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30 April 2018, Volume 39 Issue 2 Previous Issue    Next Issue

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Single Side Page Extracting Method for 3D Book Model Based on Texture TONG Lijing, WANG Fenghe, LI Bin 2018, 39(2): 179-185.  DOI: 10.11996/JG.j.2095-302X.2018020179 Abstract ( 72 )   PDF (3265KB) ( 370 )   Model segmentation has important application value in practical engineering. For the point cloud segmentation of 3D book model, a single page extraction method based on texture is proposed. For the 3D model books and disordered texture image acquired, the disordered texture of the model is transformed into orderly texture firstly. Then the pixel values are converted from RGB color space to HSI space. According to H (hue) and I (intensity), the point cloud of background model is removed. Next, the spine line is analyzed from the distribution characteristics of the spine pixels in an orderly texture image. The three-dimensional space equation of spine is calculated by the least squares method, so that the space equation can be solved for the single side page extracting. Experimental results show that the method can extract the single page stably for the 3D book model, and has higher accuracy. Related Articles | Metrics

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An Iterative Image Filter Based on Anisotropic Total Variation LU Bibo1,2, WANG Lerong1, ZHENG Yanmei1, WANG Yongmao1,LI Xiaoying1, QIN Yuxiang1 2018, 39(2): 186-192.  DOI: 10.11996/JG.j.2095-302X.2018020186 Abstract ( 118 )   PDF (966KB) ( 217 )   Spatial proximity and similarity of the pixel values of bilateral filter in the filter based on the calculation of the range of filter kernel coefficient is susceptible to noise interference. When the noise level is high, the direct use of noise image to guide the kernel weight computation program is not feasible. Therefore, in this paper, the anisotropic total variation and bilateral filtering are combined. Firstly, the image is processed by the anisotropic total variation model, and the result image with rich edge structure information is obtained. Then the calculation results of image as a guide bilateral filtering image to guide the range of filter kernel coefficient. In order to ensure the stability of the algorithm, the above process is iterated. In addition, in order to improve the computational efficiency of the anisotropic total variation model, the Split Bregman iterative algorithm is introduced to accelerate the computation. The experimental results show that the proposed algorithm can preserve more edge information while denoising. Related Articles | Metrics

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A New Method for Image Deblurring and Clearness WANG Wenhao, YAN Yunyang, JIANG Mingxin, YU Yongtao, ZHAO Wendong 2018, 39(2): 193-200.  DOI: 10.11996/JG.j.2095-302X.2018020193 Abstract ( 116 )   PDF (3710KB) ( 400 )   Due to the various limitations in real restoration process, it is difficult to get the image blur mode or point spread function (PSF). A new method for image deblurring is proposed in this paper. At first, the proposed deblurring method uses the different of Gaussian operator (DoG) to detect the counters of blur image. Then the information of transition region of original image can be predicted according to the contours of blur image. Then the objective function is established according to the original image, transition region, and point spread function. In order to overcome the influence of noise, the nonnegative penalty term and space correlation penalty term with anisotropic features are added in objective function, and the PSF is solved using the minimization method of hysteresis iteration. Finally, the clear image can be gained by the existing the non-blind image restoration methods. Experimental results show that the proposed method can effectively restore the blur images caused by various factors. It does not need to know the image blur model. Related Articles | Metrics

