a1 Department of Mechanical and Production Engineering, The National University of Singapore, Singapore-119 260, Singapore
a2 School of Mechanical and Prod. Engineering Nanyang Technological University, Singapore-639 798, Singapore
Abstract:
TDI imaging is introduced as a solution to industrial web inspection under low-light illumination. In addition to the original purpose of recording clear blur-free images of the objects moving over industrial platforms, it can also be used as a tool for profilometry and automated visual inspection when coupled with proper structured light illumination modules. This paper illustrates a system employing a pulsed laser diode, uniform intensity line generating optics and a high-speed TDI imager for recording structured light patterns from rotating cylindrical objects. Defect or shape information is coded as distortions in a regular grating pattern recorded by the TDI imager. The shape or defect profile is retrieved by employing Fourier transform and scanning spatial phase detection techniques.