 2006 (Coifman and Maggioni, 2006) and its most important feature is that it can be constructed on any kind of manifold. Classes of operators which can be used for construction of the diffusion wavelet include second order finite difference differentiation matrices. The efficiency of the method is that the same operator is used for the construction of the diffusion wavelet as well as for the discretization of the differential operator involved in the Burger’s equation. The diffusion wavelet is used for the construction of an adaptive grid as well as for the fast computation of the dyadic powers of the finite difference matrices involved in the numerical solution of Burger’s equation. In this paper, we have considered one dimensional and two dimensional Burger’s equation with Dirichlet and periodic boundary conditions. For each test problem the CPU time taken by fast adaptive diffusion wavelet method is compared with the CPU time taken by finite difference method and observed that the proposed method takes lesser CPU time. We have also verified the convergence of the given method.

Proceedings ArticleDOI
08 Jan 2014
TL;DR: Modular neural network is employed in this paper for automatic classification of power quality disturbances, employing wavelet transformation for disturbance identification and Modular artificial Neural Network technique for accurate classification of these disturbances.
Abstract: This paper presents an effective method for classification of power quality disturbances, employing wavelet transformation for disturbance identification and Modular artificial Neural Network(MANN) technique for accurate classification of these disturbances. Disturbances such as voltage sag, swell and harmonics which are typical in power system are simulated. Wavelet transform, which has the ability to analyze these power quality problems simultaneously in both time and frequency domain is used to extract features of the disturbances by decomposing the signal using multi resolution analysis. These features are used to detect and localize the disturbances. ANN, the powerful tool with parallel processing capability, is suitable to classify the disturbances. Modular neural network is employed in this paper for automatic classification of power quality disturbances. The proposed algorithm has been verified by simulating various PQ disturbances and results are analyzed using Math works MATLAB.

Journal ArticleDOI
TL;DR: In this article, a multiscale slope feature extraction technique for fault diagnosis of gear and bearing has been used, which is a wavelet based technique which provides a multiresolution analysis for fault detection.

Journal ArticleDOI
TL;DR: The proposed transform inherits the excellent properties of MR-SVD along with its own unique features, which can be useful in many research areas, and is proposed to introduce randomness in the computing process based on parameters without which one can neither decompose nor reconstruct the data correctly.

Journal ArticleDOI
TL;DR: In this paper, an adaptive fuzzy wavelet network-based fault detection and diagnosis (AFWN-FDD) scheme is proposed for non-linear systems subject to unstructured uncertainty.
Abstract: Fault is an undesired and unexpected event that changes the system behaviour resulting in performance degradation or even instability, so how to detect and diagnose fault become a great deal in engineering community. In this study, an adaptive fuzzy wavelet network-based fault detection and diagnosis (AFWN-FDD) scheme is proposed for non-linear systems subject to unstructured uncertainty. The proposed scheme is composed of a diagnostic estimator and an adaptive fuzzy wavelet network (AFWN). Diagnostic estimator is designed for residual generation and fault detection and AFWN based on multi-resolution analysis of wavelet transform and fuzzy concept is proposed to approximate the model of fault. Learning algorithm of the proposed AFWN-FDD scheme is derived in the Lyapunov stability sense. The proposed scheme can simultaneously detect and estimate multiple incipient and abrupt faults in the presence of uncertainty. Stability analysis for the presented fault detection and diagnosis (FDD) scheme is provided. Furthermore, an extension of the proposed scheme for a class of non-linear systems with unmeasured states is presented. The efficiency and performance of the proposed scheme is evaluated through simulations that are performed for two well-known case studies. Comparison results highlight the superiority and capability of the proposed scheme.

Journal ArticleDOI
TL;DR: A family of Parseval periodic wavelet frames was constructed in this paper, which has optimal time-frequency localization with respect to a family parameter and has the best currently known localization in terms of multiresolution analysis parameter.

