Aiming at the problem of 3D reconstruction for mine laneway, the technique route and step were given based on digital close range photogrammetry and traverse surveying. 3D coordinates of laneway traverse point, photog...Aiming at the problem of 3D reconstruction for mine laneway, the technique route and step were given based on digital close range photogrammetry and traverse surveying. 3D coordinates of laneway traverse point, photogrammetric station, control strip points were obtained by electronic total station based on mine coordinate system. The feature points were extracted from the scene images. The camera was calibrated by direct linear transformation (DLT). 3D relative coordinates of the arbitrary feature points in mine laneway were calculated after feature points being matched, in which the origin of coordinate system is photogrammetric station. The 3D absolute coordinates of the feature points in mine laneway can be obtained by the combined adjustment of photogrammetry and non-photogrammetric observations and coordinate conversion. The measurable 3D model of the underground laneway terrain surface was constructed with the 3D coordinates of feature points on the image pairs obtained. The measurable 3D model of a corridor was reconstructed by the mentioned method and the experiment precision with an average standard deviation of 0.013 6 m between the 3D model and practical measure was obtained by electronic total station. The experimental resulted show the validity of the proposed approach.展开更多
The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a rese...The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a research hotspot in the industry. This paper proposes a position and attitude calibration method with error correction based on the combination of the feature point and feature surface. First, the initial value of the spatial position relation-ship between each sensor of MMS is obtained by close-range photogrammetry. Second, the optimal solution for error correction is calculated by feature points in global coordinates jointly measured with International GNSS Service (IGS) stations. Then, the final transformation para-meters are solved by combining the initial values obtained originally, thereby realizing the rapid calibration of the MMS. Finally, it analyzed the RMSE of MMS point cloud after calibration, and the results demonstrate the feasibility of the calibration approach proposed by this method. Under the condition of a single measurement sensor accuracy is low, the plane and elevation absolute accuracy of the point cloud after calibration can reach 0.043 m and 0.072 m, respectively, and the relative accuracy is smaller than 0.02 m. It meets the precision require-ments of data acquisition for MMS. It is of great significance for promoting the development of MMS technology and the application of some novel techniques in the future, such as auton-omous driving, digital twin city, urban brain et al.展开更多
Aiming at the shortage of hydroelectric engineering geological logging methods on high side slope and big gallery, the photographic methods based on digital camera were studied. By integrating the application of techn...Aiming at the shortage of hydroelectric engineering geological logging methods on high side slope and big gallery, the photographic methods based on digital camera were studied. By integrating the application of technology of close range photogrammetry, digital image processing and GIS, the photographic geological logging information system was developed. The system has the functions of digital photography, orthophotoquad making, image mosaicking, logging factors extracting and measuring, CAD mapping, etc. The methods achieve more efficient and higher precision than the regular, and it provides a new way for the hydroelectric engineering geologic logging.展开更多
A new small-scale geotechnical physical model in 1-g and unconfined condition, combining the transparent soil, close-range photogrammetry and particle image velocimetry(PIV), was employed, which provides a non-intrusi...A new small-scale geotechnical physical model in 1-g and unconfined condition, combining the transparent soil, close-range photogrammetry and particle image velocimetry(PIV), was employed, which provides a non-intrusively internal deformation measurement approach to monitor the internal deformation of soil caused by expanded-base pile jacking with casing. The transparent soil was made of fused quartz and its refractive index matched blended oil, adding reflective particles(glass beads). Closerange photogrammetry was employed to record the images of the process of casing jacking and extraction in transparent soil, allowing the use of Matlab-based Geo-PIV to figure out the displacement field converted from image space to object space. Analysis of test results indicates that the maximum displacement caused by casing jacking for expandedconical-base pile is decreased by 29% compared with that for expanded-flat-base pile. The main movement happens at the early stage of casing extraction. The maximum displacement caused by casing extraction for the conical base is about 43% of that for the flatbase, while the affected zone caused by casing extraction for the conical base accounts for about 1/3 of that for the flat base. The contraction for horizontal displacements tends to decrease with the depth increasing. By contrast, the contraction under pile base decreases with the increasing of displacement. The displacements generated by jacking a conventional pile having a diameter equal to the casing diameter of the expanded-base pile were comparable to the net displacement taking place due to expanded-base pile installation for the conical base pile.展开更多
This study analyzes the function of different muscles during arm wrestling and proposes a method to analyze the optimal forearm angle for professional arm wrestlers.We built a professional arm-wrestling platform to me...This study analyzes the function of different muscles during arm wrestling and proposes a method to analyze the optimal forearm angle for professional arm wrestlers.We built a professional arm-wrestling platform to measure the shape and deformation of the skin at the biceps brachii of a volunteer in vivo during arm wrestling.We observed the banding phenomenon of arm skin strain during muscle contraction and developed a model to evaluate the moment provided by the biceps brachii.According to this model,the strain field of the area of interest on the skin was measured,and the forearm angles most favorable and unfavorable to the work of the biceps brachii were analyzed.This study demonstrates the considerable potential of applying DIC and its extension method to the in vivo measurement of human skin and facilitates the use of the in vivo measurement of skin deformation in various sports in the future.展开更多
基金Project(2010JM5009)supported by the Natural Science Foundation of Shaanxi Province,ChinaProject(09JK597)supported by the Scientific Research Program Funded of Shaanxi Provincial Education Department,China
文摘Aiming at the problem of 3D reconstruction for mine laneway, the technique route and step were given based on digital close range photogrammetry and traverse surveying. 3D coordinates of laneway traverse point, photogrammetric station, control strip points were obtained by electronic total station based on mine coordinate system. The feature points were extracted from the scene images. The camera was calibrated by direct linear transformation (DLT). 3D relative coordinates of the arbitrary feature points in mine laneway were calculated after feature points being matched, in which the origin of coordinate system is photogrammetric station. The 3D absolute coordinates of the feature points in mine laneway can be obtained by the combined adjustment of photogrammetry and non-photogrammetric observations and coordinate conversion. The measurable 3D model of the underground laneway terrain surface was constructed with the 3D coordinates of feature points on the image pairs obtained. The measurable 3D model of a corridor was reconstructed by the mentioned method and the experiment precision with an average standard deviation of 0.013 6 m between the 3D model and practical measure was obtained by electronic total station. The experimental resulted show the validity of the proposed approach.
