[직/편성물] Defect Detection in Fabrics with a Joint Transform Correlation Technique: Theoretical Basis and Simulation 출판일 : 1999.11.01 저자 : Bithika Mallik, Asit K. Datta 서지사항 : Textile Research Journal, Volume 69, No11(1999), 829-835페이지 등록일 : 2012.12.05 I 조회수 : 1059 작성자 : admin |
Abstract
The theoretical basis of a technique for real time defect detection in fabrics is presented
using a joint transform correlator. This correlation technique is an extension of Fourier
transform analysis and is extremely useful for real time pattern recognition. The regular
periodic nature of a woven fabric makes it possible to use the Fourier transform technique to
detect defects. However, classifying various defect types is difficult from the Fourier
analytical and experimental results. A solution to this problem is to use a joint Fourier
transform of a reference pattern and the test pattern, and the joint power spectrum is further
processed. Cross- and auto-correlation peaks, generated after the execution of the second
Fourier transform on the filtered joint power spectrum, indicate the existence of a particular
defect type. Because of the parallel processing ability of the optical system, implementing
the joint transform correlation technique in an optical domain is advanta geous. A fractional
power fringe adjusted filter is used for efficient detection of defects. The mathematical
formulation of the technique is supported by the simulated results for identifying some
defects such as the existence of thick yarns, knots, and missing yarns.
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