Image Quality Indicators (IQIs) are used in commercial 2D X-ray inspections to confirm detail detectability of the system. In the simplest case these are wires with well known thicknesses. It is not generally well known that 3D X-ray systems can also make 2D inspections very easily and shown below are such images of a standard IQI resolution test taken at 160, 100 and 25 microns resolution settings.
A full CT scan at 25 micron resolution allows 3D analysis of the IQI part, the 3D image below shows the plastic casing as well as the wires. Accurate measurements of the wire thickness was made using the metrology toolbox of VGStudioMax 2.2 – this allows the fitting of cylinders to central sections of the wires and calculating the diameter of the best fit cylinder. In this way sub-25 micron precision is possible. The results are as expected for the IQI test, except for the smallest wire which is not cylindrical, making a best fit cylinder problematic.
IQI Specs: DIN62FE, 10ISO16
Diameters 0.40mm, 0.32mm, 0.25mm, 0.20mm, 0.16mm, 0.13mm and 0.10mm 
See video here: video iqi
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