Speckle Quality Evaluation Based on Gray Level Co-Occurrence Matrix

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.