Evaluation of transmission based image quality optimisation for X-ray computed tomography

This paper presents a study on the optimisation of scan parameters for industrial X-ray computed tomography (XCT). The selection and optimisation of scan parameters for a specific application is typically done by the system operator, which leads to subjective and often suboptimal scan results. Standards for XCT propose a parameter optimisation based on the minimal X-ray transmission occurring during the scan. The EN 16016 standard proposes a minimal transmission of about 10 to 20%, whereas the ISO 15708 standard proposes 14% minimal transmission. Advantageously, transmission based parameter selection does not need any preliminary knowledge about the specimen?s geometry and material compared to simulation based approaches. In this work XCT scans for selected specimens, with a varying minimal transmission, are done on an industrial micro XCT device, to test and verify the applicability of transmission based parameter selection. The quality of each dataset is quantified by calculating the measures signal to noise and contrast to noise ratio for different regions and features. Afterwards the correlation between those quality measures and the minimal transmission is shown and discussed.