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Fusion of SAR and Visible Images Based on NSST-IHS and Sparse Representation SHENG Jiajia1,2, YANG Xuezhi1,2, DONG Zhangyu1,2, JIAO Wei1,2 2018, 39(2): 201-208.  DOI: 10.11996/JG.j.2095-302X.2018020201 Abstract ( 81 )   PDF (7971KB) ( 248 )   In order to solve the problem that the interested aims are not prominent and spectral distortion caused by different imaging mechanism of synthetic aperture radar (SAR) and visible images, this paper proposes a fusion algorithm based on NSST-IHS and sparse representation. Firstly, source images are transformed by intensity-hue-saturation (IHS) and non-subsampled shearlet transform (NSST). Secondly, a fusion rule based on the structure similarity and luminance difference of the sparse representation is used in low- frequency components, while a fusion rule based on sum-modified-Laplacian is used in high- frequency components. Finally, the fusion results are obtained by inverse transformation of NSST and IHS. Experiments are carried out with Sentinel-1A SAR images and landsat-8 visible images, and compared with the traditional algorithms of IHS, Wavelet, NSCT, IHS-Wavelet-SR and NSST-IHS. The results show that the new algorithm has obvious improvement whether in visual or evaluation as well as to maintain the spatial structure information and spectral information, which is beneficial to target detection and recognition. Related Articles | Metrics

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Registration Between SAR and Optical Images Based on an Improved Rapid Algorithm 2018, 39(2): 209-213.  DOI: 10.11996/JG.j.2095-302X.2018020209 Abstract ( 53 )   PDF (1022KB) ( 203 )   Registration between SAR and optical images is time-consuming and has poor accuracy when based on the scale-invariant feature transform (SIFT) algorithm. In this letter we propose a novel method to solve this problem. First, we smooth SAR image by using bilateral filter (BF). BF is also good at preserving edges in the image as opposed to Gaussian smoothing, which is used in the original SIFT. Then, keypoints are detected in the Difference-of-Gaussian (DOG) scale space and SIFT descriptors are generated. Next, we adopt the fast library for approximate nearest neighbors (FLANN) algorithm which can search matching points fast in high-dimensional space. Last, progressive sample consensus (PROSAC) algorithm is utilized to exclude false matches. Experimental results show that our approach is significantly more accurate and much faster than the original SIFT. Related Articles | Metrics

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A Thinning Method for International Phonetic Alphabet Characters SUN Xiaokun, HUANG Jifeng 2018, 39(2): 214-220.  DOI: 10.11996/JG.j.2095-302X.2018020214 Abstract ( 42 )   PDF (538KB) ( 155 )   To refine image characters can help to highlight the shape features of the character and reduce the amount of redundant information, which has important applications in the field of character recognition. After analyzing and studying the traditional thinning algorithm, aiming at the distortion and incomplete phenomenon of traditional refinement, this paper proposes a refinement method for the characters of international phonetic symbols. The algorithm makes it possible to refine the width of the international phonetic image character to a pixel width by marking the edge of the text area and judging whether the marked point satisfies the removable condition and then gradually removing the edge pixel. Experiment on the international phonetic alphabet character image shows that the algorithm proposed in this paper can accurately refine the international phonetic alphabet character image, simple and efficiently. Related Articles | Metrics

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Surface Intersection Algorithm Based on Spatial Embedded Finite#br# Element Model WANG Jiwei1, FU Yu1, WANG Yajiang2 2018, 39(2): 221-227.  DOI: 10.11996/JG.j.2095-302X.2018020221 Abstract ( 55 )   PDF (1100KB) ( 223 )   In the spatial embedded finite element model, the bar element can be embedded at any position in the concrete element. The element model is convenient because the mesh of the concrete element is not limited by the reinforcement. In the application of the element model, it is necessary to obtain the coordinates where the both ends of the steel element lie at the surface of the concrete element. Therefore, it is the premise of application of the model to solve the intersection of the reinforcement line and the concrete element surface. The existing method is only suit for the concrete element with plane surface. In this paper, the Newton iterative method and the divided block analytic method are proposed which can solve the intersection of the reinforcement line and the surface of concrete element with any shape. The method in the paper can enhance the applicability of the spatial embedded finite element model. The correctness of the two methods is verified by an example. In terms of applicability, the divided block analytic method is superior to the Newton iterative method. Related Articles | Metrics

