最新刊期
卷 5 ， 期 7 ， 2000
- 摘要：The importance of PACS has been recognized and progress of its technologies has rapid speed for the past 15 years. The Implementation of PACS still has many technical problems to solve. In this paper,firstly,the key technologies of PACS are presented and analyzed. Secondly, the standardization of Digital Imaging and Communications in Medicine of ACR/NEMA DICOM3.0 is described. Thirdly,Some software functions in image archiving,processing and display are discussed. Fourthly,a scheme for saving large data of medical imaging is proposed. Finally,the paper points out that in order to follow the stream of medical information,it is necessary to study and master the key technologies of PACS. It should to study and establish the standard for communication and store of medical image. In present condition,it should to study and set up small PACS. And large PACS will be established when there are mature conditions.关键词：Medical image;Standardization;Image communication system;Key technologies2385|151|0更新时间：2024-05-08
- 摘要：In this paper, the 3-D visualization algorithms to medical volume data are reclassified according to a clear hierarchy. Based on the traditional two algorithm classes-surface rendering and volume rendering, hybrid rendering is derived to become a new coexisting class. Volume rendering algorithms are especially classified from two points of view. About each class (or subclass) and its typical algorithms, we give a summarized description, and then generalize the characteristics and applications of them.关键词：3-D visualization;Medical image;volume data;Classification2713|191|0更新时间：2024-05-08
- 摘要：In this paper a maximization of mutual information based multi-modality medical image registration method is described. The method presented in this paper applies mutual information to measure the information redundancy between the intensities of corresponding voxels in both images, which is assumed to be maximal if the images are geometrically aligned. MI is used as a measure of similarity of two images. There exist many important technical issues to be solved about the method such as how to compute MI more accurately and how to obtain the maximization of MI, which are seldom mentioned in published papers. In this paper we provide some implementation issues, for example, subsampling, PV interpolation, outlier strategy. Powell searching algorithm is used which does not compute gradients. The combination of these computation techniques and searching strategy leads to a fast and accurate multi-modality image registration. The registration results of 3D human brain volume data of 41 CT-MR and 35 PET-MR from seven patients are validated to be subvoxel. The registration method is promising in clinical use.关键词：Medical image;registration;mutual information;Rigid body transformation;Multi-Modality3002|171|0更新时间：2024-05-08
- 摘要：Spatial data for geographic information system is as important as the petrol for vehicle. Spatial data quality is more important factor for evaluating the analysis results if they are correct or reasonable in GIS. In this paper, a spatial data quality model is presented according to the method used for evaluating the spatial data quality, and a measurement model of spatial data quality is also given. Both two models, which are used for scientific and reasonable assessment of data quality as well as exact and unitary representation of data quality, are of great importance at conceptual level.关键词：spatial data;Quality measure;Quality evaluation2895|155|0更新时间：2024-05-08
- 摘要：Polygon construction is one of the most important and difficult parts in the establishments of topological relationships of geographic data, and its automation, speed and complexity hedge the development of related modules of GISs and the establishments of geographic data bases. A speedy polygon auto-construction algorithm based on azimuth calculation is put forward in this paper, which constructs polygons and deals with the problems of“islands”and“enclaves”successfully. The algorithm's structure is concise, easily understandable and conveniently programmable.关键词：polygon;Topological relationship;Azimuth3296|185|0更新时间：2024-05-08
- 摘要：The real-time terrain generation techniques based on Digital Terrain Model (DTM) have a high requirement to hardware. And in many practical applications there is no need to simulate the terrain of certain area. Also people want to generate various terrain with different shape characters in order to meet different requirements flexibly. At this time it is obviously uneconomical to still use the method based on DTM. For this reason, the paper studies the modeling approach to 3D fractal terrain using data as little as possible for the PC. The terrain belongs to the multiresolution model that has several levels of detail coexisting. The projection of viewpoint is regarded as reference point from which a small primitive data set is generated, and forms multiresolution triangle meshes which define the shape of terrain base. Then, iteration is done by midpoint displacement and triangle edge sub-division method. It can produce natural terrains with different shapes. The construction method of multiresolution base has solved“spatial continuity”and“temporal continuity”between areas with different level of detail and avoids holes and seams, at the same time it dose not need extra computing works. Additionally, the base has a expansibility and can be expanded to needed shapes. The experimental results show that the method is simple, rapid and suitable for real-time display.关键词：Fractal terrain;real-time display;Multiresolution model;Midpoint displacement;LOD2272|146|0更新时间：2024-05-08
- 摘要：In this paper, a method for the recognition of curved object is presented which is based on the geometrical features of object. First, geometrical information including Gaussian culvature, mean culvature, histogram of culvature, entropy of culvature, etc. is extracted from scene range image, then the scence is represented as a attribute relational graph(ARG) and is matched optimizely with model ARGs of model database. The approach is designed aimming at the recognition of artificial curved objects such as machine parts and components, etc, the curved surface represent of that curved geometrical features is efficient for second order curved surface. The method has been simulated on a PC computer (PentiumII), and have got some good results. The results indicated that curved objects(such as machine parts and comonents) could be successfully recognized from range images with this method.The represent of curved surface in this paper could be extented to the represent of more complex curved surface, and the approach could also be extended to the recognition of more complex 3D curved object.关键词：Range image;Geometrical information;Culvature;ARG;3D object recognition3016|219|0更新时间：2024-05-08
- 摘要：Matching confidence is an important measure to analyses the quality of image matching. For normalized edge magnitude cross correlation matching algorithm, the measure of matching confidence based on neural network is studied. The training samples used to train a BP network are the matching results with the reference image and several sensed images. The trained network can be adopted to measure matching confidence. Experimetal results with real satellite images and aerial images prove the effectiveness of the method.关键词：Image matching;Normalized edge magnitude cross correlation;Matching confidence;BP network2215|150|0更新时间：2024-05-08
