Cone-beam computer tomography as a new testing method for industrial application

Abstract

Cone-beam computer tomography (CT) is a relatively new nondestructive testing method, used in industry, where the attenuation coefficient of an X-ray is measured. The fact that the samples are characterized by different density and thickness explains why various contrasts are obtained in the end results. Cone-beam CT uses a volumetric beam to scan the test object and therefore obtains a series of 2D images which are reconstructed into a 3D model. During the reconstruction process, the X-ray tube emits a polychromatic spectrum, called beam hardening, by which artefacts are often created. This process takes place because the low energy spectrum part in the material is better absorbed than the higher energy one. The basic application of this method is the visualization of the inner and outer structures of electronic components, packaging and interconnection technologies. This paper describes the basics of CT, the typical beam hardening artefacts and method to reduce their influence on the imaging quality of the measured objects. Additionally, examples of this testing method are presented.