ILATO – Improving Limited Angle computed Tomography by Optical data integration

The name of the project ILATO is an acronym composed of Improving Limited Angle computed Tomography by Optical data integration. From a finite number of X-rays detected after travelling through an object, sinograms representing attenuation values of specimen are acquired. The 3D information is reconstructed from a series of 2D projections mostly on a circular trajectory. This is accomplished via inverse radon transformation. Limited angle computed tomography is indicated whenever the specimen dimensions exceed cone beam limits or the object is impenetrable from certain angles. Thus, acquiring only a subset of a full circle CT scan poses problems for reconstruction algorithms due to incomplete data which introduces blurred edges and other artifacts. A surface mesh acquisition of the object obtained via structured light optical scan is not limited in angle but cannot reveal the volumetric structure inside. To support the volumetric data reconstruction algorithm a surface mesh acts as a mask defining boundaries of the reconstructed image. The project focuses on the registration of optically acquired surfaces with data acquired from computed tomography in order to enhance image quality and shorten acquisition times in X-ray based industrial quality inspection. The challenges are the correct setup, the registration of data sets created with considerably different imaging techniques, and the improvement of the applied methods. All the extracted information is used to gain an improved visualization in the sense of less noise and sharper edges especially in the areas where the limited angle reconstruction suffers from insufficient information.

Link to project website.


Name and contact of project responsible(s):

A. Beyer (Interdisciplinary Center for Scientific Computing, Heidelberg University)
Dr. H. Mara (Interdisciplinary Center for Scientific Computing, Heidelberg University)
Dr. S. Krömker (Interdisciplinary Center for Scientific Computing, Heidelberg University)
Prof. Dr. Dres. h.c. H. G. Bock (Interdisciplinary Center for Scientific Computing, Heidelberg University)

Involved scientists and partners

L. Yu (ETH Zurich and Empa)
Prof. Dr. K. Wegener (ETH Zurich)
Dr. P. Schütz (Lucerne University of Applied Sciences and Arts)
Alexander Flisch (Empa)
Dr. U. Sennhauser (Empa)

Empa, Swiss Federal Laboratories for Materials Science & Technology (deutsch: Eidgenössische Materialprüfungs- und Forschungsanstalt)


A. Beyer, H. Mara, S. Krömker: ILATO Project: Fusion of Optical Surface Models and Volumetric CT Data, in:  Computing Research Repository CoRR, 2014
Presented at the OAGM 2014 (Austrian Association for Pattern Recognition)