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24 June 2015, Volume 36 Issue 3 Previous Issue    Next Issue

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A Shape Computing Mechanism Based on Geometry He Yuanjun 2015, 36(3): 319-330.  Abstract ( 94 )   PDF (810KB) ( 237 )   Proposed a new computing mechanism called shape computing to treat a geometric problem in a geometric way. In this computing mechanism, theory and methods in geometry, algebra, descriptive geometry and modern computing tools are synthesized. A new paradigm of multi-dimensional integration is proposed, i.e. 3D thinking, 2D diagrams and linear computing. It is apt to build an algorithm framework in a macro geometric perspective. It will provide a much more efficient supplement to normal numeric computing to solve a very wide class of problems in geometric computation. Related Articles | Metrics

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Automatic Generation of Digital Oil Painting Canvas with Hinting Brushes Chen Jiazhou, Hu Wenwen, He Dong, Miao Yongwei 2015, 36(3): 331-338.  Abstract ( 105 )   PDF (2011KB) ( 313 )   A traditional digital oil painting canvas consists of lines that represent region boundaries and digits that represent specified pigments. It becomes a new popular art because amateurish users can easily draw their own oil painting by brushing provided pigments into each region. However, it costs professional artists much labor and time to design, and reduces the painting quality due to the lack of brush hints, such as their orientation and width. In this paper, we propose an automatic generation method with brush hints. It not only converts an arbitrary image into a digital oil painting canvas, but also provides effective brush hints on the canvas. Experiments demonstrate the smoothness of boundary lines, the legibility of color digits and the significant improvement of painting quality contributed by the hint of brush streamlines. Related Articles | Metrics

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Acceleration Algorithm in Ray Tracing by the Octree Neighbor Finding Zhang Wensheng, Xie Qian, Zhong Jin, Liu Junping, Hao Qing, Guo Guangli 2015, 36(3): 339-344.  Abstract ( 142 )   PDF (2110KB) ( 533 )   Octree is a kind of hierarchy structure, and is often used to accelerate ray tracing. In order to speed up the process of ray tracing, a method which used octree neighbor finding to improve the speed of collision detection between ray and octree nodes is provided. This method proposes a octree neighbor finding algorithm which has simple structure and high computational efficiency. Using this algorithm, the next collision node can be calculated by current collision node quickly, which improves the image rendering speed. The experimental results show that the efficiency increased at least 3 times if the collision detection using the neighbor finding rather than the traditional algorithm, and the proposed algorithm can greatly accelerate the ray tracing. Related Articles | Metrics

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Self-Embedding Perfectly Blind Watermarking Algorithm Based on QR Decomposition for Color Images Han Shaocheng, Zhang Hongying 2015, 36(3): 345-351.  Abstract ( 119 )   PDF (2255KB) ( 274 )   A novel self-embedding perfectly blind watermarking algorithm is proposed based on QR matrix decomposition for copyright protection of digital color images. At first, G channel component of the original image is performed with non-subsampled shearlet transform, then the low-frequency component is performed with block-QR decomposition, the feature watermark is derived by judging the number relationship between vector l1 norm from the first row elements of each sub-blocks R-matrix and the mean of vector l1 norms from the first row elements of all sub-blocks R-matrix. Secondly, the low-frequency component is obtained after DWT from B channel of original image, then it is performed with block-QR decomposition. The feature watermark is embed by modifying the first row and the least column element of the R-matrix from every blocks. The generation and embedding of feature watermark are done in two channels independently, the watermark can be detected without the original image, and the algorithm can identify an image without the additional watermark information. Experimental results show that the proposed algorithm has strong robustness to resist various common attacks such as adding noise, JPEG compression, scaling, cropping and row shifting. Related Articles | Metrics

