Loading...
Welcome to Journal of Graphics share: 

Table of Contents

    30 August 2013, Volume 34 Issue 4 Previous Issue    Next Issue

    For Selected: Toggle Thumbnails
    Graph and Graphics
    He Yuanjun, Tong Bingshu, Ding Yuming, Cai Hongming, Zhang Qiang
    2013, 34(4): 1-5. 
    Abstract ( 62 )   PDF (494KB) ( 189 )  
    Graph plays an important role same as word and number in the advancement of
    human society and economy construction, and in the development of science and technology. But
    it still exist the problems of how to define and recognize the role for graph and graphics from
    historical and developmental view. At present, some disciplines, such as Engineering Graphics,
    Computer Graphics, Computer Images, etc., have their own disciplinary position and independent
    development mode, but these disciplines may have some dispersion and limitation, because they
    lack links to graph and graphics. This paper shows the nature of graph from the view of Shapes (or
    geometry) and gives the scientific description for Shape and Graph. The concept of “Great
    Graphics” is proposed to integrate related graphic science and technology scattered in other disciplines. The definition and position of Graphics are put forward, the disciplinary frame of
    Graphics is constructed, and the disciplinary branch system of Graphics is also given. Thus the
    Graphics with another two disciplines, i.e. Literature and Mathematics, forms a solid foundation
    for science and engineering; therefore the basis and importance for Graphics are clearly exposed.
    Related Articles | Metrics
    A Grid-based Reconstruction of Global Photon Maps
    Cai Peng, Kong Dehui, Yin Baocai
    2013, 34(4): 10-15. 
    Abstract ( 75 )   PDF (954KB) ( 182 )  
    Photon mapping based on photon maps can efficiently render high-quality
    photorealistic images. It stores many photons in photon map to improve rendering qualities of
    complex illumination, leading to high memory overhead and long reconstruction time. This paper
    presents a grid-based reconstruction of global photon maps. We divide bounding box of photons
    into a number of grids. Based on the number of photons, we take a certain rate of photons in grids
    to reconstruct global photon map, and ensure conservation of total energy of photons in each grid
    before and after reconstruction, which make estimated illumination effects of photon maps before
    and after reconstruction almost same. By adding photons in special grids, we effectively reduce
    illumination error due to all kinds of geometry biases and enhance rendering effects of direct and
    indirect caustic. This paper checks a few noises in rendering pictures by simple method, and adds
    a few samples to effectively reduce these noises. Our reconstruction method of photon maps takes
    fewer time and ensures viewpoint independence of rendering pictures.
    Related Articles | Metrics
    A Novel Image Disintegration-based Computerized Embroidery Method for Random Stitch
    Xiang Jianhua, Yang Kewei, Zhou Jie, Shun Zhengxing
    2013, 34(4): 16-23. 
    Abstract ( 90 )   PDF (6587KB) ( 257 )  
    ChangZhou embroidery with disordered needles represents local culture. It's
    urgent to develop advanced technique for its protection and inheritance. This paper presents an
    approach for simulated generating method of embroidery with disordered needles based on image
    decomposition. This is achieved through decomposing an image into different object regions,
    vector fields, and image details. We obtain the simulated multilayer superposition effect of
    embroidery with disordered needles through multilayer rendering technique. Finally, we create a
    database of disordered needles, and provide realistic rendering through the method of simulating
    single string stitch. The results show that this framework can effectively reproduce the artistic
    effect and lays a foundation for digital inheritance of embroidery with disordered needles.
    Related Articles | Metrics
    A Method of Oil Paintings Rendering Based on Combining Region Brushstrokes with Gradient Brushstrokes
    Ye Peng, Wang Changbo, Zhu Qiaoming, Zhang Kang,Liu Yuhua
    2013, 34(4): 24-28. 
    Abstract ( 91 )   PDF (2715KB) ( 211 )  
    Oil paintings rendering based on brushstrokes is the most import technology in oil
    paintings rendering which simulates real artists’ painting process that use brushes to paint. This
    paper analyzes advantages and disadvantages of oil paintings rendering based on region
    brushstrokes through image segmentation, and presents a new method of oil paintings rendering
    based on combining region brushstrokes with gradient brushstrokes. Firstly, render region
    brushstrokes through image segmentation and then set gradient threshold through image
    segmentation level and render gradient brushstrokes. Experimental results confirm that the method
    has a rapid rendering speed, and not only makes brushstrokes more flexible but can fill up some
    gaps rendered due to region brushstrokes.
