The macro mechanical properties of materials with characteristics of large scale and complicated structural composition can be analyzed through its reconstructed meso-structures.In this work,the meso-structures of tal...The macro mechanical properties of materials with characteristics of large scale and complicated structural composition can be analyzed through its reconstructed meso-structures.In this work,the meso-structures of talus deposits that widely exist in the hydro-power engineering in the southwest of China were first reconstructed by small particles according to the in-situ photographs based on the self-adaptive PCNN digital image processing,and then numerical direct shear tests were carried out for studying the mechanical properties of talus deposits.Results indicate that the reconstructed meso-structures of talus deposits are more consistent with the actual situation because the self-adaptive PCNN digital image processing has a higher discrimination in the details of soil-rock segmentation.The existence and random distribution of rock blocks make the initial shear stiffness,the peak strength and the residual strength higher than those of the "pure soil" with particle size less than 1.25 cm apparently,but reduce the displacements required for the talus deposits reaching its peak shear strength.The increase of rock proportion causes a significant improvement in the internal friction angle of talus deposit,which to a certain degree leads to the characteristics of shear stress-displacement curves having a changing trend from the plastic strain softening deformation to the nonlinear strain hardening deformation,while an unconspicuous increase in cohesion.The uncertainty and heterogeneity of rock distributions cause the differences of rock proportion within shear zone,leading to a relatively strong fluctuation in peak strengths during the shear process,while movement features of rock blocks,such as translation,rotation and crossing,expand the scope of shear zone,increase the required shear force,and also directly lead to the misjudgment that the lower shear strength is obtained from the samples with high rock proportion.That,however,just explains the reason why the shear strength gained from a small amount of indoor test data is not consistent with engineering practice.展开更多
A new algorithm is proposed to determine the actual length and the number of the protruding fibres of yarn based on a combination of image acquisition technology. First, a yarn hairiness image is obtained by the serie...A new algorithm is proposed to determine the actual length and the number of the protruding fibres of yarn based on a combination of image acquisition technology. First, a yarn hairiness image is obtained by the series of image processing procedures that include grayscale transformation,skew correction,yarn binary image acquisition and yarn core binary image obtaining. Then,the hairiness is realized in single pixel width by the usage of thinning algorithm. Finally, a baseline of yarn core margin is obtained,and pixels that match 8-neighbor template correctly are found by row scanning in a certain area. From this,these pixels are judged and the real crossover points of yarn core margin and hairiness,i. e.,the starting points of hairiness,are gained. The real length of the protruding fibres is calculated by tracking hairiness from the starting point constantly.展开更多
A new parallel thinning algorithm was proposed.This paper suggests a set of 5x5cloning templates of cellular neural network for image thinning.The principle of the templatesdesign and hardware model are proposed in th...A new parallel thinning algorithm was proposed.This paper suggests a set of 5x5cloning templates of cellular neural network for image thinning.The principle of the templatesdesign and hardware model are proposed in the paper.Although the connected weights betweenthe neurons are asymmetric,it is shown that the network is stable,and it can be easily realized.展开更多
针对果园环境下双目采集系统采集的飞行时间(Time of Flight,ToF)与可见光异源图像间匹配精度差的问题,该研究提出一种基于局部峰值的目标显著区域提取策略及最大期望算法的脉冲耦合神经网络分割的ToF与可见光果园苹果图像配准方法。首...针对果园环境下双目采集系统采集的飞行时间(Time of Flight,ToF)与可见光异源图像间匹配精度差的问题,该研究提出一种基于局部峰值的目标显著区域提取策略及最大期望算法的脉冲耦合神经网络分割的ToF与可见光果园苹果图像配准方法。首先,利用高斯差函数计算可见光图像中显著性区域,对可见光图像的红绿分量进行预处理;然后,以图像局部灰度值的二维正态分布作为目标分量,使用Otsu提取具有固定阈值的前景作为局部峰值提取策略,对ToF与可见光图像初步筛选特征区域,利用最大期望算法改进脉冲耦合神经网络(Pulse Coupled Neural Network,PCNN)动态阈值,使用局部图像梯度计算链接强度计算链接强度,利用图像区域方差改进终止条件,提出一种基于最大期望的脉冲耦合神经网络(Pulse Coupled Neural Network based on Expectation Maximization,EM-PCNN)算法对预选区域进行精细化分割;接着计算连通区域不变矩,利用不变矩特征原理寻找目标中心同名点,进一步筛选特征区域;最后,同名点进行随机抽样一致算法(Random Sample Consensus,RANSAC)提纯,将提纯后的同名点坐标代入变换模型计算模型参数,完成配准。在不同光照条件下均方根误差达3.05~4.75,配准点达3~5。EM-PCNN算法对两组ToF置信图像分割的准确率分别为96.62%和73.84%。试验结果表明该方法对双目采集系统采集的ToF与可见光异源果园苹果图像可实现较好配准效果,且对图像平移、旋转、缩放均具有可抗性。研究结果对ToF与可见光异源图像在果园环境下自动配准提供了技术参考。展开更多
