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Edge-preserving algorithm of joint image restoration and volume reconstruction for rotation-scanning 4D echocardiographic images

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Journal of Zhejiang University: Science 2006年第6期7卷 960-968页

作者： Guo, Qiang Yang, Xin Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai 200030 China

A statistical algorithm for the reconstruction from time sequence echocardiographic images is proposed in this paper. The ability to jointly restore the images and reconstruct the 3D images without blurring the boundary is the main innovation of this algorithm. First, a Bayesian model based on MAP-MRF is used to reconstruct 3D volume, and extended to deal with the images acquired by rotation scanning method. Then, the spatiotemporal nature of ultrasound images is taken into account for the parameter of energy function, which makes this statistical model anisotropic. Hence not only can this method reconstruct 3D ultrasound images, but also remove the speckle noise anisotropically. Finally, we illustrate the experiments of our method on the synthetic and medical images and compare it with the isotropic reconstruction method.

关键词： Echocardiography

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Hierarchies relating topology and geometry

Hierarchies relating topology and geometry

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作者： Kropatsch, Walter G. Haxhimusa, Yll Lienhardt, Pascal Pattern Recognition and Image Processing Group 183/2 Institute for Computer Aided Automation Vienna University of Technology Austria SIC FRE CNRS 2731 University of Poitiers France

ISBN: (纸本)9783540339717

Cognitive Vision has to represent, reason and learn about objects in its environment it has to manipulate and react to. There are deformable objects like humans which cannot be described easily in simple geometric terms. In many cases they are composed of several pieces forming a "structured subset" of n or n. We introduce the potential topological representations for structured objects: plane graphs, combinatorial and generalized maps. They capture abstract spatial relations derived from geometry and enable reconstructions through attributing the relations by e.g. coordinates. In addition they offer the possibility to combine both topology and geometry in a hierarchical framework: irregular pyramids. The basic operations to construct these hierarchies are edge contraction and edge removal. We show preliminary results in using them to hold a whole set of segmentations of an image that enable reasoning and planning actions at various levels of detail down to a single pixel in a homogeneous way. We further speculate that the higher levels map the inherent structure of objects and can be used to integrate (and "learn") the specific object properties over time by up-projecting individual measurements. The construction of the hierarchies follows the philosophy to reduce the data amount at each higher level of the hierarchy by a reduction factor > 1 while preserving important topological properties like connectivity and inclusion. © Springer-Verlag Berlin Heidelberg 2006.

关键词： Geometry

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A Robust and Accurate Method for Pupil Features Extra

A Robust and Accurate Method for Pupil Features Extra

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International Conference on pattern recognition

作者： Zhifei Xu Pengfei Shi Institute of image processing and pattern recognition Shanghai Jiaotong University Shanghai China

Precise pupil features detection is an important factor for face recognition. This paper presents a robust and accurate algorithm to precisely estimate pupil features: pupil center and pupil radius. First, a pupil parameters estimation step is taken and a weight ring mask is created. Then, a weighted Hough transform is used to precisely extract pupil features. Because of the estimation step, the influence of eyelid and eyelash is largely eliminated. The experimental results show very good robustness and accuracy

关键词： Robustness Face detection Face recognition Feature extraction Facial features Computer vision Parameter estimation Eyelids Eyelashes Eyes

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A velocity-separation difference model for car-following theory and simulation tests

A velocity-separation difference model for car-following the...

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2006 IEEE International Conference on Networking, Sensing and Control, ICNSC'06

作者： Zhipeng, Li Xiaobo, Gong Yuncai, Liu IEEE Institute of Image Processing and Pattern Recognition Shanghai JiaoTong University Shanghai MN 200240 China Department of Control Science and Technology Shanghai JiaoTong University Shanghai MN 200240 China

ISBN: (纸本)1424400651

This paper attempts to introduce a velocity -separation difference model that modifies the previous models in the literature. The improvement of this new model over the previous ones lies in that it performs more realistically than others in the dynamical evolution of congestion. Furthermore, the proposed model is investigated with analytic and numerical method, with the finding that this model can demonstrate some complex physical features observed in real traffic such as the existence of three phases: free flow, coexisting flow, and jam flow;sudden flow drop;traffic hysteresis in transition between the free and the coexisting flow. © 2006 IEEE.

关键词： Control theory

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Hand-Eye Calibration Based on Screw Motions

Hand-Eye Calibration Based on Screw Motions

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International Conference on pattern recognition

作者： Zijian Zhao Yuncai Liu Institute of Image Processing & Pattern Recognition Shanghai Jiaotong University Shanghai China

When computer vision technique is used in robotics, robotic hand-eye calibration is a very important research task. Many algorithms have been proposed for hand-eye calibration. Based on these algorithms, we introduce a new hand-eye calibration algorithm in this paper, which employs the screw motion theory to establish a hand-eye matrix equation by using quaternion and gets a simultaneous result for rotation and translation by solving linear equations. The algorithm proposed in this paper has high and stable computational efficiency without non-linear minimization and can be understood easily. Both simulations and real experiments show the superiority of our algorithm over the comparative algorithms

关键词： Calibration Fasteners Robot vision systems Robot sensing systems Quaternions Iterative algorithms Cameras Computer vision Nonlinear equations Minimization methods

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Characteristic Line of Planar Homography Matrix and Its Applications in Camera Calibration

Characteristic Line of Planar Homography Matrix and Its Appl...

