DocumentCode :
962105
Title :
Noncontact Laser Inspection Based on a PSD for the Inner Surface of Minidiameter Pipes
Author :
Wu, Enqi ; Ke, Yinglin ; Du, Baojiang
Author_Institution :
Coll. of Mech. Eng., Univ. of Shanghai for Sci. & Technol., Shanghai
Volume :
58
Issue :
7
fYear :
2009
fDate :
7/1/2009 12:00:00 AM
Firstpage :
2169
Lastpage :
2173
Abstract :
A new noncontact laser-inspection technique based on a position-sensitive detector (PSD) to inspect the inner surface of minidiameter pipes is proposed, and the corresponding sensor is developed. A light spot is projected onto the pipe inner wall after the laser beam is reflected by two mirrors. At the same time, four current signals are produced when the light spot is read by the 2-D PSD. According to the magnitude of the current signals and the structure parameters of the sensor, the spot position on the inner wall can be calculated in a local 3-D coordinate system. With a micromotor, the surface of the whole inner wall can be scanned by the laser beam. This way, the coordinates of all the sample points in the section are obtained. After that, several reasonable data-processing methods are used, such as data segmentation and least squares fitting. Finally, the section curve can be reconstructed. The radius and defects of the section can also be obtained. Driven by a micropipe robot, the sensor can inspect a long curved pipe. The inspection system based on this technique can detect the inner surface of minidiameter pipes, which has an inner diameter of 9.5-10.5 mm and a curvature radius of more than 100 mm. The measurement accuracy of this inspection system for the inner diameter and surface defect reaches plusmn0.1 mm.
Keywords :
fault diagnosis; image scanners; image segmentation; inspection; least mean squares methods; light reflection; measurement by laser beam; micromotors; microrobots; mirrors; nondestructive testing; optical scanners; pipes; PSD; current signal magnitude; data segmentation; data-processing method; laser beam reflection; laser beam scanned inner wall; least squares fitting; local 3-D coordinate system; long curved pipe inspection; measurement accuracy; micromotor; micropipe robot sensor; minidiameter pipe inner surface inspection; mirror; noncontact laser inspection technique; pipe inner wall surface defect detection; position-sensitive detector; projected light spot; size 9.5 mm to 10.5 mm; Inner surface inspection; laser; minidiameter pipe; position-sensitive detector (PSD); reconstruction;
fLanguage :
English
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9456
Type :
jour
DOI :
10.1109/TIM.2008.2006727
Filename :
4657375
Link To Document :
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