In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have ...In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have been placed on the different parts and measured with accuracy ±0.2 mm from the above_mentioned piers.The main four stereopairs taken with the P31 camera around the model are simultaneously processed on the BC2 analytical plotter.The accuracy of absolute orientation is better than ±0.9 mm.Finally,about 300 sections construction drawings have been directly offered,and the close_range photogrammetric data has been used for the design and construction of the statue.展开更多
The purpose,classification,required accuracy and surveying methods of control work for close range photogrammetry have been briefly stated.The different methods for definition of space object coordinate system are als...The purpose,classification,required accuracy and surveying methods of control work for close range photogrammetry have been briefly stated.The different methods for definition of space object coordinate system are also reviewed.It is suggested that the habitually-practised rotation angle system for aerophotogrammetry in China should be used for the future teaching and researching work in the close range photogrammetry,and that the rotation angle system for terrestrial deformation photogrammetry should be left out in order to avoid the confuse and reduce the amount of expanse for making softwares.It has been emphasized that there are three improtant aspects in the close range control work with high accuracy using the conventional method of engineering surveying:the use of standard scale for measurement of distance between two general stations,the accurate determination of start direction line between two general stations and the handling method of influence of 2 C change.A method for setting up industrial surveying control net with extra-high accuracy ±(0.05-0.20) mm is presented by the author.This kind of industrial control net is necessary for batch process of large industrial components with purposes of measurement,inspect and lofting.There are some special methods of control work in the close range photogrammetry,including two methods presented by the author.展开更多
Close_range photogrammetry is to determine the shape and size of the object,instead of it’s absolute position.Therefore,at first,any translation and rotation of the photogrammetric model of the object caused by whole...Close_range photogrammetry is to determine the shape and size of the object,instead of it’s absolute position.Therefore,at first,any translation and rotation of the photogrammetric model of the object caused by whole geodesic,photographic and photogrammetric procedures in close_range photogrammetry could not be considered.However,it is necessary to analyze all the reasons which cause the deformations of the shape and size and to present their corresponding theories and equations.This situation,of course,is very different from the conventional topophotogrammetry.In this paper some specific characters of limit errors in close_range photogrammerty are presented in detail,including limit errors for calibration of interior elements for close_range cameras,the limit errors of relative and absolute orientations in close_range photogrammetric procedures,and the limit errors of control works in close_range photogrammetry.A theoretical equation of calibration accuracy for close_range camerais given.Relating to the three examples in this paper,their theoretical accuracy requirement of interior elements of camera change in the scope of ±(0.005～0.350) mm.This discussion permits us to reduce accuracy requirement in calibration for an object with small relief,but the camera platform is located in violent vibration environment.Another theoretical equation of relative RMS of base lines ( m S/S ) and the equation RMS of start direction are also presented.It is proved that the m S/S could be equal to the relative RMS of m Δ X / Δ X .It is also proved that the permitting RMS of start direction is much bigger than the traditionally used one.Some useful equations of limit errors in close_range photogrammetry are presented as well.Suggestions mentioned above are perhaps beneficial for increasing efficiency,for reducing production cost.展开更多
Accurate three-dimensional （3D） target positioning is of great importance in many industrial applications. Although various methods for reconstructing 3D information from a set of images have been available in the l...Accurate three-dimensional （3D） target positioning is of great importance in many industrial applications. Although various methods for reconstructing 3D information from a set of images have been available in the literature, few of them pay enough attention to the indispensable procedures, such as target extraction from images and image correction having strong influences upon the 3D positioning accuracy. This article puts forward a high-precision ellipse center （target point） extraction method and a new image correction approach which has been integrated into the 3D reconstruction pipeline with a concise implicit model to accurately compensates for the image distortion. The methods are applied to a copyright-reserved close range photogrammetric system. Real measuring experiments and industrial applications have evidenced the proposed methods, which can significantly improve the 3D positioning accuracy.展开更多
This paper presents a practical iterative algorithm for two-view metric reconstruction without any prior knowledge about the scene and motion in a nonsingular geometry configuration. The principal point is assumed to ...This paper presents a practical iterative algorithm for two-view metric reconstruction without any prior knowledge about the scene and motion in a nonsingular geometry configuration. The principal point is assumed to locate at the image center with zero skew and the same aspect ratio, and the interior parameters are fixed, so the self-calibration becomes focal-length cali- bration. Existing focal length calibration methods are direct solutions of a quadric composed of fundamental matrix, which are sensitive to noise. A quaternion-based linear iterative Least-Square Method is proposed in this paper, and one-dimensional searching for optimal focal length in a constrained region instead of solving optimization problems with inequality constraints is applied to simplify the computation complexity, then unique rotational matrix and translate vector are recovered. Experiments with simulation data and real images are given to verify the algorithm.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
文摘In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have been placed on the different parts and measured with accuracy ±0.2 mm from the above_mentioned piers.The main four stereopairs taken with the P31 camera around the model are simultaneously processed on the BC2 analytical plotter.The accuracy of absolute orientation is better than ±0.9 mm.Finally,about 300 sections construction drawings have been directly offered,and the close_range photogrammetric data has been used for the design and construction of the statue.
