Stn Lcd Appearance Of The Defect Detection Method

Super-twisted nematic liquid crystal display (STN-LCD) is a main display type of various electronic devices. Due to the complicated manufacturing process, various types of defects may exist on LCD panel, which is usually inspected manually. However, it is quite difficult and exhausting for human eye to locate defects less than 1 mm, a system for automatic defect detecting is desired in practical application.This thesis proposed a new method for the detection of LCD defects based on the techniques including image registration, region labeling, and image thresholding.In the proposed method, the standard template LCD image is first restored from the possible non-uniform illumination, and then the statistical information of each region is collected by image thresholding and region labeling. The template and test image are registered by control-point detection and template registration. The defects including stroke-loss and pinhole of the LCD can then be detected by using the statistical information of each display region. To improve the accuracy of image registration, special schemes for control-point selection and hybrid image interpolation are proposed. Experimental results show that the proposed method is robust and accurate in detecting all forms of STN-LCD defects. The proposed method is applicable for industrial applications, and offers advantages over the traditional manual inspection manner.