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Medical Imaging 2001 Conference

作者： Niethammer, MU Schoepf, UJ Wildberger, JE Klotz, E Fichte, H Schaller, S Siemens Med Solut Comp Tomog D-91301 Forchheim Germany

ISBN: (纸本)0819440078

Suspected pulmonary embolism (PE) is a common indication for CT scanning of the thorax. Usually, intravenous contrast agent is administered utilizing a power-injector and the vascular structures are examined for the presence of pulmonary emboli. Current Multi-Slice CT-technology allows extending this morphological analysis by adding a more functional visualization of the actual parenchymal perfusion disturbance. We have developed a new image processing technique which allows selective color encoded display of parenchymal enhancement of the lung, which will be reduced in the presence of PE. Based on thin slice reconstructions an automatic 3D segmentation of the lung is performed followed by threshold based extraction of the major airways and vascular structures. This allows applying an adaptive 3D low-pass filter to the parenchymal volume only. The filtered volume data are then color encoded and overlaid onto the original CT-images. This combination of low-resolution perfusion-weighted color maps and high-resolution gray scale structural data from the same data set greatly enhances visualization of spatial relationships. The resulting images can be displayed in axial, sagittal and coronal orientation. Initial experience indicates that this new technique provides relevant additional information for the clinical management of patients with proven PE. A larger controlled patient study is under way.

关键词： lung perfusion parenchymography segmentation algorithm pulmonary embolism computed tomography (CT)

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Optimal approach to SAR image segmentation and classification

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IEE PROCEEDINGS-RADAR SONAR AND NAVIGATION 2000年第3期147卷 134-142页

作者： Stewart, D Blacknell, D Blake, A Cook, R Oliver, C NA Software Ltd Liverpool Merseyside England DERA Malvern WR14 3PS Worcs England

Many algorithms have been proposed for the segmentation and classification of SAR imagery. Typically these are heuristic in basis, and more successful on some types of imagery than others. Methods based on global optimisation techniques can achieve the optimal solution of the posed problem;the algorithm is then characterised by an objective function and the chosen optimisation technique. The authors construct an appropriate objective function for SAR segmentation or classification, and show how to optimally quantify the relationship between the competing terms within it. This removes the previous need for the introduction of heuristics. Also described is an implementation based on simulated annealing, in which considerable attention has been paid to details, and examples are given of the resulting algorithm's performance upon real data.

关键词： RCS reconstruction SAR imagery image classification Radar theory SAR image classification Optimisation techniques real data heuristics segmentation algorithm objective function image segmentation optimal approach optimal solution algorithm performance radar cross-section simulated annealing global optimisation techniques Optical, image and video signal processing radar imaging synthetic aperture radar image reconstruction SAR image segmentation

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Scale trees far stereo vision

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IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 2000年第4期147卷 363-370页

作者： Moravec, K Harvey, R Bangham, JA Univ E Anglia Sch Informat Syst Norwich NR4 7TJ Norfolk England

The image trees described hierarchically organise image segments according to scale, with the coarsest scale, the scale of the image itself as the root of the tree and the finest scales as the leaves. The segmentation algorithm used to form the tree nodes is the sieve, a nonlinear morphological scale-space operator. The trees are a transform, so it is possible to reconstruct the associated image without loss. Scale trees may have more nodes than are needed but the trees may be simplified using a standard statistical test to reduce the number of nodes without affecting the reconstructed image significantly. These simplified trees may be used to generate regions for a stereo algorithm that reduces the errors in the resulting disparity map, particularly within sharp-edged regions with low texture - conditions where conventional methods often fail.

