Propeller blade width measurement has been extensively studied in the past using direct and indirect methods, and it plays a great role in determining the quality of the finished products. It has surveyed that previou...Propeller blade width measurement has been extensively studied in the past using direct and indirect methods, and it plays a great role in determining the quality of the finished products. It has surveyed that previous techniques are usually time-consuming and erroneous due to a large number of points to be processed in blade width measurement. This paper proposes a new method of measuring blade width using two images acquired from different viewpoints of the same blade. And a new feature points matching approach for propeller blade image is proposed in stereo vision measurement. Based on these, pixel coordinates of contour points of the blade in two images are extracted and converted to real world coordinates by image algorithm and binocular stereo machine vision theory. Then, from the real world coordinates, the blade width at any position can be determined by simple geometrical method.展开更多
目的像方无人机影像多视匹配方法忽视了影像之间的几何关系,而以MVLL(multi-view vertical line locus)为代表的物方多视匹配方法缺乏对地形之间相互约束的考虑。为此构建一种融合两类多视匹配方法优点的无人机影像物方多视匹配算法。...目的像方无人机影像多视匹配方法忽视了影像之间的几何关系,而以MVLL(multi-view vertical line locus)为代表的物方多视匹配方法缺乏对地形之间相互约束的考虑。为此构建一种融合两类多视匹配方法优点的无人机影像物方多视匹配算法。方法在MVLL匹配结构的基础上添加半全局匹配的相容性约束,不仅继承了原半全局算法对有弱纹理区域匹配效果好和物体边缘突出的优点,而且摆脱了需制作核线影像的繁琐过程;采用物方窗口SNCC(summed normalized cross correlation)一致性匹配测度计算方法,有效降低摄影角度和遮挡对匹配结果的影响;采用金字塔分层的策略以提高匹配的速度和可靠性。结果选取自主研制的旋翼无人机三轴稳定平台获取了高分辨率无人机影像作为实验数据,从匹配效果、新匹配测度性能和匹配精度3个方面对算法进行了测试实验。本文算法整体匹配效果良好,物方窗口SNCC一致性匹配测度可有效消除匹配测度中的粗差,经过测定本文匹配算法生成的点云数据的高程精度为0.049 m,即约为1个GSD(ground space resolution)对应的地面大小。结论本文算法充分利用了无人机影像的多视信息进行匹配计算,具有匹配效果好、鲁棒性强和匹配精度高的优势。展开更多
In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed, accordin...In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed, according to the fact that the light of coal mine is uneven, the strength of light changes greatly, the direction of belt movement is constant, and the position of camera was fixed, various algorithms of speed measurement by video were studied, and algorithm for template matching based on sum of absolute differences （SAD） and correlation coefficient was proposed and improved, besides, the tracking of feature regions was realized. Then, a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized. Finally, experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed, so it has a comprehensive applicability.展开更多
基金Supported by the Natural Science Foundation of China (50975133)the Innovative Foundation for Ph.D of the Jiangsu Province, China (2010-227)
文摘Propeller blade width measurement has been extensively studied in the past using direct and indirect methods, and it plays a great role in determining the quality of the finished products. It has surveyed that previous techniques are usually time-consuming and erroneous due to a large number of points to be processed in blade width measurement. This paper proposes a new method of measuring blade width using two images acquired from different viewpoints of the same blade. And a new feature points matching approach for propeller blade image is proposed in stereo vision measurement. Based on these, pixel coordinates of contour points of the blade in two images are extracted and converted to real world coordinates by image algorithm and binocular stereo machine vision theory. Then, from the real world coordinates, the blade width at any position can be determined by simple geometrical method.
文摘目的像方无人机影像多视匹配方法忽视了影像之间的几何关系,而以MVLL(multi-view vertical line locus)为代表的物方多视匹配方法缺乏对地形之间相互约束的考虑。为此构建一种融合两类多视匹配方法优点的无人机影像物方多视匹配算法。方法在MVLL匹配结构的基础上添加半全局匹配的相容性约束,不仅继承了原半全局算法对有弱纹理区域匹配效果好和物体边缘突出的优点,而且摆脱了需制作核线影像的繁琐过程;采用物方窗口SNCC(summed normalized cross correlation)一致性匹配测度计算方法,有效降低摄影角度和遮挡对匹配结果的影响;采用金字塔分层的策略以提高匹配的速度和可靠性。结果选取自主研制的旋翼无人机三轴稳定平台获取了高分辨率无人机影像作为实验数据,从匹配效果、新匹配测度性能和匹配精度3个方面对算法进行了测试实验。本文算法整体匹配效果良好,物方窗口SNCC一致性匹配测度可有效消除匹配测度中的粗差,经过测定本文匹配算法生成的点云数据的高程精度为0.049 m,即约为1个GSD(ground space resolution)对应的地面大小。结论本文算法充分利用了无人机影像的多视信息进行匹配计算,具有匹配效果好、鲁棒性强和匹配精度高的优势。
文摘In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed, according to the fact that the light of coal mine is uneven, the strength of light changes greatly, the direction of belt movement is constant, and the position of camera was fixed, various algorithms of speed measurement by video were studied, and algorithm for template matching based on sum of absolute differences （SAD） and correlation coefficient was proposed and improved, besides, the tracking of feature regions was realized. Then, a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized. Finally, experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed, so it has a comprehensive applicability.