    Related Articles | Metrics
    Human Detection based on Multi Features Fusion
    Hu Bin, Zhao Chunxia, Sun Ling
    2013, 34(4): 29-34. 
    Abstract ( 79 )   PDF (637KB) ( 255 )  
    Based on the study of the applications of three different types of feature operators
    in human detection, which are Histogram of Oriented Gradient (HOG), Local Gabor Binary
    Pattern Histogram Sequence (LGBPHS) and Histogram of Shearlet Coefficients (HSC), we
    combine them together and propose a new human detection feature operator. We employ Partial
    Least Squares (PLS) analysis, an efficient dimensionality reduction technique, to project the
    feature onto a much lower dimensional subspace. Using a linear SVM as the classifier, we
    compare the fusion feature with the three single features in INRIA person dataset. Experiments
    results shows we achieve a detection rate of 95.6% with FPPW=10-5.
    Related Articles | Metrics
    Mesh Simplification based on Visual Feature Preserved
    Yang Daguang, Hu Weiduo, Chang Bo, Wei Qing
    2013, 34(4): 35-40. 
    Abstract ( 87 )   PDF (710KB) ( 185 )  
    In allusion to the some deficiencies from the algorithm based on error metrics
    (QEM), such as neglect of some geometric features, a novel approach based on visual feature is
    proposed for mesh simplification. The approach is driven by introducing a visual feature into the
    new QEM to optimize error metrics, as well as half-edge collapse, therefore the collapse
    sequences of edge can be adjusted, and some sharp visual features of the model can be preserved.
    We define the visual feature of one vertex based on its vertex curvature entropy which reflects the
    visual variation of the region centered at this vertex. Comparing with QEM algorithm, the
    algorithm is efficient, reliable, and can maintain the visual characteristics of the model better.
    Related Articles | Metrics
    An improved Diamond Search Algorithm
    Sun Xiujuan, Yang Deyun, Hou Yingkun
    2013, 34(4): 41-45. 
    Abstract ( 132 )   PDF (536KB) ( 210 )  
    The diamond search (DS) algorithm has been adopted by MPEG4 standard, and
    currently recognized as a better search algorithm. But the speed of DS algorithm is slow when the
    motion vector is small. The improved diamond search (IDS) algorithm is presented. Rough
    location and enhanced halfway-stop operation are added to it. Lots of vehicle tracking
    experiments show that the IDS algorithm improves the search speed on the basic of ensuring the
    search performance, supplying more effective technique support for template matching. Moreover,
    contrastive experiments prove the algorithm is insensitive to mutational trajectory.
    Related Articles | Metrics
    The Solution to Determine the Bounding Rectangle with Maximum Aspect Ratio for 2D Graphics
    Zhou Min, Zheng Guolei, Chen Shulin
    2013, 34(4): 46-53. 
    Abstract ( 98 )   PDF (720KB) ( 356 )  
    The bounding rectangle with maximum aspect ratio is a potential property of 2D
    graphics. This plays important roles in applications including the intelligent design of plane
    geometry, certain packing and optimum layout problems, as well as pattern recognition. However,
    no previous research is known for the problem. In this paper, a solution based on the convex hull
    of the given graphics is proposed to determine it. By analyzing the formulae for the maximum
    aspect ratio and the rotation range of the rectangle on which four given vertexes of the polygon
    are, one significant theorem is introduced and proved to show that one side of the
    maximum-aspect-ratio enclosing rectangle must be collinear with an edge of the enclosed
    polygon. According to this theorem, we determine the target rectangle by computing and then
    comparing the aspect ratios of n bounding rectangles which respectively have a side being
    collinear with different edge of the graphics’ convex hull with n edges. The experimental results
    are showed to prove that the solution is both accurate and efficient.
    Related Articles | Metrics
    Testing the Intersection Status of Two Triangles
    Yu Haiyan, He Yuanjun
    2013, 34(4): 54-62. 