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Meteorological Measurement Automatic Temperature Testing System in the Research of Image Preprocessing Zhang Jiajia, Meng Xianluo, Jiang Tao, Liu Yu 2015, 36(3): 352-355.  Abstract ( 115 )   PDF (583KB) ( 171 )   Automation temperature calibration system based on meteorological measurement issues such as big noise, low contrast in the image, homomorphic filtering is proposed for contrast limited adaptive image preprocessing method on the basis of the image preprocessing technology. Try median filter for infrared image denoising, and use the principle of homomorphic filtering to enhance image details based on the premise that the noise would not be enhanced. However feature points and non-feature points are very confusing when the image is very poor quality in the method of homomorphic filtering, so the method of equalling limited contrast adaptive histogram is used to adjust the dynamic range of the image. The simulation results verify the feasibility of the method. Related Articles | Metrics

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Shape Analysis of a Class of Cubic Bézier Curve with Two Shape Parameters Liu Zhi, Li Chen, Xie Jin, Fei Teng 2015, 36(3): 356-362.  Abstract ( 103 )   PDF (575KB) ( 195 )   The shape features of a class of Bézier curve with two shape parameters are analyzed by using the method based on the theory of envelope and topological mapping. Investigate effects of the shape parameter on the curve shape. Necessary and sufficient conditions are derived for this curve having one or two inflection points, a loop or a cusp, or be locally or globally convex. Those conditions are completely characterized by the relative position of the edge vectors of the control polygon. Furthermore we discussed the influences of shape parameter on the shape diagram and the ability for adjusting the shape of the curve. Related Articles | Metrics

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Transition Curve between Parallel Lines Based on Bézier Curve Cai Huahui, Liu Bingxiang, Cheng Yan 2015, 36(3): 363-366.  Abstract ( 79 )   PDF (514KB) ( 211 )   By using quintic Bézier curve, the transition curve which is G2 continuous with a shape parameter is constructed between two parallel lines. This curve at t=1/2 contains a unique curvature extreme. It can be easily controlled curvature extremes and adjust the shape of the curve by using the shape parameter. Related Articles | Metrics

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Approximation by Piecewise Function Based on Generalized Barycentric Coordinates and Voronoi Tessellation Xiao Yanyang, Tu Jincan, Chen Zhonggui 2015, 36(3): 367-375.  Abstract ( 143 )   PDF (1895KB) ( 355 )   Under the generalized barycentric coordinates theory, we propose a new method to solve the problem of approximating a given function on the planar domain. To accomplishing this, an optimal piecewise function which based on the generalized barycentric coordinates is constructed. We use the Voronoi tessellation to create a partition of the domain, then an energy function that measures the approximation error is built. After deriving the gradient of the energy function, an efficient optimization method is adopted to update the tessellation. The optimal piecewise function will be constructed from the optimal tessellation. Due to its good ability of approximating discontinuous functions, our method can be applied to image approximation field. In order to demonstrate its efficacy, some experiments on analytic functions and color images are designed, which have produced good results. Related Articles | Metrics

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Stored Analysis and Ontology Expression of Cable Harness Information for Complex Mechatronic Products Wang Falin, Liao Wenhe, Guo Yu, Ju Chuanhai 2015, 36(3): 376-383.  Abstract ( 88 )   PDF (728KB) ( 260 )   It was difficult to afford unified expression and storage for semantic information and complex topological structure of the cable harness in complex mechatronic products. Aiming at this problem, a method of expression and stored analysis on complex cable harness information based on ontology and undirected graph was proposed. A cable harness information integrated model based on three-dimensional degrees of wiring design, assembly process planning and simulation analysis was established firstly. Then the expression of cable harness semantic information was enhanced through the ontology modeling of the model information by using the ontology technology. Finally, divide the cable harness part into an undirected graph by using a horizontal split algorithm. On this basis, an adjacency list of undirected graph was built, and the storage and expression of the cable harness undirected graph in the computer were realized. A certain cable harness part was taken as the application case to verify the feasibility of this method. Related Articles | Metrics

