JOURNAL OF MULTIMEDIA (JMM)
ISSN : 1796-2048
Volume : 2    Issue : 4    Date : August 2007

Automatic Deformation Detection for Aircraft Engine Disk Inspection
Dirk Padfield, Glen Brooksby, and Robert Kaucic
Page(s): 34-44
Full Text:
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Abstract
Computer vision algorithms are seeing increased use in industrial inspection applications. Here,
we present an “Aid to Visual” system that can detect post deformations of less than 0.005 inches in
jet engine high pressure turbine disks. We create a gold-standard reference post from the posts of
sample turbine disks and then use registration, edge detection, and curve-similarity algorithms to
identify unacceptable post deformations. We address the challenges associated with adapting
academic algorithms for use in functioning inspection systems. We present novel solutions to deal
with practical issues such as accuracy, speed, robustness, and ease of use. We also present a
novel, highly-efficient sub-pixel contour matching algorithm and demonstrate the effectiveness of
using sub-pixel distance calculation. We demonstrate overall error rates less than 1% on over 2400
images of posts. We have integrated our algorithms into the commercial LabVIEW software running
on the Aid To Visual workstation. Our algorithms will enable plant-factory inspectors to identify
minute post deformations that were previously difficult to detect.

Index Terms
Industrial inspection, aircraft engines, deformation detection, registration, Chamfer distance, curve
matching, sub-pixel distance calculation.