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CONTROL WORK IN CLOSE RANGE PHOTOGRAMMETRY 被引量:2
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作者 FENG Wenhao 《Geo-Spatial Information Science》 2001年第4期66-72,共7页
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... 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 habitu-ally-practised rotation angle system for aerophotogrammetry in China should be used for the future teaching and resaarching 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 accurary 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 2C 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
关键词 close range photogrammetry control work high accuracy industrial control net
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Accurate 3D Target Positioning in Close Range Photogrammetry with Implicit Image Correction 被引量:6
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作者 Zheng Jiandong Zhang Liyana Du Xiaoyu 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2009年第6期649-657,共9页
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
关键词 close range photogrammetry implicit camera model image correction feature extraction
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Simulation of the landform change process on a purple soil slope due to tillage erosion and water erosion using UAV technology 被引量:1
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作者 YANG Chao SU Zheng-an +6 位作者 FAN Jian-rong FANG Hai-dong SHI Liang-tao ZHANG Jian-hui HE Zhou-yao ZHOU Tao WANG Xiao-yi 《Journal of Mountain Science》 SCIE CSCD 2020年第6期1333-1344,共12页
Both tillage erosion and water erosion are severe erosional forms that occur widely on sloping agricultural land.However,previous studies have rarely considered the process of landform change due to continuous simulat... Both tillage erosion and water erosion are severe erosional forms that occur widely on sloping agricultural land.However,previous studies have rarely considered the process of landform change due to continuous simulation experiments of alternating tillage erosion and water erosion.To identify such changes,we applied a scouring experiment(at a 60 L min-1 water discharge rate based on precipitation data from the local meteorological station and the catchment area in the Yuanmou County,Yunnan Province,China)and a series of simulated tillage experiments where plots were consecutively tilled 5,10,and 15 times in rotation(representing 5 yr,10 yr,and 15 yr of tillage)at slope gradients of 5°,10°,and 20°.Close-range photogrammetry(CRP)employing an unmanned aerial vehicle(UAV)and a real-time kinematic global positioning system(RTK-GPS)was used to measure landform changes,and highresolution digital elevation models(DEMs)were generated to calculate net soil loss volumes.Additionally,the CRP was determined to be accurate and applicable through the use of erosion pins.The average tillage erosion rates were 69.85,131.45,and 155.34 t·hm-2·tillage pass-1,and the average water erosion rates were 1892.52,2961.76,and 4405.93 t·hm-2·h-1 for the 5°,10°,and 20°sloping farmland plots,respectively.The water erosion rates increased as tillage intensity increased,indicating that tillage erosion accelerates water erosion.Following these intensive tillage treatments,slope gradients gradually decreased,while the trend in slope gradients increased in runoff plots at the conclusion of the scouring experiment.Compared to the original plots(prior to our experiments),interactions between tillage and water erosion caused no obvious change in the landform structure of the runoff plots,while the height of all the runoff plots decreased.Our findings showed that both tillage erosion and water erosion caused a pseudo-steady-state landform evolutionary mechanism and resulted in thin soil layers on cultivated land composed of purple soil in China. 展开更多
关键词 Landform change Tillage erosion Water erosion close range photogrammetry Erosion pins Runoff plot
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A TECHNIQUE OF DIGITAL SURFACE MODEL GENERATION 被引量:1
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作者 ZHU YixuanXU Miaozhong 《Geo-Spatial Information Science》 2001年第4期61-65,72,共6页
It is usually a time-consuming process to real-time set up 3D digital surface model(DSM) of an object with complex surface.On the basis of the architectural survey project of"Chilin Nunnery Reconstruction",t... It is usually a time-consuming process to real-time set up 3D digital surface model(DSM) of an object with complex surface.On the basis of the architectural survey project of"Chilin Nunnery Reconstruction",this paper investigates an easy and feasible way,that is,on project site,applying digital close range photogrammetry and CAD technique to establish the DSM for simulating ancient architectures with complex surface.The method has been proved very effective in practice. 展开更多
关键词 digital close range photogrammetry (DCRP) PhotoModeler digital surface model(DSM) CAD
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