最新刊期
卷 5 ， 期 3 ， 2000
- 摘要：Developing a visually convincing model of fire, smoke, clouds and other irregular fuzzy objects is the most difficult and attractive problems in computer graphics. This paper relates several methods for modeling and simulating irregular objects such as fire, smoke, and clouds. Solid texture-based model, fractal-based clouds model, diffusion processes-based fire model, cellular automata-based flame model, and particle system-based fire model and clouds model presented by researchers in recent years are introduced here. Lastly, we analyze the performance such as representation of the object, a model for its spatiotemporal behavior and application environments of these existing models, especially for the models based on particle system which can represent motion, changes of form, and dynamics that are not possible with classical surfaced-based representations and can easily generate richly detailed images. For particle system, the quickly computable models have to be developed to describe these objects in the future.关键词：Modeling for irregular objects;Diffusion processes;particle system;Cellular automata;fractal3049|221|0更新时间：2024-05-08
- 摘要：In this paper, we suggest a new subband compression schemes based on Morphological Subband Coding(MSC). Compared with the classical QMF subband filters, it will not be affected by ring effect. In contrast to ASD method, it is simple and adopts the adaptive companding quantization. Moreover, the result images compared with JPEG show that: with perfect reconstruction quality, MSC has better properties such as low complexity and high robustness on transmission.关键词：Compress;Image;Subband;filter2128|163|0更新时间：2024-05-08
- 摘要：The BP neural network is widely used for classification of remote sensing image data nowadays. But it has the usual shortcomings of multilayer sensor neural network too: the question about the number of crytic layer and the number of crytic layer node, the question about local minimum, the question about training speed, and soon. In order to solve the questions thoroughly, a sort of classification algorithm of high-rank neural network is developed in this research. This algorithm has not crytic layer, so it hasn' t the question about the number of crytic layer and the number of crytic layer node. It' s interface of model classification is nonlenear, so the question about local minimum is solved thoroughly. It' s training speed is faster and the precision of model classification is greaterthan that of the BP neural network algorithm. In this article, the structure, flow chart and course control of this algorithm is introduced detailedly. Using the hyperspectral data in the destrict of Shahe town, Beijing city, an experiment is done and a excellent result is gained. The classification precision of training sample and the classification precision of test sample are all 100 percent. It is proved that the algorithm of high-rank neural network has great advantages than other algorithms of neural network in structure, speed and precision.关键词：High-rank neural network;Classification precision;Pattern recognition2355|286|0更新时间：2024-05-08
- 摘要：There are great gray-level differences between multi-sensor images, which make it very difficult to register them. An auto-correlation model of gray-level difference is described in this paper, which is assumed an ergodic wide-sense stationary two-dimensional random field with zero mean value in a local region. This research will be a powerful support to gray-level difference rectifying of multi-sensor images. Experiment results show the validity of the proposed auto-correlation model.关键词：Gray-level difference;Auto-Correlation;Wide-sense stationary;Ergedic;Randem field2264|288|0更新时间：2024-05-08
- 摘要：Shape is an important feature of objects in image and shape-based image retrieval has obtained more and more attentions in recent research on content-based management and utilization of image database system. Although several systems have been developed, two main shortcomings are still existed. The first is that the performance is not stable. The second is that the variance with respect to translation, scaling, and rotation. To cure the above problems, this paper presents a novel shape-based image retrieval algorithm. The algorithm first transforms the luminance image with wavelet modulus maximum to get multi-scale edge images, then employs a set of seven invariant moments to extract the features of image. Consequently, each image is characterized by a multi-scale moment vector in feature space. Similarity is given by the Euclidean distance between two images' normalized moment vectors. Experimental results on clothes image database show that this algorithm can well capture the shape and spatial information of image and it is invariant with respect to translation, scaling and rotation of objects. In addition, the algorithm is also tested with more complicated flower images in a database; the experimental results further verify the effectiveness of the algorithm.关键词：Image retrieval;shape feature;wavelet;invariant moments2734|196|0更新时间：2024-05-08
