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Efficient collision detection for soft tissue simulation in a surgical planning system

Efficient collision detection for soft tissue simulation in ...

11th IEEE International Conference on Computer-Aided Design and Computer Graphics(第11届IEEE国际计算机辅助设计与图形学学术会议 IEEE CAD/GRAPHICS 2009)

作者： Shengzheng Wang Jie Yang Merchant Marine College Shanghai Maritime University Shanghai 200135 China Inst. Of Image Proces Inst. of Image Processing & Pattern Recognition Shanghai Jiao Tong University Shanghai 200240 Ch

In the field of cranio-maxillofacial surgery, there is a huge demand from surgeons to be able to automatically predict the post-operative face appearance in terms of a pre-specified bone-remodeling plan. Collision detection is a promising means to achieve this simulation. In this paper, therefore, an efficient collision detection method based on a new 3D signed distance field algorithm is proposed to accurately detect the contact positions and compute the penetration depth with the moving of the bones in the simulation, and thus the contact force between the bones and the soft tissues can be estimated using penalty methods. Thereafter, a nonlinear finite element model is employed to compute the deformation of the soft tissue model. The performance of the proposed collision detection algorithm has been improved in memory requirements and computational efficiency against the conventional methods. In addition, the proposed approach has the superior convergence characteristics against other methods. Therefore, the usage of the collision detection method can effectively assist surgeons in automatically predicting the pos-operative face outline.

关键词： Signed distance field collision detection soft tissue prediction surgical simulation

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Improved algorithm for multiple infrared targets tracking

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Shanghai Jiaotong Daxue Xuebao/Journal of Shanghai Jiaotong University 2009年第3期43卷 437-442页

作者： Yang, Jin Yang, Jie Wang, Fang-Lin Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai 200240 China

Based on the mean field Monte Carlo (MFMC) algorithm, an improved one for multiple infrared targets tracking on basis of particle filter was proposed. In this new algorithm, Mean-Shift is integrated in the sampling of particles in MFMC, so before the weighting of particles, Mean-Shift will move them to the place where reaches maximum similarity and then the effectiveness of particles is greatly improved. This algorithm also revises the mechanism for message assessment in MFMC with the consideration of the sizes of targets, and it improves the self-adaptability of the mechanism. The experimental results show that this new algorithm is more robust, accurate and efficient than MFMC. It can effectively solve the issue of multiple infrared targets tracking.

关键词： Monte Carlo methods

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Three dimensional palmprint recognition

Three dimensional palmprint recognition

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IEEE International Conference on Systems, Man and Cybernetics

作者： Wei Li Lei Zhang David Zhang Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China Biometrics Research Center Department of Computing Hong Kong Polytechnic University Hong Kong China

Palmprint has been widely studied as its high accuracy and low cost. Most of the previous studies are based on two dimensional (2D) image of the palmprint. However, 2D image can be easily forged, which will threaten the security of palmprint authentication system. Furthermore, 2D image can be easily affected by noise, such as scrabbling and dirty in the palm. To overcome these shortcomings, we develop a three dimensional (3D) palmprint identification system. The structured-light imaging technology is adopted to collect the 3D palmprint data, from which the stable mean curvature image (MCI) is extracted. Then the competitive coding (CompCode) technique is used to code the 3D palmprint pattern according the MCI. By using score level fusion of MCI and its CompCode, promising recognition performance is achieved on our established 3D palmprint database.

关键词： Biometrics Authentication pattern recognition image recognition Data acquisition Time measurement Surface reconstruction image reconstruction Costs Data security

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Principal line based ICP alignment for palmprint verification

Principal line based ICP alignment for palmprint verificatio...

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IEEE International Conference on image processing

作者： Wei Li Lei Zhang David Zhang Jingqi Yan Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China Biometrics Research Center Department of Computing Hong Kong Polytechnic University Hong Kong China

image alignment is a crucial step in palmprint verification. However, most of the existing palmprint alignment methods use only some key points between fingers or in palm boundary to extract the region of interest (ROI), which is consequently used for feature extraction and matching. Such alignment methods can only give a coarse alignment of the palmprint images. This paper presents a new effective refinement method for palmprint alignment by adapting the iterative closest point (ICP) method to the palmprint principal lines. The proposed method offers a more accurate alignment of palmprints by correcting efficiently the shifting, rotation and scaling variations introduced in data acquisition. The experimental results show that the proposed method can greatly improve the palmprint verification accuracy in real time.

关键词： Iterative closest point algorithm Biometrics Fingers Feature extraction Data mining Iterative methods Authentication Shape image processing pattern recognition

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Approach to face recognition based on common vector and 2DPCA

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Zidonghua Xuebao/ Acta Automatica Sinica 2009年第2期35卷 202-205页

作者： Wen, Ying Shi, Peng-Fei Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai 200030 China

A novel approach to face recognition based on the common vector combined with 2-dimensional principal component analysis (2DPCA) is proposed in this paper. The common vector of one class is obtained by face images of the class processed by the Gram-Schmidt orthogonalization to represent the common invariant properties of the class. recognition results are obtained by 2DPCA procedure and distance test of the difference vectors between the original image and the common vector of the class. Experiments are performed on ORL and Yale face databases and the results indicate that the proposed approach achieves good recognition results.

