An optoelectronic defect detection method and system insensitive to yarn speed

摘要

Analysis of optical methods and systems used to detect defects of a yarn, e.g. chenille yarn which will simply be called yarn throughout the paper, indicates that the detection results in current methods and systems depend on the yarn speed. In this paper, we report on an optical diagram with a wide-angled light emitter that has been developed to show the optical method of defect detection. The equation expressing the difference between the real defect length and the shadow length or detected defect length formed on the detection surface is obtained. An experimental setup has been developed to examine the variation of the pulse duration—formed by the defect—with the speed, and results are given in graphical form. Finally, a two-detector method and a microprocessor based system insensitive to yarn speed has been developed.