最新刊期
卷 8 ， 期 6 ， 2003
- 摘要：This paper is the literature bibliography on computer graphics in China in 2002. We collected and classified most of important papers in computer graphics field publised in Chinese, selecting 463 references from 12 important Chinese journals published in 2002 and classified these references into different categories according to their contents. Furthermore, we inrtroducd the graphical conferences held in China in 2002. Based on the overviewing and analysis work, we found that the number of researchers and developers engaged in comuter graphics related field is increased a lot in the past fews years, and many conferences are held each year, many high level achievements are made in China. In addition, computer graphics itself develops, deriving some new research topics or directions.关键词：Computer graphics;graphics engineering;Graphics processing;Technique application2836|179|0更新时间：2024-05-07
- 摘要：Because of the complexity of the microwave radiation characteristics, the recognition for objects with comprehensive structure such as habitations from Synthetic Aperture Radar(SAR) image is still in investigation. A new method for extraction of habitation areas from SAR images is presented. In accordance with the mechanism of the microwave dispersion, the texture feature of habitation on SAR image was analyzed. Based on the technology of texture analysis , pattern recognition and color space transformation, the main steps of the new method to extract the habitation areas from SAR image are: firstly, many texture images are generated by analyzing the Gray Level Co occurrence Matrix(GLCM); Secondly, 3 suitable texture images, in which the habitation areas contrast to background clearly, are selected from all of the texture images to combine an artifical color texture image; Thirdly the color texture image is transformed into the intensity image by the HIS color space transformation technique; Finally, a threshold was used to decide whether each pixel on the intensity image belongs to habitation or not. Experiments illustrate that this method is adaptable and its right recognition rate is beyond 70 percentages.2749|161|0更新时间：2024-05-07
- 摘要：Four-dimensional(4D) matrix and four-dimensional matrix DCT(4D-MDCT) theory are proposed and applied in color video coding, in order to obtain high compression for color video under high signal-to-noise ratio. The four-dimensional matrix (4D Matrix) theory is a new and useful theory for color video processing. The color video coding method based on 4D-MDCT put several frames of color video into a unified mathematical model (i.e., 4D matrix), and various correlations in color video are eliminated utilizing 4D-MDCT. The four dimensions of 4D-MDCT used in the proposed algorithm are image width (row component), image height (column component), three channels (Y, U and V) in a color image (vertical component), and adjacent three frames of the video sequence (depth component) respectively. Similar to the method of 2D-DCT, the whole three frames of a color video sequence are also divided into“4D-blocks”, that is 4D sub-matrices, and the order of each sub-matrix is 3×3×3×3. The transform coefficients are coded by vector quantization further. The method can fully exploit correlations between adjacent pixels of an image, YUV frames of color space, and adjacent frames of video at the same time. Experimental results has proved that for the color video in applications such as videophone and video conferencing, the proposed method can achieve higher compression ratio under high signal-to-noise ratio.关键词：Computer image processing;Color video;4D matrix;DCT;video coding2422|190|0更新时间：2024-05-07
- 摘要：This paper provides an image compression scheme called SBPC algorithm based on subband bit plane coding and integer to integer wavelet transform. SBPC algorithm divides the coefficients of integer to integer wavelet transform into bit planes within each subband which are named as subband bit planes. For these subband bit planes, the algorithm uses simple but effective rate distortion optimization method to determine the coding order. Unlike the JPEG2000 standard, this R D optimized coding order is independent of images. According to the coding order , the coefficient bits are coded by adaptive MQ arithmetic coder. SBPC algorithm can compress an image at any given bit rate or image quality from lossless to lossy, and the coding stream is scalable both in spatial resolution and in image quality. The algorithm can also realize coding of images with region of interest(ROI) by compressing the ROI losslessly. The experiments show that SBPC algorithm is comparable to the float point EZW algorithm and JPEG2000 reversible coding scheme in the coding efficiency, while the coding/decoding speed is much faster than that of the other two algorithms. In addition, SBPC algorithm needs very low memory and its computation complexity is also low.关键词：Computer image processing;Integer to integer wavelet transform;Bit plane coding;MQ arithmetic coder;Image compression2913|172|0更新时间：2024-05-07
