多点动位移数字图像相关法光测技术研究

动位移测量在诸多工程领域中有着大量需求，针对现有各种测量技术仍然存在着效率低、精度差、成本高等局限性。基于数字图像相关(digital image correlation, DIC)原理，建立了一套多点动位移高精度光测技术及系统。首先设计了一种基于同心圆的靶标专用图案，用于测点的自动识别及图像的自动标定，并通过对硬件配套软件SDK(software development kit)的二次开发，构建形成了可同时适用于无线和有线工业相机的硬件架构，最终开发形成多点动位移DIC光测软件系统。采用3等精度量块对该系统进行精度校准试验，结果表明该系统测量精度为0.01 mm,系统基本误差为0.05%,灵敏度为0.2%。进一步开展典型应用场景测试，发现该系统在低频振动测量时具备与高精度激光位移传感器相当的精度，而对于高频振动场景，采用高频率相机也可实现动位移高精度实时测量。可见该系统与激光位移传感器等相比有显著优势，可在实验室测量、工程现场测试等场景中推广应用。

Digital image correlation optical measurement and system development formulti-points dynamic displacement

The measurement of dynamic displacement is highly demanded in various engineering fields. However, existing measurement technologies still have limitations such as low efficiency, poor-precision and high cost. This paper develops and a high-precision multi-point dynamic displacement optical measurement technology and system based on the principle of Digital Image Correlation (DIC). Firstly, a tailor-made target with patterns of concentric circles is designed for automatic point recognition and image calibration. The hardware architecture that integrates both wireless and wired industrial cameras is constructed through secondary development of the SDK. Finally, A multi-point displacement measurement technique using DIC is proposed. The accuracy calibration test of this technology was carried out with 3 equal-precision gauge blocks. The results show that the measurement accuracy is 0.01mm, the basic error is 0.05%, and the sensitivity is 0.2%. Further tests of typical application scenarios were conducted. Results show that the system has a comparable accuracy to high-precision laser displacement sensors under low-frequency vibration test, while real-time high-frequency displacement measurement with high-precision can also be achieved by the proposed technology using high-frequency camera. The proposed technology has significant advantages compared to conventional techniques(e.g., laser displacement sensor, LVDT), and can be extensively applied in laboratory and field test.