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Identification of superficial defects in reconstructed 3D objects using phase-shifting fringe projection
Author(s): Carlos A. Madrigal; Alejandro Restrepo; John W. Branch
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Paper Abstract

3D reconstruction of small objects is used in applications of surface analysis, forensic analysis and tissue reconstruction in medicine. In this paper, we propose a strategy for the 3D reconstruction of small objects and the identification of some superficial defects. We applied a technique of projection of structured light patterns, specifically sinusoidal fringes and an algorithm of phase unwrapping. A CMOS camera was used to capture images and a DLP digital light projector for synchronous projection of the sinusoidal pattern onto the objects. We implemented a technique based on a 2D flat pattern as calibration process, so the intrinsic and extrinsic parameters of the camera and the DLP were defined. Experimental tests were performed in samples of artificial teeth, coal particles, welding defects and surfaces tested with Vickers indentation. Areas less than 5cm were studied. The objects were reconstructed in 3D with densities of about one million points per sample. In addition, the steps of 3D description, identification of primitive, training and classification were implemented to recognize defects, such as: holes, cracks, roughness textures and bumps. We found that pattern recognition strategies are useful, when quality supervision of surfaces has enough quantities of points to evaluate the defective region, because the identification of defects in small objects is a demanding activity of the visual inspection.

Paper Details

Date Published: 28 September 2016
PDF: 8 pages
Proc. SPIE 9971, Applications of Digital Image Processing XXXIX, 99712O (28 September 2016); doi: 10.1117/12.2237445
Show Author Affiliations
Carlos A. Madrigal, Instituto Tecnológico Metropolitano (Colombia)
Alejandro Restrepo, Univ. Nacional de Colombia (Colombia)
John W. Branch, Univ. Nacional de Colombia (Colombia)


Published in SPIE Proceedings Vol. 9971:
Applications of Digital Image Processing XXXIX
Andrew G. Tescher, Editor(s)

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