CAMERA AND PROJECTOR CALIBRATION OF AN ENDOSCOPIC FRINGE PROJECTION SYSTEM
Steffen Matthias, Markus Kastner, Eduard Reithmeier
Abstract:
In this paper, we present a method of an accurate camera and projector calibration for a newly developed endoscopic micro fringe projection system. The system consists of a laser illuminated digital micro-mirror device (DMD) for the projection of arbitrary structured light patterns, such as Gray code and cos²-phaseshift patterns. These patterns are focused into a 100’000 pixel image fiber and at the endpoint projected onto the specimen via gradient index lenses. A similar fiber assembly guides the perspective-distorted patterns back from the measurement object to a CCD-camera. The design for the areal measurement of filigree inner geometries generates new challenges for the camera and projector calibration, not only because of the reduced measurement area, but also because of the reduced resolution and artifacts of the image fibers. The camera is described by the standard pinhole camera model, while the projector is modeled using a black box. Calibration is performed by positioning a planar calibration rig with a linear stage. The linear stage is employed for partial automation of the calibration while the additional positioning data is combined with the information from the planar calibration rig to create a 3D data set for the calibration algorithm. This results in a considerably more robust identification of both the pinhole and black-box model. The capabilities of both models together with the developed calibration procedure are proven by the results of measurements of an inner gearing.
Keywords:
3D-measurement, endoscopy, fringe projection, laser projector, calibration
Download:
IMEKO-TC14-2014-58.pdf
DOI:
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Event details
IMEKO TC:
TC14
Event name:
TC14 LMPMI Symposium 2014
Title:

11th Symposium on Laser Metrology for Precision Measurement and Inspection in Industry

Place:
Tsukuba, JAPAN
Time:
03 September 2014 - 05 September 2014
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