最新刊期
卷 5 ， 期 12 ， 2000
- 摘要：As one of a serial of reports, this paper is a survey on multimedia researches and applications in China, 1999. Since multimedia is a cross research area, papers about multimedia technology are distributed on various journals. We saw about 2 764 papers published on 11 Chinese journals in 1999, from which we selected 369 ones on multimedia technology and made analyses on them, and the classified data were compared with which of last year. Looking into the data we can see that researchers in China pay more and more attention at human computer interaction, multimedia data retrieval technology and distributed multimedia supporting technology, which are also the international evolution trends in a quite long period. We present here an overview on the progress in multimedia technology in China, 1999. This will be convenient for researchers looking up reference, and helpful for editors compiling journals and for authors contributing papers.关键词：multimedia;Coding;virtual reality;hypermedia;multimedia communication;CSCW2430|188|0更新时间：2024-05-08
- 摘要：For the requirement of many practical applications in the area of industry and medicine, the research in three-dimensional objects recognition is very active. In general, the dominant paradigm in 3D objects recognition system proposes to achieve recognition and localization of 3D objects from images by a two-stage process: first derive an internal representation of a scene from the sensed input data and then match it against stored representations of objects in the database. This paper presents a comprehensive survey of the achievement of 3D objects recognition system in the recent decade. The three problems are discussed which are the type of sensors used, 3D objects representation and match strategy. Furthermore, the paper classifies and summarizes the primary schemes. At last, we describe some problems requiring a thorough research on three-dimensional vision system, such as the limitation by the class of shapes that can be described in most of the representation schemes, the clustered background influence on the recognition, and the contradiction between global and local in the 3D objects representation and recognition.关键词：computer vision;3D object recognition;Range image;3D object representation;Match strategy4963|260|0更新时间：2024-05-08
- 摘要：In the multimedia safety monitoring and detecting system of coal mine, the key technology is to compress the video signals which are from the subsystem of optic-fiber industrial TV. Fractal image coding can not be used in real time coding, because this method will have a delay when the code is picked up. After analyzing the feature of industrial TV image, the image is divided into background district and motive district by means of image enhancement and edge measurement. The background district is a static image, which can be compressed by fractal image coding. After that, a method of block-based image coding and wavelet transform coding to compress the image is presented. It is a good method for fractal coding to compress the motive image. It can be used not only in coal mine industrial TV image but also in any industrial TV image which background image is still and has practical value widely. At the end of the paper, a sample of compression is given.Fractals are a modern invention, they have been recognized as useful to natural scientists only over the last 20 years. Euclidean geometry provides concise accurate descriptions of man-made objects but is inappropriate for natural shapes. Fractals provide an excellent description of many natural shapes. In general, fractals are the result of a construction procedure and algorithm that is often recursive and suited to computers. Fractal coding is a new image coding method after subband coding, model-based coding and wavelet transform. It breaks through traditional coding theory frame. In real time coding and automatic coding it will have wide research prospect.关键词：fractal coding;wavelet transform;Industrial TV image1987|133|0更新时间：2024-05-08
- 摘要：In order to achieve very good salt and pepper noise cancellation as well as preserving image details, a novel non-linear adaptive algorithm is proposed in this paper. The algorithm is developed by the following main steps. Firstly, pixels with maximum and minimum gray value in filtering window are excluded. Then, mean of the left pixels in filtering window is obtained. Then, difference of the mean and gray value of the corresponding pixel is calculated. Finally, the difference is compared to threshold to decide how to get gray value of output pixel, i.e., if the difference is larger than the threshold, the filtered output of the pixel is the mean, else the filtered output of the pixel is not changed. The threshold is adaptively chosen according distribution of image intensity. The results compared with other published algorithms show that the proposed algorithm can remove almost all the salt and pepper noise pixels while preserve image details very well. Even if the image is highly corrupted, it can still work properly and provide significant improvement over the conventional median filter.关键词：filter;salt and pepper noise;Image restoration;Non-linear;adaptive2761|210|0更新时间：2024-05-08
- 摘要：A novel adaptive decimation/interpolation algorithm, which can be applied in all kinds of blocking image coding algorithm, is proposed. The image is first divided into non-overlapping blocks. Then the horizontal and the vertical gradients of each block are calculated. According to the two gradient values, the image blocks are classified into four groups, namely smooth block, horizontal-contour block, vertical-contour block and high-detail block. Then different decimation methods are applied to different class of blocks to reduce the original data quantity. Experimental results show, compared to other decimation/interpolation algorithms, the proposed algorithm can well preserve the contour and other detail information, thus substantially improve the quality of the reconstructed images, especially the subjective quality. The proposed method increases thePSNRby 3.9 dB while keeping comparable compression ratio for high-detailed images. For low-detailed images, compression ratio and PSNRare all slightly improved.关键词：Image coding;Decimation;interpolation;Block gradients2089|154|0更新时间：2024-05-08
- 摘要：The research purpose of this paper is to develop map symbol design subsystem for our country's GIS software——Geostar, which is developed by research center of Wuhan Technical University of Surveying and Mapping. Under the technology of object-oriented, symbol classification and organization, graphical element classification design and symbol base structures have been designed, and symbol design software and dynamic link library of spatial information symbolization have been developed. We have designed a series of specifications for cartographic symbols of national standard topographic map by using our map symbol design software, and the results are satisfied to the demand of production. In this paper, we introduce mainly application problems of object-oriented technology in the course of design and developing of symbol design subsystem. The research shows that the technique route we adopted is correct, the developed software has favorable encapsulation and it is convenient to maintenance and expansion.关键词：geographic information system;object-oriented;map symbol;System;Design2846|181|0更新时间：2024-05-08
