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Indian Journal of Engineering and Materials Sciences (IJEMS) >
IJEMS Vol.17 [2010] >
IJEMS Vol.17(1) [February 2010] >
| Title: | Comparative study on the suitability of feature extraction techniques for tungsten inclusion and hotspot detection from weld thermographs for on-line weld monitoring |
| Authors: | Nandhitha, N M
Manoharan, N
Rani, B Sheela
Venkatraman, B
Kalyanasundaram, P
Raj, Baldev |
| Keywords: | Thermographs
Depths of penetration
Tungsten inclusion
Edge detection
Region growing
Euclidean distance
Feature vectors |
| Issue Date: | Feb-2010 |
| Publisher: | CSIR |
| Abstract: | Welding is the most commonly used technique for
joining metals in industries. In spite of various technological advances
defects do occur in welds. Post non-destructive testing (NDT) techniques assess
the quality of weld after completion of welding process. Monitoring and
controlling weld parameters during welding can avoid the defect or if the
defect is already intolerable the welding process can be stopped there to save
time and money. It is thus necessary to develop an automated on-line welding
system to make the correct decision. Weld thermographs are acquired on-line
with IR camera. Effective feature extraction algorithms are to be developed to
isolate and quantify the defect features from thermographs. This paper compares
the effectiveness and suitability of three different feature extraction algorithms
namely discontinuity based detection (conventional), region growing and
Euclidean distance based color image segmentation developed for on-line
monitoring and control. Tungsten inclusion and different depths of penetration
thermographs are the database considered for defect feature extraction. Online
weld monitoring necessitates a standardized feature extraction technique that
works well irrespective of the size and shape of defect. Hence, comparison is
based on the accuracy of the results, parameter independency and image
independency. It is found that feature extraction by Euclidean distance based
segmentation is best suited for on-line weld monitoring as it is parameter
independent and can be standardized for a defect. |
| Page(s): | 20-26 |
| ISSN: | 0975-1017 (Online); 0971-4588 (Print) |
| Source: | IJEMS Vol.17(1) [February 2010]
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