The purpose of this study is to develop a standard methodology for measuring the surface free energy (SFE),and its component parts of bamboo fiber materials.The current methods was reviewed to determine the surface te...The purpose of this study is to develop a standard methodology for measuring the surface free energy (SFE),and its component parts of bamboo fiber materials.The current methods was reviewed to determine the surface tension of natural fibers and the disadvantages of techniques used were discussed.Although numerous techniques have been employed to characterize surface tension of natural fibers,it seems that the credibility of results obtained may often be dubious.In this paper,critical surface tension estimates were obtained from computer aided machine vision based measurement.Data were then analyzed by the least squares method to estimate the components of SFE.SFE was estimated by least squares analysis and also by Schultz' method.By using the Fowkes method the polar and disperse fractions of the surface free energy of bamboo fiber materials can be obtained.Strictly speaking,this method is based on a combination of the knowledge of Fowkes theory. SFE is desirable when adhesion is required,and it avoids some of the limitations of existing studies which has been proposed.The calculation steps described in this research are only intended to explain the methods.The results show that the method that only determines SFE as a single parameter may be unable to differentiate adequately between bamboo fiber materials,but it is feasible and very efficient.In order to obtain the maximum performance from the computer aided machine vision based measurement instruments,this measurement should be recommended and kept available for reference.展开更多
The mean shift tracker has difficulty in tracking fast moving targets and suffers from tracking error accumulation problem. To overcome the limitations of the mean shift method, a new approach is proposed by integrati...The mean shift tracker has difficulty in tracking fast moving targets and suffers from tracking error accumulation problem. To overcome the limitations of the mean shift method, a new approach is proposed by integrating the mean shift algorithm and frame-difference methods. The rough position of the moving tar- get is first located by the direct frame-difference algorithm and three-frame-difference algorithm for the immobile camera scenes and mobile camera scenes, respectively. Then, the mean shift algorithm is used to achieve precise tracking of the target. Several tracking experiments show that the proposed method can effectively track first moving targets and overcome the tracking error accumulation problem.展开更多
To analyze the spring disturbance torque caused by motionai cable harness in a stabilized platform, the Kirchhoff theory based cable harness model has been previously developed to dynamically simulate the motional cab...To analyze the spring disturbance torque caused by motionai cable harness in a stabilized platform, the Kirchhoff theory based cable harness model has been previously developed to dynamically simulate the motional cable harness. In this paper, this model was validated by comparing the simulation results with the experiment results （ both the spring force and the deformed profile of the motional cable harness）. In the experiment, a special optical measuring instrument based on binocular vision was developed and the motion and deformation of cable harness were measured. A simpli- fied stabilized platform system was constructed, and the absolute value of spring disturbance force during the motion of this simplified frame was obtained by using a force gauge （0. 02 N precision）. The physical parameters of experimental specimen were also measured. The experimental and simulated results showed good agreement. These results should be useful for better motional cable harness layout design and reliable evaluation of the spring disturbance torque.展开更多
为解决电池模组极柱焊接缺陷检测精度低、效率低的问题,提出了一种基于机器视觉的焊接缺陷检测算法。首先,对采集图像进行预处理操作;其次,通过组件筛选结合改进的Canny算法获取目标区域的无干扰边缘轮廓,为了改善拟合干扰现象,利用基...为解决电池模组极柱焊接缺陷检测精度低、效率低的问题,提出了一种基于机器视觉的焊接缺陷检测算法。首先,对采集图像进行预处理操作;其次,通过组件筛选结合改进的Canny算法获取目标区域的无干扰边缘轮廓,为了改善拟合干扰现象,利用基于密度的聚类(density-based spatial clustering of applications with noise,DBSCAN)算法对焊接区域的内外圆边缘点集进行分离;然后,采用改进的最小二乘法对内外圆点集分别进行拟合得到精准的焊接区域;最后,以焊接区域内外圆的面积差和同心度来检测焊接面积缺陷和焊偏,通过双向扫面检测法进行焊接区域灰度值遍历,根据对应的灰度值范围和区域大小来检测焊穿和炸点缺陷。实验表明,该算法能够精确拟合焊接区域并准确识别出焊接缺陷,具有较高的检测精度和效率,能够满足工业生产需求。展开更多
