数字图像相关中亚像素位移测量算法的研究

AN INVESTIGATION OF SUB-PIXEL DISPLACEMENTS REGISTRATION ALGORITHMS IN DIGITAL IMAGE CORRELATION

为提高位移测量精度而提出的各种亚像素位移测量算法被认为是数字图像相关方法中的关键技术之一,详细了解已有各算法的性能无疑具有实际意义．总结文献中3种最常用的亚像素位移测量算法,首先用无噪声的计算机仿真散斑图对各算法的性能从计算精度和计算效率两个方面进行了比较研究,并用实际实验图片对其性能做进一步的研究,结果显示在图像子区大小相同的情况下,基于空域相关函数迭代的牛顿-拉普森方法计算结果最为精确、稳定．

The sub-pixel registration algorithm is considered as a key technique to improve displacement measurement accuracy in a digital image correlation. Various types of sub-pixel registration algorithms have been developed. However, few quantitative researches have been reported to evaluate their performances. This paper investigates three types of most commonly used sub-pixel displacement registration algorithms in terms of registration accuracy and computational efficiency using computer-simulated speckle images and real experimental images. A detailed examination of the performances of each algorithm reveals that the NewtonRapshon Method is the most accurate and stable. Accordingly, it is highly recommended to use this method in real applications.