TY - JOUR
T1 - New four points initialization for Digital Image Correlation in metal-sheet strain measurements
AU - Barranco-Gutiérrez, Alejandro Israel
AU - Padilla-Medina, José Alfredo
AU - Perez-Pinal, Francisco J.
AU - Prado-Olivares, Juan
AU - Martínez-Díaz, Saúl
AU - Gutiérrez-Frías, Oscar Octavio
N1 - Publisher Copyright:
© 2019 by the authors.
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Nowadays, the deformation measurement in metal sheets is important for industries such as the automotive and aerospace industries during its mechanical stamping processes. In this sense, Digital Image Correlation (DIC) has become the most relevant measurement technique in the field of experimental mechanics. This is mainly due to its versatility and low-cost compared with other techniques. However, traditionally, DIC global image registration implemented in software, such as MATLAB 2018, did not find the complete perspective transformation needed successfully and with high precision, because those algorithms use an image registration of the type "afine" or "similarity", based on a 2D information. Therefore, in this paper, a DIC initialization method is presented to estimate the surface deformation of metal sheets used in the bodywork automotive industry. The method starts with the 3D points reconstruction from a stereoscopic digital camera system. Due to the problem complexity, it is first proposed that the user indicates four points, belonging to reference marks of a "Circle grid". Following this, an automatic search is performed among the nearby marks, as far as one desires to reconstruct it. After this, the local DIC is used to verify that those are the correct marks. The results show reliability by reason of the high coincidence of marks in experimental cases. We also consider that the quality of mark stamping, lighting, and the initial conditions also contribute to trustworthy effects.
AB - Nowadays, the deformation measurement in metal sheets is important for industries such as the automotive and aerospace industries during its mechanical stamping processes. In this sense, Digital Image Correlation (DIC) has become the most relevant measurement technique in the field of experimental mechanics. This is mainly due to its versatility and low-cost compared with other techniques. However, traditionally, DIC global image registration implemented in software, such as MATLAB 2018, did not find the complete perspective transformation needed successfully and with high precision, because those algorithms use an image registration of the type "afine" or "similarity", based on a 2D information. Therefore, in this paper, a DIC initialization method is presented to estimate the surface deformation of metal sheets used in the bodywork automotive industry. The method starts with the 3D points reconstruction from a stereoscopic digital camera system. Due to the problem complexity, it is first proposed that the user indicates four points, belonging to reference marks of a "Circle grid". Following this, an automatic search is performed among the nearby marks, as far as one desires to reconstruct it. After this, the local DIC is used to verify that those are the correct marks. The results show reliability by reason of the high coincidence of marks in experimental cases. We also consider that the quality of mark stamping, lighting, and the initial conditions also contribute to trustworthy effects.
KW - DIC
KW - Image registration
KW - Initial condition
KW - Strain measurement
UR - http://www.scopus.com/inward/record.url?scp=85067103705&partnerID=8YFLogxK
U2 - 10.3390/app9081691
DO - 10.3390/app9081691
M3 - Artículo
AN - SCOPUS:85067103705
SN - 2076-3417
VL - 9
JO - Applied Sciences (Switzerland)
JF - Applied Sciences (Switzerland)
IS - 8
M1 - 1691
ER -