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Research on Heat Transfer Analysis Data Extraction for Air-Cooled Turbine Blade Fu Guanghui, Xi Ping, Zhang Baoyuan, Li Jixing 2015, 36(3): 384-391.  Abstract ( 87 )   PDF (1040KB) ( 175 )   Pipe-net calculation of air-cooled turbine blade is the important segment of air-cooled turbine blade heat transferring design, aiming at the requirement on heat transfer design for air-cooled turbine blades, the method of heat transfer analysis data extraction for air-cooled turbine blade model is proposed, which include the algorithms of computing units division, automatic judgment of air path, network diagram generation and data automatic extraction for heat transfer analysis, etc. Combined with the characteristics of air-cooled turbine blade structure, a data extraction system for heat transferring analyzing was developed based on UG Open API. The functions of extracting heat transfer analysis data of air-cooled turbine blade for subsequent analysis and calculation has been achieved, and the automatic degree of heat transferring calculation has been heighten, and the modeling result validated the feasibility of our method. Related Articles | Metrics

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Virtual Assembly Combining Geometric Constraint with Physical Simulation Techniques Xu Chenyang, Zhang Ruiqiu, Liu Lin, Xiong Wei 2015, 36(3): 392-396.  Abstract ( 84 )   PDF (667KB) ( 276 )   In order to solve the problem of sudden change of components position and orientation during conventional assembly allocation navigation, an algorithm based on linear interpolation and spherical linear interpolation is proposed. A method of admittance control mode is presented to solve the problem of control signal separation after assembly allocation navigation. During assembly motion navigation, force sensing constraint models are created to meet the requirement of feedback force in virtual assembly. The Bullet physics engine is integrated into virtual assembly system for physical simulation. A virtual assembly process combining geometric constraint with physically-based techniques is given and implemented in the virtual assembly prototype system. Related Articles | Metrics

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Dynamic Simulation of Ultra-High-Speed Elevator System Ma Xingfu, Chen Bingyan 2015, 36(3): 397-401.  Abstract ( 115 )   PDF (1439KB) ( 257 )   The vibration is the main force affecting elevator comfort. In order to study the dynamic characteristics of the 4.0 m/s ultra-high-speed elevator system, the lift cabin-car frame-guide rail-wire rope coupled system was taken as the study object. First, the vibration dynamic model of vertical system was built. Then, combined with automatic dynamic analysis of mechanical systems virtual prototyping technology, the elevator virtual prototype model was built by establishing ropes dynamics model, adding a contact force between the guide rail and the guide shoe, adding horizontal vibration excitation and vertical vibration excitation. Dynamic characteristic simulation was carried out for this model under setting certain constraints and drivers. The results showed that those performance indicators such as vertical vibration acceleration and horizontal vibration acceleration were meeting the requirements and the simulation results also provided design basis for the development of ultra-high-speed elevators. Related Articles | Metrics

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A New Algorithm of Image Super-Resolution Reconstruction Based on MOD Dictionary-Learning Zou Jiancheng, Zhang Wenting 2015, 36(3): 402-406.  Abstract ( 168 )   PDF (2198KB) ( 237 )   It is an important topic to reconstruct a high resolution image from a low resolution image. Yang proposed an image super-resolution reconstruction algorithm based on the joint dictionary-learning, which needs large samples, and dictionary training methods are complicated. In this paper, a new algorithm of image super-resolution reconstruction based on MOD dictionary-learning is proposed, a small amount of training samples is firstly used to replace large numbers of training samples of Yangs, then the MOD dictionary-learning algorithm is used instead of Yangs FFS dictionary-learning algorithm, at last, the resulted dictionary is applied to the image sparse representation and super-resolution reconstruction. The experimental results show that the image reconstruction speed is improved greatly with better reconstruction quality. Related Articles | Metrics