    Abstract ( 120 )   PDF (693KB) ( 372 )  
    This paper focuses on geometric singularity and algorithm speed. In our algorithm,
    a 3D problem is reduced to planes and is further divided to a linear problem. In order to simplify
    the representation of geometric problem, a computational coordinate system is constructed. Thus,
    the geometric singularity of two triangles is reduced to planar problems between a line and a
    triangle, which limits the singularity to co-points and co-lines. Consequently, the complex
    spatial geometric singularity can be represented by planar drawings simply and visually and the
    robustness of our algorithm can be certificated theoretically. This paper gives the whole algorithm
    and detailed schemes. Experiment tests show that the priority in simplifying geometric relations,
    geometric singularity and calculations is sufficient to make up for the cost of transformation. The
    speed is 1 million pairs of triangles per second on a notebook computer.
    Related Articles | Metrics
    Generalized Bézier Curves Based on Lupas q-analogue of Bernstein Operator
    Han Liwen, Chu Ying, Li Ding, Liu Feng
    2013, 34(4): 63-68. 
    Abstract ( 177 )   PDF (5092KB) ( 210 )  
    This paper presents a novel generalization of Bézier curves. Firstly, a class of
    rational functions with one shape parameter is presented. It comes from the Lupas q-analogue of
    Bernstein operator and is a natural extension to classical Bernstein basis. Then, the corresponding
    generalized Bézier curves, the so-called Lupas q-Bézier curves, are also constructed and their
    properties are studied. The new generalized Bézier curves share the degree evaluation and de
    Casteljau algorithm of the classical Bézier curves.
    Related Articles | Metrics
    The two Projective Pencils of Planes and Quadric
    Liu Fuping, Ding Yong
    2013, 34(4): 69-72. 
    Abstract ( 72 )   PDF (427KB) ( 224 )  
    With the help of the orthographic projection method, the two projective pencils of
    planes with solid lines as the base are systematically expressed for the first time. When moving or
    revolving one of them, various types of quadric cylinders, quadric cones, unparted hyperboloids
    and hyperbolic paraboloids can be produced. When an appropriate cutting plane is selected, two
    pairs of corresponding contract harnesses can be obtained. Whether or not the harnesses are
    coplanar is the sufficient and necessary condition for the existence of circular section in quadric
    surface.
    Related Articles | Metrics
    The Convergence Analysis for NURBS Curve
    Shi Mao
    2013, 34(4): 73-75. 
    Abstract ( 68 )   PDF (464KB) ( 219 )  
    This short note presents the convergence analysis of a NURBS curve when one of
    the weights goes to infinity. Limits are considered using point-wise, uniform and L1 convergence.
    Based on notion and properties of homeorphism, the L1 convergence for higher degree rational
    parametric curves is investigated.
    Related Articles | Metrics
    Research of the Information Model Design Platform of Ancient Architecture During Ming and Qing
    Wang Ru, SunWeixin, Xu Dongdong
    2013, 34(4): 76-82. 
    Abstract ( 132 )   PDF (984KB) ( 303 )  
    Compared with the achievement of advanced construction technology in ancient
    China, information technology of our country in the ancient buildings are still relatively backward.
    So it is needed to conduct some researches on protection and development on ancient building
    using modern information technology.
    The introduction of BIM Technology provides a new approach for the protection study of
    ancient architecture. After deep study on ancient architecture component construction feature,
    construction rules, decoration colored drawing, history and culture and so on, the paper researches
    and develops out ancient architecture components information model design platform. This
    platform can either provide tool for the setting up and management of ancient architecture
    information model base, or provide accurate information for ancient architecture’s repair and
    restoration, ancient architecture’s study and ancient architecture virtual reality system. This article
    emphasizes on the management methods and information store date base structure of ancient
    architecture components information under this platform.
    Related Articles | Metrics
    Method of Mapping Based on Feature Line Matching for Rescue Robot
    Xu Guoyu, Cao Huchen, Liu Shaogang
    2013, 34(4): 83-87. 
    Abstract ( 82 )   PDF (602KB) ( 312 )  
    In order to solve the environment recognition and mapping problems of rescue
    robot, the matching method based on feature line is presented. This method makes use of the laser
    radar to get the environmental information and adopts the feature extraction of matching line, so
    that speed of the system is improved. When rescue robot is moving,the system can update global
    map timely and accurately. In the rescue environment, rescue robot is used to do the environment
    recognition and mapping. The experimental results show that mapping by using the matching
    method based on feature line can get more complete environment map and the method is of very
    good practicality.
