Title 



Defining geometrical position information of a thermal camera and object curvatures using thermography
 
Author 



 
Abstract 



In nondestructive evaluation, the use of finite element models to evaluate structural behavior and experimental setup optimization can complement with the inspectors measurement experience. With the use of a finite element model, the assumption of a predefined sound area is superfluous. The use of thermography data for finite element model updating delivers the need for correct mapping of the thermal information out of the IRcamera on the correct geometrical coordinates. The mapping will be discussed in this paper. A first problem that occurs is the lens distortion due to lens curvature errors. This results in a geometrical radial offset of the pixel value. A possible solution is to use a geometrical calibration to perform lens curvature corrections. Besides, there is an increasing demand to analyze complex structures with multiple curvatures. This results in distortions of the thermal images as a result from a higher heating of surfaces planar to the heat source with respect to the surfaces perpendicular to it. The same effect occurs when the surfaces emit the absorbed energy to the camera. The investigated solution makes use of the height information from a TimeofFlight camera in order to correlate the pixel temperatures with correct height information. This height information corresponds to the geometrical profile known from a finite element model. At last the physical displacement between both cameras is discussed. The angular offset between both camera optical centers is measured and the pixel information is translated to one optical center. This paper describes a methodology to map thermal and height data on the geometrical coordinates of a test sample.   
Language 



English
 
Source (journal) 



OPTICAL MEASUREMENT TECHNIQUES FOR STRUCTURES & SYSTEMS III  
Source (book) 



6th International Conference on Optical Measurement Techniques for, Structures and Systems III (OPTIMESS2015), APR 0809, 2015, Univ Antwerp, Univ Antwerp, Antwerp, BELGIUM  
Publication 



Maastricht : Shaker publishing bv, 2016
 
ISBN 



9789042304390
 
Volume/pages 



(2016), p. 233242
 
ISI 



000373413300023
 