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Double-Step Matching Image Restoration Algorithm with Improved Priority Zhu Xiaolin, Wang Chuanqi, Fan Chengkai 2015, 36(3): 407-412.  Abstract ( 80 )   PDF (908KB) ( 202 )   Firstly, the priority in Criminisi algorithm is improved by adding the local luminance variance of the image as one metric factor of the priority, which gives more reasonable repair order to the image restoration. Secondly, the block matching process of the algorithm given in this paper is changed from one-step to double-step by use of 1 norm and the least square method, respectively, to modify the similarity measuring function. This double-step block matching process obtains more accurate matching block and better restoration result. Related Articles | Metrics

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A New LOG Edge Detection Algorithm Based on Synthetic Aperture Radar Image Li Hongan, Zhang Fei, Du Zhuoming, Kang Baosheng, Li Zhanli 2015, 36(3): 413-417.  Abstract ( 122 )   PDF (5279KB) ( 221 )   The use of tradition LOG edge detection algorithm to filter SAR image is sensitive to noise, in the meanwhile, it also damages partial low intensity edges. To solve this problem, a new edge detection algorithm is proposed. Firstly, the Gaussian function in the traditional LOG operator is replaced by Adaptive median filter and bilateral filtering. Secondly, the Laplacian is computed after the image is smoothed. Finally, the zero-crossing points are extracted as the edge of the image. With in impulse noise image, experiments results demonstrate that the new method can provide better de-noising results and preserves edges better at the same time. It also improves the accuracy of edge detection. Compared with the tradition LOG algorithm, it has a better detection result. Related Articles | Metrics

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Seismic Horizon Extraction Based on Dip Correction Liu Xin, Che Xiangjiu, Lin Senqiao 2015, 36(3): 418-424.  Abstract ( 112 )   PDF (1132KB) ( 264 )   To solve the problem of incorrect horizons extraction caused by the low signal-to-noise ratio of original seismic data sets, we present an anti-noise seismic horizon tracking algorithm, which includes following steps. Firstly, use wavelet transform for de-noising and the calculation of dip angle information. Then, estimate the initial tracking position based on the dip information. Experiments show that horizon tracking results using our method match well with the geological horizons. Related Articles | Metrics

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An Automatic Matting Method Based on Moving Saliency Objects Chen Zhihua, Zhu Nannan, Xiao Xiaolong, Zhang Jing, Yuan Yubo 2015, 36(3): 425-431.  Abstract ( 106 )   PDF (1073KB) ( 351 )   Matting technique is a popular method to extract objects from an image precisely. It takes important advantages in image editing. Most of the existing matting techniques rely on human interaction. In this paper, a novel automatic matting method is proposed and it is based on moving saliency objects. Firstly, the input image is segmented into several regions, its saliency values are calculated, a saliency gravitation model between regions is established, and the moving rules of saliency regions are constructed to obtain an accurate saliency map. Secondly, the saliency map is obtained and morphological operators are employed to correct the object regions. The corresponding trimap is generated automatically. Finally, the object regions are extracted by using learning-based matting algorithm. The experimental results show that the proposed method is more accurate and effective without human interaction or other auxiliary information. Related Articles | Metrics

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Adaptive Low Contrast Image Enhancement Algorithm Based on the RBF Neural Network Zhao Rentao, Guo Caiqiao, Li Huade, Cui Jiaxing, Zhang Zhifang, Tie Jun 2015, 36(3): 432-437.  Abstract ( 249 )   PDF (1333KB) ( 221 )   For low-contrast image enhancement problem, we propose an algorithm based on histogram correction and RBF neural network methods. Obtained the conditional probability histogram of the pixels in the presence of contrast with its neighborhood through original image, adjusting the weights of two parameters can change the conditional probability histogram and uniform distribution histogram. In this paper, RBF neural network is applied to set up the nonlinear mapping between image features and two enhanced parameters. In order to achieve adaptive image enhancement, rapid enhancement parameters are obtained according to the characteristics of the original image. The results show this method has good real-time ability, wide range of application, low computational complexity and good adaptability. Related Articles | Metrics

