基于小波变换的脉冲激光雷达回波信号去噪方法的研究

【作者】 潘海南；

【导师】 蔡喜平；

【作者基本信息】 黑龙江大学 ， 光学， 2011， 硕士

【摘要】 激光雷达的应用十分广泛,在军事和民用上都具有极高的应用价值,是目前高科技领域研究的热点。然而在实际的应用中,雷达信号不可避免地受到各种噪声和干扰的影响。为了提高激光雷达的探测精度,有效地去除噪声是非常重要的。小波变换是近年来发展起来的一种优良的信号处理理论,因此本文的目的是应用小波变换对脉冲激光雷达回波信号进行去噪处理。本文针对影响脉冲激光雷达系统的噪声特性进行了分析,建立了理想的发射和回波信号模型。首先,应用三种小波阈值去噪法对理想的回波信号进行去噪处理,通过仿真比较得出：强制阈值去噪法是最适合所选信号的小波阈值去噪方法。然后,在强制阈值去噪的基础上,提出了一种更好的处理脉冲激光雷达弱信号的方法,即强制阈值相关性去噪法。对于实时性要求不高的场合,提出了在脉冲积累的基础上应用强制阈值相关性去噪法,通过MATLAB仿真验证了此方案的可行性及优越性。对于不规则的脉冲激光雷达回波信号,在强制阈值相关性去噪法的基础上加入了自动增益控制系统,仿真结果表明：波形恢复的很好,信噪比也得到了提高。更多还原

【Abstract】 Laser radar has been extensively used both in military and civilian affairs. It is a focus in the high-tech fields at present. However in practical applications, the radar signal is inevitably influenced by various noises and interferences. Aiming to improve the detecting ability of radar, removing the noise effectively is very important. Wavelet transform is an excellent theory developing in recent years which can be used to signal processing. So the purpose of this thesis is to use wavelet transform to remove the noise of the pulse laser radar echo.The noise characteristics affecting pulse lidar system is analyzed, the model of ideal transmitting signal and the return signal are created in this paper. First, the ideal return signals are denoised using three threshold denoising method, it is concluded that the denoising method of mandatory threshold is more suitable for the selected signal by comparing the simulation results of three threshold denoising method. Subsequently, on this foundation, a new denoising approach called mandatory threshold and correlation denoising approach is proposed which is more appropriate for weak signal processing of pulse lidar system. The method of employing the mandatory threshold and correlation denoising approach after the accumulating pulse is put forwarded which is suitable for the occasions having no high real-time demand. MATLAB simulation demonstrates the method is feasible and superior. On the basis of the mandatory threshold and correlation denoising processing to be added the Automatic Gain Control system for the irregular received signals. The simulation results demonstrate that the method is effective in the restoration of signals and the improvement of SNR.更多还原