Title: Determination of metrological structural resolution of a CT system using the frequency response on surface structures
Authors: Fleßner, Matthias, ORCID: 0000-0002-6591-9988
Vujaklija, Nemanja
Helmecke, Eric
Hausotte, Tino, ORCID: 0000-0002-2923-3217
Contributors: HostingInstitution: Physikalisch-Technische Bundesanstalt (PTB), ISNI: 0000 0001 2186 1887
Pages:10
Language:en
DOI:10.7795/810.20150223B
Resource Type: Text / Report
Publisher: Physikalisch-Technische Bundesanstalt (PTB)
Dates: Available: 2015
Classifications: PACS 06.20.-f Metrology ; PACS 81.70.Tx Computed tomography (in materials testing) ; OCIS 120.3940 Metrology ; OCIS 120.4290 Nondestructive testing
File: Download File (application/pdf) 281.35 kB (288107 Bytes)
MD5 Checksum: c09da2b8070c4287c4c8762821f0e848
SHA256 Checksum: 48a6338ed1821a7d0309548ccbfa2fa3b3f116cb7883f76693cb3ecb65c7efe5
Keywords: dimensional metrology ; computed tomography ; structural resolution ; frequency response ; spatial frequency
Abstract: An important characteristic determining the quality of a Computed Tomography (CT) measurement is the structural resolution. According to guideline VDI/VDE 2630 part 1.3, the structural resolution describes “the size of the smallest structure than can still be measured dimensionally”. A low structural resolution complicates the detection of small structures and may render it impossible to carry out dimensional measurements on them. For medical CT, the modulation transfer function (MTF) is often used to characterize the resolution of the volume data. It is a very powerful method to characterize the resolution of the volume data, but it does not include the step of surface determination, which is crucial for dimensional measurements.
A novel method for the determination of the structural resolution of a CT system is presented. The method uses the damping of different spatial frequencies (i.e. the frequency response) while measuring the surface of an Aperiodic Spatial Frequency Standard (ASFS) with a CT system. The ASFS features small surface structures that are positioned aperiodically along the standard and deviate from sinusoidal shapes, resulting in spatial frequencies from a wider range when performing a Fourier analysis of the surface data. Therefore, the geometry of the standard allows it to investigate a broader range of possible structural resolutions using just one standard.
Simulations and experiments, using CT with different acquisition parameters and a fringe projection system, show that the method is a promising alternative for determining the structural resolution of a measurement system.
Table of Contents: FLEßNER, Matthias, Nemanja VUJAKLIJA, Eric HELMECKE and Tino HAUSOTTE. Determination of metrological structural resolution of a CT system using the frequency response on surface structures . Physikalisch-Technische Bundesanstalt (PTB), 2015. doi: 10.7795/810.20150223B
Other: This article is based on a presentation at the conference "MacroScale 2014 - Recent developments in traceable dimensional measurements", Vienna (Austria), 28th-30th October 2014.
Remark: This article is based on a presentation at the conference "MacroScale 2014 - Recent developments in traceable dimensional measurements", Vienna (Austria), 28th-30th October 2014.