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Construction of Support Structure Based on Voxelization Models for 3D Printing XU Wenpeng1, MIAO Longtao1, HOU Shouming1, QIANG Xiaohuan2, ZENG Yanyang1 2018, 39(2): 228-234.  DOI: 10.11996/JG.j.2095-302X.2018020228 Abstract ( 106 )   PDF (1363KB) ( 314 )   3D printing technology can fabricate models by additive accumulation of a material that is fused together layer by layer, but the overhang area should be added support structure. The support structure will not only cause a waste of printing material, but also increase the printing time and damage the appearance of the model. In this paper, we propose an algorithm on support structure based on the voxelization model, which analyzes the interaction of voxels, and introduces the support energy parameters and calculation method. Then we calculate the area of the voxels which need to add support structure, and finally, we generate the support structure according the voxels area. The experimental results show that the algorithm can add support structure of the model more accuracy. At the same time, the voxel-based support algorithm can be used for a research on internal support structure of a model. Related Articles | Metrics

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Low-Resolution RGB Image Guided Depth Image Super-Resolution WU Yulong, ZHAO Yang, CAO Mingwei, LIU Xiaoping 2018, 39(2): 235-243.  DOI: 10.11996/JG.j.2095-302X.2018020235 Abstract ( 54 )   PDF (2622KB) ( 215 )   In traditional methods of RGB image guided depth image super-resolution, the reference images are required to be high-resolution intensity images and its resolution determines the upper limit of the depth image upsampling. Moreover, in some situations only low-resolution RGB images are available, thus the traditional methods are unpractical. In this paper an arbitrary resolution RGB image guided depth image super-resolution is proposed. First, we use different image super-resolution algorithm for the input RGB image upsampling, so that a high-resolution reference RGB image can be obtained. Then we increase the resolution of the input depth image by using the second-order total generalized variation based method and adding edge cues from the reference image obtained in above step. Then the final energy objective function is defined and depth image super-resolution can be transformed into optimization problem, which can be solved by primal-dual energy minimization scheme. Finally the high-resolution depth image is generated. This paper explores the cases previously ignored by the relevant method and the proposed method can be applied to arbitrary resolution RGB images. Through the relevant experiments, we found an amazing phenomenon that, by using low-resolution color image up-sampling as a guide, we can get similar to or even better results compared with using high-resolution intensity guided image. This conclusion has some reference significance for the research and application of related issues. Related Articles | Metrics

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Data Augmentation with Multi-Model Ensemble for Fine-Grained Category Classification JIANG Jie, XIONG Changzhen 2018, 39(2): 244-250.  DOI: 10.11996/JG.j.2095-302X.2018020244 Abstract ( 66 )   PDF (2272KB) ( 359 )   In order to solve low classification precision caused by the lack of training data or the classification performance constraint of single convolutional network model, a fine-grained category classification algorithm based on data augmentation and multi-model ensemble is proposed. Firstly, the paper designs a variety of data augmentation methods to increase the number of pictures in CompCars dataset, including mirroring, rotation, multiscale scaling, Gaussian noise, random cropping and color enhancement. Then 3 differentiated models, CaffeNet, VGG16 and GoogleNet, are trained using the constructed differentiated dataset by different data sampling. A multi-layer ensemble learning method is used to integrate multi-model’s classification results. The experimental results show the fine-grained classification of the differentiated convolution network trained on the different datasets generated by the different data augmentation method. The experiment also shows the classification results of multi-model ensemble with different ensemble strategy. The final classification precision of multi-model ensemble is 94.9%. Compared with the best single model GoogleNet, the classification precision is increased 9.2%. The results verify the effectives of proposed algorithm. Related Articles | Metrics

