Macro-photogrammetry as a tool for the accurate measurement of three-dimensional misalignment in welding

Abstract Misalignment in welding presents several problems for the integrity of structures and machines. For this reason, the measurement of misalignment is relevant for the correct evaluation of quality in welds. This paper presents a new low-cost procedure based on photographic images acquired with a non-professional camera. The procedure consists on the application of macro-photogrammetry for the generation of a three-dimensional point cloud from the images. Subsequently a mathematical processing based on Principal Component Analysis (PCA) is applied to the generated point cloud in order to fit a plane to each welded plaque. The evaluation of the orientation between fitted planes allows the accurate measurement of the angle of misalignment for the welded union. The method is validated by the comparison of the results with those obtained with the metrological techniques.

[1]  Diego González-Aguilera,et al.  Development of an All-Purpose Free Photogrammetric Tool , 2016 .

[2]  Diego González-Aguilera,et al.  Thermographic test for the geometric characterization of cracks in welding using IR image rectification , 2016 .

[3]  A. Gruen.  ADAPTIVE LEAST SQUARES CORRELATION: A POWERFUL IMAGE MATCHING TECHNIQUE , 1985 .

[4]  Inge Lotsberg,et al.  Stress concentrations due to misalignment at butt welds in plated structures and at girth welds in tubulars , 2009 .

[5]  H. Hirschmüller.  Accurate and Efficient Stereo Processing by Semi-Global Matching and Mutual Information , 2005, CVPR.

[6]  Mia Hubert,et al.  Robust statistics for outlier detection , 2011, WIREs Data Mining Knowl. Discov..

[7]  H. C. Longuet-Higgins,et al.  A computer algorithm for reconstructing a scene from two projections , 1981, Nature.

[8]  Horst Biermann,et al.  Crack observation methods, their application and simulation of curved fatigue crack growth , 2010 .

[9]  Tat-Hean Gan,et al.  Shaft angular misalignment detection using acoustic emission , 2014 .

[10]  D. Passoni,et al.  UAV PHOTOGRAMMETRY: BLOCK TRIANGULATION COMPARISONS , 2013 .

[11]  Jean-Michel Morel,et al.  ASIFT: A New Framework for Fully Affine Invariant Image Comparison , 2009, SIAM J. Imaging Sci..

[12]  Liguo Zhang,et al.  A novel laser vision sensor for weld line detection on wall-climbing robot , 2014 .

[13]  Diego González-Aguilera,et al.  Procedure for quality inspection of welds based on macro-photogrammetric three-dimensional reconstruction , 2015 .

[14]  Maria V. Felice,et al.  Accurate depth measurement of small surface-breaking cracks using an ultrasonic array post-processing technique , 2014 .

[15]  Lionel Moisan,et al.  A Probabilistic Criterion to Detect Rigid Point Matches Between Two Images and Estimate the Fundamental Matrix , 2004, International Journal of Computer Vision.

[16]  G. Mathers.  The welding of aluminium and its alloys , 2002 .