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Rapid automatic segmentation and visualization of teeth in CT-scan data

Journal of Applied sciences 2009年第11期9卷 2031-2044页

作者： Akhoondali, H. Zoroofi, R.A. Shirani, G. Control and Intelligent Processing Center of Excellence Faculty of Engineering School of Electrical and Computer Engineering University of Tehran Tehran Iran Department of Oral and Maxillofacial Surgery Faculty of Dentistry Medical Science University of Tehran Tehran Iran

In this study, a fast automatic method is proposed for the segmentation and visualization of teeth in multi-slice CT-scan data of the head. The algorithm consists of five main procedures. In the first part, the mandible and maxilla are separated using maximum intensity projection in the y direction and a step like region separation algorithm. In the second part, the dental region is separated using maximum intensity projection in the z direction, thresholding and cropping. In the third part, the teeth are rapidly segmented using a region growing algorithm based on four thresholds which are used to distinguish between seed points, teeth and none teeth tissue. In the fourth part, the results are visualized using iso-surface extraction and surface and volume rendering. A semi-automatic method is also proposed for rapid metal artifact removal. Results on multiple dadasets have shown the success of the algorithm with the dental region separation and segmentation procedure taking an average of only 2.4 sec to complete for each jaw making it at least tens of times faster than any previously proposed method. © 2009 Asian Network for Scientific Information.

关键词： Computerized tomography

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Fully automatic extraction of panoramic dental images from CT-scan volumetric data of the head

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Journal of Applied sciences 2009年第11期9卷 2106-2114页

In this study, a fully automatic technique is proposed for the extraction of panoramic dental images from CT-scan images of the teeth. The process is performed in three steps: Mandibular region isolation, mandibular curve creation and panoramic image extraction. First the mandibular region is isolated. To do this the maxilla and mandible are separated from each other by finding the slice separating them. Then an image of the maximum intensity projection of the slices containing the mandible is obtained. The projection of the mandible is then isolated from the other bones. Using the isolated mandible region an initial curve is created. Nine control points are then selected on the curve. These control points are used to create a fine curve using cubic splines. The formula for each spline segment is used to find the perpendicular lines to the spline on each point on the spline. These perpendicular lines are then used in all slices (mandible and maxilla) to create the panoramic images. The algorithm has many advantages over earlier methods. Results using multiple datasets have shown that the algorithm is robust. © 2009 Asian Network for Scientific Information.

关键词： Computerized tomography

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Adaptive sliding mode control for Takagi-Sugeno fuzzy systems

Adaptive sliding mode control for Takagi-Sugeno fuzzy system...

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48th IEEE Conference on Decision and control held jointly with 2009 28th Chinese control Conference, CDC/CCC 2009

作者： Zhang, Jinhui Shi, Peng Xia, Yuanqing Fu, Mengyin Key Laboratory of Complex System Intelligent Control and Decision School of Automation Beijing Institute of Technology Beijing 100081 China Faculty of Advanced Technology University of Glamorgan Pontypridd CF37 1DL United Kingdom School of Engineering and Science Victoria University Australia

ISBN: (纸本)9781424438716

This paper is devoted to robust adaptive sliding mode control for a class of nonlinear systems in the Takagi-Sugeno forms with mismatched parametric uncertainties. Sufficient conditions for the existence of linear sliding surfaces are given in terms of linear matrix inequalities, by which the corresponding adaptive reaching motion controller is also designed. Simulation studies show the effectiveness of the control scheme. ©2009 IEEE.

关键词： Linear matrix inequalities

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Decoupled fixed point transformation based adaptive control of the generalized 2 DOF Φ6-type Van der Pol oscillator 10

Decoupled fixed point transformation based adaptive control ...

