.Non-contact inspection for inner surface of small-diameter pipes based on laser-PSD[J].Optoelectronics Letters,2005,1(1):61-64 |
Non-contact inspection for inner surface of small-diameter pipes based on laser-PSD |
WU En-qi KE Ying-lin LI Jiang-xiong |
[1]College of Mechonical and Energy Engineering, Zhejiang University, Hangzhou 310027, China |
Abstract: |
A new non-contact inspection technique based on laser-PSD (position sensitive detector) to inspect the inner surface of small-diameter
pipe is proposed, and the corresponding sensor has been developed. After being reflected by two mirrors in series, a laser
beam is projected onto the inner wall of a pipe as a small light spot and is read by a two-dimensional PSD. Based on the signals
from the PSD and the structure parameters of the sensor, the spot position on the wall can be calculated in a local 3D coordinate
system. The spot controlled by the micro-motor driven mirrors will scan a closed section ring on the inner wall of the pipe
to obtain the relative coordinates of all the sampled points. The data will be then processed through data segmentation and
least square fitting, to reconstruct the section curve used for obtaining the radius and the defect description of the section.
Driven by a micro-pipe robot, the sensor can inspect a long curved pipe and obtain its 3-D reconstruction. An inspection system
based on this technique can detect the mini-diameter pipe with an inner diameter of 9.5 mm≈10.5 mm and a curvature radius
larger than 100 mm at a measurement accuracy of the inner surface defect of ±0.1 mm.
This work Supported by the National High-Tech Program (No. 2001AA423130) |
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