- 摘要：Curve fitting has been applied in many fields such as image processing and reverse engineering. In B-spline curve fitting, the parametrization of data points is a key problem. In this paper, an ICP-based algorithm to rectify the parameter values of data points is presented. The ICP algorithm always converges monotonically to the nearest local minimum. The proof of the convergence theorem is given. The analysis of experimental results demonstrates the validity and robustness of our algorithm.关键词：B-spline;curve fitting;ICP(Iterative Closest Point);Parameter rectification3425|212|0更新时间：2024-05-08
- 摘要：Firstly, this paper has briefly introduced the images degenerated model, elements and image restoration method. Secondly, it has improved the local maximum entropy algorithm by applying the statistic property and the characteristics of different type image region. Experiment has proved that the algorithm has independence with degeneration model and the size of local image region. It can keep the image details as well as improve the balance of gray and the contrast of image. The algorithm has a small computing cost and flexibility.关键词：Degenerated image;point spread function;Local maximum entropy;local variance;Local mean2593|157|0更新时间：2024-05-08
- 摘要：Images with severe geometrical distortions,which are induced by camera lens and position, must be corrected before extracting quantitative measurements.In this paper,we present a geometric calibration method for lens camera by applying polynomial warping and bilinear interpolation,and discusses the selection pattern of control points.First,we implement a general polynomial warping algorithm and a bilinear interpolation algorithm in Visual C++5.0,then we demonstrate that,for common optical lens,images with geometric distortions can be rectified with cubic polynomial warping method using only a few control points.This method is simple and practical,and can be used in camera-fixed situations,such as operating table and on-line industry inspection,to acquire lossless images. Practical application in lottery printing quality inspection shows that the method is reliable and valid.关键词：Polynomial warping;bilinear interpolation;Geometric rectification3266|162|0更新时间：2024-05-08
- 摘要：After reviewing some international recommendations for video compression, the application of Matching Pursuit on video compression at very low bit rate is introduced. This algorithm decomposes the signal into linear expansions of waveforms using an overcomplete basis of Gabor functions. With adapting Matching Pursuit to the motion residual, a substantial improvement in both PSNR and perceived visual quality can be gotten. The dictionary which is not block-based can reduce block distortions compared with the low bit rate DCT systems. When coding motion residual, bits are assigned progressively to high energy areas in the motion residual. Thus the decoded image can show the areas where motion changes quickly. Another advantage is the flexible choice of dictionary.关键词：H.261;MPEG-I;H.263;Matching Pursuit;Very low bit rate2497|168|0更新时间：2024-05-08
- 摘要：The method of applying evolutionary strategies to converge Hopfield neural network is proposed in this paper. Genetic search of evolutionary strategies(ES) consists of three consecutive processes. ES performs local search in some small domain in the first process,and the search domain grows in the second process. Then ES performs the global search in whole domain in the third process. We use the dynamic equation to indicate the ES search direction to speed up the local search speed obviously. The ES search domain is small in the first process, and the second and the third process are based on the optimization results of their previous processes,therefore the convergence speed of the proposed method is much faster and it needs less memory space.关键词：pattern recognition;Evolutionary strategies;Hopfield neural network;optimization2284|134|0更新时间：2024-05-08
- 摘要：A new filtering algorithm, i.e., the directional medial filtering with weights is proposed. The directional image of the fingerprint and the idea of the fuzzy theory are utilized to construct filtering template, so the method is simple and the speed is high. Moreover, comparatively correct result can be worked out when the direction isn't exact, which strengthens the capability of the algorithm against disturbance.关键词：fingerprint;weight;directional image;Directional medial filtering2900|156|0更新时间：2024-05-08
- 摘要：With the growing emphasis of industrial automation in manufacturing, vision techniques play an important role in many applications. Since different surfaces have different textures, the techniques of texture analysis can be used for the recognition of surfaces. In this paper, a novel non-contacted approach to measure the roughness of machined surfaces based on texture analysis techniques is presented. When using Gabor filters, It is more complex to classify multiple textural images than to distinguish the texture between two images. According to other related paper and our experiments, the surface of a measured specimen can be classified coarsely according to its gray-level variance. Then, the roughness of the surface can be detected using Gabor filters. We present the method of designing the filters and the experiments show better results as well. The approach can detect the surface roughness automatically and quickly. It is invariant to rotation, and has fewer classifiers. Furthermore the cost of the device for implementing the approach is low and the parameters can be set easily. If the system is connected with the control system of a machine, we can realize real-time close looped control of the machining procedure.关键词：texture analysis;Surface roughness;computer vision;Gabor filter3295|188|0更新时间：2024-05-08
- 摘要：In this paper, we propose a new geometric registration algorithm which can register multi-view range data of 3D free-form object efficiently. This method is based on the Iterative Closest Point(ICP) algorithm, but adding a restriction to the corresponding points in estimation of optimal rotation matrix. Further more, we takes a membership of weighting value to points of 3D surface reconstructed using structure lighting to reduce the reconstruction error influence to the registration. The experiments demonstrate the feasibility of our approach.关键词：compute vision;Free-form object;registration2589|161|0更新时间：2024-05-08
- 摘要：Because the rate of lump coal influence the price directly, so coal enterprises hope to have a method to control the rate of lump coal and increase the economy profit. Previously manual work in statistics is processed. Now the new method is proposed in this paper to use image processing and image recognition to monitor the rate of lump coal. The image segmentation in the image of lump coal is discussed and the statistic method using diameter measuring is used in the paper.关键词：Image processing;Rate of lump coal;Monitoring;Image grabber;Image recognition2216|160|0更新时间：2024-05-08
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