Song Luming, Shi Guang, Liu Hong, Lin Hongyi, Zhang Fumin, Sun Dong
School of Optoelectronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China.
School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
Sensors (Basel). 2022 Apr 10;22(8):2904. doi: 10.3390/s22082904.
Frequency sweeping interferometry (FSI) based absolute distance ranging has high precision and no ranging blind area. It can be used to realize large-scale and non-cooperative target measurement. However, the nonlinear frequency modulation of the laser seriously affects the ranging accuracy. In this manuscript, a measurement method assisted by Hilbert Transform (HT) and Chirp-z Transform (CZT) is proposed, which can realize the phase unwrapping of the beat signal, the length reduction in the delay fiber of auxiliary optical path, and the improvement of the frequency resolution. The narrow-band frequency suitable for HT is further studied. In the experiment, the ranging resolution is 70 μm and the standard deviation is 12.6 μm within a distance of 4005 mm.
基于扫频干涉术（FSI）的绝对距离测量具有高精度且无测距盲区。它可用于实现大规模和非合作目标测量。然而，激光的非线性频率调制严重影响测距精度。本文提出了一种由希尔伯特变换（HT）和线性调频Z变换（CZT）辅助的测量方法，该方法可以实现拍频信号的相位展开、辅助光路延迟光纤中的长度缩减以及频率分辨率的提高。进一步研究了适用于HT的窄带频率。在实验中，在4005毫米的距离内，测距分辨率为70微米，标准偏差为12.6微米。
