Laser & Optoelectronics Progress, Volume. 58, Issue 14, 1412004(2021)
Speckle Area Extraction Based on Weighted Entropy of Laplacian Pyramid
In digital image correlation calculations, it is usually necessary to manually select a speckle area for limiting the search area. With the development of industrial automation, it is often necessary to obtain the real-time displacement field and strain field of a material surface. It is particularly important to find a fast and accurate speckle area extraction algorithm. There exist the problems that the second-order gradient entropy function takes too much time in the speckle area extraction process and the speckle area cannot be accurately extracted for a complex and variable speckle. In light of these problems and according to the distribution characteristics of speckles, an algorithm for speckle area extraction is proposed, which is based on the weighted entropy of Laplacian pyramid. This algorithm not only reduces the amount of calculation, but also can flexibly and automatically determine the threshold value according to the entropy value distribution histograms of different speckle images. The research results show that in the extraction process of speckle areas, the proposed algorithm can flexibly select the threshold value to complete the automatic extraction of speckle areas, and simultaneously reduces the calculation time by more than 90%. This proposed algorithm is better than the second-order gradient entropy function, which can basically achieve the extraction of speckle areas under complex backgrounds and the extraction speed is significantly improved.
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Yuqiao Yang, Kun Ma, Yue Yuan, Houchuang Chen, Yuxuan Xue. Speckle Area Extraction Based on Weighted Entropy of Laplacian Pyramid[J]. Laser & Optoelectronics Progress, 2021, 58(14): 1412004
Category: Instrumentation, Measurement and Metrology
Received: Oct. 30, 2020
Accepted: Nov. 18, 2020
Published Online: Jul. 8, 2021
The Author Email: Ma Kun (453937936@qq.com)