On the metrology of interparticle contacts in sand from x-ray tomography images
On the metrology of interparticle contacts in sand from x-ray tomography images
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DOI：
10.1088/1361-6501/aa8dbf
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发表时间：
2017-11
影响因子：
2.4
通讯作者：
Max Wiebicke;E. Andò;I. Herle;G. Viggiani
中科院分区：
文献类型：
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作者：
Max Wiebicke;E. Andò;I. Herle;G. Viggiani
在颗粒材料力学中，颗粒间接触起着重要作用。这些在历史上很难通过实验进行研究，但 X 射线显微断层扫描的出现可以识别代表性机械测试所需的所有数千个单个颗粒。本文研究了检测颗粒间接触并从此类图像中测量其方向的计量学。使用球体的合成图像和两种截然不同的颗粒材料（球形和大角度）的高分辨率断层扫描作为基本事实，我们发现这些测量结果绝非微不足道。例如，如果使用物理上正确的阈值将颗粒与孔隙分离，则会出现系统性的过度检测接触。我们提出了一种对非角粒子有效的改进方法。当从构成接触区域的像素测量接触方向时，标准分水岭方法会产生显着的系统误差。我们确认并建立在先前的结果之上，这些结果表明使用粒子分离的改进概念可以改进取向测量。在此坚实的基础上，未来的工作应重点关注接触拓扑和测量误差之间的联系，以及评估使用局部表面法线进行方向测量。
In the mechanics of granular materials, interparticle contacts play a major role. These have been historically difficult to study experimentally, but the advent of x-ray microtomography allows the identification of all the thousands of individual particles needed for representative mechanical testing. This paper studies the metrology of detecting interparticle contacts and measuring their orientation from such images. Using synthetic images of spheres and high-resolution tomographies of two very different granular materials (spherical and very angular) as ground truths, we find that these measurements are far from trivial. For example, if a physically correct threshold is used to separate particles from pores there is a systematic over-detection of contacts. We propose a method of improvement that is effective for non-angular particles. When contact orientations are measured from the pixels that make up the contact area, standard watershed approaches make significant systematic errors. We confirm and build upon previous results showing the improvement in orientation measurement using a refined notion of particle separation. Building on this solid basis, future work should focus on a link between contact topology and measurement error, as well as evaluating the use of local surface normals for orientation measurement.