数字图像相关测量中若干关键问题研究

Digital image correlation (DIC) has become the most active measurement method in the field of photomechanics due to its simple equipment, low environmental vulnerability and other advantages. However, the consistency of measurement is easily affected by various factors, such as speckle preparation qualities, calculation methods, parameters selection and so on. In this case, for high-precision measurement, it’s difficult to verify and quantify the correctness of the results. These causes really restrict the wider industrial applications of DIC and have become the bottleneck to the process of DIC industrialization. To solve these problems, this project aims to undertake the following researches: optimization design and standardization manufacture of the speckle fields, optimal algorithms and preferred parameters selection, establishment and verification of surface deformation field measurement standard. Through standardization of speckle image and physical parameters of the system, fixing the calculation methods, the consistency of measurement is achieved consequently. Under the premise of consistency, interferometry technique in laser wavelength traceability can be used to calibrate the metering and to establish a complete verification program of calibration, so that reliability and validity of the measurement results can be assured. Therefore, making this method verified and certified by metrology will have significant importance to speed up the industrialization of DIC if the measuring equipment met the demand of the whole field deformation measurement.

数字图像相关测量方法以其设备简单、使用环境要求低等优势，已成为光测力学研究领域最为活跃的测量方法。然而，对于高精度测量，由于受散斑质量、硬件条件、计算方法、参数选取等诸多因素影响，测量结果的一致性难以保证，因此导致无法对其测量结果的正确性进行计量检定。这就使得该方法在更加广泛的工业应用方面受到了极大的制约，成为该方法在工业化进程中的瓶颈。针对这些问题，本项目将开展散斑场优化设计与规范制作、算法与参数优选、表面变形场计量标准及检定方法等研究。通过规范化散斑图样和系统物理参数，固定计算方法，实现测量结果一致性。在一致性得以保证的前提下，进一步利用溯源于激光波长的干涉计量术进行定标，建立起一套完整的表面变形计量检定方案，确保测量结果的可靠性和正确性。使数字图像测量方法真正成为一种可以被计量检定认证，能满足全场变形测量需要的计量测试手段，这对加快数字图像相关测量技术的工业化应用有着极其重要的意义。