X-ray flat-panel detector geometry correction to improve dimensional computed tomography measurements. (20th December 2019)

• Record Type: Journal Article
• Authors: Lüthi, Melina; Bircher, Benjamin A; Meli, Felix; Küng, Alain; Thalmann, Rudolf
• Is Part Of: Measurement science & technology. Volume 31:Number 3(2020)
• Publication Date: 2019-12-20
• Subjects: x-ray flat-panel detector -- geometrical image distortions -- error correction -- dimensional metrology -- x-ray computed tomography; Physical measurements -- Periodicals; Scientific apparatus and instruments -- Periodicals; Equipment and Supplies -- Periodicals; Science -- instrumentation -- Periodicals; Technology -- instrumentation -- Periodicals; Mesures physiques -- Périodiques; Physical measurements; Scientific apparatus and instruments; Periodicals; 502.87
• DOI: 10.1088/1361-6501/ab52b1
• Languages: English
• ISSNs: 0957-0233

Abstract

Abstract: To improve the accuracy of dimensional x-ray computed tomography (CT), error sources have to be characterised and accounted for. A variety of error sources have been comprehensively described in the literature. However, the influence of geometrical distortion of the flat-panel detector has rarely been considered. In this paper, the deviation from nominal geometry of a flat-panel x-ray detector was characterised using a calibrated ball plate. In-plane deviations were separated from the detector topography by varying the source–detector distance, resulting in a 3D detector geometry. A correction model for arbitrary source–detector distances was developed, which reduced the maximum errors of sphere centre-to-centre distances in scale-corrected CT measurements from ±3.9 µm to below ±0.8 µm. This fivefold improvement emphasises the importance of such correction for dimensional CT.