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2009 10th European control Conference, ECC 2009

作者： Tar, Jozsef K. Rudas, Imre J. Bito, Janos F. Machado, Jose A. Tenreiro Kozlowski, Krzysztof R. Institute of Intelligent Engineering Systems John von Neumann Faculty of Informatics Budapest Tech Bécsiút 96/B BudapestH-1034 Hungary Department of Electrotechnical Engineering Institute of Engineering of Porto Rua Dr. Antonio Bernardino de Almeida Porto4200-072 Portugal Control and Systems Engineering Computing Science and Management Poznan University of Technology ul. Piotrowo 3a Poznan60-965 Poland

ISBN: (纸本)9783952417393

In this paper a possible application of a novel adaptive control approach is reported that fits to the 'traditional line of thinking' according to which in the most practical cases neither very precise, nor even complete system model is needed for obtaining precise control for dynamical systems. The validity of this statement is briefly pointed out in the most popular approaches as the main idea of the Robust Sliding Mode / Variable Structure controllers, in Lyapunov's 2nd Method, and in a recently published problem tackling based on the simple geometric interpretation of the Singular Value Decomposition. In the present approach differential equations are deduced from iterative Cauchy sequences to realize adaptive control of a coupled nonlinear system in 'decoupled manner', using single dimensional projections of the 'acceleration space'. The paradigm on which the method is demonstrated is a 2 dimensional generalization of the originally single dimensional Φ6-type Van der Pol oscillator that is a popular paradigm of chaotic systems. Further possible generalizations of the novel method is outlined, too. © 2009 EUCA.

关键词： Chaotic systems

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Decoupled fixed point transformation based adaptive control of the generalized 2 DOF Φ6-type Van der Pol oscillator

Decoupled fixed point transformation based adaptive control ...

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European control Conference (ECC)

作者： József K. Tar Imre J. Rudas János F. Bitó José A. Tenreiro Machado Krzysztof R. Kozłowski John von Neumann Faculty of Informatics Institute of Intelligent Engineering Systems John von Neumann Faculty of Informatics Budapest Tech Budapest Hungary John von Neumann Faculty of Informatics Institute of Intelligent Engineering Systems Budapest Hungary Institute of Engineering of Porto Portugal Control and Systems Engineering Computing Science and Management Poznan University of Technology Poznan Poland

In this paper a possible application of a novel adaptive control approach is reported that fits to the “traditional line of thinking” according to which in the most practical cases neither very precise, nor even complete system model is needed for obtaining precise control for dynamical systems. The validity of this statement is briefly pointed out in the most popular approaches as the main idea of the Robust Sliding Mode / Variable Structure controllers, in Lyapunov's 2nd Method, and in a recently published problem tackling based on the simple geometric interpretation of the Singular Value Decomposition. In the present approach differential equations are deduced from iterative Cauchy sequences to realize adaptive control of a coupled nonlinear system in “decoupled manner”, using single dimensional projections of the “acceleration space”. The paradigm on which the method is demonstrated is a 2 dimensional generalization of the originally single dimensional Φ 6 -type Van der Pol oscillator that is a popular paradigm of chaotic systems. Further possible generalizations of the novel method is outlined, too.

关键词： Decision support systems Bismuth Europe Adaptive control

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A higher order adaptive approach to tackle the swinging problem

A higher order adaptive approach to tackle the swinging prob...

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10th International Symposium of Hungarian Researchers on Computational Intelligence and Informatics, CINTI 2009

作者： Tar, József K. Rudas, Imre J. Bitó, János F. Tenreiro Machado, José A. Kozlowski, Krzysztof R. Telematics and Communications Informatics Knowledge Centre Hungary John Von Neumann Faculty of Informatics Institute of Intelligent Engineering Systems Budapest Tech Bécsi út 96/B H-1034 Budapest Hungary Department of Electrotechnical Engineering Institute of Engineering of Porto Rua Dr. Antonio Bernardino de Almeida 4200-072 Porto Portugal Poznan University of Technology Control and Systems Engineering Computing Science and Management Piotrowo 3a 60-965 Poznan Poland

