Computerized Tomography

The analysis of random samples as well as the inspection and verification of prototypes, e.g. in aluminium casting industry, demand fast non-destructive testing methods with high geometrical resolution and 3D imaging capability. X-ray computerized tomography (CT) is specially suited to this and reached increasing importance due to the fast development of system components and software during the last few years. A complete examination of an object with two dimensional computerized tomography (2D-CT) is very time consuming because all objects slices have to be measured one after each other. In contrast to this three-dimensional computerized tomography (3D-CT) is able to examine a complete object volume with one single scan. For a 3D-CT measurement the sample is rotated through 360° in the X-ray beam cone at constant height. X-ray source and the two dimensional X-ray detector are stationary. By means of a mathematical reconstruction algorithm the 3-dimensional distribution of the X-ray absorption coefficient in the object volume is reconstructed from the measured projections taken at different angles. The reconstructed volume of the samples can be inspected using visualisation software. In this presentation the principle of computed tomography is outlined and examples of industrial applications are presented.