Method to choose X-ray computed tomography settings for dimensional metrology using 2D image analysis prior to reconstruction

Mohamed Chahid (Speaker), Townsend, A. (Speaker), Ahmed Tawfik (Speaker), Bills, P. (Speaker), Christopher Dawson (Speaker), Racasan, R. (Speaker)

Activity: Talk or presentation typesOral presentation

Description

Conference Presentation was originally called - Ranking of XCT setting
combinations for dimensional metrology using 2D image analysis prior to
reconstruction

Currently, no standards or guidelines can assist in selecting an exact X-Ray computed tomography (CT) setting combination for a part of which the material and internal shape is unknown. Research showed that different users select different CT settings when scanning the same part, leading to different measurement results [1].
The objective of this research is to rank six CT settings’ combinations by analysing their 2D projection image quality. The dimensional workpiece measured is machined from Ti6Al4V Eli bar stock and composed of two features. Two parallel planes used for voxel scaling correction and an outer diameter used for validation. The dimensional workpiece is the same used in [2].
The method starts by taking full scans of the part, in this case, six scans of different CT settings’ combinations (Changing the voltage, current and filter). All 1582 2D projections of each CT scan combination are averaged and analysed using the new suggested SFN equation and Fiji, an open source image processing software based on ImageJ. The settings combinations are then ranked from the ideal to the least ideal depending on their averaged assessed image quality. To validate the ranking, a voxel scaling is done using the part’s parallel planes. The outer diameter value is then extracted and compared with the CMM measured one. The 3D volume CT scans are ranked from the one with the least variance with the CMM.
The two rankings showed a high correlation, concluding the validity of the SFN equation and the proposed method. The method can assist in gaining a massive amount of time, minimising user involvement, chances of error and maximising the accuracy of CT scanning.
Period25 Jun 2019 - 26 Jun 2019
Held at4th Dimensional X-ray Computed Tomography Conference
Event typeConference
Conference number4
LocationHuddersfield, United Kingdom
Degree of RecognitionNational