    Related Articles | Metrics
    Discrete Modeling of the Tooth Profile of the Stationary Internal Toroidal Based on Numerical Method
    Hong Mei, Yao Ligang
    2013, 34(4): 88-93. 
    Abstract ( 110 )   PDF (1360KB) ( 175 )  
    The tooth surface of the stationary internal toroidal gear that is the key parts of the
    toroidal drive is a complex space curved surface. In order to realize the complex surface of the NC
    processing and using the finite element method for the contact analysis, whether obtaining the
    accurate entity model of the stationary internal toroidal gear or not is the key to resolving the
    problem. In this paper aiming at the stationary internal toroidal gear digital modeling problems,
    according to the mathematical model of the stationary internal toroidal gear, the grid division
    method of the helical tooth surface is given, the method of the stationary internal toroidal gear
    discrete modeling based on the numerical method is put forward. The method adopts cutting
    planes to scatter the stationary internal toroidal gear model into data point cloud, so as to get the
    stationary internal toroidal gear discrete model as the basis for later complex curved surface
    interpolation reconstruction.
    Related Articles | Metrics
    Face Pose Estimation Based on Sparse Model
    Qiu Limei, Wu Long, Jin Fangwei, Xiong Changjiong
    2013, 34(4): 94-97. 
    Abstract ( 95 )   PDF (2014KB) ( 216 )  
    The method of face pose estimation is vulnerable to ‘self-occlusion’ at present. To
    solve this problem, an improved ASM algorithm is used to extract facial feature points, and the
    geometric statistical knowledge of the face shape is used to estimate the depth of the facial feature
    points. Then the sparse face model is established based on the main features of human face. After
    estimating the face pose approximately with relevant face feature points, 3D space face pose is
    estimated accurately via the algorithm of least-squares method. The experiment results show that
    the method has better estimated results for the case of ‘self-occlusion’, and has better estimation
    accuracy compared with the same kind of method.
    Related Articles | Metrics
    Simulation Analysis of Movable Support System Based on ANSYS
    Zhang Jianchao, Wang Jun, Liu Tao, Lu Yongjie
    2013, 34(4): 98-104. 
    Abstract ( 80 )   PDF (1830KB) ( 184 )  
    To study the static mechanics performance of Movable Support System, the finite
    element analysis is needed based on ANSYS software and a series of static mechanics tests are
    completed for it. Firstly, the paper introduces the integral structure and working principle of
    Movable Support System, establishes its finite element model, then analyzes its static mechanics
    performance of typical working conditions such as positioning, making beam preparation, making
    beam and moving guide beam, and the analysis results are discussed in details. Finally, a series of
    static mechanics tests are completed. Test results and performance analysis results based on
    ANSYS are found to be consistent. The result demonstrates that the analysis method for the
    design and production of Movable Support System will exert positive guidance.
    Related Articles | Metrics
    The Structural Design of Shaft-end Generator in Railway Wagons Based on Virtual Prototype Technology
    Wang Hengliang, Lu Zhenggang, Sun Xiaojie, Zhang Baoan
    2013, 34(4): 105-111. 
    Abstract ( 69 )   PDF (1066KB) ( 182 )  
    The technology of Virtual Prototype (VP) and the software of Pro/Engineer
    (Pro/E) are introduced. The characteristics of structure and function of shaft-end generator in
    railway wagons are described, as well as Three Dimensional (3D) design process of its VP Model.
    The applications of the idea of modularity and the method of concurrent design in the general
    design of shaft-end generator are presented, and the application of the method of parametric
    design in its detail design is described in detail, mainly including component dimension
    parameterization, assembling constrain parameterization and two parametric tools, namely
    external copied geometry and external preference. The function of multi-disciplinary analysis in
    the structural design is presented with the example of regarding the thickness of permanent
    magnet as parametric variable. Via the work of the structural design of shaft-end generator in
    railway wagons, practice shows that advanced 3D design technique and excellent
    multi-disciplinary analysis methods are very most important tools and parts in the product
    structural design based on virtual prototype technology, and also, the design cycle and cost can be
    reduced and the product can be guaranteed to meet the requirements of users.
