最新刊期
卷 5 ， 期 10 ， 2000
- 摘要：This paper is the literature bibliography on computer graphics in China in 1999. Based on the current status of the research on graphics engineering as well as the distribution of related publications in China, we selected about 394 references from 11 important Chinese journals published in 1999 and classified these references into different categories according to their contents. We hope that the paper could provide readers with a general and up-to-date overview of graphics engineering in China.关键词：computer graphics;graphics engineering;graphics processing;technique application2503|126|0更新时间：2024-05-08
- 摘要：The massive information and world-covered network makes the information management and sharing more urgent than ever, in order to attain invalid management and sharing of geospatial information on WebGIS, the detailed research and design on definition, role, content, implementation, application of geospatial metadata has been discussed in this paper. Combined with the frontier of international geospatial metadata standard, the geospatial metadata standard draft has been advanced here. Also taking advantages of the newest Internet technology and integrated with WebGIS, geospatial metadata management system, which had been running on Internet, has been designed and achieved. And some of demonstrations of various functions of this system have been presented finally. In the current times of information and Digital Earth, it will promote the sharing of geospatial information and propel the progress of Chinese standard, at the same time, this system provided the bases for constructing National Spatial Information Infrastructure (NSII) and Digital Earth.关键词：WebGIS;Geospatial metadata;Geospatial data2171|143|0更新时间：2024-05-08
- 摘要：This paper presents an approach to recognize human activity based on principal component analysis (PCA). By a Gaussian model of skin color in HSI color space, our system tracks human face and hands incorporating with the constraints of motion and region continuity. A constant acceleration motion estimation and Schwarz representation based shape matching are applied to create correspondence between frames. Then motion parameters of faces and hands are represented and matched with the parameter curves of exemplars in PCA framework. Through modeling the spatio-temporal variants of each type of activity, recognition can be achieved although subject and imaging condition are different from those of exemplars. Examples of Taiji postures recognition are studied and discussed to illustrate our method. The experiment shows that this activity recognition approach is of low confusion rate and robust in some degree. We believe this approach can be applied to develop an activity interpretation system.Applications fields of this work include indexing video based on motion semantic description, assistant exercise training, video surveillance efficient video coding, etc.关键词：activity recognition;Area tracking;Principal component analysis2139|119|0更新时间：2024-05-08
- 摘要：The technology of management for spatial data in RDBMS is currently one of the research focus. In GIS integrated environment, the embedded database engine of spatial database and attribute database is encapsulated entirely by GIS platform and its efficiency is quite high. But it is difficult for spatial database engine (SDE) to operate mass database and manage application system of GIS with client (browser)/server structure. Although the functions of commercial enterprise RDBMS are very perfect, it do not still meet special demands of GIS, that is, it must be able to process spatial data (maps) in database. The spatial database engine (SDE) makes the RDBMS to be able to manage the spatial data and build relationships with attribute data. In this paper, a data structure model of spatial data engine (SDE) is presented. The paper analyses the system structure of the data model, the data organization and the expression of spatial graphical features. According to the given data structure model, we realize the operation of storage, topologic arithmetic and topologic analysis for spatial graphical data in RDBMS based on SQL Server. The application in land registration system shows that Spatial Database Guide (SDG) based on given data structure model runs reliably and well which cab be used widely in development of GIS.关键词：Spatial database guide;Data structure model;data organization;Spatial graphical features1939|124|0更新时间：2024-05-08
- 摘要：A subpixel multisensor image registration method based on edge and contour information is proposed in this paper. The purpose of this method is to realize subpixel matching of low-resolution images by using high-resolution images. By effectively considering the edge and contour information preserved in the multisensor images, and unifying feature-based matching and least-square matching, this method is work well in general. In addition, it is computationally efficient, and robust to noise. The application of image registration between NOAA-AVHRR, Landsat TM and 1∶1 000 000 digital map data have shown that.关键词：Image registration;threshold selection;Image segmentation;Multisensor Image2424|120|0更新时间：2024-05-08
- 摘要：The methods of obtaining satellite snowcover information were described and discussed in this paper. The threshold value of snow was used for extracting snowcover information from NOAA/AVHRR images,and the Normalized Difference Snow Index (NDSI)was used for acquiring snowcover image from Landsat TM data. In order to derive more detail snowcover information, the matching technique of NOAA/AVHRR and TM images was also involved in the research. The results showed that the accuracy can be improved when the methods were used in the extraction of snowcover information from satellite images.关键词：Satellite;Snowcover;NDSI;The threshold selection;Extracting methods2479|129|0更新时间：2024-05-08
- 摘要：In this paper, we define 1-D and 2-D real discrete Gabor transforms (RDGT) for finite discrete signal and image representation. By replacing the complex Gabor basis functions of the complex discrete Gabor transform (CDGT) with real Gabor basis functions, a significant computation of the RDGT can be saved as compared with the computation of the CDGT. The similarity between the RDGT and the discrete Hartley transform (DHT) allows the RDGT to utilize the fast DHT algorithms for fast computation. In addition, not only does the RDGT have a simple relationship with the CDGT such that the CDGT coefficients can be directly computed from the RDGT coefficients, but the RDGT coefficients also have the same properties as the CDGT coefficients. Some simulation results are given at the end of this paper.关键词：Discrete gabor transforms;Discrete hartley transforms;signal processing;Image processing2118|127|0更新时间：2024-05-08
