Industrial X-ray computed tomography (CT) is the only technology in geometric metrology that can measure both internal and external features of a workpiece non-destructively. However, to specify the measurement uncertainty for a certain measurand, twenty repeated measurements on a calibrated work piece have to be executed according to the state of the art (VDI/VDE 2630 Part 2.1). Since the measurement with real CT systems is time-consuming and cost-intensive, the numerical determination of the task-specific measurement uncertainty with simulation is currently researched. This method will be similar to the state of the art in tactile coordinate metrology (cf. VDI/VDE 2617 Part 7, GUM Supplement 1). Therefore, radiographic simulation softwares to simulate measurement tasks currently receive considerable attention. Simulations offer advantages through time-, cost- and resource-efficiency. However, the reliability of the different available simulation environments is currently not quantifiable. For end users to trust and apply the simulation systems, an evaluation of the simulation system’s accuracy is necessary. A standardized test procedure would also allow for a standard- respectively guideline-conformity in applications.
Thus, the result of this project will be a draft for a new VDI/VDE standard VDI/VDE 2630 Part 2.2 “Restricted Qualification of Software for the Simulation of Geometrical Measurements using X-ray Computed Tomography”. On this basis, it will be possible to evaluate the suitability of a simulation environment for determining the task-specific measurement uncertainty. For this purpose, a test framework will be developed with which radiographic simulation software can be restrictedly qualified. A restricted qualification describes a qualification with regard to typical measurement scenarios that are perceived as relevant.
Several steps are necessary to create the test framework. First, a requirements analysis defines the requirements for the used simulation software. These requirements are summarized in a specification. For the development of the test framework, it is necessary to convert the requirements of the specification into concrete test scenarios. For this purpose, reference geometries and reference data sets must be developed. Based on the simulation results for the various test scenarios, the corresponding simulation software can be evaluated. For this purpose, an evaluation matrix is developed. The final test framework will be validated by comparing real and simulated measurement data for positively evaluated simulation software based on the dimensional measurement results.
In order to retain the normative character of this project, it will be ensured that this basic qualification with the test framework is also possible for other simulation software systems that are not represented in the project.
This project is funded in the program WIPANO. WIPANO projects are financed by the German Federal Ministry for Economic Affairs and Energy and managed by Project Management Jülich. The funding is granted based on a decision by the German parliament.