关键词: 缺陷提取, 感兴趣区域（ROI）识别, 实时检测, 手机液晶屏

Abstract: Currently，the image defects of LCD products mainly rely on manual detection.This algorithm realizes automatic real-time detection of image defects.Firstly，the real-time images are captured from the buffer of image acquisition card quickly by DirectShow technology.Then the weighted-averaged frame of real-time frames can reduce the bad effect of the bad frames.It removes the noise by Gaussian pyramid sampling.Dynamic threshold value，getting from each RGB 3-channels by recursive iteration，is helpful to detecting the screen rectangle，and then auto-correcting the cell phone position，extracting ROI，completing the image preprocessing.Finally，it detects the contours of defect using the Canny algorithm，and combined with Douglas-
Peucker algorithm and Freeman chain code，it extracts the information of defect，and then tests the image defects of phone screen：the number of bad pixels，geometric distortion，chromatic aberration.This algorithm is real-time and efficient.It can be widely used in LCD products for image defect detection relying on the relevant national standards，and it is worth promoting.

Key words: defect extraction, Region of Interest（ROI） identification, real time detection, phone LCD screen