- 摘要：In Intelligence Traffic System (ITS), the accurate detection of traffic flux at real time on road scene is very important steps. The still camera based video detection approach is one of the most important methods with much superiority to others. In this paper, a knowledge based video traffic flux detection system is presented. The traffic segmentation and recognition is the main algorithm of this system. According to the knowledge of vehicles' movement, vehicles have huge inertia, we assure that vehicles are moving at straight line in short period. With this premise, we reproject the movement of features to the road plane. The reprojected velocity of a points of the vehicle have a proportion with the height to the road plane. In the detection system, the Canny edge feature was used to fit a straight line and to match in image sequences. In the recognition stage, we assign a vehicle model and the height to the type of vehicle and reconstruct the 3D space model and verify this model with rules. The experiment results show that this algorithm is better than previous method to detect vehicle in congest, occlusion and shadow cases.关键词：Computer image proceesing;3D restructure;3D structure recognition;Intelligence traffic system;Traffic flux detection;Rules based detection2584|179|0更新时间：2024-05-07
- 摘要：In this paper, A three dimensional discrete cosine transform(3D DCT) coder for still color images is presented, which can not only achieve high compression ratio but also ensure good image quality. In the proposed method, the original image is splitted into non-overlapped 8×8 blocks and segments subblocks of the image into four different classes based on local energy magnitude. Then those subblocks with the same class are gathered to form 3D cuboids, and employs 3D DCT to the 3D cuboids. This improves the efficiency of compression.Computer simulation results show that thePSNR(average Peak Signal-Noise-Ratio) of reconstructed images achieve 29dB with high fidelity when the compression ratios are higher than 40. Compared to JPEG, it advances more than 5dB in the same situation. The proposed method achieves higher fidelity of decoded images than by JPEG.关键词：Computer image processing;Image compression;3D discrete cosine transform2527|186|0更新时间：2024-05-07
- 摘要：This paper presents a new method to implement the digital image morphing based on Delaunay triangulation. Contrasting to the usually used quadrilateral meshes, the character regions are defined by triangular meshes, which can allow a more freely selection of control points and much less number of the selected control points. The two triangular meshes are determined by the corresponding control points on the two morphing images. In order to define a unique triangular mesh using a set of points on the integer grids as in digital images, three additional criterions are proposed as the complementary rule to the Delaunay triangulation. According to the large amount of computation in the coordinate transform process, a new algorithm of coordinate transform is presented based on the classical Bresenham algorithm, only addition and subtraction computation is employed, the multiplication and round computation are avoided, and then the whole process was accelerated greatly. With the new method a satisfying morphing result has been acquired.关键词：Computer image processing;Image metamorphosis;Triangular mesh;Control point;Delaunay triangulation2930|193|0更新时间：2024-05-07
- 摘要：A new method to determine 3D motion and structure based on spare optical flow is presented. Motion analysis can be roughly classified as feature based or flow based, according to if the data they use are a set of features matches or an optical flow field. The proposed method integrates feature based and flow based method by using the corner points as feature points and estimating sparse optical flow field. Firstly, detecting and tracking corner points in image sequence and the locations of tracked corner points were recorded. Then, we proved that optical flow field could be replaced using displacement field approximately in theoretically, so the optical flow field was estimated at sparse locations by measuring the displacement of corner points between consecutive frames. Finally, a new linear method is derived to determine the 3D motion and structure at each corner point from known optical flow field. Experimental results using real image sequences showed that the presented method provided a good estimation of the optical flow field and 3D motion and structure.关键词：Computer image processing;Corner point tracking;Displacement field;Optical flow field;3D motion and structure;Linear algorithm2816|193|0更新时间：2024-05-07
- 摘要：Interpolation is an important method for super resolution technology. We believe that visual quality of an interpolated image mainly depends on two factors of an edge profile: (1) The gray value across the edge orientation is sharp; (2) The gray value along the edge orientation is smooth. For this reason, we propose a new interpolation method in this paper. Firstly, we detect the edge using Canny operator and interpolate along the edge. Secondly, we retain edge information of the original image by retaining pixels abutting against the edge in low resolution image abut against the edge in high resolution image and we smooth along pixels abutting against the edge in high resolution image for protecting edge information. Thirdly, we process the smooth region. Finally, we interpolate pixels between the pixel abutting against the edge and smooth region. By this method, we can create a clear edge image and therefore obtain a better magnified digital image.关键词：Computer image processing;Edge detection;Retain edge information;Protect edge information2456|176|0更新时间：2024-05-07
