TY - JOUR

T1 - Adapted Fringe Projection Sequences for Changing Illumination Conditions on the Example of Measuring a Wrought-Hot Object Influenced by Forced Cooling

AU - Quentin, Lorenz

AU - Beermann, Rüdiger

AU - Reinke, Carl

AU - Kern, Pascal

AU - Kästner, Markus

AU - Reithmeier, Eduard

N1 - Funding Information: Funding: This research was funded by Deutsche Forschungsgemeinschaft (DFG); Collaborative Research Centre 1153 (CRC) “Process Chain to Produce Hybrid High-performance Components Through Tailored Forming”; Subproject C5 “Multiscale Geometry Inspection of Joining Zones”; 252662854.

PY - 2021/2/25

Y1 - 2021/2/25

N2 - Optical 3D geometry reconstruction, or more specific, fringe projection profilometry, is a state-of-the-art technique for the measurement of the shape of objects in confined spaces or under rough environmental conditions, e.g., while inspecting a wrought-hot specimen after a forging operation. While the contact-less method enables the measurement of such an object, the results are influenced by the light deflection effect occurring due to the inhomogeneous refractive index field induced by the hot air around the measurand. However, the developed active compensation methods to fight this issue exhibits a major drawback, namely an additional cooling of the object and a subsequent transient illumination component. In this paper, we investigate the cooling and its effect on temporal phase reconstruction algorithms and take a theoretical approach to its compensation. The simulated compensation measures are transferred to a fringe projection profilometry setup and are evaluated using established and newly developed methods. The results show a significant improvement when measuring specimens under a transient illumination and are easily transferable to any kind of multi-frequency phase-shift measurement.

AB - Optical 3D geometry reconstruction, or more specific, fringe projection profilometry, is a state-of-the-art technique for the measurement of the shape of objects in confined spaces or under rough environmental conditions, e.g., while inspecting a wrought-hot specimen after a forging operation. While the contact-less method enables the measurement of such an object, the results are influenced by the light deflection effect occurring due to the inhomogeneous refractive index field induced by the hot air around the measurand. However, the developed active compensation methods to fight this issue exhibits a major drawback, namely an additional cooling of the object and a subsequent transient illumination component. In this paper, we investigate the cooling and its effect on temporal phase reconstruction algorithms and take a theoretical approach to its compensation. The simulated compensation measures are transferred to a fringe projection profilometry setup and are evaluated using established and newly developed methods. The results show a significant improvement when measuring specimens under a transient illumination and are easily transferable to any kind of multi-frequency phase-shift measurement.

KW - Fringe projection profilometry

KW - Harsh conditions

KW - Hot measurement object

UR - http://www.scopus.com/inward/record.url?scp=85101302031&partnerID=8YFLogxK

U2 - 10.3390/s21051599

DO - 10.3390/s21051599

M3 - Article

C2 - 33668803

AN - SCOPUS:85101302031

VL - 21

JO - Sensors

JF - Sensors

SN - 1424-8220

IS - 5

M1 - 1599

ER -