BACKGROUND RESEARCH LEADING TO THE APHIUS DEVELOPMENT PROJECT

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Authors
  1. Matthews, J.R.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
DREA Dockyard Laboratory began research in Pattern Recognition of weld defects in 1980. This research was aimed at producing signal processing that would allow the isolation of volumetric and crack life defects in weldments. With this ability a two level condemnation criteria, or weld reject criteria could be employed based on defect type with a projected savings in rework costs in the millions of dollars. The work began with the generation of basic weld defects for the collection of ultrasonic data and production of software to extract features in the time, frequency, auto correlation, cross correlation and convolution domains. Features were evaluated by producing histograms from twenty signals. In this way we were able to isolate potentially useful features for determining the different defect types. As soon as the research showed that pattern recognition would be successful, parallel work began with Tektrend to produce a system that would map defects and permit storage of rf waveforms for these defects. It was intended that data thus collected would be analysed in the lab and that defect maps would be produced with defect type determined by pattern recognition. Three prototype inspection systems have been produced over the past twelve years with more and more power and capability being available to the inspector with real time defect classification and defect mapping now a reality. TRUNCATED
Report Number
DREA-NAMT-93-5-PAP-20 — CONTAINED IN 99-00578
Date of publication
30 Apr 1993
Number of Pages
4
DSTKIM No
99-00599
CANDIS No
510325
Format(s):
Hardcopy;Document Image stored on Optical Disk

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