Journal ArticleDOI
25 Jul 2014
TL;DR: In this article, the theory of p-adic wavelets and their relation to the spectral theory of pseudodifferential operators are discussed. But, unlike real wavelets, wavelets are related to the group representation theory; they are the orbits of padic transformation groups (systems of coherent states).
Abstract: The theory of p-adic wavelets is presented. One-dimensional and multidimensional wavelet bases and their relation to the spectral theory of pseudodifferential operators are discussed. For the first time, bases of compactly supported eigenvectors for p-adic pseudodifferential operators were considered by V.S. Vladimirov. In contrast to real wavelets, p-adic wavelets are related to the group representation theory; namely, the frames of p-adic wavelets are the orbits of p-adic transformation groups (systems of coherent states). A p-adic multiresolution analysis is considered and is shown to be a particular case of the construction of a p-adic wavelet frame as an orbit of the action of the affine group.

Journal ArticleDOI
TL;DR: This paper presents a simple, yet efficient, multiresolution approach to distinguish CG from PG based on uniform gray-scale invariant local binary patterns LBPs with the help of support vector machines SVM.
Abstract: With the ongoing development of rendering technology, computer graphics CG are sometimes so photorealistic that to distinguish them from photographic PG images by human eyes has become difficult. To this end, many methods have been developed for automatic CG and PG classification. In this paper, we present a simple, yet efficient, multiresolution approach to distinguish CG from PG based on uniform gray-scale invariant local binary patterns LBPs with the help of support vector machines SVM. We select YCbCr as the color model. The original Joint Photographic Experts Group JPEG coefficients of Y, Cb, and Cr components and their prediction errors are used for two LBP operators. From each 2D array and each LBP operator, we obtain 59 uniform LBP features. In total, 12 groups of 59 features are obtained from each image. But after multiresolution analysis, we select six groups of 59 features for CG and PG classification. The proposed features have been tested with thousands of CG and PG. Classification accuracy reaches 95.1% with support vector machines and outperforms the state-of-the-art works. Copyright © 2013 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: The shortest distance technique and a database approach have been proposed to determine the faulty section of a high-impedance fault in a national grid in Malaysia using the PSCAD software.
Abstract: Locating the faulty section of a high-impedance fault (HIF) is quite challenging for the underground distribution network of a power system. The complexity of the distribution network, such as branches, nonhomogenous lines, and HIF, contributes to the difficulties in locating the faulty section. In this paper, the shortest distance (SD) technique and a database approach have been proposed to determine the faulty section. A multiresolution analysis based on discrete wavelet transforms is chosen to extract the unique features from voltage signals during the HIF event. The output coefficients from the decomposition process is stored in a database and used as the input data for the SD algorithm. The first, second, and third level of detailed coefficients of the postdisturbance voltage signal were utilized for the identification of the faulty section using the proposed method. A ranking analysis was created to provide a number of possibilities of faulty section. In this paper, a 38-node underground distribution network system in a national grid in Malaysia was modeled using the PSCAD software. The proposed method was able to successfully determine the faulty section. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Proceedings ArticleDOI
01 Dec 2014
TL;DR: Result suggests that the identification of leather defects can be automated with the application of image processing technique using SVM Classifier with wavelet feature extraction technique.
Abstract: This paper describes the application of image processing techniques for identification of leather defects using wavelet feature extraction method. Defects occur in leather and are identified at different stages of processing such as pre tanning, post tanning, crust, finishing etc., Manual defect inspection and analysis varies from person to person and is labor intensive, tedious, misjudgment occurs due to fatigue etc., As a consequence, the identification of leather defects becomes ambiguous that affects the quality control clearance of global trading and thus reducing the productivity. The objective of this research work is to identify leather defects from leather image library using wavelet based feature extraction technique. Captured leather images were processed in frequency domain with the help of using wavelet transform and were stored in the leather image library. Frequency component of an image can be analyzed better than its pixel intensities of an image because edges and uncorrelated pixels were well projected in frequencies. In wavelet transform, the frequency components of image was organized such that the lower and higher frequencies were separated, it also gives the image variations at different scales because of its Multiresolution analysis and hence makes wavelet more suitable for leather defect identification. The leather defects were identified by its texture using wavelet statistical features and wavelet co-occurrences matrix features such as Entropy, Energy, Contrast, Correlation, Cluster Prominence Standard Deviation, Mean, and local homogeneity. The classification of leather defects was done by employing Support Vector Machine (SVM) Algorithm with wavelet based feature extraction technique. Comparative analysis of different kernels used in SVM classifier was also discussed. Result suggests that the identification of leather defects can be automated with the application of image processing technique using SVM Classifier with wavelet feature extraction technique.

