Department of Electronics, Information and Bioengineering Politecnico di Milano, 20133 Milan, Italy.
Sensors (Basel). 2021 Feb 11;21(4):1301. doi: 10.3390/s21041301.
A low-cost optical reflectivity sensor is proposed in this paper, able to detect the presence of objects or surface optical properties variations, at a distance of up to 20 m. A collimated laser beam is pulsed at 10 kHz, and a synchronous digital detector coherently measures the back-diffused light collected through a 1-inch biconvex lens. The sensor is a cost-effective solution for punctual measurement of the surface reflection at different distances. To enhance the interference immunity, an algorithm based on a double-side digital baseline restorer is proposed and implemented to accurately detect the amplitude of the reflected light. As results show, the sensor is robust against ambient light and shows a strong sensitivity on a wide reflection range. The capability of the proposed sensor was evaluated experimentally for object detection and recognition, in addition to dedicated measurement systems, like remote encoders or keyphasors, realized far from the object to be measured.
本文提出了一种低成本的光学反射率传感器，能够在 20 米的距离内检测物体的存在或表面光学特性的变化。采用 10 kHz 的脉冲准直激光束，通过 1 英寸双凸透镜收集背向漫射光，同步数字探测器对其进行相干测量。该传感器是一种经济有效的解决方案，可用于在不同距离处对表面反射进行定点测量。为了提高抗干扰能力，提出并实现了一种基于双边数字基线恢复器的算法，以准确检测反射光的幅度。结果表明，该传感器对环境光具有很强的抗干扰能力，并且在宽反射范围内具有很强的灵敏度。此外，还评估了所提出的传感器用于物体检测和识别的能力，以及用于远程编码器或键相器等专用测量系统的能力，这些系统远离待测量的物体进行实现。