基金Project(2013BAB06B00) supported by the National Key Technology R&D Programof ChinaProject(2011CB013504) supported by the National Basic Research Program of ChinaProject(50911130366) supported by the National Natural Science Foundation of China
文摘The macro mechanical properties of materials with characteristics of large scale and complicated structural composition can be analyzed through its reconstructed meso-structures.In this work,the meso-structures of talus deposits that widely exist in the hydro-power engineering in the southwest of China were first reconstructed by small particles according to the in-situ photographs based on the self-adaptive PCNN digital image processing,and then numerical direct shear tests were carried out for studying the mechanical properties of talus deposits.Results indicate that the reconstructed meso-structures of talus deposits are more consistent with the actual situation because the self-adaptive PCNN digital image processing has a higher discrimination in the details of soil-rock segmentation.The existence and random distribution of rock blocks make the initial shear stiffness,the peak strength and the residual strength higher than those of the "pure soil" with particle size less than 1.25 cm apparently,but reduce the displacements required for the talus deposits reaching its peak shear strength.The increase of rock proportion causes a significant improvement in the internal friction angle of talus deposit,which to a certain degree leads to the characteristics of shear stress-displacement curves having a changing trend from the plastic strain softening deformation to the nonlinear strain hardening deformation,while an unconspicuous increase in cohesion.The uncertainty and heterogeneity of rock distributions cause the differences of rock proportion within shear zone,leading to a relatively strong fluctuation in peak strengths during the shear process,while movement features of rock blocks,such as translation,rotation and crossing,expand the scope of shear zone,increase the required shear force,and also directly lead to the misjudgment that the lower shear strength is obtained from the samples with high rock proportion.That,however,just explains the reason why the shear strength gained from a small amount of indoor test data is not consistent with engineering practice.
基金National Natural Science Foundation of China(No.61301276)Xi’an Polytechnic University Young Scholar Backbone Supporting Plan,ChinaDiscipline Construction Funds of Xi’an Polytechnic University,China(No.107090811)
文摘A new algorithm is proposed to determine the actual length and the number of the protruding fibres of yarn based on a combination of image acquisition technology. First, a yarn hairiness image is obtained by the series of image processing procedures that include grayscale transformation,skew correction,yarn binary image acquisition and yarn core binary image obtaining. Then,the hairiness is realized in single pixel width by the usage of thinning algorithm. Finally, a baseline of yarn core margin is obtained,and pixels that match 8-neighbor template correctly are found by row scanning in a certain area. From this,these pixels are judged and the real crossover points of yarn core margin and hairiness,i. e.,the starting points of hairiness,are gained. The real length of the protruding fibres is calculated by tracking hairiness from the starting point constantly.
基金the National Natural Science Foundation of China.
文摘A new parallel thinning algorithm was proposed.This paper suggests a set of 5x5cloning templates of cellular neural network for image thinning.The principle of the templatesdesign and hardware model are proposed in the paper.Although the connected weights betweenthe neurons are asymmetric,it is shown that the network is stable,and it can be easily realized.
文摘针对果园环境下双目采集系统采集的飞行时间(Time of Flight,ToF)与可见光异源图像间匹配精度差的问题,该研究提出一种基于局部峰值的目标显著区域提取策略及最大期望算法的脉冲耦合神经网络分割的ToF与可见光果园苹果图像配准方法。首先,利用高斯差函数计算可见光图像中显著性区域,对可见光图像的红绿分量进行预处理;然后,以图像局部灰度值的二维正态分布作为目标分量,使用Otsu提取具有固定阈值的前景作为局部峰值提取策略,对ToF与可见光图像初步筛选特征区域,利用最大期望算法改进脉冲耦合神经网络(Pulse Coupled Neural Network,PCNN)动态阈值,使用局部图像梯度计算链接强度计算链接强度,利用图像区域方差改进终止条件,提出一种基于最大期望的脉冲耦合神经网络(Pulse Coupled Neural Network based on Expectation Maximization,EM-PCNN)算法对预选区域进行精细化分割;接着计算连通区域不变矩,利用不变矩特征原理寻找目标中心同名点,进一步筛选特征区域;最后,同名点进行随机抽样一致算法(Random Sample Consensus,RANSAC)提纯,将提纯后的同名点坐标代入变换模型计算模型参数,完成配准。在不同光照条件下均方根误差达3.05~4.75,配准点达3~5。EM-PCNN算法对两组ToF置信图像分割的准确率分别为96.62%和73.84%。试验结果表明该方法对双目采集系统采集的ToF与可见光异源果园苹果图像可实现较好配准效果,且对图像平移、旋转、缩放均具有可抗性。研究结果对ToF与可见光异源图像在果园环境下自动配准提供了技术参考。
