Correlation between camera image and photodiode signal during laser welding

0511782 - ÚPT 2020 DE eng A - Abstract
Horník, Petr - Mrňa, Libor - Šebestová, Hana
Correlation between camera image and photodiode signal during laser welding.
Lasers in Manufakturing. LIM 2019. Book of Abstracts. München: WLT, 2019.
[Lasers in Manufakturing. LIM 2019. 24.06.2019-27.06.2019, München]
R&D Projects: GA TA ČR(CZ) TH04010366; GA TA ČR TG03010046
Institutional support: RVO:68081731
Keywords : laser welding * photodiode * high-speed camera * correlation * monitoring
OECD category: Automation and control systems

Photodiodes are often used to monitor weld quality. This solution has the advantage of simplicity and low cost, but it may be more difficult to interpret the measured data. Moreover, measurement with multiple photodiodes indicates dependency of the measured intensity on the photodiode position. The purpose of this study is to better understand the data measured during the laser welding process. Therefore we explore which part of the high-speed camera image best corresponds to photodiode intensity during welding. Regions of interest including weld pool and vapour plume are selected from camera images. The regions are compared with the photodiode using correlation coefficient. Subsequently, the task is generalized, and the photodiode is compared directly with each pixel of the camera. This creates a map describing which parts of the image most closely correspond to the photodiode signal. In addition, the results are also viewed in relation to back-reflected laser radiation.
Permanent Link: http://hdl.handle.net/11104/0302030