    Related Articles | Metrics
    Study of Diversity Generating Method of Virtual Crowd
    Zheng Liping, Zhang Juan, Zhao Jianming, Liu Yufei, Liu Xiaoping
    2013, 34(4): 112-118. 
    Abstract ( 67 )   PDF (1120KB) ( 205 )  
    In crowd simulation, if all of the virtual characters look alike, it will appear to be
    clones and lack reality as in real world. The paper studies the diversified appearance of characters
    from aspect of models, textures, postures and so on. The paper realizes character model
    differentiation by using Hasler model library, achieves diversification of the appearance by texture
    templates, and obtains the various postures by skeleton embedding technology for the model. The
    results show that the proposed method can generate plausible virtual crowd with good diversity.
    Related Articles | Metrics
    3D Visualization of Macromolecular Conventional Expression Based on Particle System
    Lü Zhihan, Su Tianyun
    2013, 34(4): 119-125. 
    Abstract ( 55 )   PDF (1074KB) ( 340 )  
    The crowd sourcing is becoming a popular solution to big data problems, and virtual
    community is gradually applied to scientific research. People also begin to pursue the high-quality
    rendering as well the universal rendering methods. This paper studies a protein macromolecules 3D
    visualization method, which is to manage the large number of atoms by the particle system, so as to
    reduce the rendering time of each atom by improving the coloration method, thus it can express
    Licorice and Van der Waals model, the secondary structure and some other conventional expressions.
    Taking molecules from the 103 to105 scale as application examples, comparison of the static and
    interactive efficiency between the particle system method and the popular method shows that the
    former has better performances in both aspects. The domain decomposition of the molecular
    structure is optimized, and the interactive performance is improved apparently. The results can run
    smoothly when being published to the iPhone
    Related Articles | Metrics
    Design and Realization of a Virtual Simulation System for a Ship Engine Control Room
    Shen Haosheng, Zhang Jundong, Zeng Hong
    2013, 34(4): 126-131. 
    Abstract ( 83 )   PDF (5367KB) ( 216 )  
    On the basis of analyzing the present virtual reality technology and the ship engine
    control room, the paper implements the establishment of the three-dimension model by using
    3D-MAX and the roam and interaction in virtual scene by using XNA, compiles the
    two-dimension simulation software by adopting C#, implements the communication between
    three-dimension virtual scene and two-dimension based on UDP protocol. According to the
    mathematical model of lighting effect, the paper implements one kind of shader based on GPU by
    using High level Shader Language (HLSL) which lowers the transmission burden between GPU
    and CPU and enhances the sense of reality of virtual scene.
    Related Articles | Metrics
    The Study on Teaching Content System Reform of Civil and Hydraulic Engineering Drawing
    Zhang Mandong, Liang Guoxing, Yang Shengqiang, Zhao Hongsheng
    2013, 34(4): 132-134. 
    Abstract ( 90 )   PDF (400KB) ( 236 )  
    Based on the analysis of the teaching characteristics and situation of “Civil and
    Hydraulic Engineering Drawing”, the authors have expatiated the ideas and implementations of
    teaching content system reform on “Civil and Hydraulic Engineering Drawing”. Measures taken
    are such that: (1) actively introducing the computer aided drawing about 2D and 3D to suit for
    current teaching development; (2) conformity of traditional civil and hydraulic engineering
    drawing of teaching contents, finding the common portions as well as considering difference,
    implementations of two types of contents amalgamation; (3) based on “Technology Drawing”
    State Standard terms, giving attention to traditional professional terms, correctly dealing with both
    relationships. This is convenient for teaching arrangements, and is beneficial to the training
    engineering talents, and to the enhancement of students’ knowledge and their working abilities.
    Related Articles | Metrics
    The Current Situation and Exploration of Educational Experience on ABS Model Making in Industrial Design
    Lin Jiaxin, Wang Huabin, Feng Xuelun, Zeng Shuting, Chen Xi
    2013, 34(4): 135-139. 
    Abstract ( 57 )   PDF (577KB) ( 233 )  
    ABS plastic model making is an important part of modern education of Industrial
    Design. The support for educational experience of design model making in universities in China is
    relatively inadequate, which influences the educational experience of ABS plastic model making.