In numerous practical applications precise control of a subsystem passively connected to a precisely controllable subsystem by elastic connection is needed. As typical example is a crane carrying its payload swinging on an elastic string can be mentioned. From the point of view of control technology this task is interesting since the connected degree of freedom has little damping and it is apt to keep swinging accordingly. The traditional approaches apply the input shaping technology to assist the human operator responsible for the manipulation task. In the present paper a novel adaptive approach applying fixed point transformations based iterations having local basin of attraction is proposed for simultaneously tackle the problems originating from the imprecisions of the available dynamic model of the system to be controlled and the swinging phenomenon. In the simulation investigations presented a simple model consisting of two connected masspoints is considered: one of them can directly by controlled by control forces, the other one (in the role of the payload) is dragged by the controlled point via an elastic spring. The control considers the 4th time-derivative of the trajectory of the dragged system.

关键词： Degrees of freedom (mechanics)

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Polynomial kernel function and its application in locally polynomial neurofuzzy models

Polynomial kernel function and its application in locally po...

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International CSI Computer Conference, CSICC

作者： A. Shirvani H. Chegini S. Setayeshi C. Lucas Tehran Science and Research Branch Computer Engineering Department Islamic Azad University Iran Faculty of Nuclear Engineering and Physics Amirkabir University of Technology슠 Tehran Iran Electrical and Computer Engineering Department Control and Intelligent Processing Center of Excellence University of Tehran Tehran Iran

Polynomials are one of the most powerful functions that have been used in many fields of mathematics such as curve fitting and regression. Low order polynomials are desired for their smoothness, good local approximation and interpolation. Being smooth, they can be used to locally approximate almost any derivable function. This means that when linear functions fail in approximation (e.g. where the first order Taylor expansion equals zero) polynomial functions can be used in local approximation, such that one can achieve better estimations at extremums. In this paper, application of polynomial kernel functions in locally linear neurofuzzy models is shown. Using polynomial kernels in local models, better local approximations in prediction of chaotic time series such as Mackey-Glass is achieved, and the capability of the neurofuzzy network is enhanced.

关键词： Polynomials Kernel Neurons Predictive models Power engineering and energy Chaos Application software Physics computing Power engineering computing Taylor series

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Evaluation of Liver Shape Approximation and Characterization

Evaluation of Liver Shape Approximation and Characterization

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International Conference on intelligent Information Hiding and Multimedia Signal Processing (IIHMSP)

作者： Farshid Babapour Mofrad Reza Aghaeizadeh Zoroofi Yen-Wei Chen Ali Abbaspour Tehrani-Fard Yoshinobu Sato Akira Furukawa Faculty of Engineering Science and Research Branch Islamic Azad University Tehran Iran Control and Intelligent Processing Center of Excellence School of Electrical and Engineering College of Engineering University of Tehran Tehran Iran College of Information and Science Ritsumeikan University Shiga Japan Electrical and Electronic Engineering School Sharif University of Technology Tehran Iran Division of Image Analysis Graduate School of Medicine Osaka University Osaka Japan Department of Radiology Shiga University of Medical Science Shiga Japan

A computational framework is presented for 3-D liver shape approximation and characterization in order to determine the accuracy of shape reconstruction via Spherical Harmonics expansion. Spherical Harmonics is a powerful mathematical tool for expanding the shape. But in medical domain, livers have very variation geometry, in shape, size, and volume. In this regards, we evaluated and optimized the Spherical Harmonics to create 3-D parametric surface of the liver from Computed Tomography (CT) imaging system which may useful for Shape modeling, surface representation, physical measurement of objects and mathematical model. We select randomly 5 livers from more 100 dataset. Mean Hausdorff distance Errors and Dice similarity coefficient DSC by liver volumes was measured. The experimental results showed that the best order of Spherical Harmonics Expansion for livers is between 12~17.

关键词： Liver Computed tomography Shape measurement Mathematical model Image reconstruction Power system harmonics Biomedical imaging Geometry Surface reconstruction Power system modeling

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Possible adaptive control by tangent hyperbolic fixed point transformations used for controlling the Φ6-Type Van der Pol Oscillator

Possible adaptive control by tangent hyperbolic fixed point ...

