Chang-Do JUNG, Hyunduk KIM¹, Se-Yun KIM, Yongdo LIM¹, and Kil-Houm PARK^*

School of Electrical Engineering and Computer Science, Kyungpook National University, Daegu 702-701, Korea
¹Department of Mathematics, Kyungpook National University, Daegu 702-701, Korea

(Received April 27, 2011; Accepted June 3, 2011)

Detecting defects in thin film transistor liquid crystal display (TFT-LCD) panels can be difficult due to non-uniform background brightness and slightly different brightness levels between the defective regions and the background. One well-known method is to inspect the defects of TFT-LCD panels using the polynomial approximation method. However, there are some problems such as determination of the polynomial degree and ghost objects. In this paper, to overcome these problems, we propose a new algorithm using the piecewise linear regression twice and Niblack's method which do not require to determine the polynomial degree for the approximation. Our algorithm effectively removed ghost objects. The experimental results show that our proposed method performed well and was good enough to substitute the polynomial approximation method.

Key words: inspection of defect, TFT-LCD, polynomial approximation, piecewise linear regression, Niblack's method

^*E-mail address: khpark@ee.knu.ac.kr