最新刊期
卷 5 ， 期 6 ， 2000
- 摘要：Terrain Visualization has become increasingly interesting in recent years because it has wide application backgrounds. In this paper, we summarize the terrain visualization to four categories in terms of digital terrain model, terrain simplification, multiresolution model and terrain reality. Based on the survey, discussion and comparison of existing methods and results, we formalize the concepts and research contents of terrain visualization. At last, the potential applications of this domain are predicated.关键词：terrain visualization;DTM(Digital Terrain Model);Terrain simplification;Multiresolution model;LOD(Levels of Detail);Terrain texture;View dependent3159|158|0更新时间：2024-05-08
- 摘要：Virtual Studio uses computer-generated scene as its background. It applies computer technology and video compositing technology to combine the actors and the virtual scene seamlessly, and gives audience a full new vision effect. It brings up a revolution to video making. The structure of Virtual Studio system includes three parts: camera tracking, background rendering and video compositing. Its key technology consists of camera tracking, camera switching and focusing, blue room design and background rendering, synchronization and compositing, etc. This paper addresses the structure, technology and some problems of Virtual Studio.关键词：Virtual studio;Chromakey;virtual reality;Background rending;camera tracking;compositing2685|121|0更新时间：2024-05-08
- 摘要：Triangular irregular networks (TIN) have important application in Geographic Information System and Virtual Reality. As for as the algorithms of triangular irregular networks (TIN) generation are regarded, divide conquer algorithm and triangulation growth algorithm have each different virtue and defect. For using resources of time and space more reasonably, this article provides an new TIN construction algorithm based on self-adapt clump organization idea, which takes advantages of the traditional prevalent delaunay triangulation generation algorithms-divide-conquer and triangulation growth. The last experiment illustrates the created triangulation has not intersected、repeated and inclusion Delaunay properties,so the algorithm is more correct and efficient in the view of time and space. The main design ideas of generation algorithm can extend to the 3D space.关键词：TIN;Delaunay triangulation;self-adapt clump organization3019|159|0更新时间：2024-05-08
- 摘要：Threshold selection is very important for image segmentation. How to get fine threshold is an old, but difficult problem in image processing. We have to make new method for threshold selection in some image analysis because all threshold rule have been put forward for image segmentation can't work well for all images. A pattern about making the method for threshold selection is put forward in this paper. Application in many old methods and some new methods show how to use it to get a new method for threshold selection in practice.关键词：Image;threshold selection;Making of method2531|136|0更新时间：2024-05-08
- 摘要：CRTs(Cathode Ray Tubes)are major display devices in computers. In practical cases, in order to display colors on a CRT on standard, we must do color calibration work for it, which is the problem of color notation conversion between the RGB space of the CRT and the XYZ space of CIE system. Neural networks is one of methods in color notation conversion. In this paper, we proposes a BP Neural networks with four-hidden-layer to perform the color notation conversion from RGB space to XYZ space in a computer controlled CRT system. The experimental results show our method is better than the method which using only 2~3 hidden layers, and the color conversion precision of our experiment is about 1.5 CIELUV units.关键词：CRT colorimetry;Computer color;BP neural networks;Color conversion2372|143|0更新时间：2024-05-08
- 摘要：Edge extraction is an usual method in the field of image processing. But it's not enough to exactly describe the detected object only using edge information in the practical applications. So how to restore the binary image according to the direction chain codes is an important problem in image processing field. A binary image can be described by using one or several direction chain codes that record the contour of this binary image. Many methods heve been proposed in the literature, but there still exist the drawbacks such as large computation and inaccurate restoration. In this paper, a new and fast method for restoration of binary image is presented to solve the problems, which is based on the sort of edge points and the chain coding of the boundaries. Experimental results show that this method is computationally faster than the previous methods and does not miss any part of the interior. It's a good restoration method, and already has been used in the practical application.关键词：Direction code;Chain coding;Filling algorithm;Filling point2320|144|0更新时间：2024-05-08
- 摘要：Enhancement is one of the important methods of Low-light-level image processing. The Histogram- Equlization(HE), a traditional enhancement algorithm, has several drawbacks to process such images. (1) The brightness information will be lost during the process of HE. (2) Degeneracy will happened during the process. This paper presents an algorithm that can preserve brightness and gray levels, which may decrease the disadvantages of the traditional methods.关键词：image enhancement;Histogram equalization;Gray-level3565|116|0更新时间：2024-05-08
- 摘要：In this paper, a new method to generate the texture image by use of Multi-layer feed-forward neural network is presented. This method can be used conveniently to generate different kinds of texture image sets. Each image in texture image sets corresponds to a group of definite weights and thresholds of neural network. This characteristic of the method is very useful for image' s saving and then a lot of storage space can be saved.关键词：Multilayer feed forward neural network;Texture image;BP algorithm2870|140|0更新时间：2024-05-08
