最新刊期
卷 5 ， 期 4 ， 2000
- 摘要：Three dimensional terrain is one of important factors of the natural scenes in virtual environment. It is also a significant composition of view system in virtual simulation field. The paper presents terrain generation techniques based on real terrain datasets, and terrain simulation techniques that are based on fractal geometry as well as data fitting methods respectively. Among the terrain generation techniques based on real terrain datasets, emphasis is laid on the real-time display of terrain and some typical data simplification algorithms are introduced according to their appearing time: discrete LOD, continuous LOD, and multiresolution model. Related conceptions and features of those algorithms are also discussed. In terrain simulation techniques based on fractal geometry, the paper gives an overview of several fractal modeling methods, and then makes a further discussion on two kinds of typical recursive subdivision plans of midpoint displacement that is the most practical approach in some applications. In data fitting techniques, plane fitting, curved surface fitting, and real terrain simulation according to some given topographic parameters are introduced. Finally, the development tendencies of all these techniques are discussed.关键词：Three dimensional terrain;virtual environment;DTM;LOD;real-time display;fractal geometry;data fitting3101|179|0更新时间：2024-05-08
- 摘要：Video contains the most affluent information but implies huge storage and complicated semantics. To search for required fragments among huge quantity of video is a tedious and time-consuming task for traditional manual indexing and sequential searching methods which certainly cannot meet the performance requirements of video databases. What the users want is to query by contents, that is, to get the desired fragments of video with just some given examples or feature descriptions. Because of the complicated structure and temporal variation of video data, it is very difficult to index video by content. Researchers have worked out various methods and techniques to solve the problem. The essential steps for content-based video indexing are video segmentation, key frame selection, static and dynamic feature extraction and video clustering. Starting from a brief description of the structures and characteristics of video, this paper generalizes the methods and techniques used in content-based video indexing, analyses in depth the newly proposed ones and their respective advantages and drawbacks. As a conclusion, the paper discusses some of the problems in content-based video indexing that are worth to be tackled in future researches.2802|157|0更新时间：2024-05-08
- 摘要：In this paper,the basic theory of the soft morphology is presented and the soft morphology applied to detecting edge is discussed by its monotonicity, extensibility and anti-extensionality. The soft morphology is a non-linear operations based on standard morphological operations. The idea of soft morphological operations is to relax the standard definitions a little, in such a way that a degree of robustness is achieved while most of the desirable properties of standard morphological operations are maintained. The traditional edges detection methods are compared with the algorithms based on the soft morphological operators after analyzing their geometrical properties and the effects of the structuring element. The simulation results, which are better than the traditional operators illustrate the attractive property of the method. Especially, in the noising condition the method can detect edges without filtering.关键词：Soft mathematical morphology;Detecting image edge;Structuring element2252|165|0更新时间：2024-05-08
- 摘要：In this paper, an approach for image segmentation incorporating the theory of hypergraph with the spatial-frequency features of image is proposed. Based on the multiresolution wavelet analysis and the theory of Gaussian-Markov random field, the features characterizing the local spatial structure of image are extracted, a neighborhood hypergraph with respect to the similarities of the features is constructed, segmentation is implemented via the adapted Covering-Selection algorithm.The adaptability and reliability have been tested through simulations. The approach is effective for segmentation of images with low SNR.关键词：Multiresolution wavelet analysis;Spatial structure feature;Neighborhood-hypergraph;Image segmentation2028|150|0更新时间：2024-05-08
- 摘要：In this paper, a theory of color-scale morphology is proposed, which is an evolution of mathematical morphology from gray-scale image to color image. Based on RGB(red-green-blue) coordinate system, some colorscale morphological operators are presented, and their properties are discussed. The relationships between colorscale morphology and gray-scale morphology are established. Using the basic color-scale morphological operations, the other composite color-scale morphological transforms, such as color-scale opening, closing, iterative morphological filters, color-scale morphological gradient and color-scale top-hat transform etc., can be constructed. Some experimental results are given. As an extension of mathematical morphology to color space, the transformation can be directly and efficiently used to process color image, encode image and extract shape features of objects.关键词：mathematical morphology;Color-scale morphological transformation;Color image processing2062|183|0更新时间：2024-05-08
- 摘要：Research on right quality assessment of image is very meaningful in the image information project, but the objective quality assessment of image cannot always be in accordance with human vision. Any reasonable quality assessment method of image should abide fully by human subjective vision. Due to many factors such as visual psychology, culture background, surrounding environment, different applications and so on, an image can be divided into different regions of interest (ROI) by vision interests. To best advantage of human visual interests, a simplified method for subjective assessment of image is presented to an image with only one ROI in this paper. The degree of visual interest to the ROI of the image is regarded approximately to be an inverse measure of the acreage of the ROI. As the acreage of the ROI is zero, the method will become the objective quality assessment of image, that is to say, the objective quality assessment of image is a specific case of the method in this paper. The experimental results have shown the effectiveness of the proposal scheme. It is in better accordance with human subjective vision.关键词：Quality Assessment of Image;Region of interest;Visual interest2839|168|0更新时间：2024-05-08
- 摘要：In the conventional hierarchical template matching, there exists a typical problem of sophisticated calculation and correction. In this paper a new multiresolution template matching algorithm based on wavelet transform has been studied. According to the numerical and experimental comparison, it is showed that the new algorithm has eliminated the background intensity effect to the template matching, and it has the advantage of easy to calculate and parallel process.关键词：wavelet transform;Gaussian pyramid;Hierarchical template matching2502|222|0更新时间：2024-05-08