- 摘要：In recent years, many scholars have successfully applied the Kohonen s self-organizing feature map (SOFM) neural networks to vector quantization image compression encoding. The two main shortcomings of the basic SOFM method are its high computation complexity and its poor codebook quality compared to the conventional LBG algorithm. In order to improve the codebook performance, some modification is made in the weight factor adjustment of the basic SOFM algorithm in this paper. In order to reduce the computation complexity of the basic SOFM algorithm, some fast search methods are used in SOFM iterations during the search for the winning neuron. The proposed algorithm is used to generate vector quantization codebook and the generated codebooks are used for image compression encoding in this paper. Simulation shows that the reduction of computation is substantial and the codebook performance is improved. Compared to the basic SOFM algorithm, the reduction of computation is about 75%. For not only image in the training set but also the image outside the training set, the encoding quality can be improved by 0.80dB~0.90dB compared to the basic SOFM algorithm.关键词：vector quantization;Self-organizing feature map neural network;Image compression2139|137|0更新时间：2024-05-08
- 摘要：As a kind of nonlinear filters, stack filters can suppress impulse noise effectively, and keep edges and details at the same time. Those have two important properties: the threshold decomposition and the stack properties, which ensure that the filtering process go on in binary field parallelly. The optimal stack filters under mean absolute error (MAE) criterion can be developed with least mean absolute error (LMA) algorithm. The filters developed directly are non-recursive filters. Based on the above, the recursive implementation approach of optimal stack filters under MAE criterion are advanced. Two approaches are used: direct recursive approach and optimal recursive approach, the latter resolve the matching between filter and input signals. The result of simulation with computer software illustrate that, the characteristics of noises removing of recursive stack filters are superior to that of non-recursive filters, and the characteristics of edges and details preserving of the former are similar to the latter. So we can conclude that the advanced recursive approaches improve the function of the stack filters, which is meaningful to the advanced study for theory of stack filtering.关键词：Stack filtering;Recursive filtering;nonlinear filtering2470|121|0更新时间：2024-05-08
- 摘要：In the field of texture image segmentation, method based on visual perception become a new effective way to solve this kind of problem. This paper just does such research work on texture image segmentation. In the paper an approach which combines wavelet transform with orientational filtering is proposed. First wavelet package can be used to extract main frequency of the texture since wavelet transform has the character of multi-channel filtering. And then we use a 2D orientational filter to extract the others information about the orientation and frequency, etc. Finally we use a human texture image in the experiment to test the approach of this paper. And we get the processed result of the image. The experiment shows the effectiveness of this method.关键词：Image segmentation;multi-resolution;wavelet transform;Orientational filter2259|130|0更新时间：2024-05-08
- 摘要：The level dividing rules and classifying principles of engineering semantics of the practical engineering drawings are advanced for the first time. According to the process of the projection expression, the semantics are divided into expression mode semantics, projection relation semantics and dimension constraint semantics. Furthermore, every level is classified to lower explicit semantics and upper hidden semantics, which the engineering semantics is characterized by dynamic, hierarchy and formalization through analyzing systematic the explicit semantics and digging deepening the hidden semantics.关键词：Engineering semantics;Expression mode;Projection relation;Dimension constraint;Graphrecognition;Mechanical engineering drawings2593|142|0更新时间：2024-05-08
- 摘要：We develop one Marine Geographic Information Systems for synthetically forecasting marine oil and gas resources because Marine Geographic Information Systems has many advantages in the study field about marine. At first, we describe domestic and foreign study status about Marine Geographic Information Systems based on analysis of its study background. In succession, one integrated system for forecasting marine oil and gas resources developed by us is introduced in detail. Here, we mainly introduce its system environment, work flow, structure and central functions. At last, conclusions about this study are discussed and its development prospect is described. The study promotes industrialization development of the study of the project about synthetically forecasting marine oil and gas resources, and lay a foundation for study of Marine Geographic Information Systems in our country.关键词：Marine field;Marine geographic information systems;Marine oil and gas resources;Integrated system for forecasting marine oil and gas resources2238|147|0更新时间：2024-05-08
- 摘要：This paper introduces function and configuration of power plant simulator. As an important watching window of power plant, Furnace's flame TV supplies the combustion case for the operators. The simulation of flame is very important in the power plant simulator. The article gives a method application Java technique how to realize simulation boiler's flame of power plant. We have realized the flame simulation of part of boiler combustion work condition, and think the flame simulation under all work conditions of combustion can be realized Java's technique.关键词：Power plant simulation;Furnace flame TV;Java techniques1811|112|0更新时间：2024-05-08
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