- 摘要：Image coding has been the important problem in the computer world nowadays. Vector quantization (VQ) is a lossy image compression technique presented recently. It has the advantages of low bit rate and simple decoding method. However,the encoding phase of the full search method need much computation. In order to reduce the encoding time,a lot of fast search algorithms are presented in the literatures. However,lots of these methods cannot further reduce the bit rate. In this paper,a novel image encoding algorithm based on the fast correlation vector quantization (CVQ) is presented. The diagonal encoding sequence is adopted in this paper. During the encoding process,the correlation between the current processing block and the adjacent encoded blocks is used to predict the index of the input vector,thus both the average codeword searching range of each input vector and the bit rate are greatly reduced. Test results show that,compared with the image encoding algorithms based on the conventional full-search method,the partial distortion search method and the double test method,the proposed algorithm needs much shorter encoding time and lower bit rate,although the encoding quality of the proposed algorithm is a little degraded.关键词：vector quantization;Correlation vector quantization;Image encoding2132|119|0更新时间：2024-05-08
- 摘要：Edge detection is a important process in computer vision, currently popular method firstly smooth original image using Gaussian or B-Spline, then finding the extremum of first derivative or zero-crossing of second derivative as edge point. But the residual between the original image and smoothing image may include some edge feature point. In order to finding the edge feature point in residual possibly, this paper put forward a novel image edge detection method by modifying profit and loss data by B-Spline smoothing formula. Its principle is that firstly we modify original image intensity for decreasing the residual between smoothing image and original image and then use modified data for zero-crossing edge detection by B-Spline smoothing formula. Practical numerical experimental results showed that this method have a stronger edge detection ability and produced a better effect compare with kindred method.关键词：B-Spline;Compact support;Marr operator;edge detection;Profit and loss modifying2028|131|0更新时间：2024-05-08
- 摘要：It is possible to map a coseismic displacement field resulting from a major earthquake by differential SAR intereferometry and to achieve results comparable in magnitude to those obtained by conventional field survey techniques. Here we use differential SAR interferometry to capture the movements produced by the 1998 earthquake (Ms=6.2) in Zhangbei, Hebei province. Three interferograms constructed from ESR-1/2 SAR data were used to analyze the earthquake mechanism by three-pass method. The differential interferogram reveals fine geometrical features and seismic fault. Since we require only remotely sensed satellite data with no additional requirements for ancillary information, the technique is well suited for wide range seismic monitoring and analysis.关键词：Differential;SAR;Interferometry;Zhangbei;Coseismic displacement2146|122|0更新时间：2024-05-08
- 摘要：Model-based coding is recognized to be a perspective method of low bit-rate image compression method. Due to some merits which cannot be drawn a parallel with ordinary, Edge Model-based Coding is given more and more attention by researchers now. In such method, the ambient region of Edge Model-based whose most of the higher frequency is cut has a smooth gray change in background. The area which was left is about 10 percent of the whole image. In this paper, in order to compress the ambient image by traditional JPEG method, we present a sensitive region filling method by using 8×8 block filled with DC. Thus the blank area which was filled can provide as much DC as possible. At the receiver, the sensitive region is added to the decompressed ambient region. Experiments and data show that the filled image is adapt to be compressed by using JPEG and can get good compression ratio, simultaneously the subjective quality of reconstructed image is also better than that of by using JPEG directly.关键词：Image compression;Edge model-based;Regional filling2208|130|0更新时间：2024-05-08
- 摘要：The research target is developing WebGIS. JAVA applet is used in“Browser/Applet”Two Tier Architecture. Next is the work theory of“Browser/Applet”Architecture Web GIS applet. A WebGIS software—GeoWindos Web1.0 is formed in the research. Technique features of GeoWindows Web1.0, including interface, function, data managing strategy, display controlling mechanism and so on, are introduced in the paper. The running test result of GeoWindows Web1.0 is reported.By testing,GeoWindows Web1.0 works very well in high speed Intranet, too slowly in dial up way. Some experience and thinking of author about WebGIS are given. Some differences of JAVA working in different Browsers are discussed, and the solving methods are given. The author thinks that the running speed bottleneck of GeoWindow Web1.0 is data loading speed. The importance of integrating with HTML, JAVA, JavaScript predominance in WebGIS is emphasized in the paper.关键词：Internet/Intranet;Web;GIS;Java;Applet;GeoWindows3300|149|0更新时间：2024-05-08
