期刊 基于改进EWT的浅水激光雷达回波信号降噪  

Shallow-Water LiDAR Echo Signal Denoising Based on Improved EWT

作  者:魏婷婷 杨家志[1] 周国清[2] 周祥[2,3] 农学勤 

Wei Tingting;Yang Jiazhi;Zhou Guoqing;Zhou Xiang;Nong Xueqin(College of Information Science and Enginering,Grilin University of Technology,Guilin,Guangxi 541006,China;Guangxri Key Laboratory of Spatial Information and Geomatics,Grilin University of Technology,Guilin,Guangxi 541006,China;School of Microelectronics,Tianjin University,Tianjin 300072,China;The 34 th Research Institute of China Electronics Technology Group Corporation,Guilin,Gruangxi 541004,China)

机构地区:[1]桂林理工大学信息科学与工程学院,广西桂林541006 [2]桂林理工大学广西空间信息与测绘重点实验室,广西桂林541006 [3]天津大学微电子学院,天津300072 [4]中国电子科技集团公司第三十四研究所,广西桂林541004

出  处:《中国激光》2021年第11期152-163,共12页Chinese Journal of Lasers

Shallow-Water LiDAR Echo Signal Denoising Based on Improved EWT

基  金:国家自然科学基金(41961065);广西创新驱动发展专项资金(桂科AA18118038);广西科技基地和人才专项(桂科AD19254002)。

摘  要:浅水激光雷达回波信号中混有高斯白噪声及系统自由振动时产生的固有频率成分,因此较难从较低信噪比.的回波信号中获取目标的距离与特征,需要进行降噪处理。根据全波形回波及固有频率的频域特点,提出了一种改进的经验小波变换方法,并将其用于浅水激光雷达信号的降噪。首先对实验室自制的测深激光雷达系统测到的回波信号进行分解,得到降噪后的回波、噪声及固有频率成分,然后针对降噪后的回波信号,进行非线性阻尼最小二乘算法拟合优化,最终得到全波形回波的分解信号并测得水深。利用MATLAB建立信号模型,对比常用降噪算法处理的降噪效果,结果显示,改进的算法在计算时间、信噪比和均方误差等方面有明显优势;对比0.5~3.0m水深范围内不同降噪算法的实测回波处理效果,经所提方法降噪后,回波信号的测深误差小于0.1m。

Objective It is difficult to reap the target distance and features from the shallow-water LIDAR echo signals with a low SNR,hence noise reduction is imperative.The noises in full-waveform echo signals caused by the LIDAR system in our laboratory can be divided into background noise,detector noise and preamplifier noise.Background noises stem from artificial light sources and the scattering of air,target,water surface,glass pentrough and mirrors,which are usually filtered by optical filters.Detector noises,such as shot noise,thermal noise,flicker noise and composite noise,are generated by the photons of the light source and current carriers or thermions of the device during the conversion of the optical signals received by the detector into electrical signals.In the trans impedance amplifier,not only these noises in the weak signals will be amplified,but also its circuit devices will produce new noise.While the echo signal obtained by our experimental system also contains a natural frequency(eigen-frequency)component,which is represented as a signal that changes over time according to the law of sine or cosine.Except flicker noise,all other noises can be regarded as additive noises and conform to a Gaussian distribution.The eigen frequency is much higher than that of a full-waveform echo signal,and the decomposition and reconstruction method can be consequently utilized to filter out most noises at high frequencies.Methods The processing process of shallow-water LiDAR echo signals comprises echo signal noise reduction and full-waveform signal decomposition.The extractions of amplitude,position and full width at half maximum are associated with the distance and characteristics of the target,accordingly the procedure needs to further fit and optimize.And noise reduction of the model signal and the measured signal can be considered to verify the usability of the EWT.First,the improved boundary detect method of EWT based on the frequency characteristics of shallow-water LIDAR echo signals and established Gaussian LiDA

关 键 词:遥感与传感器 浅水激光雷达 全波形回波信号降噪 经验小波变换 固有频率 

Remote Sensing and Sensors shallow-water LiDAR full-waveform echo signal denoising empirical wavelet transform natural frequency 

分 类 号:TN957.51[电子电信—信号与信息处理]

 

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