It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be...It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.展开更多
In the context of the deep integration of digitalization and innovation and entrepreneurship education,this study focuses on the characteristics of schools and courses,investigates students’expectations and needs for...In the context of the deep integration of digitalization and innovation and entrepreneurship education,this study focuses on the characteristics of schools and courses,investigates students’expectations and needs for ideological and political elements,and deeply explores ideological and political cases such as the Beidahuang spirit,Daqing spirit,model worker spirit,and role models around them.It explores the integration practice of“curriculum ideological and political”in extracurricular tutoring teaching of engineering graphics,aiming to guide students to establish patriotism,love for schools,knowledge of agriculture,and love for agriculture,and effectively enhance the coordinated development of students’graphic skills and ideological and political literacy.Practice has shown that integrating ideological and political resources,incorporating ideological and political elements into curriculum content and practical activities,can effectively enhance the collaborative development of students’graphic skills and ideological and political literacy.At the same time,it provides new ideas and references for expanding ideological and political education to extracurricular tutoring courses.展开更多
The newly emerging neural radiance fields(NeRF)methods can implicitly fulfill three-dimensional(3D)reconstruction via training a neural network to render novel-view images of a given scene with given posed images.The ...The newly emerging neural radiance fields(NeRF)methods can implicitly fulfill three-dimensional(3D)reconstruction via training a neural network to render novel-view images of a given scene with given posed images.The Instant Neural Graphics Primitives(Instant-NGP)method further improves the position encoding of NeRF.It obtains state-of-the-art efficiency.However,only a local pixel-wised loss is considered when training the Instant-NGP while overlooking the nonlocal structural information between pixels.Despite a good quantitative result,it leads to a poor visual effect,especially the completeness.Inspired by the stochastic structural similarity(S3IM)method that exploits nonlocal structural information of groups of pixels,this paper proposes a new method to improve the completeness of fast novel view synthesis.The proposed method first extends the thread-wised processing of the Instant-NGP to the processing in a customthread block(i.e.,a group of threads).Then,the relative dimensionless global error in synthesis,i.e.,Erreur Relative Globale Adimensionnelle de Synthese(ERGAS),of a group of pixels corresponding to a group of threads is computed and incorporated into the loss function.Extensive experiments validate the proposed method.It can obtain better quantitative results than the original Instant-NGP with fewer iteration steps.PSNR is increased by 1%.Amazing qualitative results are obtained,especially for delicate structures and details such as lines and continuous structures.With the dramatic improvements in the visual effects,our method can boost the practicability of implicit 3D reconstruction in applications such as self-driving and augmented reality.展开更多
A constrained partial permutation strategy is proposed for matching spatial relation graph (SRG), which is used in our sketch input and recognition system Smart Sketchpad for representing the spatial relationship amon...A constrained partial permutation strategy is proposed for matching spatial relation graph (SRG), which is used in our sketch input and recognition system Smart Sketchpad for representing the spatial relationship among the components of a graphic object. Using two kinds of matching constraints dynamically generated in the matching process, the proposed approach can prune most improper mappings between SRGs during the matching process. According to our theoretical analysis in this paper, the time complexity of our approach is O(n 2) in the best case, and O(n!) in the worst case, which occurs infrequently. The spatial complexity is always O(n) for all cases. Implemented in Smart Sketchpad, our proposed strategy is of good performance.展开更多
Currently,some photorealistic computer graphics are very similar to photographic images.Photorealistic computer generated graphics can be forged as photographic images,causing serious security problems.The aim of this...Currently,some photorealistic computer graphics are very similar to photographic images.Photorealistic computer generated graphics can be forged as photographic images,causing serious security problems.The aim of this work is to use a deep neural network to detect photographic images(PI)versus computer generated graphics(CG).In existing approaches,image feature classification is computationally intensive and fails to achieve realtime analysis.This paper presents an effective approach to automatically identify PI and CG based on deep convolutional neural networks(DCNNs).Compared with some existing methods,the proposed method achieves real-time forensic tasks by deepening the network structure.Experimental results show that this approach can effectively identify PI and CG with average detection accuracy of 98%.展开更多
