title: Scanning moiré and phase shifting with time delay and integration imaging.
abstract: Scanning moiré is generated by undersampling of a phase-modulated grating pattern. In projection profilometry the scanning moiré pattern represents equal height and depth contours on a test object. By use of time delay and integration (TDI) imaging, it is possible to generate an on-line scanning moiré pattern from the complete periphery of a rotating cylindrical object. For automated phase and profile unwrapping from scanning moiré fringes, phase-shifting interferometry techniques are most desirable. However, lack of spatial information in the undersampled scanning moiré fringes introduces serious errors in phase unwrapping. We report a method that uses oversupply of data to balance the effect of undersampling. This oversupply is achieved with a TDI feature that permits programmable image magnification in the scanning direction.
authors.forename: M R
authors.initials: MR
authors.lastname: Sajan
authors.forename: C J
authors.initials: CJ
authors.lastname: Tay
authors.forename: H M
authors.initials: HM
authors.lastname: Shang
authors.forename: A
authors.initials: A
authors.lastname: Asundi