关键词： segmentation algorithm image segmentation image matching sharp-edged regions Computer vision and image processing techniques tree nodes texture conditions stereo image processing transform disparity map nonlinear morphological scale-space operator tree data structures Optical, image and video signal processing image texture image segments reconstructed image image trees statistical test scale trees image reconstruction mathematical operators mathematical morphology stereo vision

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A segmentation algorithm for collision avoidance in telerobotics applications

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ROBOTICA 1996年第6期14卷 603-610页

作者： Strenn, S Hsia, TC Wilhelmsen, K UNIV CALIF DAVIS DEPT ECEDAVISCA 95616 LAWRENCE LIVERMORE NATL LAB LIVERMORECA 94550

This paper proposes a new algorithm, known as the segmentation algorithm, which provides model-based, real-time, whole-arm collision avoidance for telerobotic applications. The work presented here is an extension and modification of potential field theory. Novel aspects of the algorithm include the application of a hierarchical segmentation technique to minimize on-line processing and the development of procedures which account for workspace object translation, rotation, and grasping. The SA outputs torques, which, when applied to the control arm, prevent the teleoperator from driving the remote arm into a collision. The teleoperator actually feels workspace objects that are spatially close to the remote arm - an experience known as virtual force-reflection. The SA's performance has been analyzed in terms of its speed and efficiency vis a vis various system parameters, including workspace object distribution, size, and number. Simulation results show that the SA succeeds in providing real-time collision avoidance where less elegant brute force algorithms fail.

关键词： telerobotics collision avoidance segmentation algorithm real-time

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Method for searching bridge in IR images

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IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE 1998年第7期13卷 21-24页

作者： Chen, HX Shen, ZK Shen, JJ Natl Univ Def Technol ATR Lab Dept EE Changsha 410073 Peoples R China

A method for searching bridges in IR images is presented in this paper. It is a time-consuming image understanding task to recognize targets in low SCR images. As in IR images, the bridges usually have almost the same gray level range of the background, the typical segmentation algorithm cannot get correct segmentation labels and edge sites of the bridges. The gray level characters of both the lands, which connect the bridge, and the river are fully considered resulting in a method that can be realized effortlessly and quickly. The criteria are also presented to decide whether there exist bridges or not in the given images, so the method endows the system with the ability to seize the target automatically. Some experimental. results are presented demonstrating that the method can effectively recognize bridges in IR images.

关键词： edge detection image segmentation infrared imaging IR images background bridge search edge sites gray level range low SCR images river segmentation algorithm segmentation labels Edge detection Infrared imaging image segmentation rivers

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A lexicon driven approach to handwritten word recognition for real-time applications

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IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1997年第4期19卷 366-379页

作者： Kim, G Govindaraju, V Department of Computer Science Center of Excellence for Document Analysis and Recognition (CEDAR) State University of New York at Buffalo Amherst NY

A fast method of handwritten word recognition suitable for real time applications is presented in this paper. Preprocessing, segmentation and feature extraction are implemented using a chain code representation of the word contour. Dynamic matching between characters of a lexicon entry and segment(s) of the input word image is used to rank the lexicon entries in order of best match. Variable duration for each character is defined and used during the matching. Experimental results prove that our approach using the variable duration outperforms the method using fixed duration in terms of both accuracy and speed. Speed of the entire recognition process is about 200 msec on a single SPARC-IO platform and the recognition accuracy is 96.8 percent are achieved for lexicon size of 10, on a database of postal words captured at 212 dpi.

关键词： handwritten word recognition segmentation algorithm variable duration chain code representation dynamic programming

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IMAGE segmentation FOR COMPRESSION OF IMAGES AND IMAGE SEQUENCES

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IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 1995年第1期142卷 15-21页

作者： SANDERSON, H CREBBIN, G UNIV WESTERN AUSTRALIA DEPT ELECT & ELECTR ENGNNEDLANDSWA 6009AUSTRALIA

Region-based image coding schemes, the so-called second generation techniques, have gained much favour in recent years. For still picture coding, they can increase the compression ratio obtained by transform coding by an order of magnitude, while maintaining adequate image representation. The success of these techniques relies on the ability to describe regions in an image succinctly by their shape and size, The algorithms presented describe methods for segmenting images. Unlike most other region based algorithms, these algorithms incorporate knowledge of the border coding process in deciding how to partition the image. The extension from single image compression to sequential image compression is also considered. A new, efficient segmentation scheme is proposed that exploits temporal redundancies between successive images, and reduces some problems associated with error accumulation in error images.

