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用坐标换算方法计算曲线上任一点的坐标 被引量:2
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作者 林少敏 《测绘通报》 CSCD 北大核心 1995年第2期24-27,共4页
用坐标换算方法计算曲线上任一点的坐标林少敏一、前言在道路(特别是城市道路)工程测量中,经常在所设计(或规划)的道路中线上有很多建筑物。这时采用切线支距法、偏角法、弦长支距法、弦长偏距法等在实地测设曲线桩都比较困难,而... 用坐标换算方法计算曲线上任一点的坐标林少敏一、前言在道路(特别是城市道路)工程测量中,经常在所设计(或规划)的道路中线上有很多建筑物。这时采用切线支距法、偏角法、弦长支距法、弦长偏距法等在实地测设曲线桩都比较困难,而且往往需要计算曲线上任一点的坐标,... 展开更多
关键词 道路 工程测量 坐标换算法 曲线 坐标
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抵偿高程面上的坐标换算 被引量:2
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作者 王文忠 《城市勘测》 2016年第2期113-115,118,共4页
在高海拔或高程变化较大的地区进行工程测量时,为了限制投影变形,一般采用具有抵偿高程面的工程坐标系。本文通过分析工程椭球与国家参考椭球之间的内在联系与差异,推导了工程椭球大地坐标的改正值公式,给出了工程椭球的建立方法及坐标... 在高海拔或高程变化较大的地区进行工程测量时,为了限制投影变形,一般采用具有抵偿高程面的工程坐标系。本文通过分析工程椭球与国家参考椭球之间的内在联系与差异,推导了工程椭球大地坐标的改正值公式,给出了工程椭球的建立方法及坐标换算方法,从而保证顺利地建立具有抵偿高程面的工程坐标系。 展开更多
关键词 抵偿高程面 抵偿带 工程椭球 直接坐标换算
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GPS控制网起算点精度的检核方法 被引量:4
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作者 赵景泉 孟长虹 《测绘与空间地理信息》 2011年第2期144-146,共3页
结合实际经验,阐述了起算点精度对GPS控制网兼容的重要性,介绍了几种检核起算点精度的有效方法。
关键词 GPS 起算点 兼容性 平差结果直观 同名基线分析 坐标换算检核
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Flexible Calibration Method for 3D Laser Scanner System 被引量:2
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作者 杨中东 王鹏 +1 位作者 李晓慧 孙长库 《Transactions of Tianjin University》 EI CAS 2014年第1期27-35,共9页
In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the un... In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square(RMS) error of distance was 0.000 7 mm. 展开更多
关键词 structured light laser scanner flexible planar target cross ratio CALIBRATION
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A Flexible and High Speed Digital Scan Converter for High Frequency Ultrasound Imaging
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作者 QIU Wei-bao YU Yan-yan SUN Lei 《Chinese Journal of Biomedical Engineering(English Edition)》 2011年第3期109-114,共6页
This paper presents a flexible and high speed digital scan converter (DSC) with the ability to handle high frequency ultrasound imaging in real-time. The characteristics in imaging system such as focus length of trans... This paper presents a flexible and high speed digital scan converter (DSC) with the ability to handle high frequency ultrasound imaging in real-time. The characteristics in imaging system such as focus length of transducer, the swing radius and sampling length etc. could be changed easily in compliance with the researcher's application based on this flexible digital scan converter. Linear interpolation is employed to achieve the coordinate transformations algorithm. Custom-built software is programmed to preliminarily handle the algorithm according to different ultrasound imaging applications. High performance FPGA will implement high speed interpolation calculation based on the preliminary data which are stored in the DDR2 SDRAM from the software. 64 bit 66 MHz PCI is employed to accomplish high speed data transmission. Experiment has shown that more than 500 frame rate could be achieved based on this high speed digital scan converter. The designed flexible and high speed digital scan converter could be used in current FPGA based high frequency ultrasound imaging system. 展开更多
关键词 flexible digital scan conversion high frequency ultrasound imaging FPGA
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Biological object recognition approach using space variant resolution and pigeon-inspired optimization for UAV 被引量:8
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作者 XIN Long XIAN Ning 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第10期1577-1584,共8页
Recognizing the target from a rotated and scaled image is an important and difficult task for computer vision. Visual system of humans has a unique space variant resolution mechanism(SVR) and log-polar transformations... Recognizing the target from a rotated and scaled image is an important and difficult task for computer vision. Visual system of humans has a unique space variant resolution mechanism(SVR) and log-polar transformations(LPT) is a mapping method that is invariant to rotation and scale. Motivated by biological vision, we propose a novel global LPT based template-matching algorithm(GLPT-TM) which is invariant to rotational and scale changes; and with pigeon-inspired optimization(PIO) used to optimize search strategy, a hybrid model of SVR and pigeon-inspired optimization(SVRPIO) is proposed to accomplish object recognition for unmanned aerial vehicles(UAV) with rotational and scale changes of the target. To demonstrate the efficiency, effectiveness and reliability of the proposed method, a series of experiments are carried out. By rotating and scaling the sample image randomly and recognizing the target with the method, the experimental results demonstrate that our proposed method is not only efficient due to the optimization, but effective and accurate in recognizing the target for UAV. 展开更多
关键词 biological vision space variant resolution mechanism (SVR) log-polar transformations (LPT) pigeon-inspiredoptimization (PIO) object recognition
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