Large deformation contact problems generally involve highly nonlinear behaviors,which are very time-consuming and may lead to convergence issues.The finite particle method(FPM)effectively separates pure deformation fr...Large deformation contact problems generally involve highly nonlinear behaviors,which are very time-consuming and may lead to convergence issues.The finite particle method(FPM)effectively separates pure deformation from total motion in large deformation problems.In addition,the decoupled procedures of the FPM make it suitable for parallel computing,which may provide an approach to solve time-consuming issues.In this study,a graphics processing unit(GPU)-based parallel algorithm is proposed for two-dimensional large deformation contact problems.The fundamentals of the FPM for planar solids are first briefly introduced,including the equations of motion of particles and the internal forces of quadrilateral elements.Subsequently,a linked-list data structure suitable for parallel processing is built,and parallel global and local search algorithms are presented for contact detection.The contact forces are then derived and directly exerted on particles.The proposed method is implemented with main solution procedures executed in parallel on a GPU.Two verification problems comprising large deformation frictional contacts are presented,and the accuracy of the proposed algorithm is validated.Furthermore,the algorithm’s performance is investigated via a large-scale contact problem,and the maximum speedups of total computational time and contact calculation reach 28.5 and 77.4,respectively,relative to commercial finite element software Abaqus/Explicit running on a single-core central processing unit(CPU).The contact calculation time percentage of the total calculation time is only 18%with the FPM,much smaller than that(50%)with Abaqus/Explicit,demonstrating the efficiency of the proposed method.展开更多
This paper discuss the stereographic method of martensitic transformation (MT)in the view of computer graphics (CG) and programs are programmed to realize this method. Habit plane resulting from the programs agrees wi...This paper discuss the stereographic method of martensitic transformation (MT)in the view of computer graphics (CG) and programs are programmed to realize this method. Habit plane resulting from the programs agrees with that of numerical analysis in terms of the lattice parameters of austenite and martensite and shear mechanism supposed in Fe-22%Ni-0.8%C alloy, so does orientation relationships.展开更多
文摘It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.
基金financed by Project of Heilongjiang Higher Education Society“Research on Graphics Curriculum Based on Innovation and Entrepreneurship Education under the Background of Digital Education”(23GJYB035)the 2024 Annual Planning Project of the“14th Five Year Plan”of Educational Science in Heilongjiang Province“Research and Exploration on Ideological and Political Teaching of‘Computer Graphics’Course under the Concept of OBE in New Engineering”(GJB1424113).
文摘In the context of the deep integration of digitalization and innovation and entrepreneurship education,this study focuses on the characteristics of schools and courses,investigates students’expectations and needs for ideological and political elements,and deeply explores ideological and political cases such as the Beidahuang spirit,Daqing spirit,model worker spirit,and role models around them.It explores the integration practice of“curriculum ideological and political”in extracurricular tutoring teaching of engineering graphics,aiming to guide students to establish patriotism,love for schools,knowledge of agriculture,and love for agriculture,and effectively enhance the coordinated development of students’graphic skills and ideological and political literacy.Practice has shown that integrating ideological and political resources,incorporating ideological and political elements into curriculum content and practical activities,can effectively enhance the collaborative development of students’graphic skills and ideological and political literacy.At the same time,it provides new ideas and references for expanding ideological and political education to extracurricular tutoring courses.
基金supported in part by National Natural Science Foundation of China under Grant No.62473013Key Project of Science and Technology Innovation and Entrepreneurship of TDTEC(No.2022-TDZD004).
文摘The newly emerging neural radiance fields(NeRF)methods can implicitly fulfill three-dimensional(3D)reconstruction via training a neural network to render novel-view images of a given scene with given posed images.The Instant Neural Graphics Primitives(Instant-NGP)method further improves the position encoding of NeRF.It obtains state-of-the-art efficiency.However,only a local pixel-wised loss is considered when training the Instant-NGP while overlooking the nonlocal structural information between pixels.Despite a good quantitative result,it leads to a poor visual effect,especially the completeness.Inspired by the stochastic structural similarity(S3IM)method that exploits nonlocal structural information of groups of pixels,this paper proposes a new method to improve the completeness of fast novel view synthesis.The proposed method first extends the thread-wised processing of the Instant-NGP to the processing in a customthread block(i.e.,a group of threads).Then,the relative dimensionless global error in synthesis,i.e.,Erreur Relative Globale Adimensionnelle de Synthese(ERGAS),of a group of pixels corresponding to a group of threads is computed and incorporated into the loss function.Extensive experiments validate the proposed method.It can obtain better quantitative results than the original Instant-NGP with fewer iteration steps.PSNR is increased by 1%.Amazing qualitative results are obtained,especially for delicate structures and details such as lines and continuous structures.With the dramatic improvements in the visual effects,our method can boost the practicability of implicit 3D reconstruction in applications such as self-driving and augmented reality.