为了解决传统接触式位移传感器在实际桥梁位移检测中存在的安装复杂、测量范围受限等问题,将SURF(Speeded Up Robust Features)特征点检测与KLT(Kanade-Lucas-Tomasi)特征追踪算法相结合,提出了一种基于计算机视觉的特征光流桥梁位移测...为了解决传统接触式位移传感器在实际桥梁位移检测中存在的安装复杂、测量范围受限等问题,将SURF(Speeded Up Robust Features)特征点检测与KLT(Kanade-Lucas-Tomasi)特征追踪算法相结合,提出了一种基于计算机视觉的特征光流桥梁位移测量方法。利用消费级相机对实验室斜拉桥模型进行测试,并与传统激光测量方法进行了对比,验证了本文所提方法的有效性。同时,从有无靶标、相机距离、光线强弱3个方面探讨了该算法的鲁棒性,最后将本文所提方法与主流视觉方法进行了对比分析。结果表明,特征光流法能够精确测量桥梁的振动位移,最大误差仅为0.73 mm,为桥梁在复杂环境下的非接触式实时位移监测提供了新的思路。展开更多
基金the National Natural Science Foundation of China(No.31101085)the Scientific Research and Development Foundation for Start-up Projects of Zhejiang Agriculture and Forestry University (No.2034020044)
文摘The purpose of this study is to develop a standard methodology for measuring the surface free energy (SFE),and its component parts of bamboo fiber materials.The current methods was reviewed to determine the surface tension of natural fibers and the disadvantages of techniques used were discussed.Although numerous techniques have been employed to characterize surface tension of natural fibers,it seems that the credibility of results obtained may often be dubious.In this paper,critical surface tension estimates were obtained from computer aided machine vision based measurement.Data were then analyzed by the least squares method to estimate the components of SFE.SFE was estimated by least squares analysis and also by Schultz' method.By using the Fowkes method the polar and disperse fractions of the surface free energy of bamboo fiber materials can be obtained.Strictly speaking,this method is based on a combination of the knowledge of Fowkes theory. SFE is desirable when adhesion is required,and it avoids some of the limitations of existing studies which has been proposed.The calculation steps described in this research are only intended to explain the methods.The results show that the method that only determines SFE as a single parameter may be unable to differentiate adequately between bamboo fiber materials,but it is feasible and very efficient.In order to obtain the maximum performance from the computer aided machine vision based measurement instruments,this measurement should be recommended and kept available for reference.
基金supported by the Fundamental Research Funds for the Central Universities Project(CDJZR10170010)
文摘The mean shift tracker has difficulty in tracking fast moving targets and suffers from tracking error accumulation problem. To overcome the limitations of the mean shift method, a new approach is proposed by integrating the mean shift algorithm and frame-difference methods. The rough position of the moving tar- get is first located by the direct frame-difference algorithm and three-frame-difference algorithm for the immobile camera scenes and mobile camera scenes, respectively. Then, the mean shift algorithm is used to achieve precise tracking of the target. Several tracking experiments show that the proposed method can effectively track first moving targets and overcome the tracking error accumulation problem.
基金Supported by the National Natural Science Foundation of China(50805009)
文摘To analyze the spring disturbance torque caused by motionai cable harness in a stabilized platform, the Kirchhoff theory based cable harness model has been previously developed to dynamically simulate the motional cable harness. In this paper, this model was validated by comparing the simulation results with the experiment results （ both the spring force and the deformed profile of the motional cable harness）. In the experiment, a special optical measuring instrument based on binocular vision was developed and the motion and deformation of cable harness were measured. A simpli- fied stabilized platform system was constructed, and the absolute value of spring disturbance force during the motion of this simplified frame was obtained by using a force gauge （0. 02 N precision）. The physical parameters of experimental specimen were also measured. The experimental and simulated results showed good agreement. These results should be useful for better motional cable harness layout design and reliable evaluation of the spring disturbance torque.
文摘为解决电池模组极柱焊接缺陷检测精度低、效率低的问题,提出了一种基于机器视觉的焊接缺陷检测算法。首先,对采集图像进行预处理操作;其次,通过组件筛选结合改进的Canny算法获取目标区域的无干扰边缘轮廓,为了改善拟合干扰现象,利用基于密度的聚类(density-based spatial clustering of applications with noise,DBSCAN)算法对焊接区域的内外圆边缘点集进行分离;然后,采用改进的最小二乘法对内外圆点集分别进行拟合得到精准的焊接区域;最后,以焊接区域内外圆的面积差和同心度来检测焊接面积缺陷和焊偏,通过双向扫面检测法进行焊接区域灰度值遍历,根据对应的灰度值范围和区域大小来检测焊穿和炸点缺陷。实验表明,该算法能够精确拟合焊接区域并准确识别出焊接缺陷,具有较高的检测精度和效率,能够满足工业生产需求。
文摘为了解决传统接触式位移传感器在实际桥梁位移检测中存在的安装复杂、测量范围受限等问题,将SURF(Speeded Up Robust Features)特征点检测与KLT(Kanade-Lucas-Tomasi)特征追踪算法相结合,提出了一种基于计算机视觉的特征光流桥梁位移测量方法。利用消费级相机对实验室斜拉桥模型进行测试,并与传统激光测量方法进行了对比,验证了本文所提方法的有效性。同时,从有无靶标、相机距离、光线强弱3个方面探讨了该算法的鲁棒性,最后将本文所提方法与主流视觉方法进行了对比分析。结果表明,特征光流法能够精确测量桥梁的振动位移,最大误差仅为0.73 mm,为桥梁在复杂环境下的非接触式实时位移监测提供了新的思路。
