Adjusting Accuracy of Digital Image Correlation Through Variable Subsets and Application in Airship Envelope

doi:10.1007/s12204-023-2613-z

Abstract

Abstract: The stratospheric airship is affected by harsh conditions in the stratosphere environment. To ensure the safety of the airship, it is necessary to detect the material state of the airship envelope. Since digital image correlation possesses non-contact strain measurement ability, this paper explores the influence of different shapes of the subset on measurement accuracy. Through the results, it is found that increasing the aspect ratio of subsets can improve the strain accuracy measured in the x-direction, and reducing the aspect ratio can improve the strain accuracy measured in the y-direction. This trend becomes more obvious as the strain increases. Based on this discovery, a subset adaptive algorithm is proposed. The feasibility of the algorithm is verified by experiments, and the precision of strain measurement can be effectively improved by adjusting the threshold value. Therefore, the algorithm can be utilized to increase the measurement accuracy in the larger strain direction without changing the size of the subset.

Key words: shape of subset, digital image correlation, strain of airship envelope, self-adaptive selection

摘要： 平流层飞艇受到平流层恶劣环境条件的影响。为了保证飞艇的安全，需要监测飞艇蒙皮的材料状态。由于数字图像相关方法具有较好的非接触应变测量效果，所以本文探究不同子区形状对于测量精度的影响。结果发现增大子区宽高比能提升x方向应变精度，降低宽高比能提升y方向应变测量精度。并且这种趋势随着应变增大而更加明显。基于此，本文提出了一种子区自适应算法。通过试验验证了算法的可行性，并且调整阈值能有效地提升应变测量精度。因此利用该算法能够在不改变子区大小情况下提升较大应变方向上的测量精度。

关键词: 子区形状，数字图像相关，飞艇蒙皮应变，自适应选择

CLC Number:

V219

Zhu Fangtao, Wang Quanbao, Xie Weicheng, Duan Dengping. Adjusting Accuracy of Digital Image Correlation Through Variable Subsets and Application in Airship Envelope[J]. J Shanghai Jiaotong Univ Sci, 2025, 30(2): 239-251.

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