This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and po...This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and position of peaks and craters.In order to detect those two types of structures,a series of horizontal planes are applied to truncate the joint PDF with contour lines generated.Starting with the analysis of contour lines in a single plane,shape characteristics of the peak and the crater can be reflected on the contour lines in the aspects of gradient direction and inclusion relationship.Aided by the properties of PDF,the information about gradient direction and inclusion relationship of contour lines can be obtained simultaneously if the contour tree is built.According to the contour tree,the contour lines can be classified as two groups.Then the corresponding relation between contour lines in different planes is discussed.Based on the corresponding relation,clustering analysis about contour lines belonging to the same group but having different heights is performed.Two sets of contour lines are finally obtained as the simplest expression of geometrical characteristics of a joint PDF.They can be used to obtain the number and position of each peak and crater.Three oscillators of different types are chosen to test this method,which shows that this method can pave the way for numerical calculation about the stochastic P-bifurcation of multi-dimensional systems.展开更多
A contour tree is a good graphical tool for representing the spatial relations of contour lines and has many applications in map generalization, map annotation, terrain analysis, etc. A new method for generating conto...A contour tree is a good graphical tool for representing the spatial relations of contour lines and has many applications in map generalization, map annotation, terrain analysis, etc. A new method for generating contour trees by introducing a Voronoi based interior adjacency concept is proposed in this paper. The immediate interior adjacency set is employed to identify all of the children contours of each contour without contour elevations. It has advantages over existing methods such as the geometric method and the region growing based method.展开更多
This paper deals withthe automatic connection of contourlines extracted from a scanned browngeographical map.For the variety oftopographical elements contained on amap,the factors causing the interrup-tion of contour ...This paper deals withthe automatic connection of contourlines extracted from a scanned browngeographical map.For the variety oftopographical elements contained on amap,the factors causing the interrup-tion of contour line are also multiform,which make the connection task verydifficult.On the basis of separatingthose elements always making the con-tours break and regarding them as ref-erent layers,a layering-based methodis presented.The purpose is to takeinto account property information(likeinclination and configuration)of con-tour lines when they come across otherdifferent symbols,such as gully,cliff,dry land and elevation annotation etc.In this paper,the authors propose thatit should be far more effective and di-rect to adopt different algorithmic op-erators to different factors than usingsingle one operator to all.展开更多
This paper introduces the rough machining of territorial machining and contour line machining based on the CAXA manufacturing engineer 2004, and gives an analysis of the combined machining of territorial machining and...This paper introduces the rough machining of territorial machining and contour line machining based on the CAXA manufacturing engineer 2004, and gives an analysis of the combined machining of territorial machining and contour line machining. Finally, it proves the superiority of the combined machining by the example of high speed machining of an aluminium alloy lamina part.展开更多
Stress calculation formulae for a ring have been obtained by using Airy stress function of the plane strain field with the decomposition of the solutions for normal stresses of Airy biharmonic equation into two parts ...Stress calculation formulae for a ring have been obtained by using Airy stress function of the plane strain field with the decomposition of the solutions for normal stresses of Airy biharmonic equation into two parts when it is loaded under two opposite inside forces along a diameter. One part should fulfill a constraint condition about normal stress distribution along the circumference at an energy valley to do the minimum work. Other part is a stress residue constant. In order to verify these formulae and the computed results, the computed contour lines of equi-maximal shear stresses were plotted and quite compared with that of photo-elasticity test results. This constraint condition about normal stress distribution along circumference is confirmed by using Greens’ theorem. An additional compression exists along the circumference of the loaded ring, explaining the divorcement and displacement of singularity points at inner and outer boundaries.展开更多
In computer graphics, non-photorealistic rendering(NPR) is an important branch. NPR technology is to achieve a variety of artistic effects through the computer, such as oil painting, cartoon, watercolor and other effe...In computer graphics, non-photorealistic rendering(NPR) is an important branch. NPR technology is to achieve a variety of artistic effects through the computer, such as oil painting, cartoon, watercolor and other effects. The purpose of this paper is to automatically convert the 3D model into two-dimensional Chinese ink painting effect on graphics processing unit(GPU), and has improved the traditional algorithm that has some lacks of rendering effect. The algorithm is divided into two major steps: contour line rendering, and interior rendering. For contour line rendering, on the basis of the traditional extraction of contours, this paper adds self-bold, particle diffusion and other steps. For interior rendering, on the basis of the traditional layered rendering of diffuse lighting, two methods are added. The first method is based on the mean filtering, and the filter kernel is stratified by the principle of percentage-closer soft shadows(PCSS). The second method is Noise texture mapping, to obtain an ink diffusion effect.展开更多
基金supported by the National Program on Key Basic Research Project(Grant No.2014CB046805)National Natural Science Foundation of China(Grant No.11372211).
