基于匹配滤波的Gm-APD激光雷达三维重构算法研究

Research on 3D range reconstruction algorithm of Gm-APD lidar based on matched filter

  • 摘要: Geiger mode Avalanche Photo Diode(Gm-APD)激光成像雷达三维重构常用的峰值法对于异常峰会提取到错误的目标位置,阈值选取整数会造成重构三维像信噪比不高及目标缺失等。针对此问题,提出了基于加权一阶类高斯匹配滤波算法,通过对脉冲回波触发频数直方图的拟合归一化得到权重窗口平滑直方图再次选取峰值位置进行重构。应用基于Poisson分布的Gm-APD触发模型理论推导得到该算法的探测率及虚警率表达式并与峰值法对比,理论结果为使用基于加权一阶类高斯匹配滤波算法提取到目标的概率更高,通过Monte Carlo仿真验证了理论推导结果。最后使用两种算法对真实实验数据进行三维重构,主观及客观对比其重构得到的三维距离像,基于加权一阶类高斯匹配滤波算法在复原效果上较峰值法有了明显提升。结果表明,基于加权一阶类高斯匹配滤波算法在处理低信噪比、实时三维重构等方面具有良好的实际应用前景。

     

    Abstract: The peak-picking method which is commonly used in Gm-APD laser radar 3D reconstruction always gets the wrong target position when there is an abnormal peak, and the reconstructed image has low signal-to-noise ratio and target missing because the threshold can only be integer. To solve these problems, a weighted Gaussian-like matched filtering algorithm was proposed. Fitting the echo firing histogram and normalizing can get the weight. Then the weighted window smoothing histogram was used and the peak position was selected again for reconstruction. According to the Poisson distribution of Gm-APD, the detection probability and false-alarm probability expression of the algorithm can be obtained, then compared with the peak method. The result show that the weighted Gaussian-like matched filter algorithm is better for the target in the middle of the gate. The theoretical derivation results are verified by Monte Carlo simulation. At last, by using the real experimental data and reconstructing data with two kinds of algorithms, the consequence shows that the weighted Gaussian-like matched filtering algorithm has a significant improvement on the restoration subjective and objective compared with the peak method. The results show that this algorithm has a good practical application prospect in dealing with low SNR and real-time 3D reconstruction.

     

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