Proceedings ArticleDOI
10 Nov 2014
TL;DR: A technique based on Hybrid Wavelets to extract texture features of Dynamic Handwritten (On-line) signature using the hybrid wavelets to generate the wavelet energy distribution of the pressure pattern of dynamic signatures, velocity magnitude, Azimuth & Altitude vectors.
Abstract: On-line handwritten Signature is one of the important behavioural biometric trait. On-line signature have more information such as x, y, z variations, pressure levels, Azimuth and Altitude of pen tip, due to this better accuracy can be achieved when signatures are captured in real time with digitizer device. In this paper a technique based on Hybrid Wavelets to extract texture features of Dynamic Handwritten (On-line) signature is proposed. Hybrid wavelets are flexible and combine the advantage of transforms and Multiresolution analysis. Proposed system uses the hybrid wavelets to generate the wavelet energy distribution of the pressure pattern of dynamic signatures, velocity magnitude, Azimuth & Altitude vectors. Hybrid Wavelet of Type I and Type II are used and their performance is compared. Hybrid Wavelets are found to give highest Performance Index of 83.96% for Azimuth and Altitude based feature vector.

Proceedings ArticleDOI
01 Dec 2014
TL;DR: In this paper, a wavelet-based technique was proposed to detect and classify various faults on transmission line, which was able to discriminate non-fault transients such as capacitance, inductance and load switching from fault transients.
Abstract: This paper presents a Wavelet based alienation technique to detect and classify various faults on transmission line. The proposed scheme analyses the absolute values of three phase current signals over a half cycle to obtain detail coefficients. These detail coefficients of half a cycle are compared with those of previous half cycleto compute alienation coefficients which are further utilized to detect and classify the faults. The proposed technique was able to discriminate non-fault transients such as capacitance, inductance and load switching, from fault transients. The increase in the sensitivity of protection scheme, due to utilization of wavelet based detail decomposition, has been established by case studies. The proposed algorithm is tested for different locations and various types of faults. The algorithm is proved to be successful in detecting and classifying various types of faults in a half cycle.

Posted Content
TL;DR: The ability of HIPA cc to generate code for the implementation of multiresolution applications on FPGAs and embedded GPUs is demonstrated.
Abstract: Multiresolution Analysis (MRA) is a mathematical method that is based on working on a problem at different scales. One of its applications is medical imaging where pro- cessing at multiple scales—based on the concept of Gaussian and Laplacian image pyramids—is a well-known technique. It is often applied to reduce noise while preserving image detail on different levels of granularity without modifying the filter kernel. In scientific computing, multigrid methods are a popular choice, as they are asymptotically optimal solvers for elliptic Partial Differential Equations (PDEs). As such algorithms have a very high computational complexity that would overwhelm CPUs in the presence of real-time constraints, application-specific processors come into consideration for implementation. Despite of huge advancements in leveraging productivity in the respective fields, designers are still required to have detailed knowledge about coding techniques and the targeted architecture to achieve efficient solutions. Recently, the HIPA cc framework was proposed as a means for automatic code generation of image processing algorithms, based on a Domain-Specific Language (DSL). From the same code base, it is possible to generate code for efficient implementations on several accelerator technologies including different types of Graphics Processing Units (GPUs) as well as reconfigurable logic (FPGAs). In this work, we demonstrate the ability of HIPA cc to generate code for the implementation of multiresolution applications on FPGAs and embedded GPUs. I. INTRODUCTION

