摘要
针对交通数据采集应用,设计了一种符合一级激光安全等级的中短距离、高速、高精度脉冲激光扫描器(Laser Scanner)。为了解决激光扫描器的快速、高精度测距问题,提出了一种数字化全波形脉冲检波方法。该方法通过脉冲波形前沿拟合判定激光脉冲的达到时刻,以模拟数字转换器(Analog to Digital Converter,ADC)的采样时钟作为计数器,对回波延时进行计算;再根据回波信号的强度对测距结果进行补偿修正,显著减小了测距幅相误差。扫描器的信号处理基于高速ADC和FPGA实现。测试结果显示,激光扫描器的测距频率达到50000点/s,单点测距精度为士4 cm,能够满足车型自动分类、交通流量调查和客流密度检测等系统的数据采集需求。
A medium and short distance, high speed and high precision pulse laser scanner which meets the first level of laser safety is designed for traffic data collection. To solve the problem of the laser scanner in rapid and high precision ranging, a digital full waveform pulse detecting method is proposed. The method judges the arriving time of the laser pulse by fitting the front edge of the laser pulse waveform. Taking the sampling clock of an Analog Digital Converter （ADC） as a counter, the delay of the laser echo signal is calculated. Then, according to the intensity of the laser echo signal, the ranging result is compensated. Thus, the Walk error is reduced greatly. The signal processing of the laser scanner is implemented on the basis of the high speed ADC and FPGA. The test results show that the laser scanner has its ranging frequency of 50000 points/s and its single point measuring precision is ＋4 cm. It can meet the data collection requirements of automatic vehicle recognition, traffic flow investigation and passenger density detection.
出处
《红外》
CAS
2015年第11期30-35,40,共7页
Infrared