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A Method for Removal of Rain in Single Image Zhou Yuan, Han Yusheng, Zhou Pucheng 2015, 36(3): 438-443.  Abstract ( 127 )   PDF (1898KB) ( 568 )   Under the condition of rainy day, because of the rain has the bad influence on imaging system, it will lead the decrease of the quality of the image, and does not help to further processing image information. To deal with this problem, a kind of automatic image rain removal approach is proposed. Firstly, the rainy image is decomposed into rough sub-graph and detail sub-graph based on internal generative mechanism theory. And then, the sparse decomposition based on morphological component analysis method was used to divide the detail sub-graph into rainy component and non-rain component. Finally, the rough sub-graph was combined with non-rain component so as to reconstruct the rain-free image. The experimental results show that the proposed method can effectively remove the rain streaks in image and keep the state-of-the-art detail information of the scene. Related Articles | Metrics

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Adaptive Weighted Interpolation Based on Rational Function over Triangular Domain Ning Yang, Zhang Yunfeng, Gao Shanshan, Chi Jing, Zhang Caimin 2015, 36(3): 444-451.  Abstract ( 91 )   PDF (1056KB) ( 252 )   This paper proposed a novel image interpolation algorithm based on the rational function model. The interpolation function is carried out by a simple and explicit mathematical representation through a parameter and the shape of the interpolation surface can be modified by using the parameter for the unchanged interpolation data. Firstly, we change the domain of definition of the interpolation function into a special domain (the domain of the isosceles right triangle), then the interpolation surface will be smoother and the interpolation precision will be improved effectively. Secondly, we have given more consideration to the directional information of the image. Finally, the image is divided into smooth area and non-smooth area by drawing contour lines. Then we select a random or a fixed parameter in smooth area and choose the optimal parameter in non-smooth area. The experimental results show that the algorithms proposed by this paper achieve comparatively good effects and the common interpolation artifacts (ringing, aliasing, etc) are greatly reduced. Related Articles | Metrics

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Research on Intelligent Acquisition of the Grasping Position of Packing Tubular Workpiece Guo Hui, Shen Xia, Wang Yong 2015, 36(3): 452-456.  Abstract ( 91 )   PDF (1488KB) ( 193 )   When manipulator grasps intelligently the workpiece, the acquisition of grasping position about workpiece is the key of accurate assembly based on machine vision. For the grabbing link on assembly of packing tubular workpiece in the more complex environment as the object of study, a reasonable machine vision system is established, and the method combined with Gaussian fitting and Hough transform is proposed by using the feature of the forward lighting system reflecting straight light on the surface of workpiece. Firstly, Gaussian fitting method is used to extract the center coordinates of each light stripe in normal direction, then the coordinates of point set is fitted by using Hough transform, finally the workpiece grasping position is calculated according to the obtained each light center line. The experimental results show that this method not only can achieve the fitting of multiple light line, and can suppress interference and noise commendably, and effectively realize the intelligent acquisition of grasping position of packing workpiece. Related Articles | Metrics

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Improvement of Motion Estimation Algorithm and Experiment Based on DS-CDS Liu Yan 2015, 36(3): 457-561.  Abstract ( 98 )   PDF (458KB) ( 183 )   To improve the compression efficiency of the video, based on diamond search algorithm and cross diamond search algorithm, combined with the feature that motion vector was mainly focused on horizontal direction vector in actual motion images, the thesis put forward an improved search algorithm which combined partial to horizontal cross template search with biased toward double diamond template search. Comparative experiments were conducted to test the effect of improved algorithm. The result of the performance contrast experiment shows that the thesiss improved algorithm suits all kinds of motional video sequences, especially those sequences changing poignantly in movement. Under the condition that the PSNR and the BR value are very close to the optimal level, compared to the FS algorithm, the improved algorithm decreases approximately 95% of the motion estimation time of the QCIF pictures, and decreases about 94% of the motion estimation time of the CIF pictures, thus decreases greatly the motion estimation time. Related Articles | Metrics