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Recursion on Generalized Barycentric Coordinates QIAN Yijia, TANG Shuo, WANG Xuhui 2018, 39(2): 251-255.  DOI: 10.11996/JG.j.2095-302X.2018020251 Abstract ( 53 )   PDF (1012KB) ( 127 )   From the view of the solution space of a system of linear equations, the recursion formula is worked out on generalized barycentric coordinates (GBCs) from n -gons to n 1 -gons. Unlike the classical way to construct GBCs, which based on geometric meaning of coordinate functions, a new method is provided to construct GBCs for planar n -gons if a coordinate function is chosen which satisfies constraint condition. To get the recursion formula, since a (n  1) -gons (n≥3) can be seen as a n -gons plus one extra vertex, the extra vertex can be represented by affine linear combination of the vertices of the n -gons. Hence the GBCs in (n 1) -gons can be rewritten by homogeneous coordinates in n -gons. Conditions for the (n 1) th coordinate function are presented to satisfy the requirement of GBCs. Related Articles | Metrics

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Research on Packing Problem and Cutting Path Optimization of Rectangle with Surface Orbit Characteristics ZHOU Jiali1, GUO Qi1, WU Chao1, WU Min2 2018, 39(2): 256-262.  DOI: 10.11996/JG.j.2095-302X.2018020256 Abstract ( 62 )   PDF (2432KB) ( 145 )   The purpose of this paper is to solve the equilateral rectangular packing problem characterized by surface orbit arised in practical production. We focus on the optimization system based on adaptive genetic algorithm and graph theory, and greatly improve the cutting efficiency. Our method target the optimization of the machining path, in this method, the path optimization problem is turned into an undirected graph connectivity problem, and using genetic algorithm to find the optimized machining path. The optimal solution of the final search is used to arrange the rectangular parts according to BL positioning strategy. Through the improvement of genetic algorithm, such as: ① the judgment of the legitimacy of the initial individual genes, and using the depth first traversal results evaluation of individual performance. ② The crossover and mutation operators use adaptive mechanism, and the object that performs the mutation operation is limited to a broken point set on a chromosome, which greatly improves the performance of the algorithm. Finally, the experiments show that the algorithm can provide the available solution in most cases, and it is also a very reliable method. Related Articles | Metrics

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An Improved Solid Boundary Treatment Algorithm of Fluid Simulation ZHU Xiaolin, YIN Jingcun, WANG Huanhuan 2018, 39(2): 263-268.  DOI: 10.11996/JG.j.2095-302X.2018020263 Abstract ( 54 )   PDF (2340KB) ( 167 )   Fluid simulation is an important research branch of computer graphics, solid boundary treatment of fluid has always been the focus of fluid simulation, image particle method in smooth particle hydrodynamics is an important method to deal with solid boundary. Image particle method deals with solid boundary problems by dynamically generating corresponding mirror particles outside the boundary by fluid particles near the boundary. However, with the improvement of the complexity of the boundary, the complexity of the traditional mirror particle method to generate the mirror particles is also increased, and the simulation efficiency is reduced. In order to solve the above problem, the mirror particle method is improved in this paper by giving a new technique for calculating values of mirror particle field, which effectively reduces the complexity of the generation of traditional mirror particles with complex boundary conditions, and the field of fluid particles near the boundary is more uniform. A lot of simulation results show that this method becomes more efficient compared with the mirror particle method with the increasement of the number of particles and the complexity of the scene. Related Articles | Metrics

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The Dehazing Algorithm Based on Visual-Physical Model MA Shiping, LI Quanhe, MA Hongqiang, BI Duyan 2018, 39(2): 269-277.  DOI: 10.11996/JG.j.2095-302X.2018020269 Abstract ( 74 )   PDF (1260KB) ( 317 )   Aiming at the problem that the existing image dehaze algorithm can not effectively enhance degraded images in complex atmospheric environment, animage dehaze algorithm based on visual physical model (VPM) is proposed bycombiningmonochrome atmospheric scattering model (MASM), atmospheric transmission function (ATF) and retinex. The model can describethe image degradation under complex atmospheric conditions such as non-uniform light degradation, haze degradation, and noise degradation. Environmental light degradation is first obtained though variational method. And then, markov random field is introduced to convert the problem of scene reflection rate to the maximum posterior probability. Finally, the brightness of scene reflectance is adjustedwith adaptive histogram equalization, and this is the final dehazed image. Experimental results show that VPM can enhance degraded images under complex atmospheric environment and has better physical fidelity and visual pleasure compared. Related Articles | Metrics