- 摘要：One of the hot key in medical image processing is how to suppressing speckle noise in ultrasound image. The low quality of ultrasound imaging brings some difficulty to sequential image processing and image analysis due to the effect of its inherent speckle noise. In this paper, a speckle suppression method for medical ultrasound image is presented. First, the logarithmic transform of the original image is analyzed into the multiscale wavelet domain. Then, the wavelet domain multiscale representation of image is regarded as Hidden Markov Tree model. The model is trained by the efficient EM algorithm,which is called Baum weltch algorithm. Speckle noise of ultrasound image is reduced by Bayesian estimator based on Hidden Markov model. Finally, the invert discrete wavelet transform and the exponent transform of the estimated wavelet coefficients obtain the denoised image in turn. Performance of the proposed method has been tested on ultrasound image. The results show the method effectively reduces the speckle while preserving the edges of the original image. Current state of the art methods, such as soft and hard thresholding, are applied on actual ultrasound medical images and compared with the novel method. The achieved performance improvement is quantified. The experiment results show the proposed method is feasible and reasonable.关键词：Computer image processing;Hidden markov tree model;Speckle noise;wavelet decomposition2347|186|0更新时间：2024-05-07
- 摘要：In order to protect the copyright of the image in the condition of the image quality,It brings forward a kind of the image non watermarking method. It introduces the non watermarking scheme,then it discusses the concrete process of this scheme at length. This method changes the traditional doings that the copyright of the image is protected by embedding the watermarking into the image to the method that the watermarking is drew out from the image, The central idea of this method is: the image wavelet coefficients are selected correctly firstly, then they are located and managed as the basic informations of the image.When the authentication image is to be identified,the same process is done to draw the informations out from the authentication image and those informations will be analyzed and detected to judged the copyright and the ownership of the image.It demonstrates this method is right by some tests. These tests prove that the method could make image distortion free and be robust,simple,easy to use. Lastly, it makes the method broaden and watermarking can be drew out from the image and embedded outside the image.This method not only can satisfy the need of the image authentication,but also can be used to hide the data.2815|181|0更新时间：2024-05-07
- 摘要：Accurately locating the root collar of seedling is important for the measurement of seedling morphological characteristics in the computer vision system of seedling grading. A RC ASL ( Root Collar Automatic Searching and Locating ) method based on fuzzy neural network (FNN) has been studied to resolve the key problem in the field of conifer seedling feature extraction. In the computer vision system, the features of the object may be extracted based on the hue variation of the image. Three line features of the seedling image are selected based on the hue variation in every line of the image as the input vector of the FNN, And the corresponding membership function has been chosen to accomplish the fuzzy processing of these features. BP algorithm is selected to optimize the weights of the membership function and the stimulation function of the neural networks. With the training of the FNN, a FNN structure used to search and locate the root collar of seedling is achieved. The foliage, stem, root and the root collar of the conifer seedlings is recognized from the seedling image and then the root collar is located by the FNN. The experimental results show that this method has the capability to meet the requirement of seedling grading operation.关键词：Computer image processing;Automatic locating;Conifer seedling;Root Collar;fuzzy neural network2435|170|0更新时间：2024-05-07