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ICCC 2008 - IEEE 6th International Conference on Computational Cybernetics

作者： Tar, József K. Bitó, János F. Rudas, Imre J. Kozlowski, Krzysztof R. Tenreiro Machado, José A. Budapest Tech John Von Neumann Faculty of Informatics Inst. of Intelligent Engineering Systems Bécsi út 96/B Budapest H-1034 Hungary Poznan University of Technology Computing Science and Management Chair of Control and Systems Engineering ul. Piotrowo 3a 60-965 Poznan Poland Institute of Engineering of Porto Department of Electrotechnical Engineering Rua Dr. Antonio Bernardino de Almeida 4200-072 Porto Portugal

ISBN: (纸本)9781424428755

In this paper a further step towards a novel approach to adaptive nonlinear control developed at Budapest Tech in the past few years is reported. Its main advantage in comparison with the complicated Lyapunov function based techniques is that its fundament is some simple geometric consideration allowing to formulate the control task as a Fixed Point Problem for the solution of which various Contractive Mappings can be created that generate Iterative Cauchy Sequences for Single Input - Single Output (SISO) systems. These sequences can converge to the fixed points that are the solutions of the control tasks. Recently alternative potential solutions were proposed and sketched by the use of special functions built up of the "response function" of the excited system under control. These functions have almost constant values apart from a finite region in which they have a "wrinkle" in the vicinity of the desired solution that is the "proper" fixed point of these functions. It was shown that at one of their sides these fixed points were repulsive, while at the opposite side they were attractive. It was shown, too, that at the repulsive side another, so called "false" fixed points were present that were globally attractive, with the exception of the basins of attraction of the "proper" ones. This structure seemed to be advantageous because no divergences could occur in the iterations, the convergence to the "false" values could easily be detected, and by using some ancillary tricks in the most of the cases the solutions could be kicked from the wrong fixed points into the basins of attraction of the "proper ones". It was expected that via adding simple rules to the application of these transformations good adaptive control can be developed. However, due to certain specialties of these functions practical problems arose. In the present paper novel transformations are presented that seem to evade these difficulties. Their applicability is illustrated via simulations in the ad

关键词： Lyapunov functions

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Volumetric non-rigid registration via thin-plate spline model

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作者： Babapour Mofrad, Farshid Abbaspour, A. Zoroofi, R. Akhlaghpoor, S.H. Engineering Faculty Science and Research Campus Islamic Azad University P. O. Box 14515-775 Tehran Iran Control and Intelligent Processing Center of Excellence Elec. and Comp. Eng. Department University of Tehran Tehran 14399 Iran Department of Radiology Faculty of Medicine Tehran University of Medical Sciences Tehran Iran

ISBN: (纸本)9783540790389

Registration and warping are essential steps in volumetric data fusion. Medical images are of major parts in diagnosing and treatment and actually are considered a total evaluation of work. In resent years medicines have been using diagnosing devices contain computers as a complementary in detecting harms, evaluating the amount of harm deciding the way of treatment. By quick developing in construction of three dimensional medical imaging devices, high resolution modalities could be used to produce lots of images. This issue is crucial specially in case of medical imaging like Ultrasound, CT and MRI which helps medicines in diagnosing, treatment and investigations. In radiation therapy these information includes surface texture, extracting specified object area in image, and detecting of tumor which can increase the power of medical doctor diagnosing power and usage of image processing techniques will become important in these area. Finding the exact location of target with enough magnification is one of the primary needs in effective radiation therapy. Results show that a Thin Plate Spline is a sufficient model for a volumetric non-rigid registration. The technique is evaluated by mapping of a sphere to a cube and then on a medical object. Experimental result declares that the employed technique is robust in the presence of the noise, changing the number of control points and works effectively in different object resolutions. © 2008 Springer-Verlag.

关键词： Medical imaging

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