检索结果-内蒙古大学图书馆

Orthogonal symmetric prefilter banks for discrete multiwavelet transforms

IEEE signal processing LETTERS 2006年第3期13卷 145-148页

作者： Hsung, TC Lun, DPK Ho, KC Hong Kong Polytech Univ Dept Elect & Informat Engn Ctr Multimedia Signal Proc Hong Kong Hong Kong Peoples R China Univ Missouri Dept Elect & Comp Engn Columbia MO 65211 USA

Traditional design of critically sampled prefilters for discrete multiwavelet transform ignores the preservation of the linear phase property, which is important for many applications, such as image coding and digital communications. Balanced multiwavelets;solve this problem but make the filters longer. By using linear phase filter banks, we propose a simple algorithm for the design of orthogonal symmetric prefilter banks that can be used with the discrete multiwavelet transform. The prefilter bank resulted is orthogonal and critically sampled and can preserve the approximation power or the multiwavelet as well as the linear phase property. Experimental results show that the systems using the proposed symmetric prefilter banks give better performance as compared with using nonlinear phase prefilters.

关键词： approximation order linear-phase paraunitary filterbank multiwavelets orthogonality prefilter wavelets

来源：评论

学校读者我要写书评

暂无评论

Iterative satellite image segmentation by fuzzy hit-or-miss and homogeneity index

引用

IEE PROCEEDINGS-VISION image AND signal processing 2006年第2期153卷 206-214页

作者： Intajag, S. Paithoonwatanakij, K. Cracknell, A. P. King Mongkuts Inst Technol Fac Engn Dept Instrumentat Engn Bangkok 10520 Thailand King Mongkuts Inst Technol Fac Engn Dept Elect Bangkok 10520 Thailand Univ Dundee Dept Appl Phys & Elect & Mech Engn Dundee DD1 4HN Scotland

Object-based segmentation is the first essential step for image processing applications. Recently, satellite image segmentation techniques have been developed, but not enough to preserve the significant information contained in the small regions of an image. The proposed method is to partition the image into homogeneous regions by using a fuzzy hit-or-miss operator with an inherent spatial transformation, which enables the preservation of the small regions. In the algorithm proposed here, an iterative segmentation technique is formulated as consequential processes. Then, each time in iterating, hypothesis testing is used to evaluate the quality of the segmented regions with a homogeneity index. The segmentation algorithm is unsupervised and employs few parameters, most of which can be calculated from the input data. This comparative study indicates that the new iterative segmentation algorithm provides acceptable results as seen in the tested examples of synthetics and satellite images.

关键词： iterative methods Other topics in Earth sciences Interpolation and function approximation (numerical analysis) geophysical signal processing object-based segmentation fuzzy set theory image segmentation Combinatorial mathematics Optical, image and video signal processing image processing Geophysical techniques and equipment Geophysics computing Computer vision and image processing techniques iterative satellite image segmentation homogeneity index remote sensing fuzzy hit-or-miss

来源：评论

学校读者我要写书评

暂无评论

M-band filter banks and dual-tree wavelets for engine combustion and geophysical image analysis

<i>M</i>-band filter banks and dual-tree wavelets for engine...

引用

Conference on Wavelet applications in Industrial processing IV

作者： Duval, Laurent Chaux, Caroline Pesquet, Jean-Christophe IFP Energies Nouvelles Technol Comp Sci & Appl Math Div F-92500 Rueil Malmaison France Univ Marne la Vallee Inst Gaspard Monge F-77454 Champs Sur Marne Marne La Vallee France Univ Marne la Vallee CNRS UMR 8049 F-77454 Champs Sur Marne Marne La Vallee France

ISBN: (纸本)9780819464811

signals and images in industrial applications are often subject to strong disturbances and thus require robust methods for their analysis. Since these data are often non-stationary, time-scale or time-frequency tools have demonstrated effectiveness in their handling. More specifically, wavelet transforms and other filter bank generalizations are particularly suitable, due to their discrete implementation. We have recently investigated a specific family of filter banks, the M-band dual-tree wavelet, which provides state of the art performance for image restoration. It generalizes an Hilbert pair based decomposition structure, first proposed by N. Kingsbury and further investigated by I. Selesnick. In this work, we apply this frame decomposition to the analysis of two examples of signals and images in an industrial context: detection of structures and noises in geophysical images and the comparison of direct and indirect measurements resulting from engine combustion.

