基于全波形高斯分解的激光测高点筛选

发布时间：2018-05-28 01:42

本文选题：全波形激光雷达 + 优化Levenberg-Marquard算法　；参考：《山东科技大学》2017年硕士论文

【摘要】：高精度的激光测距值是实现无地面控制大比例尺摄影测量测图的关键与保障。将高精度的激光测距值作为控制约束条件,参与影像的区域网平差计算,实现地面点高程精度的提高。当激光足印内地形起伏较大或者目标地物比较复杂时,距离测量精度和激光点定位精度将会受到影响。文中通过采用优化LM(Levenberg-Marquard)算法对全波形激光雷达数据进行高斯分解,在此基础上提取足印内目标地物特征信息,并依据1:10000测图精度的要求进行筛选实验,制定筛选准则,从而获取满足测图精度要求的激光测高点。因此,开展激光测高点筛选工作对于后续提升高程精度的研究有着十分重要的意义。本文的主要研究内容有:(1)研究了机载LVIS和星载GLAS的数据格式,并按照格式进行数据解析,这是进行本课题研究的基础。(2)采用阈值和高斯滤波相结合的方法对回波信号进行去噪处理,实验表明该方法在保留有效信号的同时,噪声得以去除,为下一步的波形分解提供数据支持。(3)分析了全波形高斯分解的研究现状和传统LM算法原理,并通过控制雅克比矩阵的更新以及阻尼系数的调整对LM算法进行了优化,然后分别采用传统LM算法和优化LM算法对LVIS和GLAS数据进行波形分解对比分析实验,验证了采用优化LM算法进行全波形高斯分解不但简化了计算过程,而且得到的拟合波形非常逼近原始波形,从而辅助进行后续的激光测高点筛选。(4)依据1:10000测图精度要求对激光测高点筛选进行了研究,通过仿真实验分析地形地物对回波信号的影响,借助全波形高斯分解得到的各波形分量提取足印内目标地物特征参数,并研究分析了坡度对测距精度的影响,在此基础上进行筛选实验,制定筛选准则,进而对威海市文登区的30条GLAS光斑数据结合Google earth影像进行激光测高点筛选,最终获得满足测图精度要求的激光测高点。
[Abstract]:High precision laser ranging is the key and guarantee to realize large scale photogrammetry without ground control. The high precision laser ranging value is taken as the control constraint condition to participate in the calculation of the regional network adjustment of the image, and the elevation accuracy of the ground point can be improved. The precision of distance measurement and laser point location will be affected when the topography in the laser footprint is large or the object is more complicated. In this paper, the Gao Si decomposition of the full waveform lidar data is carried out by using the optimized LMC Levenberg-Marquard algorithm, and on this basis, the feature information of the target in the footprint is extracted, and the screening experiment is carried out according to the requirement of 1: 10000 mapping accuracy, and the screening criteria are worked out. In order to obtain the laser survey height to meet the requirements of mapping accuracy. Therefore, it is very important to carry out the work of laser height screening for further research on elevation accuracy. In this paper, the data formats of airborne LVIS and spaceborne GLAS are studied, and the data are analyzed according to the format. This is the basis of this research. (2) denoising the echo signal by combining threshold and Gao Si filter. The experiment shows that the noise can be removed while the effective signal is retained. Provide data support for the next wave decomposition.) analyze the research status of full waveform Gao Si decomposition and the principle of traditional LM algorithm, and optimize the LM algorithm by controlling the updating of Jacobian matrix and adjusting the damping coefficient. Then the conventional LM algorithm and the optimized LM algorithm are used to compare and analyze the waveform decomposition of LVIS and GLAS data, which proves that the optimal LM algorithm not only simplifies the calculation process, but also simplifies the whole waveform Gao Si decomposition. Moreover, the fitting waveforms obtained are very close to the original waveforms, so as to assist in the subsequent laser height screening. (4) according to the accuracy requirements of 1: 10000 mapping, the laser height screening is studied. The influence of terrain and ground objects on echo signal is analyzed by simulation experiment. The characteristic parameters of target in foot-print are extracted with the help of all waveform components decomposed by Gao Si, and the influence of slope on ranging accuracy is studied and analyzed. On this basis, the screening experiment was carried out, and the screening criteria were established, and then 30 GLAS spot data from Wendeng District of Weihai City were screened with Google earth images, and the laser height was obtained to meet the requirements of mapping accuracy.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P237

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