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3D Surfaces Reconstruction Algorithm Via Detaching Delaunay#br# Triangular Mesh and Search-Ball Approach YUAN Qinglie1, WU Xuequn2 2018, 39(2): 278-286.  DOI: 10.11996/JG.j.2095-302X.2018020278 Abstract ( 61 )   PDF (6187KB) ( 164 )   3D surface reconstruction are becoming increasing important in geometric modeling and related applications such as in computer graphics, 3D GIS, reverse engineering. This paper presents an algorithm that holds the advantages of both region- growth approaches and Delaunay based on unorganized point cloud. Separation angle is defined and deduced the related conclusion according to the nature of the surface axis, which is applied to extract triangles from the surface of model and increase the initial growth area of the region. An approach of adaptive search-ball method is presented to speed up searching the neighbourhood-triangles and identify the surface boundary. Compared with the traditional Delaunay-based approach, this algorithm requires only one-pass Delaunay computation and reconstruct surfaces rapidly without calculation of pole and the vector. Compared with the traditional region growing method, this algorithm inherits the structural characteristics of the Delaunay triangulation with fewer holes and accurate the 3D geometry information and topology. Experimental results shows that it is highly  efficient compared with other existing algorithms and capable of handling surfaces with complex topology, boundaries, which holds the advantages of both region- growth approaches and Delaunay. Related Articles | Metrics

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Adaptive B-spline Curve Fitting Based on Regularized Progressive Iterative Approximation LIU Mingzeng, GUO Qingjie, WANG Siqi 2018, 39(2): 287-294.  DOI: 10.11996/JG.j.2095-302X.2018020287 Abstract ( 65 )   PDF (1456KB) ( 251 )   The use of progressive iterative approximation (PIA) to fit data points has received a deal of attention benefitting from its simplicity and flexibility. To obtain a fitting curve satisfying the shape high fidelity, we present an adaptive B-spline curve fitting algorithm based on regularized progressive iterative approximation (RPIA) and the selection of dominant points. Firstly, the initial dominant points are selected from the given points in terms of curvature estimates and an initial progressive iterative approximation curve is constructed. Then the fitting curve based on RPIA is updated by means of the fitting error and the selection of refinement dominant points according to the curvature distribution of given points. The fitting curve possesses fewer control points at flat regions but more at complex regions. By the use of a regular parameter, progressive iterative approximation is generalized and the flexibility of PIA is promoted. Finally, numerical examples are provided to demonstrate that compared with the conventional least square approaches the proposed method can achieve a higher fitting precision with far fewer control points. Related Articles | Metrics

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A Family of Spacial PH Curves Represented by Algebraic-Trigonometric Functions and Their Applications WU Weidong1,2, YANG Xunnian1 2018, 39(2): 295-303.  DOI: 10.11996/JG.j.2095-302X.2018020295 Abstract ( 40 )   PDF (914KB) ( 167 )   A class of spacial curves are defined over the algebraic-trigonometric space Ω=span{1,θ ···, θm+1, sinθ, cosθ, θsinθ, ···, θn cosθ}. By choosing proper integral kernels, the projection of the spacial integral curve on the xy-plane has intrinsic definition, or the whole spacial curve is a PH curve. The Cartesian coordinates of the curve can be explicitly evaluated by integrals of the predefined kernels. Besides, techniques of interpolation of integral curves with different integral kernels have been studied. Given the boundary data, the coefficients within the kernel functions are obtained by solving a system. Finally, we use PH curves to design a family of frames, which can be used to construct a rational swept surface. Experimental results show that the piecewise swept surface is G1 continuous at the ridge line and is nearly G1 continuous at the remaining junctions. Related Articles | Metrics

