Distortion correction of a microscopy lens system for deformation measurements based on speckle pattern and grating基于散斑图案与光栅的变形测量显微镜头系统畸变校正

Abstract摘要

Microscope-lens distortion can introduce substantial displacement errors in digital image correlation at high magnification. This work identifies the distortion by combining rigid-body translation tests of a microspeckle pattern with phase analysis of a cross-grating using Fourier-transform methods. A first-order radial-distortion model is fitted by least squares and used to correct the measured displacement field. The correction reduces the average standard deviation by about 60% for microspeckle DIC and about 97% for the cross-grating phase method, demonstrating that microscale DIC can provide reliable deformation measurements when optical distortion is calibrated.

高倍率显微镜头的畸变会给数字图像相关测量带来明显的位移误差。本研究结合微散斑图案的刚体平移实验，以及基于傅里叶变换的交叉光栅相位分析来识别镜头畸变。通过最小二乘法拟合一阶径向畸变模型，并据此修正测得的位移场。校正后，微散斑 DIC 的平均标准差降低约 60%，交叉光栅相位分析方法降低约 97%，说明在完成光学畸变标定后，微尺度 DIC 能够提供可靠的变形测量。