Fundamental correction strategies for accuracy improvement of dimensional measurements obtained from a conventional micro-CT cone beam machine

This paper describes specific correction methods applied for dimensional measurements when using a non-measuring oriented computed tomography machine. These methods were developed to correct two factors that have a predominant influence in dimensional measurements using CT systems: the threshold and the scale factor. The correction procedures were designed to correct the two factors independently, by using some of the geometry features of the parts themselves, i.e. without external help of additional reference samples or standards. The correction methods proposed here are intentionally as simple as possible, so that they can be easily applied in industry, especially in the cases when non-measuring oriented CT systems are used for metrology applications. The results obtained are presented, showing how the methods can substantially improve the accuracy by decreasing the measurement errors, on average, down to 20 times lower than the errors obtained from uncorrected measurements.