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Reducer Virtual Disassembly and Assembly Experiment Based on Unity3D FENG Guizhen1, CHI Jianbin1, XING Haijun1, ZHANG Zengqiang1, JIA Shuang2 2018, 39(2): 304-308.  DOI: 10.11996/JG.j.2095-302X.2018020304 Abstract ( 111 )   PDF (1615KB) ( 397 )   Unity3D, as a powerful and good cross-platform 3D engine, has great application space in building interactive virtual scenes, and it is of great practical significance for teaching. In view of this, by analyzing the basic structure of the reducer, and on the basis of studying the method and key technology of constructing three-dimensional interactive virtual scenes with Unity3D, taking some kinds of reduces as examples, a reducer virtual disassembly and assembly experiment is constructed, which can run based on many platforms. And APP which independently runs based on mobile platform and no needs web support, is more convince and available, has achieved good teaching effect in application, such as structure cognition, product disassembly, curriculum design, etc. Related Articles | Metrics

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Implementation and Application of 3D Virtual Hairstyle Try-on System Based on Mobile Platform ZOU Xiao1, CHEN Zhengming1,2, ZHU Hongqiang1, TONG Jing1,2 2018, 39(2): 309-316.  DOI: 10.11996/JG.j.2095-302X.2018020309 Abstract ( 67 )   PDF (6461KB) ( 188 )   Hairstyle has a very important impact on one’s appearance and temperament, resulting in an increasing number of related consumption. Consumers’ hairstyle cannot recover after changing, so a preview of hairstyle and hair color is necessary. There are obvious defects in the existing solutions, such as hairstyle pictures and hairstyle try-on applications based on two-dimensional images processing technology, which provide unreal effect. In this paper, we propose a 3D virtual hairstyle try-on system for mobile platform. Combining with virtual reality technology and the reconstruction algorithm of 3D head model based on single photo, this system can provide much more real effect. Users can have multi-angle observation and change hair color or accessories. In addition, the system is built on the mobile platform and optimized through reasonable framework design and resource management to improve user experience and practicality and meet the needs of mobile users. Related Articles | Metrics

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VR System Information Visualization Model Cognition SUN Hui, LV Jian, CUN Wenzhe 2018, 39(2): 317-326.  DOI: 10.11996/JG.j.2095-302X.2018020317 Abstract ( 97 )   PDF (4146KB) ( 299 )   An information visualization resource model based on distributed cognition was proposed to solve the unequal user cognitive load and resource allation problem in virtual environment, with the analysis of information explicit expression in human brain cognitive activities. The system obtains user action, behavior, task and other information in virtual environment based on the computer-aware technology. Resource allocation scheme was used to optimize the mapping between resource and information, and stored in the form of information imagery. The information imagery was riched by imagery library to optimize the visual elements of interactive interface. The usability evaluation experiment about virtual reality system prototype were carried out on eye tracking equipment. The experimental results demonstrate that the visualization resource model is realized to decrease user’s cognitive burden and improves user experience. Related Articles | Metrics

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Application of EEG Technology in Emotional Design of Cultural and Creative Products DENG Li, CHEN Bo, PANG Qianyue, WEN Rong, XIE Bingyu 2018, 39(2): 327-332.  DOI: 10.11996/JG.j.2095-302X.2018020327 Abstract ( 79 )   PDF (1252KB) ( 207 )   In order to obtain consumers’ preferences for cultural elements, PAD emotional scale was used to group the cultural elements according to the pleasure value and emotional state, and then the brain waves induced by cultural elements with different pleasure were recorded by EEG. Based on the pleased cultural elements selected by experiment, a set of Shu culture castor was designed. The results of EEG experiment showed that under the stimulation of the pleased pictures, the average power of left frontal α wave was significantly lower than that of the right frontal. Under the stimulation of the unpleased pictures, the average power of the right frontal α wave was significantly lower than that of the left frontal. Under the stimulation of the pleased pictures, the average power of α wave in the central region was significantly higher than that under the stimulation of the unpleased pictures. The study found that according to the theory of frontal alpha asymmetry, the frequency-domain characteristics of α wave can be used to study the emotional characteristics of users. This method can help designers to design cultural and creative products so as to meet the perceptual needs of consumers. Related Articles | Metrics