文摘This paper presents a method for extracting geometrical features of the joint probability density function(PDF)of two-dimensional systems based on its contour lines,with particular interests given to the number and position of peaks and craters.In order to detect those two types of structures,a series of horizontal planes are applied to truncate the joint PDF with contour lines generated.Starting with the analysis of contour lines in a single plane,shape characteristics of the peak and the crater can be reflected on the contour lines in the aspects of gradient direction and inclusion relationship.Aided by the properties of PDF,the information about gradient direction and inclusion relationship of contour lines can be obtained simultaneously if the contour tree is built.According to the contour tree,the contour lines can be classified as two groups.Then the corresponding relation between contour lines in different planes is discussed.Based on the corresponding relation,clustering analysis about contour lines belonging to the same group but having different heights is performed.Two sets of contour lines are finally obtained as the simplest expression of geometrical characteristics of a joint PDF.They can be used to obtain the number and position of each peak and crater.Three oscillators of different types are chosen to test this method,which shows that this method can pave the way for numerical calculation about the stochastic P-bifurcation of multi-dimensional systems.
文摘A contour tree is a good graphical tool for representing the spatial relations of contour lines and has many applications in map generalization, map annotation, terrain analysis, etc. A new method for generating contour trees by introducing a Voronoi based interior adjacency concept is proposed in this paper. The immediate interior adjacency set is employed to identify all of the children contours of each contour without contour elevations. It has advantages over existing methods such as the geometric method and the region growing based method.
基金the Scientific Research Foundation of Wuhan University(No.40071071).
文摘This paper deals withthe automatic connection of contourlines extracted from a scanned browngeographical map.For the variety oftopographical elements contained on amap,the factors causing the interrup-tion of contour line are also multiform,which make the connection task verydifficult.On the basis of separatingthose elements always making the con-tours break and regarding them as ref-erent layers,a layering-based methodis presented.The purpose is to takeinto account property information(likeinclination and configuration)of con-tour lines when they come across otherdifferent symbols,such as gully,cliff,dry land and elevation annotation etc.In this paper,the authors propose thatit should be far more effective and di-rect to adopt different algorithmic op-erators to different factors than usingsingle one operator to all.
基金supported by the Natural Science Foundation of Xi'an University of Architecture and Technology under Grant No.JC0919
文摘This paper introduces the rough machining of territorial machining and contour line machining based on the CAXA manufacturing engineer 2004, and gives an analysis of the combined machining of territorial machining and contour line machining. Finally, it proves the superiority of the combined machining by the example of high speed machining of an aluminium alloy lamina part.
文摘Stress calculation formulae for a ring have been obtained by using Airy stress function of the plane strain field with the decomposition of the solutions for normal stresses of Airy biharmonic equation into two parts when it is loaded under two opposite inside forces along a diameter. One part should fulfill a constraint condition about normal stress distribution along the circumference at an energy valley to do the minimum work. Other part is a stress residue constant. In order to verify these formulae and the computed results, the computed contour lines of equi-maximal shear stresses were plotted and quite compared with that of photo-elasticity test results. This constraint condition about normal stress distribution along circumference is confirmed by using Greens’ theorem. An additional compression exists along the circumference of the loaded ring, explaining the divorcement and displacement of singularity points at inner and outer boundaries.
基金Supported by National Natural Science Foundation of China(NSFC)(61672260)
文摘In computer graphics, non-photorealistic rendering(NPR) is an important branch. NPR technology is to achieve a variety of artistic effects through the computer, such as oil painting, cartoon, watercolor and other effects. The purpose of this paper is to automatically convert the 3D model into two-dimensional Chinese ink painting effect on graphics processing unit(GPU), and has improved the traditional algorithm that has some lacks of rendering effect. The algorithm is divided into two major steps: contour line rendering, and interior rendering. For contour line rendering, on the basis of the traditional extraction of contours, this paper adds self-bold, particle diffusion and other steps. For interior rendering, on the basis of the traditional layered rendering of diffuse lighting, two methods are added. The first method is based on the mean filtering, and the filter kernel is stratified by the principle of percentage-closer soft shadows(PCSS). The second method is Noise texture mapping, to obtain an ink diffusion effect.