    In order to improve the current situation, investigating and analyzing current construction of
    educational experience of ABS plastic model making and taking part in specific processes, and
    exploring the situation positively in every aspects can avoid unnecessary reworking, material
    waste and machine wear, and enrich educational experience of ABS plastic model making
    effectively, which has important significance to the educational construction of Industrial Design
    in universities and development of students’ individual capability.
    Related Articles | Metrics
    Research and Application of the Teaching Quality Evaluation of Computer Graphics Course Based on BPNN
    Luo Juchuan, Qing Yanmei
    2013, 34(4): 140-145. 
    Abstract ( 76 )   PDF (560KB) ( 216 )  
    The computer graphics course, which is very practical, is a requirement for
    teachers of the theory and practice of combining teaching of professional basic courses, How to
    improve teaching quality is the current focus of higher education, and how to objectively and
    exactly evaluate the teaching quality have positive and important meanings for improving the
    teaching quality, Taking advantage of BP neural network theories, This paper establishes a
    reasonable and effective model for evaluating the teaching quality of computer graphics course
    which is based on working the index system out. After that, in order to find the existed problems
    in our teaching process, which provide a direction of teaching innovation, the teaching quality of
    computer graphics course in our university was evaluated by using this model.
    Related Articles | Metrics
    Spatial Thinking and Drawing Teaching
    Liu Jia
    2013, 34(4): 146-149. 
    Abstract ( 116 )   PDF (368KB) ( 284 )  
    The basic concept of spatial thinking is discussed, and the connection and
    differences between spatial thinking and imagery thinking are showed. The two basic features of
    spatial thinking are analyzed. It is pointed out that targeted training topics should be designed for
    developing and improving the students’ spatial thinking ability in drawing teaching according to
    the characteristics of spatial thinking. Meanwhile, the introduction of 3D graphics software can
    also promote the improvement of students' space thinking ability. In a word, to cultivate the
    students' space thinking ability must both strengthen the drawing practice training and guide them
    through the correct method of thinking.
    Related Articles | Metrics
    The Improved Algorithm for Vehicle Tracking and Retrograde Motion Detection under the Complicated Background
    Guo Feng, Wang Bingzheng, Yang Chenhui
    2013, 34(4): 150-153. 
    Abstract ( 55 )   PDF (436KB) ( 258 )  
    To solve the problem of low vehicle tracking accuracy of traditional algorithms in
    complex background, an improved method is proposed in this paper. It exploits vehicle tracking
    polygon window and more exact prediction of search area to realize multiple feature matching
    vehicle tracking, which is applied to detect vehicles retrograde motion. The experimental results
    show that the algorithm has higher vehicle tracking accuracy while satisfying the need of real-time
    and stability requirement than traditional ones.
    Related Articles | Metrics
    The Amendment Ideas and Additional Recommendations on Road Engineering Drawing Standard in Effect
    Ma Zhiying
    2013, 34(4): 154-158. 
    Abstract ( 97 )   PDF (556KB) ( 261 )  
    Some items of the current Road Engineering Drawing Standard (GB50162-92) are
    imprecise, difficult to understand and apply, and out-of-date compared with the Chinese National
    Standards of Technical Drawing. These items are analyzed and some amending suggestions to
    these items are also put forward based on the experience and understanding of road engineering
    drawing teaching and road engineering design drawing. In addition, other proposals on the basic
    notation, general and simple drawing method of sectional view and cutaway view are also put
    forward in this article. The purpose is to arouse extensive discussion for the current Road
    Engineering Drawing Standard and to promote its revision.
    Related Articles | Metrics
    Research on License Plate Location Based on HSV Color Space and Mathematical Morphology
    Chang Qiaohong, Gao Mantun
    2013, 34(4): 159-162. 
    Abstract ( 110 )   PDF (1003KB) ( 405 )  
    The license plate recognition system has been widely used in highway toll gate
    and garage management of residential quarters, and license plate location is the precondition of
    the realization of the whole recognition system. The effects of localization methods based on
    gray-scale image and color-plate image are not ideal. By making full use of the license plate of a
    priori information, a method of license plate location based on the HSV color space and
    mathematical morphology is proposed. First, get the possible objects by using color information
    as a filter, then generate connected regions by using mathematical morphology techniques and
    generate the final correct license plate region, and last use radon transform to tilt correction.
    Related Articles | Metrics