基于CPCI总线的激光雷达数据采集及滤波技术研究

发布时间：2018-04-23 11:24

本文选题：激光雷达 + 数据采集　；参考：《西安理工大学》2017年硕士论文

【摘要】：CPCI总线作为一种工程化数据总线,具有数据吞吐量大,抗干扰能力及兼容性强等优点,在测控系统中有广泛的应用。本课题依托西安理工大学激光雷达遥测研究中心,首先开展了基于CPCI总线的激光雷达回波信号数据采集应用化研究:分析了激光雷达回波信号的采集需求,针对工程化应用,设计了基于CPCI总线的激光雷达数据采集系统方案,并开发了相应硬件电路;针对双通道激光雷达回波信号的采集需求,设计了 FPGA并行采集架构,编写了并行采集控制程序;基于PLX SDK工具包,开发了针对CPCI总线协议的底层驱动,设计并编写了 I/O模式与DMA模式相结合的数据交互程序,实现了回波信号的数据采集、传输、预处理等功能。激光雷达的回波信号具有信号微弱、随机干扰强的特点,而小波变换在时频局部化、多尺度分析等方面具有独特优势,为此,本文也开展了基于小波变换的激光雷达回波信号滤波去噪算法研究:在对比分析不同小波基和小波分解层数对小波去噪效果影响的基础上,选择使用db4小波,对激光雷达回波信号进行5层分解,并选择软阈值函数进行滤波去噪;根据应用化需求,在C++环境下编写了小波阈值去噪算法程序,并与数据采集系统融合,实现了回波信号的在线滤波、去噪;信噪比分析证明,该算法具有明显的滤波去噪效果。本论文设计、实现的激光雷达数据采集系统及小波阈值去噪算法,在激光雷达大气探测系统中经过了初步的应用,取得了一定的效果。本系统具有可高速采集,无脉冲丢失,功能丰富的特点,将进一步促进激光雷达技术的推广及应用。
[Abstract]:As a kind of engineering data bus, CPCI bus has many advantages, such as large data throughput, strong anti-interference ability and strong compatibility. It is widely used in measurement and control system. Based on the laser radar telemetry research center of Xi'an University of Science and Technology, the research of data acquisition and application of laser radar echo signal based on CPCI bus is carried out firstly, and the requirement of acquisition of laser radar echo signal is analyzed. This paper designs the scheme of laser radar data acquisition system based on CPCI bus, and develops the corresponding hardware circuit, designs the FPGA parallel acquisition architecture and compiles the parallel acquisition control program according to the demand of dual-channel laser radar echo signal acquisition. Based on the PLX SDK toolkit, the bottom driver of the CPCI bus protocol is developed, and a data interaction program combining I / O mode and DMA mode is designed and written. The functions of data acquisition, transmission and preprocessing of echo signal are realized. The echo signal of lidar has the characteristics of weak signal and strong random interference. Wavelet transform has unique advantages in time-frequency localization and multi-scale analysis. In this paper, we also study the filtering and denoising algorithm of laser radar echo signal based on wavelet transform. On the basis of comparing and analyzing the influence of different wavelet basis and wavelet decomposition layer number on the effect of wavelet denoising, we choose to use db4 wavelet. The laser radar echo signal is decomposed into five layers, and the soft threshold function is selected for filtering and denoising. According to the requirement of application, the wavelet threshold de-noising algorithm program is written in C environment, and the wavelet threshold denoising algorithm is integrated with the data acquisition system. The on-line filtering and denoising of echo signal are realized, and the signal-to-noise ratio (SNR) analysis shows that the algorithm has obvious filtering and denoising effect. In this paper, the laser radar data acquisition system and wavelet threshold de-noising algorithm are designed and implemented, which have been applied in the laser radar atmosphere detection system and achieved certain results. The system has the characteristics of high speed acquisition, no pulse loss and rich functions, which will further promote the promotion and application of lidar technology.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN958.98

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