Advances in Computed Tomography for Geomaterials: GeoX 2010

Determination of 3D Displacement Fields between X-ray Computed Tomography Images Using 3D Cross-Correlation

Problems and Solutions

M. Razavi¹ — B. Muhunthan²

¹Mineral Engineering DepartmentNew Mexico Institute of Mining and Technology801 Leroy PlaceSocorro, NM [e-mail]

 

²Civil Engineering DepartmentWashington State University Pullman, WA [e-mail]

ABSTRACT. The difficulties associated with applying the method of cross correlation to determine the 3D displacement fields between x-ray computed tomography (x-ray CT) images are discussed in this study. The high-resolution 3D x-ray CT images of Silica sand specimens were obtained using the x-ray CT facility at Washington State University. A computer code, M-DST, was developed determine the 3D displacement fields between the x-ray CT images of the soil specimen before and after moving the specimen. Displacement fields obtained by changing the x-ray CT scan parameters as well as different computer programming approaches in M-DST code show that the effect of x-ray source fluctuation is reduced by increasing the number of images to generate radiographs. In addition, computing time is reduced significantly by defining a limited search region around the template and using running sum to calculate the 3D cross correlation.

 

KEYWORDS: x-ray computed tomography, cross-correlation, displacement field, M-DST

1. Introduction

Detection of the internal displacement fields for a specimen under loading in real time ...