Abstract
In order to calibrate the stripe precision of a leveling rod, an automatic
laser interferometer and a vision measurement system were designed by
Xi’an University of Technology in China. The rod was driven by a
closed-loop control and the data were collected at the stop state to
ensure precision. The laser interferometer provided not only the long
distance data but also a position feedback signal in the automatic control
loop. CCD camera and a vision measurement method were used to inspect the
stripe edge position and defect. A pixel-equivalent self-calibration
method was designed to improve precision. ROI (regions of interest) method
and an outline tracing method were designed to quickly extract multiple
stripe edges. A combination of the image data with the interferometer data
reduces control difficulty and ensures the measurement accuracy. The
vision measurement method reached sub-pixel precision and the defective
edges were reported. The system can automatically calibrate a stripe
leveling rod with a high degree of efficiency and precision.
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