文摘The purpose,classification,required accuracy and surveying methods of control work for close range photogrammetry have been briefly stated.The different methods for definition of space object coordinate system are also reviewed.It is suggested that the habitually-practised rotation angle system for aerophotogrammetry in China should be used for the future teaching and researching work in the close range photogrammetry,and that the rotation angle system for terrestrial deformation photogrammetry should be left out in order to avoid the confuse and reduce the amount of expanse for making softwares.It has been emphasized that there are three improtant aspects in the close range control work with high accuracy using the conventional method of engineering surveying:the use of standard scale for measurement of distance between two general stations,the accurate determination of start direction line between two general stations and the handling method of influence of 2 C change.A method for setting up industrial surveying control net with extra-high accuracy ±(0.05-0.20) mm is presented by the author.This kind of industrial control net is necessary for batch process of large industrial components with purposes of measurement,inspect and lofting.There are some special methods of control work in the close range photogrammetry,including two methods presented by the author.
文摘Close_range photogrammetry is to determine the shape and size of the object,instead of it’s absolute position.Therefore,at first,any translation and rotation of the photogrammetric model of the object caused by whole geodesic,photographic and photogrammetric procedures in close_range photogrammetry could not be considered.However,it is necessary to analyze all the reasons which cause the deformations of the shape and size and to present their corresponding theories and equations.This situation,of course,is very different from the conventional topophotogrammetry.In this paper some specific characters of limit errors in close_range photogrammerty are presented in detail,including limit errors for calibration of interior elements for close_range cameras,the limit errors of relative and absolute orientations in close_range photogrammetric procedures,and the limit errors of control works in close_range photogrammetry.A theoretical equation of calibration accuracy for close_range camerais given.Relating to the three examples in this paper,their theoretical accuracy requirement of interior elements of camera change in the scope of ±(0.005～0.350) mm.This discussion permits us to reduce accuracy requirement in calibration for an object with small relief,but the camera platform is located in violent vibration environment.Another theoretical equation of relative RMS of base lines ( m S/S ) and the equation RMS of start direction are also presented.It is proved that the m S/S could be equal to the relative RMS of m Δ X / Δ X .It is also proved that the permitting RMS of start direction is much bigger than the traditionally used one.Some useful equations of limit errors in close_range photogrammetry are presented as well.Suggestions mentioned above are perhaps beneficial for increasing efficiency,for reducing production cost.
基金National Natural Science Foundation of China （50875 130） Doctoral Discipline Foundation of China （200802870016） Science Foundation of Jiangsu, China （BE2008136）
文摘Accurate three-dimensional （3D） target positioning is of great importance in many industrial applications. Although various methods for reconstructing 3D information from a set of images have been available in the literature, few of them pay enough attention to the indispensable procedures, such as target extraction from images and image correction having strong influences upon the 3D positioning accuracy. This article puts forward a high-precision ellipse center （target point） extraction method and a new image correction approach which has been integrated into the 3D reconstruction pipeline with a concise implicit model to accurately compensates for the image distortion. The methods are applied to a copyright-reserved close range photogrammetric system. Real measuring experiments and industrial applications have evidenced the proposed methods, which can significantly improve the 3D positioning accuracy.
文摘This paper presents a practical iterative algorithm for two-view metric reconstruction without any prior knowledge about the scene and motion in a nonsingular geometry configuration. The principal point is assumed to locate at the image center with zero skew and the same aspect ratio, and the interior parameters are fixed, so the self-calibration becomes focal-length cali- bration. Existing focal length calibration methods are direct solutions of a quadric composed of fundamental matrix, which are sensitive to noise. A quaternion-based linear iterative Least-Square Method is proposed in this paper, and one-dimensional searching for optimal focal length in a constrained region instead of solving optimization problems with inequality constraints is applied to simplify the computation complexity, then unique rotational matrix and translate vector are recovered. Experiments with simulation data and real images are given to verify the algorithm.
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.
