Optical Configurations, Methods and Algorithms for the Automatic Inspection on Metallic Surfaces

Ingo Maximilian Reindl

Research output: ThesisDoctoral Thesis


This work deals with the automated inspection of distinctive three-dimensional metallic surfaces, based on the light-sectioning technique. In industry, this method, where the position and the run of a projected laser-line are registered, builds a well-established optical dimensional-measurement technique. The distribution of the light intensity, which is reflected from the surface, is usually used as a kind of weighting-function to determine the average curve progression of the mapped laser-line in the camera chip. A method is presented, which takes advantage of local variations of the reflected light-intensity that occurs during the acquisition-process over a continuously moved surface. These inhomogeneities are used as additional information for the geometrical surface inspection. Two mirror-symmetrical arranged cameras register the gradients of the reflectance properties, which are pronounced particularly at the edges of surface cracks. In the course of a feasibility study, transversal orientated cracks (up to width of 0.2mm) embedded in the rounded edges of continuous-castings could be detected.
Translated title of the contributionOptische Anordnungen, Methoden und Algorithmen für die automatische Inspektion von metallischen Oberflächen
Original languageEnglish
  • O'Leary, Paul, Assessor A (internal)
  • Brand, Clemens, Assessor B (internal)
Publication statusPublished - 2006

Bibliographical note

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  • surface inspection light sectioning Scheimpflug surface approximation

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