We propose a paintmeter for noncontact and remote monitoring of the thickness and drying progress of a paint film based on the time-of-flight measurement of the echo signal of a terahertz (THz) electromagnetic pulse. The proposed method is effectively applied to two-dimensional mapping of the painting thickness distribution for single-layer and multilayer paint films. Furthermore, adequate parameters for the drying progress are extracted from the THz pulse-echo signal and effectively applied to monitor the wet-to-dry transformation. The THz paintmeter can be a powerful tool for quality control of the paint film on the in-process monitoring of car body painting.
© 2005 Optical Society of America
(110.6960) Imaging systems : Tomography
(120.4290) Instrumentation, measurement, and metrology : Nondestructive testing
(300.6270) Spectroscopy : Spectroscopy, far infrared
(310.1620) Thin films : Interference coatings
Instrumentation, Measurement, and Metrology
Takeshi Yasui, Takashi Yasuda, Ken-ichi Sawanaka, and Tsutomu Araki, "Terahertz paintmeter for noncontact monitoring of thickness and drying progress in paint film," Appl. Opt. 44, 6849-6856 (2005)