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A Boundary Correction Method of SPH Fluid Simulation Liu Xu, Ban Xiaojuan, Yang Mingyuan, He Liangliang 2015, 36(3): 462-467.  Abstract ( 96 )   PDF (761KB) ( 331 )   This article presents a boundary correction method in fluid simulation based on smoothed particle hydrodynamics. We sample boundaries as boundary particles with fast Poisson disk algorithm, interpolate mass of boundary particles, and calculate force between fluid particles and boundary particles as simulation of fluid-boundary interaction. The presented method can also avoid penetration and holdup. Experiments demonstrated conduct experiments to prove the validity of our method. Related Articles | Metrics

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Review on Post-Processing of Intravascular Ultrasound Images Sun Zheng 2015, 36(3): 468-476.  Abstract ( 232 )   PDF (1437KB) ( 522 )   Intravascular ultrasound (IVUS) imaging, an invasive imaging modality, has been widely used in clinical diagnosis of vascular diseases. With IVUS, the morphology of the vessel wall and lumen including atherosclerosis plaques as well as components of plaques can be obtained in vivo. Automatic or semi-automatic processing and analysis of IVUS images with digital image processing techniques is important for computer-aided diagnosis and planning of treatment of vascular diseases. This paper provides a survey on the current process of post-processing of IVUS images. The improvements of this topic in the last several years are discussed in detail including image segmentation and tissue characterization, suppression of motion artifacts, vessel reconstruction, measurement of morphological and hemodynamic parameters, tissue characterization imaging, and fusion of IVUS with other imaging modalities. The discussion assesses the progress so far, and outlines some future directions. Related Articles | Metrics

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Research of Anti-Noise Image Segmentation Method Based on Fuzzy C-Means Su Zhiyuan, Liu Hui, Li Qiuping 2015, 36(3): 477-484.  Abstract ( 95 )   PDF (1207KB) ( 253 )   This paper proposes a new algorithm based on traditional fuzzy C-means algorithm regard to the noise and uneven light in medical images. Fuzzy C-means clustering algorithm has been rapid developed in image segmentation applications, as simple description, easy to implement, works well for segmentation. But there are also other issues such as noise sensitive. Considering that the medical images data must contain noise, a modified objective function J(u, v) has been proposed, adding a punishment factor on the basis of introducing the pixel neighborhood information. The new algorithm covers the shortage of traditional fuzzy C-means clustering algorithm, which makes the algorithm clustering with noise more effectively. Experimental results show that the algorithm is effective and practical. Related Articles | Metrics

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Based on Annotated Function New Outlook to Civil Engineering Design Du Ruifeng, Shen Gang, Jia Guoqiang 2015, 36(3): 485-488.  Abstract ( 93 )   PDF (565KB) ( 204 )   AutoCAD issued by Autodesk Corporation is the widely used software in civil engineering design, and concepts of being annotating and annotating objects in the high version of the software are introduced. By comparison with the current architectural design drawing, the detailed use of annotation is introduced in this paper, and significant advantages of annotation in the design industry of civil engineering and its new outlook are described. Moreover annotation can be good inspiration to other industries such as building decoration engineering and mechanical design which are related to engineering graphic. But presently the importance of annotation has not been understood, actively calling for further promotion, study and application is necessary in civil engineering design and teaching practice. Related Articles | Metrics

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A Fast Image Reconstruction Method for the Layout of Real-Time Train Information Zou Dong 2015, 36(3): 489-493.  Abstract ( 74 )   PDF (549KB) ( 201 )   Image reconstruction is an important topic in many video applications. This paper proposes a novel fast image reconstruction method for the layout of real-time train information. It adopts double buffers to avoid flashing of pictures. Its drawing module encapsulates many basic graphic units and these units have similar interfaces. Furthermore, the proposed reconstruction method adopts partly drawing method to further improve reconstruction speed. Thus, the proposed real-time reconstruction has better extensibility and flexibility. This reconstruction module has been applied in real-time train information system very well. Related Articles | Metrics