采用数字图像相关(DIC)法对物体表面形变进行测量,并通过散斑场的形变对被测物的真实变化进行研究。对散斑质量评价方法进行研究,以求在测量前即可判定所采用的散斑对测量精度的影响。根据DIC法对散斑图像的具体要求,提出基于灰度共生矩阵(GLCM)的散斑质量评价方法。对实际散斑图像进行亚像素刚体平移仿真模拟,采用GLCM中的能量、熵、对比度和相关性指标与DIC法的测量结果进行对比分析,并与平均灰度二阶导数和香农熵进行对比实验。通过改变散斑图像的整体亮度等级与亮度分布情况,探究不同光照情况对实验结果准确度的影响。实验结果表明,GLCM在散斑图像质量评价中具有一定的有效性。

The digital image correlation (DIC) method is used to measure the surface deformation of the object, and the true change of the measured object is studied through the deformation of the speckle field. The evaluation method of speckle quality is researched in order to determine the influence of speckle used on measurement accuracy before measurement. According to the specific requirements of the DIC method for speckle images, a speckle quality evaluation method based on gray level co-occurrence matrix (GLCM) is proposed. Perform sub-pixel rigid body translation simulation simulation on the actual speckle image, compare the energy, entropy, contrast, and correlation indicators in GLCM with the measurement results of the DIC method for comparison and analysis, and perform comparison experiments with the average gray second derivative and Shannon entropy. By changing the overall brightness level and brightness distribution of the speckle image, the influence of different lighting conditions on the accuracy of the experimental results is explored. The experimental results show that GLCM is effective in evaluating the quality of speckle images.