STNLCD外观缺陷检测方法研究

【作者】 张宏刚；

【导师】 沈会良；

【作者基本信息】 浙江大学 ， 物理电子学， 2008， 硕士

【摘要】 超扭曲向列液晶显示器件(STN-LCD)是各类仪器仪表和电子设备的主要显示方式.由于制备过程较复杂,生产过程中难免会出现各类缺陷。由于人眼很难分辨直径只有零点几毫米的缺陷,而且长时间的工作极易引起视觉疲劳,因此需要一种STN-LCD缺陷的自动检测技术,以实现高效的自动化.本文研究了图像配准区域标记二值化等的原理与技术,提出一种基于图像配准的STN-LCD缺陷检测方法,并开发了相应的软件系统。该方法首先对标准模板图像做不均匀光照消除、二值化以及区域信息提取;然后通过控制点检测和模板匹配实现待检测图像和模板图像之间的配准;并利用各图形区域的灰度平均值等统计信息,检测缺段、针孔等各类缺陷。为提高图像配准精度,进一步提出了有效控制点筛选方案以及混合插值方法。实验结果表明,该方法设计思路合理可行,可代替人眼实现对STN-LCD各类外观缺陷的快速、自动检测,满足实际应用需求。更多还原

【Abstract】 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.更多还原