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International Conference on pattern recognition

作者： Jianhua Wang Yuncai Liu Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China

ISBN: (纸本)0769525210

In this paper, we employ the concept of characteristic line to show some useful properties of planar homography matrix. These properties relate the characteristic line of a planar homography matrix with Euler angles of the planar pattern. Based on the characteristic line, a new method of linear camera calibration is proposed and a strategy to select poses of planar pattern during taking calibration images is suggested. This strategy can help ensure accuracy of calibration. Experiment results including both simulated data and real images validate the method and strategy

关键词： Transmission line matrix methods Cameras Calibration pattern recognition image processing Computational modeling Computer vision Layout Constraint theory Equations

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A new adaptive diffusion equation for image noise removal and feature preservation

A new adaptive diffusion equation for image noise removal an...

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International Conference on pattern recognition

作者： Shoushui Chen Xin Yang Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China

Anisotropic diffusion can remove noise to some extent in image processing. However the contradiction between diffusion and preservation still exists. In this paper, a new nonlinear diffusion model for image noise removal and feature preservation is presented. This model treats inhomogeneity region and image feature adaptively by discontinuity measure and local gradient information. A well balance between diffusion and preservation is also made in this new diffusion method. Experiments results show that the proposed method has high performance compared to other literature methods and is an ideal edge-preserving filtering method. In addition, we use block-based noise estimation to estimate deviation in diffusion equation

关键词： Equations Additive noise Smoothing methods image processing pattern recognition Filtering Low pass filters Anisotropic magnetoresistance Pollution measurement Noise reduction

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Facial Components Detection with Boosting and Geometric Constraints

Facial Components Detection with Boosting and Geometric Cons...

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International Conference on pattern recognition

作者： Tiesheng Wang Pengfei Shi Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China

ISBN: (纸本)0769525210

An efficient framework utilizing both local features and geometrical distribution for detecting facial components is presented. First, candidate facial components are efficiently collected by cascaded boosting of Haar-like features. The candidates may include false positives and multiple detections. Then, geometrical distribution of facial components is imposed on the candidates to select the optimal configuration. For simplicity, we suppose full dependence between the components and model it with multivariate Gaussian. The effectiveness of the framework is evaluated with experiments

关键词： Face detection Boosting pattern recognition image processing Humans Eyes Mouth Nose Shape Face recognition

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Classification Fusion in Wireless Sensor Networks

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自动化学报 2006年第6期32卷 947-955页

作者： LIU Chun-Ting HUO Hong FANG Tao LI De-Ren SHEN Xiao Institute of Image Processing ＆ Pattern Recognition Shanghai Jiaotong University Shanghai 200240 State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan 430079

In wireless sensor networks, target classification differs from that in centralized sensing systems because of the distributed detection, wireless communication and limited resources. We study the classification problem of moving vehicles in wireless sensor networks using acoustic signals emitted from vehicles. Three algorithms including wavelet decomposition, weighted k-nearest-neighbor and Dempster-Shafer theory are combined in this paper. Finally, we use real world experimental data to validate the classification methods. The result shows that wavelet based feature extraction method can extract stable features from acoustic signals. By fusion with Dempster's rule, the classification performance is improved.

关键词： Wireless sensor networks classification fusion wavelet decomposition weighted k-nearest-neighbor Dempster-Shafer theory

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Dynamical Model of Traffic Congestion with the Consideration of the Next-nearest- neighbor Interaction

Dynamical Model of Traffic Congestion with the Consideration...

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World Congress on Intelligent Control and Automation (WCICA)

作者： Zhipeng Li Xiaobo Gong Yuncai Liu Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China

By introducing the velocity difference between the preceding car and the car before the preceding one into the optimal velocity model (OVM), we present an extended dynamical model which takes into account the next-nearest-neighbor interaction. The stability condition of this model is derived by considering a small perturbation around the uniform flow solution with finding that traffic congestion is suppressed efficiently by incorporating the effect of new consideration. Then we investigate the property of the model using numerical methods. The results indicate that the next-nearest-neighbor interaction has important impacts on the coexisting flow, the relation between flow and density, and the propagation speed of small disturbance (PSSD). In addition, we have a try to further enhance the stability of traffic flow by introducing the relative velocity of an arbitrary number of cars in front, but the analysis of linear stability shows it is poor for our purpose

关键词： Traffic control Stability analysis Vehicle dynamics Difference equations image processing pattern recognition Numerical models Transportation Physics Mathematical model

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