Terahertz sensor for non-contact thickness measurement of car paints

We propose to use terahertz pulsed imaging (TPI) as a novel tool to characterise the thickness and uniformity of up to four layers of car paint on both metallic and non-metallic substrates. Results of the terahertz measurements are compared with other techniques, i.e. ultrasound, eddy current measurements, and X-ray computed tomography and good consistency is found between the techniques. Compared to other measurement techniques TPI has the advantage that it is a non-contact method.