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Image Restoration for Detecting Muras in TFT-LCD Panels  

Choi, Kyu-Nam (서울대학교 전기컴퓨터공학부)
Yoo, Suk-I. (서울대학교 전기컴퓨터공학부)
Publication Information
Journal of KIISE:Software and Applications / v.34, no.11, 2007 , pp. 953-960 More about this Journal
Abstract
To correctly detect muras, visual defects in TFT-LCD panels, image distortion occurring on the profess of capturing panels should be corrected. In general vision systems, there are several known methods to restore the observed image. However, the vignetting effect particularly shown only in panel images cannot be easily restored through traditional methods because it is combined with background non-uniformity due to the unique characteristic of panel. To increase the reliability of image restoration, the vignetting effect should be properly corrected after being separated from image background. Therefore, in this paper we present a new method to analyze and correct the vignetting effect of panel images using principal component analysis. Experimental results for a total of 175 test images showed that the average contrast error of the muras in the distorted images was reduced from 37% to 11% and the mura misidentification rate was decreased from 14.8% to 2.2% by image restoration.
Keywords
Image Restoration; TFT-LCD; Mura; Principal Component Analysis; Vignetting;
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