Regularizing Finite-Element Digital Image Correlation (FE-DIC) problems is essential when using fine meshes, for instance to get a direct bridge with simulation tools or in view of performing data assimilation. Shape optimization brings comparable concerns so it is proposed to draw inspiration from this field of research. In this respect, a new general spline-based non-invasive regularization scheme is proposed, based on the Free-Form Deformation (FFD) concept that offers the opportunity to decouple the design space from that of the actual geometry to be updated. The main idea is to embed the input FE mesh, with any element type or size, into a simple cuboid B-spline box and to relate the nodal FE dof of the measured field to another more regular field discretized by the box. The regularization length is thus directly driven by the box refinement. A specific care is taken to handle possible conditioning problems caused by non-influential control points. From a practical point of view, the method can be interpreted as a projection on a reduced basis; therefore, it results in a regularized but conventional FE measured field which can be simply computed from a standard FE-DIC code. The developed scheme is applied for FE displacement measurement using DIC and for mesh-based measurement in stereo-DIC. For the latter, a novel procedure based on additional projections over local directions complements the FFD method for full efficiency. The performance of the strategy is assessed on real images coming from various experimental tests and comparisons are made with other published techniques to prove its effectiveness.

使用精细网格时，正则化有限元数字图像相关 (FE-DIC) 问题是必不可少的，例如使用仿真工具获得直接桥接或为了执行数据同化。形状优化带来了可比较的关注，因此建议从该研究领域中汲取灵感。在这方面，一种新的基于通用样条的非侵入式正则化提出了基于自由形式变形 (FFD) 概念的方案，该概念提供了将设计空间与要更新的实际几何体的空间分离的机会。主要思想是将具有任何元素类型或尺寸的输入 FE 网格嵌入到一个简单的长方体 B 样条框中，并将测量场的节点 FE 自由度与由该框离散的另一个更规则的场相关联。因此，正则化长度直接由框细化驱动。特别注意处理由非影响控制点引起的可能的调节问题。从实践的角度来看，该方法可以解释为一种简化的投影；因此，它产生了一个正则化但传统的 FE 测量场，可以从标准的 FE-DIC 代码中简单地计算出来。开发的方案适用于使用 DIC 的 FE 位移测量和立体 DIC 中基于网格的测量。对于后者，一种基于局部方向附加投影的新程序补充了 FFD 方法，以提高效率。该策略的性能在来自各种实验测试的真实图像上进行评估，并与其他已发表的技术进行比较以证明其有效性。