To resolve high-precision deformation from low-quality speckle images, a high-order time-domain digital image correlation algorithm is proposed. This algorithm is based on the nonlinear optical flow equation for low-quality speckle images collected in extreme testing environments. A subpixel displacement image containing Gaussian white noise is established by using the simulated speckle method. The displacement of the high-order time-domain digital image correlation algorithm is solved by the least squares iteration method, and the test accuracy of the proposed algorithm is analyzed. The results show that the nonlinear optical flow equation can describe the time continuity of pixel gray level changes before and after deformation. The proposed algorithm can also analyze the velocity and acceleration term of deformation. The high-order time-domain digital image correlation algorithm is insensitive to the change in image grayscale and has high measurement accuracy. Therefore, this method can solve the problem of resolving high-precision deformation from low-quality speckle images.

为了解决低质量散斑图像的高精度变形问题，提出了一种高阶时域数字图像相关算法。该算法基于在极端测试环境中采集的低质量散斑图像的非线性光流方程。利用模拟散斑法建立了包含高斯白噪声的亚像素位移图像。采用最小二乘迭代法求解高阶时域数字图像相关算法的位移，分析了所提算法的测试精度。结果表明，非线性光流方程能够描述变形前后像素灰度变化的时间连续性。所提出的算法还可以分析变形的速度和加速度项。高阶时域数字图像相关算法对图像灰度变化不敏感，测量精度高。因此，该方法可以解决从低质量散斑图像中解析高精度变形的问题。