Cavedo Federico, Esmaili Parisa, Norgia Michele
Department of Electronics, Information and Bioengineering, Politecnico di Milano, 20133 Milan, Italy.
Sensors (Basel). 2022 Nov 3;22(21):8456. doi: 10.3390/s22218456.
Optical rangefinders based on Self-Mixing Interferometry are widely described in literature, but not yet on the market as commercial instruments. The main reason is that it is relatively easy to propose new elaboration techniques and get results in controlled conditions, while it is very difficult to develop a reliable instrument. In this paper, we propose a laser distance sensor with improved reliability, realized through a wavelength modulation at a different frequency, able to decorrelate single measurement errors and obtain improvement by averages. A dedicated software is implemented to automatically calculate the modulation pre-emphasis, needed to linearize the wavelength modulation. Finally, data selection algorithms allow to overcome signal fading problems due to the speckle effect. A prototype demonstrates the approach with about 0.1 mm accuracy up to 2 m of distance at 200 measurements per second.
基于自混合干涉测量法的光学测距仪在文献中已有广泛描述，但尚未作为商业仪器推向市场。主要原因是提出新的处理技术并在受控条件下获得结果相对容易，而开发可靠的仪器却非常困难。在本文中，我们提出了一种具有更高可靠性的激光距离传感器，它通过不同频率的波长调制实现，能够消除单次测量误差并通过平均得到改进。实现了一个专用软件来自动计算使波长调制线性化所需的调制预加重。最后，数据选择算法能够克服由于散斑效应导致的信号衰落问题。一个原型展示了该方法，在每秒200次测量的情况下，距离可达2米时精度约为0.1毫米。