关键词： M-band wavelets Hilbert transform dual-tree image denoising direction analysis

来源：评论

学校读者我要写书评

暂无评论

Low-rate and flexible image coding with redundant representations

引用

IEEE TRANSACTIONS ON image processing 2006年第3期15卷 726-739页

作者： Ventura, RMFI Vandergheynst, P Frossard, P Ecole Polytech Fed Lausanne Signal Proc Inst Swiss Fed Inst Technol CH-1015 Lausanne Switzerland

New breakthroughs in image coding possibly lie in signal decomposition through nonseparable basis functions that can efficiently capture edge characteristics, present in natural images. The work proposed in this paper provides an adaptive way of representing images as a sum of two-dimensional features. It presents a low bit-rate image coding method based on a matching pursuit (NIP) expansion, over a dictionary built on anisotropic refinement and rotation of contour-like atoms. This method is shown to provide, at low bit rates, results comparable to the state of the art in image compression, represented here by JPEG2000 and SPIHT, with generally a better visual quality in the NIP scheme. The coding artifacts are less annoying than the ringing introduced by wavelets at very low bit rate, due to the smoothing performed by the basis functions used in the NIP algorithm. In addition to good compression performances at low bit rates, the new coder has the advantage of producing highly flexible streams. They can easily be decoded at any spatial resolution, different from the original image, and the bitstream can be truncated at any point to match diverse band-width requirements. The spatial adaptivity is shown to be more flexible and less complex than transcoding operations generally applied to state of the art codec bitstreams. Due to both its ability for capturing the most important parts of multidimensional signals, and a flexible stream structure, the image coder proposed in this paper represents an interesting solution for low to medium rate image coding in visual communication applications.

关键词： adaptive coding image compression multidimensional transform nonlinear representation redundant expansions

来源：评论

学校读者我要写书评

暂无评论

Modelling and predicting flow regimes using wavelet representations

Modelling and predicting flow regimes using wavelet represen...

引用

Conference on Wavelet applications in Industrial processing IV

作者： Goodwin, David A. Barber, Stuart Aykroyd, Robert G. Univ Leeds Leeds W Yorkshire England

ISBN: (纸本)9780819464811

The aim of industrial process control is to convert measurements, taken while the process is evolving, into parameters which can be used to control the process. To be of practical use this must all be computationally efficient allowing real-time feedback. Electrical tomography measurements have the potential to provide useful data without intruding into the industrial process, but produce highly correlated and noisy data, and hence need sensitive analysis. The commonly used approaches, based on regularized image reconstruction are slow, and still require image post-processing to extract control parameters. An alternative approach is to directly work with the measurement data. We demonstrate an approach using wavelets to relate such electrical measurements to the state of flow within a pipe, and hence classify the state of the flow to one of a number of regimes. wavelets are an ideal tool for our purpose since their multi-scale nature enables the efficient description of both transient and long-term signals. The resulting wavelet models can be used to classify flow into one of a set of regimes, either for later study of the flow profile or for monitoring of an ongoing process. We illustrate our methods by application to simulated data sets.

关键词： wavelets logistic regression classification process monitoring

来源：评论

学校读者我要写书评

暂无评论

Closed-form pose estimation from metric rectification of coplanar points

引用

IEE PROCEEDINGS-VISION image AND signal processing 2006年第3期153卷 364-378页

作者： Lucchese, L. Oregon State Univ Sch Elect Engn & Comp Sci Corvallis OR 97331 USA

A new analytic method for estimating the pose of a calibrated camera from a single view of a planar target with a known geometry is presented. A set of fiducial points is extracted from an image of this target and metrically rectified through a 2D homography. The author's contribution consists in deriving from the coefficients of this transformation the analytic expressions of the 3D rigid motion parameters defining the pose of the camera. Experiments with synthetic data show the effectiveness of the proposed method against another gold-standard method for pose estimation and its robustness against perturbations of the fiducial points. These features make the algorithm a perfect candidate for all those applications where pose estimation has to be performed reliably and in real time.

关键词： coplanar points metric rectification feature extraction calibrated camera closed-form pose estimation 2D homography Optical, image and video signal processing geometry cameras fiducial points computational geometry Computer vision and image processing techniques Computational geometry matrix algebra Algebra

来源：评论

学校读者我要写书评

暂无评论

Application of wavelet analysis in active thermography for non-destructive testing of CFRP composites

Application of wavelet analysis in active thermography for n...

引用

Conference on Wavelet applications in Industrial processing IV

作者： Zauner, G. Mayr, G. Hendorfer, G. Univ Appl Sci Upper Austria Campus WelsStelzhamerstr 23 A-4600 Wels Austria

ISBN: (纸本)9780819464811

Active infrared thermography is a non-destructive testing (NDT) technique used for non-contact inspection of components and materials by temporal mapping of thermal patterns by means of infrared imaging. Through the application of a short heat pulse, thermal waves of various amplitudes and frequencies are launched into the specimen allowing a signal analysis based on amplitude and phase information (pulsed phase thermography PPT). The wavelet transform (with complex wavelets) can be used with PPT data in a similar way as the classical Fourier transform however with the advantage of preserving time information of the signal which can then be correlated to defect depth, and in this way allowing a quantitative evaluation. In this paper we review the methodology of PPT and the associated signal analysis (Fourier analysis, wavelet analysis) to obtain quantitative defect depth information. We compare and discuss the results of thermal FEM simulations with experimental data and show the advantages of wavelet based signal analysis for defect depth measurements and material characterization.