Journal ArticleDOI
TL;DR: The proposed image denoising using fuzzy support vector machine (FSVM) can preserve edges very well while removing noise and can obtain better performances in terms of both subjective and objective evaluations than those state-of-the-art Denoising techniques.
Abstract: Denoising of images is one of the most basic tasks of image processing. It is a challenging work to design a edge-preserving image denoising scheme. Extended discrete Shearlet transform (extended DST) is an effective multi-scale and multi-direction analysis method, it not only can exactly compute the shearlet coefficients based on a multiresolution analysis, but also can provide nearly optimal approximation for a piecewise smooth function. Based on extended DST, an image denoising using fuzzy support vector machine (FSVM) is proposed. Firstly, the noisy image is decomposed into different subbands of frequency and orientation responses using the extended DST. Secondly, the feature vector for a pixel in a noisy image is formed by the spatial regularity in extended DST domain, and the FSVM model is obtained by training. Then the extended DST detail coefficients are divided into two classes (edge-related coefficients and noise-related ones) by FSVM training model. Finally, the detail subbands of extended DST coefficients are denoised by using the adaptive Bayesian threshold. Extensive experimental results demonstrate that our method can obtain better performances in terms of both subjective and objective evaluations than those state-of-the-art denoising techniques. Especially, the proposed method can preserve edges very well while removing noise.

Journal ArticleDOI
TL;DR: In this article, a vector-valued non-uniform multiresolution analysis (VNUMRA) is introduced, where the associated subspace of has, an orthonormal basis, a collection of translates of a vectorvalued function of the form where, is an integer and is an odd integer with such that and are relatively prime and is the set of all integers and the corresponding dilation factor is.
Abstract: We consider a generalization of the notion of non-uniform multiresolution analysis (NUMRA) which is called vector-valued non-uniform multiresolution analysis (VNUMRA). The concept of NUMRA was introduced by Gabardo and Nashed based on the theory of spectral pairs. Xia and Suter introduced vector-valued multiresolution analysis and orthogonal vector-valued wavelets. We introduce VNUMRA where the associated subspace of has, an orthonormal basis, a collection of translates of a vector-valued function of the form where , is an integer and is an odd integer with such that and are relatively prime and is the set of all integers and the corresponding dilation factor is . We obtain the necessary and sufficient condition for the existence of associated wavelets and present a construction of VNUMRA.

Proceedings ArticleDOI
10 May 2014
TL;DR: A comprehensive review of the techniques employed in fault analysis which have evolved over the last decade is presented in this article, which mainly focuses on the implementation of discrete wavelet transform (WT), multi-resolution analysis (MRA) artificial neural networks (ANN) and fuzzy logic for fault analysis.
Abstract: Transmission lines faults are an inevitable part of any power system. They cause a disruption in the power supply, which is undesirable. With an ever-increasing demand for better performance and minimal interruptions, accurate fault analysis is necessary to restore a system to its normal operation by detecting and clearing the transmission line fault. This paper presents a comprehensive review of the techniques employed in fault analysis which have evolved over the last decade. This review paper mainly focuses on the implementation of discrete wavelet transform (WT), multi-resolution analysis (MRA) artificial neural networks (ANN) and fuzzy logic for fault analysis.

Journal ArticleDOI
TL;DR: A new image denoising approach in extended Shearlet domain using hidden Markov tree (HMT) model is proposed that can preserve edges very well while removing noise and can obtain better performances in terms of both subjective and objective evaluations than other state-of-the-art HMTDenoising techniques.

Posted Content
TL;DR: This work proposes an empirical Bayes approach, which estimates a multiscale dictionary using geometric multiresolution analysis in a first stage, and uses this dictionary within aMultiscale mixture model, which allows uncertainty in component allocation, mixture weights and scaling factors over a binary tree.
Abstract: Although Bayesian density estimation using discrete mixtures has good performance in modest dimensions, there is a lack of statistical and computational scalability to high-dimensional multivariate cases. To combat the curse of dimensionality, it is necessary to assume the data are concentrated near a lower-dimensional subspace. However, Bayesian methods for learning this subspace along with the density of the data scale poorly computationally. To solve this problem, we propose an empirical Bayes approach, which estimates a multiscale dictionary using geometric multiresolution analysis in a first stage. We use this dictionary within a multiscale mixture model, which allows uncertainty in component allocation, mixture weights and scaling factors over a binary tree. A computational algorithm is proposed, which scales efficiently to massive dimensional problems. We provide some theoretical support for this geometric density estimation (GEODE) method, and illustrate the performance through simulated and real data examples.