- 摘要：This paper introduces the principle, design method and main characteristics of class-based interior design CAD system. How to use ObjectARX to derive the classes a base class is discussed. The system was developed based on AutoCAD R14. It involves interior design functions (door design, window design, wall design, roof design, stair design and so on) and a block-database navigator. It can work in conjunction with AutoCAD's native functions. AutoCAD programming environment provides an object-oriented C++application interface that enables developers to use, customize, and extend AutoCAD. We take advantage of AutoCAD' s open architecture and ObjectARX to customize the main object's structure and styles. The system can dynamically create versatile objects and change the objects to satisfy the needs of users.关键词：object-oriented;Interior design;Class-based;ObjectARX;CAD2230|137|0更新时间：2024-05-08
- 摘要：A new edge thinning method based on Sobel operator is proposed in this paper. A gray edge image (P1) is obtained by introduces a attenuation factor,the gray edge image can also be processed using Sobel operator, then another gray edge image (P2) is get from the previous gray edge image. Another gray edge image(P3) is obtained by subtracting P2 from P1 and the pixels of negative value in P3 are set to zero to eliminate the extra points on both side of the detected edges therefor a image with thinner edge can be obtained. And this procedure can repeat several times to obtain thinner edges(but not necessarily continuous). This method also has effect on the edges that detected by other edge detection methods. Edge thinning can be used to get the exact position of object' s edge. This method can not only get fairly thin edge but can also reserve the edges of low step change and this advantage can overcome the segmentation error that due to improperly selected threshold.关键词：edge detection;Sobel operator;Edge thinning3912|190|0更新时间：2024-05-08
- 摘要：Detection, identification, and selection of moving target through image sequence are very important to Air Traffic Control System and Air Defense System. To study image sequence of moving target, parameters of nmoving target should first be estimated, and its structure be identified, furthermore an observable model should be built to enable speedily display the performance of visible light radiation of flying target on computer screen adopting three-Dimensional display technology. Based on normal probability model under three-Dimensional observing with error, the generation and optimal estimation of motion parameters of moving target image sequence are realized by using OpenGL three-Dimensional graphics library. Hence the generated image sequence possesses the features of smooth, life-like and high speed. The result of dynamic display of moving target through simulating radar data is satisfactory. If the moving target image are synchronized with practical environment picture, this method will meet the requirement for flight performance test and simulation operation and has greatly valuable in this area.关键词：Image sequence;Moving target;Three-dimensional;feature point;Normal probability model2352|126|0更新时间：2024-05-08
- 摘要：The paper discusses the restoration method for motion-blurred images. The large errors observed in inverse filter or Wiener filter restorations of images are mainly due to the fact that a truncated region of image data is available for processing. Wiener filter is less sensitive to noise than inverse filter for the restorations of motionblurred images. However, there is a large error component, called the edge error, that arises due to the fact that real images seldom have the periodicity assumed by discrete Fourier transform operation. Optimal windows for image restoration are designed on the basis of mathematical expressions for the restoration errors. With these optimal windows, near-perfect restorations can be obtained except the narrow L-shape border at the right and bottom edges of the image, which we have to sacrifice for reduction of restoration errors over the rest of the image. The images that vary gradually in intensity near their borders have the best results, as demonstrated in actual restorations of test images. The paper also proves that we can only directly setup two dimensional point spread function, instead of first restoring in x direction and then in y direction. A procedure for estimating point spread functions of real-world motion-blurred images is provided in this paper.关键词：Wiener filter;Inverse filter;Edge error;point spread function(PSF)3340|128|0更新时间：2024-05-08
- 摘要：This paper presents a new filter, called Averaging-Based Adaptive Filter (ABA Filter), whose objective is to overcome the deficiency of current filters that they can not simultaneously possess the merits of both efficiency and simplicity when dealing with mixed noise. Although adaptive filters are robust owing to their effectual structures, the complexity of these filters is generally too great to be realized in real time. However, for video applications, it is very important to design a fast filter. Compared with other adaptive filters, ABA filter uses averaging as its major operation and the averaging value is utilized repeatedly in its adaptive processing so that it needs much less processing time. The adaptive structure makes ABA filter able to adopt different algorithms according to different noise and different image areas. The experimental results show clearly that, when the density of impulse noise is lower than 10%, ABA filter is capable of eliminating the mixed Gaussian noise and impulse noise with much fewer operations.关键词：Image processing;Adaptive filter;mixed noise;Noise removal;edge detection;Video processing2624|157|0更新时间：2024-05-08
- 摘要：In this paper, the structure and characteristic of TMS320C80 is presented, the basic principle of fast DCT algorithm is analysed, the implementation of fast DCT algorithm on TMS320C80 is discussed and the result is gived at last.关键词：TMS320C80;Image compression;DCT2538|172|0更新时间：2024-05-08
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