关键词： active thermography pulsed phase thermography non-destructive testing NDT carbon fiber reinforced plastic CFRP signal analysis complex wavelets

来源：评论

学校读者我要写书评

暂无评论

wavelets with composite dilations and their MRA properties

引用

APPLIED AND COMPUTATIONAL HARMONIC ANALYSIS 2006年第2期20卷 202-236页

作者： Guo, KH Labate, D Lim, WQ Weiss, G Wilson, E N Carolina State Univ Dept Math Raleigh NC 27695 USA SW Missouri State Univ Dept Math Springfield MO 65804 USA Washington Univ Dept Math St Louis MO 63130 USA

Affine systems are reproducing systems of the form A(C)={DcTk psi(l):1 <= l <= L, k is an element of Z(n), c is an element of C} which arise by applying lattice translation operators T-k to one or more generators psi(l) in L-2(R-n), followed by the application of dilation operators D-c associated with a countable set C of invertible matrices. In the wavelet literature, C is usually taken to be the group consisting of all integer powers of a fixed expanding matrix. In this paper, we develop the properties of much more general systems, for which C = {c = ab: a is an element of A. b is an element of B} where A and B are not necessarily commuting matrix sets. C need not contain a single expanding matrix. Nonetheless, for many choices of A and B, there are wavelet systems with multiresolution properties very similar to those of classical dyadic wavelets. Typically, A expands or contracts only in certain directions, while B acts by volume-preserving maps in transverse directions. Then the resulting wavelets exhibit the geometric properties, e.g., directionality, elongated shapes, scales, oscillations, recently advocated by many authors for multidimensional signal and image processing applications. Our method is a systematic approach to the theory of affine-like systems yielding these and more general features. (c) 2005 Elsevier Inc. All rights reserved.

关键词： affine systems frames multiwavelets wavelets

来源：评论

学校读者我要写书评

暂无评论

Weighted median filters for multichannel signals

引用

IEEE TRANSACTIONS ON signal processing 2006年第11期54卷 4271-4281页

作者： Li, Yinbo Arce, Gonzalo R. Bacca, Jan Univ Delaware Dept Elect & Comp Engn Newark DE 19716 USA

Weighted medians over multichannel signals are not uniquely defined. Due to its simplicity, Astola et al.'s Vector Median (VM) has received considerable attention particularly in image processing applications. In this paper, we show that the VM and its direct extension the Weighted VM are limited as they do not fully utilize the cross-channel correlation. In fact, VM treats all sub-channel components independent of each other. By revisiting the principles of Maximum Likelihood estimation of location in a multivariate signal space, we propose two new and conceptually simple multichannel weighted median filters which can capture cross-channel information effectively. Their optimal filter derivations are also presented, followed by a series of simulations from color image denoising to array signal processing where the advantages of the new filtering structures are illustrated.

关键词： multichannel signal processing nonlinear filtering vector medians weighted medians

来源：评论

学校读者我要写书评

暂无评论

Car tracking by quantised input LMS, Qx-LMS algorithm in traffic scenes

引用

IEE PROCEEDINGS-VISION image AND signal processing 2006年第1期153卷 37-45页

作者： Yazdi, HS Lotfizad, M Fathy, M Tarbiat Moallem Univ Sabzevar Fac Engn Sabzevar Iran Tarbiat Modares Univ Dept Elect Engn Tehran Iran Iran Univ Sci & Technol Fac Comp Engn Tehran Iran

The tracking algorithm is an important tool for motion analysis in computer vision. A new car tracking algorithm is proposed which is based on a new clipping technique in the field of adaptive filter algorithms. The uncertainty and occlusion of vehicles increase the noise in vehicle tracking in a traffic scene, so the new clipping technique can control noise in prediction of vehicle positions. The authors present a new quantised version of the LMS, namely the Qx-LMS algorithm, which has a better tracking capability in comparison with the clipped LMS (CLMS) and the LMS and also involves less computation. The threshold parameter of the Qx-LMS algorithm causes controllability and the increase of tracking and convergence properties, whereas the CLMS and LMS algorithms do not have these capabilities. The Qx-LMS algorithm is used for estimation of a noisy chirp signal, for system identification and in car tracking applications. Simulation results for noisy chirp signal detection show that this algorithm yields a considerable error reduction in comparison to the LMS and CLMS algorithms. The proposed algorithm, in tracking some 77 vehicles in different traffic scenes, shows a reduction of the tracking error relative to the LMS and CLMS algorithms.

关键词： adaptive filters least mean squares methods quantised input LMS system identification computer vision image denoising image motion analysis traffic scenes Computer vision and image processing techniques motion analysis Filtering methods in signal processing quantisation (signal) adaptive filter algorithms Interpolation and function approximation (numerical analysis) car tracking algorithm Optical, image and video signal processing noisy chirp signal estimation clipping technique noisy chirp signal detection road traffic vehicle tracking automobiles

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：