- 摘要：Road edge detection and tracking is a key technique for auto navigation of vehicle based on the information of road edge or road region. This paper presents pre knowledge based on human visual experience and prediction knowledge based on the kinematics equation of vehicle. With the selected road shape model, road edge detection and following for intelligent vehicle was executed by the combination of two modules. The road edge detection module is used to get the information about road edge when vehicle being started with the pre knowledge, while the edge following module is started to predict the position of road edge when vehicle running stably with the prediction knowledge, then two control equation parameters location and orientation deviation are calculated for auto navigation of vehicle based on preview unique visual. In the concluding, this paper analyzed the result of the real road tracking experimentation, which proved the effective and precise of the presented method.关键词：Pattern recognition;Machine vision;Auto navigation;Edge detection;Edge following2967|221|0更新时间：2024-05-07
- 摘要：A license plate recognition system and a new license plate location algorithm, which is called Vector Map Location Algorithm (VMLA), are introduced in this paper. The algorithm is based on the feature that the stroke of license plate characters and numbers have two edges which have the maximum cross correlation values. Thus by using the same method of flow PIV (Particle Image Velocimetry), a kind of vector map can be calculated and showed. VMLA is a real time and plate size adaptivity algorithm at a large range. At the same time, the contrast condition about the character to the background and a coarse estimation to the width of the stroke of license plate characters and numbers also can be derived from the map. Those above information are important to location precisely, character segmentation and recognition. The testing result of 540 images is that it costs about 0 2 second to process an image and 98 9 percent of the picture have good result, which shows that VMLA is a fast, high accuracy rate and promising location algorithm.关键词：Pattern recognition;Auto recognition system;License plate;Cross correlation;Vector map2423|200|0更新时间：2024-05-07
- 摘要：Iris location velocity and accurate is crucial in iris identification system. A iris location algorithm using geometric symmetry feature and two intersecting chord properties is presented. Based on this idea, edge detector and gray distributing information are used to extract iris interior edges , intersecting chord properties and voting scheme is used to search iris circle center. Then iris interior and exterior radius detected by using 1D radius histogram of Hough transform. At last the experiment results of iris location algorithms is showed, and the location time and accurate are compared with other method. Simulation results show that the method can improve location speed and isn't sensitive to noise effect.关键词：Medical image;iris location;Iris identification;Circle detector;hough transform2428|170|0更新时间：2024-05-07
- 摘要：Mesh parameterization is a primary task in many computer graphics applications, such as texture mapping, digital geometry processing and geometry compression, etc. This paper proposes a global parameterization method of meshes with arbitrary topology. For a given manifold triangle mesh with zero genus, it is firstly turned into a PM representation by means of edge collapse, the two vertices of the age to collapse are locally parameterized over the neighborhood of the new vertex obtained through pair contraction. Edge collapse is iteratively carried out until a simple convex base mesh with local parameterization information is reached, then this base mesh is center protected onto a unit sphere, and vertices deleted during edge collapse are added back and positioned on the unit sphere according to the local parameterization information one by one with an inverse order which they are deleted until an isomorphic mesh of original mesh is produced. By this means, global parameterization over the unit sphere of the original mesh is completed. To avoid fold back, relaxation operator is adopted.关键词：Computer graphics;Progressive mesh;mesh parameterization;Mesh analysis3369|188|0更新时间：2024-05-07
- 摘要：In order to discuss the micromechanism and the simulating method of the curve like coastline. On the basic of the method calculating fractal dimension, and taking the Jiangsu Province coastline as an example, this paper uses the midpoint subdivision interpolation method and the Koch curve method to explore the simulated coastline generation. It puts emphases on the method of Koch curve; introduces its principle of realization and its process of simulation. According to different conditions and needs for simulation, it can not only simulate a section of coastline, calculate its dimension, but also can generate the coastline which dimension is appointed. By this way and with the support of GIS technology, the author designs a utility programmer for simulation based on fractal, and introduces flow of the programmer and analyzes its function in brief. Finally, the coastline of Jiangsu which scale is 1:2000000 is simulated by this program. Finally,some significant conclusions are drawn:(1)the coastline has the fractal character, it's self simulation. (2)the degree of the coastline is direct proportion to the fractal dimension. (3)if the method of simulation is different, the result is also not the same. (4)the technology of GIS is fitting for simulating the coastline.关键词：Computer graphics;fractal;Dimension;Coastline;Simulate;Geographic information systems2202|173|0更新时间：2024-05-07