- 摘要：Spatio-Temporal Analysis and Modeling Based on the Integration of GIS and CA Model关键词：Spatio-temporal analysis;Cellular automata;Transition rule;Urban expansion2512|141|0更新时间：2024-05-08
- 摘要：In GIS it is necessary to optimize the analysis function of the shortest path as the hinge of spatial network analysis, which includes shortest path analysis, resource allocation and isochrone, and so on. Here derived from the traditional calculating method, i.e. Dijkstra algorithm, the analysis procedure of the shortest path is improved by adopting the data structure of binary heap to complete the operation of priority queue. Initialization, Extraction, and Relzxztion. The topological structure of geographical network data and the detailed implementing steps of the shortest path are also discussed. Furthermore, the visualizing calculation of the shortest path is completed by COM(Component Object Model) techniques, and the calculating procedure is encapsulated into the component of the geographic network class. The complexity analysis and the case of this algorithm showes that the modified algorithm is applicable to improve the efficiency of spatial analysis of the net system.关键词：Dijkstra algorithm;Priority queue;Binary heap3303|219|0更新时间：2024-05-08
- 摘要：Aiming at the shortcomings of prevalent visual surveillance system, an intelligent surveillance system which can accomplish automatic detection and classification of moving objects by making use of the computer system is presented in this paper. It mainly consists of such modules as cameras, video capuring, change detection, classification, human interface, alarm log and image database etc. Because current image difference techniaue raises shcu problems as refreshing frequency of reference image and binary threshold selection problems after subtraction of pixel brightness, such comcepts as detecting block, extraction function, binary output function are introduced in this paper to resolve these problems. In addition to, there are complex scenes and lots of disturbance in outdoor environments, so some key techniques such as projection histogram of silhouette pattern, accumulation based on space-time information and geometric model based on edge detection are presented to solve the difficulty of human body recognizing and decrease the ratio of missing alarm and false alarm.关键词：Surveillance system;visualization;intelligence2607|136|0更新时间：2024-05-08
- 摘要：The investigation of the problem that concerns the match and composition between the virtual 3D computer graphics or image for the architecture planed to build and the real environment image sequence has been carried out. The major research way is to make anti-perspective calculation on the image sequence extracted from the video clip about the real environment based on photogrammetry and make analysis of lighteness, average square error and average chroma on the image sequence. The algorithm has been studied to get the parameters of the virtual camera by calculating out the parameters of the real camera with linear asymptote iterative calculation based on the technology of single photo analytical photography in photogrammetry. The algorithm of dynamic masking has been put forward to synthesize virtual image sequence and real environment image sequence based on keyframe technology when the segmentation edge varies with time. The model of virtual sunlight in computer's virtual 3D world coordinate space has been established based on the rules of the elliptical motion of planet in the solar system and the rules of earth's rotation to simulate the sunlight at any time in a year and in any position with arbitrary longitude and latitude in the world. These algorithms have been applied to the 3D dynamic simulation system based on real environment images. The result of experiments proves that these algorithms are effective.关键词：Perspective match;World coordinate system;Image masking;Model of lighting2265|144|0更新时间：2024-05-08
- 摘要：In this paper, we propose a new approach to recognize occluded objects. The information of the magnitude of the local extreme of the open angles in the contour of a model(occluded image) at a scale, the information of the distance and relative location between the two adjacent dominant points are suitably integrated as a set of features for describing a model(occluded image), the features are invariant under rotation, uniform scaling, and translation of the curve. The magnitude of opened angle at a pointpiin the contour can be easily calculated by the law of cosines, and its local extreme correspond to the sharper changes of the contour of the mode (scene). The feature matching is to define the correspondence between the model features and the scene features. Each correspondence between a model feature and a scene feature constitutes a“feature correspondence pair”, they are mapped onto the Hopfield neural network that is used to perform global feature matching. The proposed approach has been implemented on PⅡpersonal computer in Matlab5.2 programming language and examples are presented. The experimental results show that our proposed method can efficiently recognize an object from an image of occluded objects, and be implemented easily.关键词：Occluded objects;recognition;contour;Evident points;Hopfield neural network2500|174|0更新时间：2024-05-08
- 摘要：In recent yeras, as a novel way of exchanging and gleaning information, the Web browser has become more and more important, From the prinmarily support for only tedious characters to the ability to display a variety of images, HTML, the basic file format for the browsing and exchanging of data from Internet/Intranet, is taking an indispensable role. As the development of Web browser, HTML, however, cannot meet the new needs and its disadvantages are becomign obvious. The first shortcoming lies in the fact that the HTML specification adopts fixed tags, which is more limited and meaningless. As a result, intelligent searching on the Internet is rather difficult. In addition, not supporting vector graphics can be another weakness of HTML. Classic Web browsers, such as Internet Explorer and Netscape Navigator, simply display images downloaded from Web sites without any further processing. Meanwhile, the images bring some more shortcomings, too big file size and variable appearances among different devices, for instance. As a solution, SVG, a new image and graphic specification supporting scalable vecor graphics for Web browsing, is put forward. As a member of the XML family, SVG inherits the advantages of XML and fully supports vector graphic, image and text by means of defining extensible tags. The SVG specification is presented in this paper. The characteristics and advantages of the specification are analyzed in detail in the view of technique. A typical example is demonstrated to reinforce the specification. Finally some advice is given at the end of the paper.2600|161|0更新时间：2024-05-08
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