In traditional Fourier transform profilometry, the conversion from phase to height is deduced depending on the supposition that not only are the projector and the camera at the same height above the reference plane, but also their axes must cross at the same point on the reference plane. When these conditions are too strict to be satisfied, a large measurement error will be introduced. An improved optical geometry of the projected-fringe technique is discussed and phase-height mapping formula is deduced in this paper. Employing the new optical geometry, a simple calibration model is developed based on absolute phase extraction and space mapping techniques. , which make the environmental parameters is not as critical as before. Furthermore, a virtual space pattern is used to provide the reference points for camera calibration based on Zhang's calibration method. The calibration can be accomplished merely with a planar pattern, which extremely reduce the cost of device and make the process of measurement more convenient. The experiment result shows the good accuracy of the system.
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|State||Published - 2009|
|Event||2008 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Applications - Beijing, China|
Duration: 16 Nov 2008 → 19 Nov 2008
- Fourier-transform profilometry
- Phase-height relationship
- Unknown orientation views