- 摘要：It is difficult to neatly realize spatio temporal expression in traditional georelational data model for its complex organizing and storing on spatial data. But object relationship GIS simplify its complexity. Based on object relationship GIS, this paper puts forward the improved base state with amendments model, after analyzing some typical spatio temporal data model. This model takes the current state as base, and recorders the spatial objects' change procedure. All changes are reduced to "add" and "delete". Because taking the current state as base, it could avoid the spending for the frequently loading current map. Because its special method of recording change, it would randomly and rapidly generate spatial data of any past time on the support of SQL. In this paper, this model is also expatiated from three aspects: recovering snapshots, analyzing spatio temporal topology and reasoning the change of spatial object. These techniques are realized in an instance about land use change under the support of GeoMedia3 0. The successful test indicates that it is simple and facile to realize the improved base state with amendments model in object relationship GIS.关键词：Geographic information system;Object relationship GIS;Spatio temporal model;Improved base state with amendments model2393|178|0更新时间：2024-05-07
- 摘要：Map Overlay is an important spatial analysis in Geographic Information Systems. This paper presents a novel dual loop algorithm based on R tree to process vector map overlay analysis. The paper first figures out intersection points of line segments with enumerating method of polygon intersection, then uses the matching principle of "import export intersection point" to form the result arcs and further realize the dual loop algorithm of polygon on polygon and line on polygon vector overlay analysis; finally, perfects the algorithm through an efficient spatial access method-R tree index and it's efficient query and filter mechanism to spatial data, so excludes large amounts of unused graphics elements and advances the computational speed very much. This algorithm has been applied to the software development of the commercial geographic information systems. Performance tests confirm that the R tree map overlay algorithm is quick and efficient, and has powerful practical merits.3137|192|0更新时间：2024-05-07
- 摘要：The integration and interoperation of distributed inhomogeneity GIS system is the direction of GIS development. Based on the reserach of WMS(Web Map Service), WFS(Web Feature Service) and GML, this paper presented a new XML RPC based distributed computing model of internet GIS. The Model is composed of three tiers, the diverse geo processing of geo processing enabled client, the GIS distributed computing mid ware and the geo processing server. XML RPC is used to carry out the communication between geo processing client and geo processing server by GIS distributed computing mid ware. Login?Logout?GetCapability?GetCapability?GetMap?GetFtrInfo?GetSelFtrs?GetThemeMap?GetStatMap are defined as the basic GIS computing command in XML. GML 2 0 is used to present the geo spatial data and geo processing result. The geo processing sever may implement the XML RPC interface directly, such as Web Map Serve, or use a adapter to encapsulate the geo processing service. The geo processing client uses these basic commands and their combination to call the geo processing service. The geo processing sever execute the geo processing using its own geo spatial data, application model and computing resources. Then the geo processing client receives the geo processing results as image stream and/or feature stream encoded in GML 2 0 and thus integrate the distributed inhomogeneous geo processing server system.s关键词：Geographic information system;Internet GIS;Distributed computing;XML RPC2501|205|0更新时间：2024-05-07
- 摘要：Based on the analysis of the development of GIS application and technology, this paper brought forward the concept of CoGIS, namely Cooperative Operation GIS. Outer space earth man computer relationship in CoGIS was analyzed, CoGIS was GIS supporting human human interaction, and geographical information group communication in CoGIS was discussed, all of which made it differ from former GISs. CoGIS should embody the human oriented idea. Then, the characteristics of general CSCW application and the complexity of Geographical Information Science were analyzed, and the conclusion that CoGIS was not a simple GIS layer on CSCW was reached. Further, this paper brought forward the research content of CoGIS, and discussed some of them in detail as following: modeling theory and system architecture, distributed multi source GIS and knowledge sharing platform, group spatial decision making, CoGIS and VR(virtual reality), CoGIS and multi agents. Finally, this paper analyzed CoGIS application mode in brief.关键词：Geographic information system;Cooperative Operation GIS;Outer space earth man computer relationship;Cooperative group;Human human interaction;Complexity;sharing;virtual reality;Agent2831|187|0更新时间：2024-05-07
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