文摘A constrained partial permutation strategy is proposed for matching spatial relation graph (SRG), which is used in our sketch input and recognition system Smart Sketchpad for representing the spatial relationship among the components of a graphic object. Using two kinds of matching constraints dynamically generated in the matching process, the proposed approach can prune most improper mappings between SRGs during the matching process. According to our theoretical analysis in this paper, the time complexity of our approach is O(n 2) in the best case, and O(n!) in the worst case, which occurs infrequently. The spatial complexity is always O(n) for all cases. Implemented in Smart Sketchpad, our proposed strategy is of good performance.
基金This work is supported,in part,by the National Natural Science Foundation of China under grant numbers U1536206,U1405254,61772283,61602253,61672294,61502242In part,by the Jiangsu Basic Research Programs-Natural Science Foundation under grant numbers BK20150925 and BK20151530+1 种基金In part,by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundIn part,by the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund,China.
文摘Currently,some photorealistic computer graphics are very similar to photographic images.Photorealistic computer generated graphics can be forged as photographic images,causing serious security problems.The aim of this work is to use a deep neural network to detect photographic images(PI)versus computer generated graphics(CG).In existing approaches,image feature classification is computationally intensive and fails to achieve realtime analysis.This paper presents an effective approach to automatically identify PI and CG based on deep convolutional neural networks(DCNNs).Compared with some existing methods,the proposed method achieves real-time forensic tasks by deepening the network structure.Experimental results show that this approach can effectively identify PI and CG with average detection accuracy of 98%.
基金This work was supported by the National Key Research and Development Program of China[Grant No.2016YFC0800200]the National Natural Science Foundation of China[Grant Nos.51778568,51908492,and 52008366]+1 种基金Zhejiang Provincial Natural Science Foundation of China[Grant Nos.LQ21E080019 and LY21E080022]This work was also sup-ported by the Key Laboratory of Space Structures of Zhejiang Province(Zhejiang University)and the Center for Balance Architecture of Zhejiang University.
文摘Large deformation contact problems generally involve highly nonlinear behaviors,which are very time-consuming and may lead to convergence issues.The finite particle method(FPM)effectively separates pure deformation from total motion in large deformation problems.In addition,the decoupled procedures of the FPM make it suitable for parallel computing,which may provide an approach to solve time-consuming issues.In this study,a graphics processing unit(GPU)-based parallel algorithm is proposed for two-dimensional large deformation contact problems.The fundamentals of the FPM for planar solids are first briefly introduced,including the equations of motion of particles and the internal forces of quadrilateral elements.Subsequently,a linked-list data structure suitable for parallel processing is built,and parallel global and local search algorithms are presented for contact detection.The contact forces are then derived and directly exerted on particles.The proposed method is implemented with main solution procedures executed in parallel on a GPU.Two verification problems comprising large deformation frictional contacts are presented,and the accuracy of the proposed algorithm is validated.Furthermore,the algorithm’s performance is investigated via a large-scale contact problem,and the maximum speedups of total computational time and contact calculation reach 28.5 and 77.4,respectively,relative to commercial finite element software Abaqus/Explicit running on a single-core central processing unit(CPU).The contact calculation time percentage of the total calculation time is only 18%with the FPM,much smaller than that(50%)with Abaqus/Explicit,demonstrating the efficiency of the proposed method.
文摘This paper discuss the stereographic method of martensitic transformation (MT)in the view of computer graphics (CG) and programs are programmed to realize this method. Habit plane resulting from the programs agrees with that of numerical analysis in terms of the lattice parameters of austenite and martensite and shear mechanism supposed in Fe-22%Ni-0.8%C alloy, so does orientation relationships.
