This paper introduced the machine vision technology into the LCD (Liquid Crystal Display) panel flaw inspection system, in order to detect flaws accurately and quickly. There are two major kinds of flaws in LCD panel: white dots and black dots. Image segmentation can be used to inspect flaws, and a general method is applying a threshold to the whole image. But because of illumination unconformity, the acquired image has varied pixel brightness, and some pixels in the border even have a lower brightness than the black dots. So gradient thresholding based on local pixels is adopted, but because the image sensor and the LCD panel both have a array frame, there exists moiré fringes in the image. Thus, a novel method of gradient thresholding based on moiré fringes is put forward. And noises handling is discussed at end. Experimental results show that the proposed novel method is effective

Date Published: 20 May 2009
PDF: 4 pages
Proc. SPIE 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 72834E (20 May 2009); doi: 10.1117/12.828824

Published in SPIE Proceedings Vol. 7283:
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; James C. Wyant; Robert A. Smythe; Hexin Wang, Editor(s)