- 摘要：DPIV (Digital Particle-Imaging Velocimetry) has been attached importance to and applied wisely interiorly and overseas. But at present, its most difficult problem is the precision. Because the tracer particle images of DPIV are sampled by CCD and image digitizer, the noise (mainly the noise of particle image size, the size of interrogation window, local velocity gradients, the number of particles within the sampling window and quantization effects) that is imported inevitably in the process of experiment falls the precision of DPIV experiment. This paper presents the image (simulative and practical image) noise removing in DPIV based on wavelet transform whose characteristic is the multiresolution. This method is compared with image noise removing by Wiener and median filter. The result shows that image noise removing in DPIV based on wavelet transform improves the precision of DPIV experiment, and it is the most precise to rebuild the velocity field based on cross-correlation after image noise removing in DPIV using wavelet transform.关键词：wavelet transform;Noise removing;DPIV1940|177|0更新时间：2024-05-08
- 摘要：Firstly, an improvement was made on mutation of adaptive genetic algorithm (AGA). The combination of one-point mutation and two-point mutation could prevent AGA from converging to the local optimum. Secondly, a new method for image segmentation using the improved AGA was put forward. The method of Otsu, the method of histogram based on gray difference and the entropy-based methods were compared with this algorithm. The improved AGA was proved to give attention to the main information by experiments. Good results can be achieved from some images. And much less time was used by the algorithm.关键词：Image segmentation;Adaptive genetic algorithm(AGA);Crossover;Mutation1956|211|0更新时间：2024-05-08
- 摘要：This paper introduces a new type of B-ultrasonic system based on PCI bus. Using the ample software and hardware resource of personal computer, this system achieves as good image quality as top grade B-ultrasonic diagnosis systems, and offers stronger functions than general low-end ones with comparatively cheap price. Its performance can sufficiently meet common needs of ordinary users. This system can accomplish functions that traditoional B-ultrasonic diagnosis equipment can't do, such as multiframe image replaying, storage, processing and transmission of ultrasonic images, superposition of characters and remote diagnosis, etc. The unique featrue of this system is that it uses PCI bus to import the B-ultrasonic image into the personal computer in real time and utilize the computer terminal to display the image. The scan mode used by this system is D/4. This paper discusses the D/4 scan mode, the PCI interface mode, and the functions of the system modules.关键词：PCI bus;B-ultrasonic system;D/4 scan mode2025|148|0更新时间：2024-05-08
- 摘要：The problem of autonomous driving and co-navigating has received increasing attention in recent years. This paper researches on road recognition and tracking in automatic visual road vehicle guidance system by processing and analysing a long sequence stereo images of real road which are gathered on an autonomous vehicle driveing outside. An algorithm is proposed for estimating the parameters of three-dimensional motion, based on long sequence stereo images processing. It is our core method to build the road's curvature dynamic model, vehicle's state kinematic model and camera's perspective model, and to estimate the 3D motion parameters using Kalman filter. The algorithm is fast,robust and practical. Experimental results with real scene images are given. Experiments prove that the results are satisfying for road recognition and tracking, so the approach could actively improve the research on the performance of the visual road vehicle guidance system.关键词：Kinematic model;Long sequence of stereo images;Estimation of motion parametrs;Road recognitionand tracking2228|184|0更新时间：2024-05-08
- 摘要：In this paper, a new approach for feature points correspondence in non-rigid image sequences is proposed. First of all, according to the very short time interval between consecutive frames in image sequences, the paper points out that the motion of feature points is smooth, and a cost function that describes the smooth degree of motion feature points is presented. Then the object tracking technique is introduced into the tracking of feature points, using two 1D Kalman filter to track the two coordinates of feature points. In the process of feature points correspondence between the two consecutive frames, the distance between the predicted position of feature points and the position of feature points in the next image frame, and the cost function of feature points are used to correctly judge the extension of every motion trajectory. The occlusion problem can be solved by the position prediction in the process of the tracking of feature points. Results show the approach can establish correct correspondence of feature points and can solve the problem of occlusion.关键词：Image sequence;Non-rigid motion;Feature correspondence;Motion smoothness;Feature point tracking2192|151|0更新时间：2024-05-08