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Research on BIM Parametric Modeling Method of Chinese Classical Architectures GAO Dai1, WANG Hongyang2, DU Jiahe2, CAI Ziang2, LOBSANG Tsring2 2018, 39(2): 333-338.  DOI: 10.11996/JG.j.2095-302X.2018020333 Abstract ( 87 )   PDF (1730KB) ( 332 )   From the perspective of building information modeling (BIM) technology, this article studies and systematically classifies the structure features of Chinese classical architectures (CCA). Based on the parametric modeling methods of BIM, informatization method of CCA is studied. This paper proposes the CCA classification scheme and modeling procedure suitable for BIM. Then, taking Zhengxinguagong of Dougong as an example, the modeling procedure is detailed demonstrated. The presented parametric modeling method can be applied to the wooden building components and other materials used in CCA, therefore it has an important significance in forming CCA building components system and optimizing the part family libraries. Related Articles | Metrics

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Research and Practice of Site Surveying by UAV LiDAR and BIM Planning Design TIAN Xianbin, ZHANG Yongli, WU Jianwen, CAI Zhen, YU Yue 2018, 39(2): 339-345.  DOI: 10.11996/JG.j.2095-302X.2018020339 Abstract ( 68 )   PDF (5790KB) ( 208 )   Which havethe characteristics of rapid, activity and precision that gaining the digital terrain models and ground photographsby unmanned aerial vehicle (UAV) LiDAR. And the digital results are propitious to be used by building information modeling (BIM) software. This research does the mapping experiment using UAV LiDAR, and analyzed the accuracy of the result data, and made use of the experiment data to project planning design using BIM. The results of this paper verified that the survey data can be used as basic data in the stage of engineering planning, which improved the efficiency of BIM design, and expanded the form of data chain for the project life-cycle. Related Articles | Metrics

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BIM Modeling Tool Development for Main Structure of Concrete Continuous Girder Based on Dassault CAA Architecture QI Chenglong 2018, 39(2): 346-351.  DOI: 10.11996/JG.j.2095-302X.2018020346 Abstract ( 67 )   PDF (613KB) ( 167 )   Traditional building information modeling (BIM) modeling method forcontrete continuous girder main structure is inefficient, and the data stability is not guaranteed. To prevent the defects of traditional modeling method, this paper develops a modeling tool for concrete continuous girder, following the “skeleton-template” modeling idelogy. Taking user dialog window and excel table as the delivery medium, by dint of geometry modeler, feature modeler, mechanical modeler, the program’s interstructureis reasonably arranged through interface module, feature module and segment topological module. Finally, segment feature instantiation and segment parts assembly is successfully realized. It indicates that this modeling tool can highly improve the modeling efficiency and guarantee the data stability. This paper also supply other BIM resrarches which is based on Dassault/CAA secondary development with insparition and method. Related Articles | Metrics

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The Method of 3D Anthropometry Automatically Extracted Based on Mesh Model YU Ying1, CHEN Jihua2, LU Xueliang3 2018, 39(2): 352-356.  DOI: 10.11996/JG.j.2095-302X.2018020352 Abstract ( 39 )   PDF (656KB) ( 173 )   In the face of a large number of accurate measurement of human body, a complete automatic measurement method based on mesh model is constructed in this paper. Firstly, The point cloud is modeled to generate the mesh model. Secondly, a cutting direction and slice thickness adaptive slicing are proposed to deal with the mesh model, and a series of two-dimensional cross sections are obtained. Thirdly, the analysis method of convex analysis and cross section within the containment section automatically find the characteristics of the human body landmarks. Finally, the accuracy and repeatability of real male model and female mode are tested, and the results show that the method is effective. Related Articles | Metrics