关键词： Principal component analysis

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Analysis of appearance features for human matching between different fields of view

Analysis of appearance features for human matching between d...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： Xiaowei Lv Qing-Jie Kong Fei Weng Yuncai Liu Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai China Beckman Institute Department of Electrical and Computer Engineering University of Illinois Urbana-Champaign Urbana IL USA

Human matching between different fields of view is a difficult problem in intelligent video surveillance; whereas fusing multiple features has become a strong tool to solve it. In order to guide the fusion scheme, it is necessary to evaluate the matching performance of these features. In this paper, four typical features are chosen for the evaluation. They are the color histogram, UV chromaticity, major color spectrum histogram, and scale-invariant features (SIFT). Quantities of video data are collected to test their general accuracy, robustness, and real-time applicability. The robustness is measured under the conditions of illumination changes, Gaussian and salt noises,foreground errors, resolution changes, and camera angle differences. The experimental results show that the four features bear distinctive performances under the different conditions, which will provide important references for the feature fusion methods.

关键词： Humans Colored noise Histograms Noise robustness Video surveillance Testing Noise measurement Lighting Gaussian noise Cameras

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A framework for craniofacial surgery simulation based on pre-specified target face configurations

A framework for craniofacial surgery simulation based on pre...

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IEEE International Symposium on Biomedical Imaging

作者： Shengzheng Wang James C. Gee Jie Yang Merchant Marine College Shanghai Maritime University Shanghai China Institute of Image Processing & Pattern Recognition Shanghai Jiaotong University Shanghai China Department of Radiology University of Pennsylvania PA USA

ISBN: (纸本)9781424439317

This paper presents a novel method for assisting surgeons in automatically computing an optimal surgical plan by directly specifying the desired correction to a facial outline. First, the desired facial appearance is prescribed using a 3D sculpturing tool, while the cut regions of the skull are defined based on facial anatomy. Then, the deformation of the face meshes is performed using an improved biomechanical model in which virtual external forces are driven by the displacements corresponding to the differences of node coordinates between the original and specified face meshes, and free nodes and fixed nodes are defined in terms of the contact surfaces between the soft tissues and the bones within the cut regions. Finally, the shape of the contact surfaces is updated following the deformation of the soft tissues. After registering the deformable contact surfaces and the cut surfaces, the final positions of the cut bones are estimated. Evaluation of preliminary experimental results quantitatively demonstrates the effectiveness of the proposed approach.

关键词： Surgery Biological tissues Deformable models Bones Content addressable storage Skin Computational modeling Finite element methods Material properties Biological materials

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Kalman filtering based watermarking algorithm

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Journal of Information and Computational Science 2009年第6期6卷 2193-2198页

作者： Zhang, Fan Ding, Aiping Shang, Dongfang Institute of Image Processing and Pattern Recognition Henan University Kaifeng 475001 China College of Computer and Information Engineering Henan University Kaifeng 475001 China Department of Information Engineering Yellow River Conservancy Technical Institute Kaifeng 475001 China

A digital watermark algorithm based on Kalman filter and image fusion is proposed. Digital watermarking is considered as a process of image fusion. Watermark image and original image are unified in a new state equation, and then the corresponding measurement equation is built. Digital watermark is embedded into original image according to the optimal estimation in the case of minimum estimation error variance. Experimental results show that the proposed algorithm has a good robustness and invisibility. © 2009 Binary Information Press.

关键词： Kalman filters

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A Novel Method for Boundary Condition Computation in Soft Tissue Deformation

A Novel Method for Boundary Condition Computation in Soft Ti...

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Computer Science and Information Engineering, CSIE, WRI World Congress on FLAGGED

作者： Shengzheng Wang Jie Yang Kai Xie Merchant Marine College Shanghai Maritime University Shanghai China Institute of Image Processing & Pattern Recognition Shanghai Jiaotong University Shanghai China The Methodist Hospital Research Institute Cornell university Houston TX USA

Simulating the soft tissue deformation based on bone-related planning is one of the most difficult issues in generating realistic motion of soft tissues. The difficulty of this problem arises from unclear boundary conditions. In facial soft tissue deformation, the boundary conditions of the finite element modeling are related to the bone movements. In order to better map the bone movements to the soft tissue model, a fast and robust computational strategy for boundary conditions is presented in this paper. First, a collision detection algorithm is employed to query contact position after repositioning of bones. Then, an improved 3D discrete distance field algorithm is proposed to perform imposed displacement computation of contact vertices. Finally, boundary conditions are calculated in terms of the imposed displacements. This approach can automatically handle boundary conditions of the complex geometrical modeling without prior assumption or knowledge about the position of contacts. The effectiveness of our method is demonstrated on complex soft tissue deformation.

关键词： Boundary conditions Biological tissues Deformable models Computational modeling Finite element methods Bones Surgery Detection algorithms Solid modeling Skull

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A New Circle Targets Extraction Algorithm

A New Circle Targets Extraction Algorithm

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The First International Conference on Multimedia Information Networking and Security(第一届国际多媒体网络信息安全会议 MINES 2009)

作者： Chen Zhong Deng He Wang Guoyou Intelligence Control Institute for Pattern Recognition and Artificial Intelligence Huazhong University of Science and Technology Multi-Spectral Information Processing State Key Laboratory Wuhan P.R.China

According to the drawback of the traditional circle target extraction algorithm used by Hough Transform, such as computation complexity, low efficiency and etc, an new circle target extraction algorithm is proposed in this paper which can extract multiple circle targets with different radius at one time. First, the Average Absolute Difference is implemented to enhance the edge of the circle targets and suppress the noise of the background; Second, the locally self-adaptive segmentation algorithm is implemented to obtain the binary image. Thirdly, the thinning algorithm is implanted to obtain the single pixel edge of the circle targets and in order to reduce the computation times in the following process, a pruning algorithm is necessary; finally, a modified Hough transform algorithm is proposed to obtain the circle targets. The new circle targets have three advantages: low time consuming, high detection rate, robust to noise and fragmentary boundaries. The experimental results demonstrate that the new algorithm can extract the multiple circle targets quickly and accurately.

关键词： circle extraction hough transformation Average Absolute Difference thinning

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