- 摘要：Corner feature is a usually used local invariant. It is widely applied for national defense and industry technology. Using different methods: the splitting-merging algorithm, the improved Hough transform method and the extended corner invariant algorithm, different corner features is extracted to recognize occluded objects in this paper. Finally, Dempster-Shafer evidential reasoning method is adopted for data fusion at report level. This method can use information from different sources and decrease uncertainty of the recognition system. The classification experiment shows that this method effectively improves the matching precision of the recognition system.关键词：Fusion;pattern recognition;Local feature;Corner feature;Occluded image recognition2116|169|0更新时间：2024-05-08
- 摘要：In constructing Digital Elevation Model (DEM) from image pairs, often the elevation data of point cannot be directly recoverd, due to the limitation of the mapping algorithm adopted and the mutual hiding of the terrain itself. Therefore it is very important to construct a dense terrain model from these sparse data by means of interpolation. In this paper, based on the fractal features of natural terrain, a Spacial Polyhedron Model Deformation algorithm is presented, which can generate realistic dense terrain model from sparse points that are irregularly distributed. The experimental results are satisfactory.关键词：Surface interpolation;Natural terrain;Fractal;Spacial polyhedron model deformation1961|148|0更新时间：2024-05-08
- 摘要：Because of the existence of regional variability in natural and economical condition in agricultural production, proper agricultural division is essential that different developing strategy can be adopted for every zone. However, establishment of agricultural division requires large, unwiedly geographical-referenced data sets and spatial adjacency relationship, it is difficult to utilize many cenventional mathematical methods. In the study, Geographical Information System was used to manipulate and analysis spatial data, Optimal-tree Cluster was adopted for division. This integrated methodology was programmed as applied model and embedded in Soil Information System, case on Longyou county, Zhejiang province. Advantage of this integrated methodology is easily and quickly with low cost, compared to agricultural division by local bureau. Furthermore, the result is also suitable for the practical situation.关键词：Optimal-tree cluster;Agricultural division;geographic information system2162|175|0更新时间：2024-05-08
- 摘要：For the sake of vehicle identification and intelligent management, it's necessary to recognize the characters on the license in high accuracy. Selection of a feature extraction method is probably the most important factor in recognition process. The feature of number and letter character construction can be extracted by wavelet transform effectively and described by moments. A method of character recognition based on linearity moments and wavelet transform is presented in this paper. The result of experiment shows high recognition rate above 97%, which indicates that the method can be put into practical use.关键词：character recognition;feature vector;Moments;wavelet transform2419|165|0更新时间：2024-05-08
- 摘要：A two-step location approach combining coarse location with fine location is presented, and an extant iris location algorithm is improved in order to fasten the speed of iris location and make the iris location algorithm more robust. Grey scale projection approach is used for the coarse iris location and a kind of dynamic circular edge template is adopted by the fine iris location. Experiments show that the method has good performance of sub-pixel precision and about 1 second on speed compared with 3~5 seconds by the original iris location method. The two-step location approach can fasten location speed and decrease the blindness of search computation, and the improved iris location algorithm is reasonably more robust than the original one.关键词：iris location;Iris identification;iris2814|194|0更新时间：2024-05-08
- 摘要：In order to make mine surveying be quality standard and automation, the design on the automated mapping system of engineering plan for excavation is discussed in the paper. Then based on AutoCAD,an automate mapping system of coal mine engineering plan for excavation is developed. It has been used in a producing coal mine, which indicates the system has the following features: practice, norm, reliability, flexibility, easy operation and so on.关键词：Engineering plan for excavation;Computer-aided mapping;AutoCAD2780|183|0更新时间：2024-05-08
- 摘要：Based on a brief discussion of the basic structure of the DVB receiver,this paper analyses the variable rate QPSK demodulation and FEC error correction in the digital satellite receiver and compares two types of integrated circulation.关键词：QPSK;FEC;Error correction2005|178|0更新时间：2024-05-08
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