The Department of Numerical Instrumentation joins expertise on different research fields through experimental and software platforms. In the Monitoring, Control and Diagnostic Unit, one of the important research areas is the industrial inspection with X-ray methods. Within this framework, a robotic inspection facility is being employed for innovative research and validation of new algorithms and on instrumentation aspects.
One of the most important features of robotic inspection is the possibility to scan large samples. In most application cases, region-of-interest areas are defined, for which a higher spatial resolution is targeted. In this context, a research program covering several topics is proposed, with the main objective of facilitating the setup and the use of the robotic inspection configuration for industrial application cases. A focus can be set on one or two research topics, depending on the background and on personal R&D interests and initiatives of the candidate.

A first topic will consist of developing CT reconstruction algorithms for a scan configuration using a variable magnification ratio, in a first phase with analytical algorithms such as the one proposed by Dennerlein [1] and then to adapt iterative reconstruction algorithms of SART type.

A second topic will consist on a work related to adapt the algorithms towards a multi-resolution representation of the reconstructed volumes, through octree or wavelet decomposition. An approach involving the correlation of experimental data to the CAD model of the sample will allow a better implementation in order to improve the VOI (volume of interest) tomography.

A third topic focused on instrumentation will deal with the experimental validation and additionally it will aim to develop a system capable to verify the accurate positioning of the scene elements with the help of precision distance sensors. A simultaneous measure of the distance source - to part surface together with the radiographic image will allow implementing corrections for positioning errors for every scan point and in a second phase to use this additional information directly in the reconstruction process.