- 摘要：This paper investigates multiwavelet image coding. Firstly, unlike many papers on multiwavelets, we describe multiwavelets from the viewpoint of Mallat's frame of multiresolution analysis and deduce a fast algorithm of multiwavelet transform. Secondly, combining two preprocessing methods of multiwavelet transform of images commonly used in many papers, we propose a new preprocessing method. Lastly, we reveal the dependence between different components of a vector-subimage emerged after multiwavelet transforming an image and perform image coding based on this dependence. The theoretical analysis and experimental results presented in this paper show that multiwavelet image coding is a promising way to compress an image.关键词：Multiwavelet;Image coding;Dependence2425|148|0更新时间：2024-05-08
- 摘要：In this paper, the aperiodic matrix model of deconvolution is described firstly, whose kernel matrix is a high order matrix. It's difficult to calculate this large matrix in practical image restoration problem directly by maximum entropy algorithm at a common computer for larger image. Second in this paper, we show a kind of deconvolution for overcoming the store problem of kernel matrix and use the conjugate gradient algorithm for the iterate convergence problem. The experimental results show its total computational burden and the memory requirement are moderate. It can run on a common PC and is suitable for many kinds of image blurring.关键词：Maximum entropy;Image restoration;Aperiodic deconvolution2275|188|0更新时间：2024-05-08
- 摘要：Attention was focused on Delaunay triangulation for its processed result is whole optimization. While according to the study on some Delaunay triangulation algorithms, there is a bug in a common Delaunay triangulation algorithm[1,2]on 2D arbitrary polygon. According to the judge rule of the algorithm, it is possible to make result of Delaunay triangulation wrong with the effect of the“irregular position”vertex of polygon,“irregular position”vertex is the vertex which is in the candidate vertex set during the processing, but would break the“incircle”rule of classical Delaunay triangulation if that vertex is selected for Delaunay triangle in the end. This question was analyzed and discussed in the paper, and then an improvement upon the algorithm is presented, i.e, adjusting the data structure of algorithm or modifying the judge rule to make the resultant triangle set correct and satisfied, the former method is better than the latter, but it costs more to the original algorithm.关键词：Delaunay triangulation;Algorithm;Robustness;Irregular position2558|159|0更新时间：2024-05-08
- 摘要：Genetic algorithm is a soft computing method and new optimization searching algorithm. Being used in processing image, it is an intellective information processing method. When processing grayscale image, because the amount of data and computing of image is very large and traditional genetic algorithm has early convergence problems, the quality of image restoration is wrong. The paper designs a new chromsome coding method, and introduces the combination of simulated annealing and genetic algorithm into genetic operation in restoring of grayscale image. This new method of image restoration by the paper presented solved the problem that the quality of image restoration is bad, because of early convergence in traditional genetic algorithm. By experimenting of medicine image, it's results show the quality of image restoration using this new method is good than traditional genetic algorithm.关键词：Genetic algorithm;Image processing;Image restoration;Simulated annealing algorithm1969|160|0更新时间：2024-05-08
- 摘要：In this paper, the important property of convex object morphology addition is proved that F(S,u)=F(A,u) F(B,u) based on integral geometry, this can be popularized to concave set, then the two objects' morphology operator can be calculated through the two point sets' Minkowsky addition which have the same normal vector. The concept of vector sphere is provided, and the Minkowsky operator can be turned to the combination of two vector spheres. With the introduction of“Negative Object”, a unified model of graphic morphology operators is developed by combining the three concepts. This model unifies the morphology addition, subtraction of 2D and 3D objects in algorithm theory, and guaranties the correctness of the model' s theory.关键词：Morphology operator;computer graphics;Normal vector sphere;Convex analysis2072|156|0更新时间：2024-05-08
- 摘要：This paper presents a texture classification approach based on function link network. Image texture is characterized by the second order Gauss MRF model, and the least square error estimation is employed for the estimation of model parameters. However, these parameters are proved to be inefficient in texture classification. To solve this problem, we introduced a function link network to improve the classification performance. Experiment shows that better classification results can be obtained than traditional euclidean distance approach, and it has the advantage of simple processing procedure and fast convergence speed.关键词：texture analysis;Markov random field;neural network2174|141|0更新时间：2024-05-08
- 摘要：Facial features extraction is one of the essential techniques in automated visual interpretation and recognition of human faces. According to the basic theory, methods and techniques of active contour/snake model, a series of algorithms are presented. In this paper, facial features are described accurately about contour but not express simpllely with datas. In the experiments, the contours of eye are captured by deformable template model, the shapes of the eyebrow are extracted by active contour/snake model and the results show that using the algorithms for facial feature extraction can get good adaptability and robustness.关键词：face recognition;Active contour/snake model;feature extraction2387|149|0更新时间：2024-05-08
- 摘要：To resolve the problems existed in unitary algorithm for digital image registration, a hybrid algorithm combining unitized product and phase correlations is put forward. It upgrades the registration probability efficiently. To improve probability and speed of registration more, side-constraint-competition is used to constraint the edge of image in the paper, and reduction of resolution is taken to decrease calculation scale and increase speed of registration. Simulation shows that the algorithm is successful and practical.关键词：Image registration;Unitized product correlation;phase correlation;Side-constraint-competition2380|171|0更新时间：2024-05-08
- 摘要：The paper shows how to use Object-ARX to build Block management system. It describes the way to store many blocks in a drawing file. It explanis the structure of the blockbase and the stucture of the named object dictionary which stores block information. It also describes how to add blocks to the blockbase, how to get a block from the blockbase and how to manage block information.关键词：computer aided design;Named object dictionary;Object-orentied;Block management2231|152|0更新时间：2024-05-08
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