基金This research was funded by the National Natural Science Foundation of China[grant number 41971350 and 41571437]Beijing Advanced Innovation Centre for Future Urban Design Project[grant number UDC2019031724]+4 种基金Teacher Support Program for Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture[grant number JDJQ20200307]State Key Laboratory of Geo-Information Engineering[grant number SKLGIE2019-Z-3-1]Open Research Fund Program of LIESMARS[grant number 19E01]National Key Research and Development Program of China[grant number 2019YFC1520100]The Fundamental Research Funds for Beijing University of Civil Engineering and Architecture[grant number X18050].
文摘The measurement accuracy of the Mobile Mapping System (MMS) is the main problem, which restricts its development and application, so how to calibrate the MMS to improve its measure-ment accuracy has always been a research hotspot in the industry. This paper proposes a position and attitude calibration method with error correction based on the combination of the feature point and feature surface. First, the initial value of the spatial position relation-ship between each sensor of MMS is obtained by close-range photogrammetry. Second, the optimal solution for error correction is calculated by feature points in global coordinates jointly measured with International GNSS Service (IGS) stations. Then, the final transformation para-meters are solved by combining the initial values obtained originally, thereby realizing the rapid calibration of the MMS. Finally, it analyzed the RMSE of MMS point cloud after calibration, and the results demonstrate the feasibility of the calibration approach proposed by this method. Under the condition of a single measurement sensor accuracy is low, the plane and elevation absolute accuracy of the point cloud after calibration can reach 0.043 m and 0.072 m, respectively, and the relative accuracy is smaller than 0.02 m. It meets the precision require-ments of data acquisition for MMS. It is of great significance for promoting the development of MMS technology and the application of some novel techniques in the future, such as auton-omous driving, digital twin city, urban brain et al.
文摘Aiming at the shortage of hydroelectric engineering geological logging methods on high side slope and big gallery, the photographic methods based on digital camera were studied. By integrating the application of technology of close range photogrammetry, digital image processing and GIS, the photographic geological logging information system was developed. The system has the functions of digital photography, orthophotoquad making, image mosaicking, logging factors extracting and measuring, CAD mapping, etc. The methods achieve more efficient and higher precision than the regular, and it provides a new way for the hydroelectric engineering geologic logging.
基金sponsored by the National Natural Science Foundation of China (Project No. 51508282)K. C. Wong Magna Fund in Ningbo University, China Postdoctoral Science Foundation(No.2017M611674)Fundamental Research Funds for the Central Universities (2017B13614)
文摘A new small-scale geotechnical physical model in 1-g and unconfined condition, combining the transparent soil, close-range photogrammetry and particle image velocimetry(PIV), was employed, which provides a non-intrusively internal deformation measurement approach to monitor the internal deformation of soil caused by expanded-base pile jacking with casing. The transparent soil was made of fused quartz and its refractive index matched blended oil, adding reflective particles(glass beads). Closerange photogrammetry was employed to record the images of the process of casing jacking and extraction in transparent soil, allowing the use of Matlab-based Geo-PIV to figure out the displacement field converted from image space to object space. Analysis of test results indicates that the maximum displacement caused by casing jacking for expandedconical-base pile is decreased by 29% compared with that for expanded-flat-base pile. The main movement happens at the early stage of casing extraction. The maximum displacement caused by casing extraction for the conical base is about 43% of that for the flatbase, while the affected zone caused by casing extraction for the conical base accounts for about 1/3 of that for the flat base. The contraction for horizontal displacements tends to decrease with the depth increasing. By contrast, the contraction under pile base decreases with the increasing of displacement. The displacements generated by jacking a conventional pile having a diameter equal to the casing diameter of the expanded-base pile were comparable to the net displacement taking place due to expanded-base pile installation for the conical base pile.
基金This study was supported by the National Natural Science Foun-dation of China(NSFC)(No.11902074).
文摘This study analyzes the function of different muscles during arm wrestling and proposes a method to analyze the optimal forearm angle for professional arm wrestlers.We built a professional arm-wrestling platform to measure the shape and deformation of the skin at the biceps brachii of a volunteer in vivo during arm wrestling.We observed the banding phenomenon of arm skin strain during muscle contraction and developed a model to evaluate the moment provided by the biceps brachii.According to this model,the strain field of the area of interest on the skin was measured,and the forearm angles most favorable and unfavorable to the work of the biceps brachii were analyzed.This study demonstrates the considerable potential of applying DIC and its extension method to the in vivo measurement of human skin and facilitates the use of the in vivo measurement of skin deformation in various sports in the future.