关键词： IMAGE PROCESSING segmentation algorithm

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A PARTICLE segmentation METHOD BASED ON NUCLEATION AND GROWTH OF THE BACKGROUND

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JOURNAL OF MICROSCOPY-OXFORD 1994年第2期173卷 165-172页

作者： ZHENG, X KOLB, M CNRS INST RECH CATALYSEF-69626 VILLEURBANNEFRANCE

A new algorithm for image segmentation is proposed, which is capable of extracting particles in the presence of noise and background fluctuations. It begins with the detection of small regions belonging to the background, called background nuclei, and then lets these nuclei grow to become the entire background. Edge information and region information of the image are used simultaneously.

关键词： ELECTRON MICROSCOPY IMAGE ANALYSIS segmentation algorithm IDENTIFICATION OF PARTICLES

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SEGMENTING SIMPLY CONNECTED MOVING-OBJECTS IN A STATIC SCENE

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IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1994年第11期16卷 1138-1142页

作者： BICHSEL, M Dept. of Comput. Sci. Zurich Univ. Switzerland

A new segmentation algorithm is derived, based on an object-background probability estimate exploiting the experimental fact that the statistics of local image derivatives show a Laplacian distribution. The objects' simply connectedness is included directly into the probability estimate and leads to an iterative optimization approach that can be implemented efficiently. This new approach avoids early thresholding, explicit edge detection, motion analysis, and grouping.

关键词： Layout Poisson equations Computer vision Image segmentation Image edge detection Image motion analysis Application software Optical computing Iterative methods Probability INSPEC: Controlled Indexing image segmentation probability statistical analysis optimisation iterative methods INSPEC: Non-Controlled Indexing iterative optimization approach simply connected moving objects static scene segmentation algorithm object-background probability estimate statistic local image derivatives Laplacian distribution

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A RECOGNITION SYSTEM FOR JAPANESE ZIP CODE USING ARC FEATURES

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 1994年第7期E77D卷 810-816页

作者： YOSHIMURA, M SHIMIZU, T YOSHIMURA, I Chubu Univ Kasugai-shi Japan

An automatic zip code recognition system for Japanese mail is proposed in this paper. It is assumed that a zip code is composed of three numerals and required to be written in a specified frame. In actual images, however, the three numerals sometimes extend outside the specified frame and are not clearly separated. Considering this situation, the authors devised a system with two stages, the segmentation stage and the recognition stage. The segmentation stage consists of five steps: setting and adjusting of initial areas for numeral images (figures), calculation of the center of gravity of each figure, search for the horizontal and vertical boundaries of each figure, determination of the final area for each figure, and normalization of the figure in each final area. In the recognition stage, the Localized Arc Pattern Method (Arc method) proposed by Yoshimura et al. (1991) is implemented hierarchically;that is, a simpler Arc method is applied first to each figure and a more complex one is applied subsequently unless the figure is identified in the first step. In the recognition process, every figure is judged as a numeral or otherwise rejected. The proposed system was applied to a database provided by the Institute for Post and Telecommunications Policy (IPTP). The segmentation algorithm yielded an adequate result. The recognition algorithm yielded scores as high as 90.6% in correct recognition rate and 0.7% in error rate. The best score of the precision index (P-index) specified by the IPTP was as low as 15.7 for the above mentioned IPTP database, while the score for another IPTP database was 16.9.

关键词： HANDWRITTEN NUMERALS JAPANESE ZIP CODE LOCALIZED ARC PATTERN METHOD NUMERIC CHARACTER RECOGNITION segmentation algorithm

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