激光测高卫星全波形回波数据的参数优化小波降噪  

Parameter Optimization Wavelet Denoising Algorithm for Full-Waveforms Data of Laser Altimetry Satellite

作　　者：刘俊 姚予木 李培楠 刘静云 Liu Jun;Yao Yumu;Li Peinan;Liu Jingyun(College of Urban Railway Transportation,Shanghai University of Engineering Science,Shanghai 201620,China;College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China)

机构地区：[1]上海工程技术大学城市轨道交通学院,上海201620 [2]东华大学环境科学与工程学院,上海201620

出　　处：《中国激光》2021年第23期122-133,共12页Chinese Journal of Lasers

基　　金：中央高校基本科研业务费专项资金资助(21D111320)。

摘　　要：针对城市复杂场景,全波形回波中混有多种噪声,这对有效信号的提取产生了很大的影响。为解决这一问题,提出一种参数优化下的小波降噪算法。该算法首先根据波形特征设定5个输入参数类型,参照小波公式和一维降噪函数重构回波波形,其次依据信噪比提取出各种验证波形的对应最佳参数组合,最后依据降噪效果评价指标对取得的实验结果进行分析。在实验过程中,参数优化小波降噪算法对验证波形实现了较好的滤波效果,与其他方法对比显示,本文滤波方法相较于传统的高斯类滤波,其滤波效果大幅提升,并且参数优化小波降噪在波形分解提取地物高度中也具有一定的应用价值。Objective For some complex urban scenes under laser echo,the corresponding full-waveform echo data is inevitably mixed with various noises,which affects the extraction of effective signals.Traditional Gaussian noise reduction algorithms struggle to meet the filtering requirements of both effective and noise signals.In recent years,there has been a greater focus on the filtering effect of wavelet noise reduction,which is affected by several parameters.Therefore,in this paper,aparameter optimization wavelet noise reduction algorithm is proposed to improve the filtering effect of full-waveform data.Methods The parameter selection of wavelet denoising is the central issue of this research.This paper employs one-dimensional wavelet denoising function(WDEN)in MATLAB to select the threshold selection criterion(TPTR),threshold usage method(SORH),threshold processing with noise change parameter(SCAL),decomposition layer(NBD),and wavelet basis function name(WNAME)five control parameters for filtering,calculates the filtering results under each parameter combination,and compares to obtain the wavelet optimal combination of control parameters.The specific steps of the parameter optimization wavelet denoising algorithm and its verification process are as follows:1)Set five input parameter types(TPTR,SORH,SCAL,NBD,WNAME)according to the waveform characteristics,and reconstruct the echo waveform by referring to the wavelet formula(Eqs.1~7)and the onedimensional noise reduction function.2)Taking the maximization of signal-to-noise ratio as the optimization goal,extract the corresponding best parameter combination of each verification waveform.3)In the final verification,analyze the obtained experimental results according to the evaluation index of noise reduction effect.Results and Discussions Table 3 is the optimal control parameter combination of ten waveforms,which is determined according to the maximum signal-to-noise ratio in each waveform parameter combination.The trend of these parameters is clearly visible in this table,

关 键 词：遥感 激光测高卫星 全波形回波 ICESat/GLAS 小波降噪 

分 类 号：P228.3[天文地球—大地测量学与测量工程]