The quality of Digital Volume Correlation (DVC) full-field displacement measurements depends directly on the characteristics of the X-ray Computed Tomography (XCT) equipment, and scan procedures used to acquire the tomographic images. We seek to experimentally study the effects of XCT equipment and tomographic scan procedures on the quality of these images for DVC analysis, and to survey the level of DVC error that may be achieved using standard XCT operating procedures. Six participants in an interlaboratory study acquired high-quality XCT scans of a syntactic foam before and after rigid body motion. The resulting images were correlated using commercial DVC software to quantify error sources due to random image noise, reconstruction artifacts, as well as systematic spatial or temporal distortion. In the absence of rigid body motion, the standard deviation of the displacement measurements ranged from 0.012 to 0.043 voxels using a moderate subvolume size, indicating that subvoxel measurement resolution could readily be achieved with a variety of XCT equipment and scan recipes. Comparison of consecutive scans without rigid body motion showed transient dilatational displacement gradients due to self-heating of the X-ray source and/or thermal expansion of the foam. Evaluation of the scans after rigid body motion showed significant, machine-specific spatial distortion in the displacement fields of up to 0.5 voxels; new approaches to remove this error need to be developed. Analysis of the scan protocols used in the interlaboratory study, as well as a complementary parametric sensitivity study, showed that the DVC error was strongly influenced by the XCT equipment, but could be mitigated by adjusting the total scan duration.

中文翻译：

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X 射线计算机断层扫描设备和扫描参数引起的数字体积相关误差的实验室间研究：DVC 挑战的更新

数字体积相关 (DVC) 全场位移测量的质量直接取决于 X 射线计算机断层扫描 (XCT) 设备的特性以及用于获取断层扫描图像的扫描程序。我们试图通过实验研究 XCT 设备和断层扫描程序对这些用于 DVC 分析的图像质量的影响，并调查使用标准 XCT 操作程序可能实现的 DVC 误差水平。一项实验室间研究的六名参与者在刚体运动前后获得了复合泡沫的高质量 XCT 扫描。使用商业 DVC 软件对所得图像进行关联，以量化由于随机图像噪声、重建伪影以及系统空间或时间失真造成的误差源。在没有刚体运动的情况下，位移测量的标准偏差范围为 0.012 到 0.043 体素，使用中等大小的子体积，表明使用各种 XCT 设备和扫描配方可以轻松实现子体素测量分辨率。没有刚体运动的连续扫描的比较显示了由于 X 射线源的自热和/或泡沫的热膨胀导致的瞬态膨胀位移梯度。刚体运动后的扫描评估显示，在高达 0.5 体素的位移场中，显着的、特定于机器的空间失真；需要开发消除这种错误的新方法。对实验室间研究中使用的扫描协议以及补充参数灵敏度研究的分析表明，DVC 误差受到 XCT 设备的强烈影响，