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Application of Region Filling Algorithm in Multi Nested Polygon Graph QIU Guoqing 2018, 39(2): 357-361.  DOI: 10.11996/JG.j.2095-302X.2018020357 Abstract ( 60 )   PDF (644KB) ( 159 )   Region filling algorithm is widely used in drawing, but the arbitrary polygon nested region filling algorithm is very difficult to achieve, in order to solve this problem, puts forward new area filling algorithm that based on equidistant parallel lines. Firstly, draw a set of parallel lines use the same intervals. Secondly, calculation the intersection that all parallel lines with arbitrary nesting the polygon. Finally, use the interval value as a parameter sub block of size, each line contains the parallel calculation of the number of blocks and coordinates and filling, completion of the entire region filling at last. In the process of the experiment, solve the problem of computing in intersection of the nested polygons with the parallel lines is solved. Use multi group data through the application of independent design show that the algorithm can quickly and accurately complete any number of nested polygon area filling and explain the technical difficulties and algorithm complexity which arise in the process of experiment. Related Articles | Metrics

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Research and Practice on Student-Centered Mixed Teaching Mode in Mechanical Engineering Graphics DING Qiao, ZHANG Mengmei, LI Maosheng, SUN Yihong, HAN Liyan 2018, 39(2): 362-366.  DOI: 10.11996/JG.j.2095-302X.2018020362 Abstract ( 234 )   PDF (709KB) ( 212 )   Nowadays, It is not easy for students in the common universities to imagine the shape of a 3D object from a group of 2D views when they are learning the course of the mechanical engineering graphics. Some students are less self-binding and their learning initiative is not high. Therefore, the blended learning has been carried out in the process of instruction, based on the Bloom’s mastery learning theory and the American undergraduate education reform in Research-oriented universities which has been developed on the student centered (SC) Learning since 1980s. It includes SC large class teaching and small class discussion, online and offline class, combination of theory and practice. The result shows the blended learning has promoted students self-study and improved the quality of teaching. Related Articles | Metrics

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Research on Teaching Reform of “Mechanical CAD Foundation” Course Combine with Cloud Classroom WANG Min, ZHANG Zongbo, NIU Wenjie, CAO Qingyuan 2018, 39(2): 367-372.  DOI: 10.11996/JG.j.2095-302X.2018020367 Abstract ( 51 )   PDF (780KB) ( 207 )   Most university engineering students need to learn “Mechanical CAD Foundation” course, this course is more practical and learned in the computer classroom. The advantages of online teaching gradually appeared with the application of “Internet+” technology in university teaching, and this course is particularly suitable the teaching mode of combining online with offline. The “Mechanical CAD Foundation” course website is built in China University of Petroleum Cloud Classroom. The teaching reform of course resources construction, teaching activities design. Interactive learning, learning data statistics, and big data feedback are practiced. A new teaching model of cloud classroom and offline teaching is constructed. This model provides a useful exploration and practice for the using of “Internet+” in university teaching. Related Articles | Metrics

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Research on the Multiple Associated Engineering Graphics Test Database with Multi Attribute and the Multi-Mode Intelligent Test Paper Generating System LI Ruisen1, ZHANG Shuyou1, YI Guodong1, XUE Lihua2, TAN Jianrong1 2018, 39(2): 373-380.  DOI: 10.11996/JG.j.2095-302X.2018020373 Abstract ( 50 )   PDF (5575KB) ( 187 )   A bottom-up construction and development plan of engineering graphics test database system was presented to meet the requirement of test database which used in engineering graphics curriculum examinations and evaluations. This article constructed a multiple associated test model with multi attribute, analyzed the process of test paper generating in engineering graphics course. The multi-mode test selection method based on attributes, technology of test paper generating based on the feature extraction of existing paper and the graphical interactive layout method of test paper were researched. Finally, the engineering graphics test paper generating system based on test database was developed. Related Articles | Metrics