In the production and transportation p rocesses of the light guide plate,various defects,in particular,slight line scra tches,are inevitably caused.These defect areas cannot be accurately extracted by using the existing algorithm.In this paper,based on the analysis of the cause and imag ing characteristics of the slight scratch on the light guide plate,a method for detecting the slight line scratch on the light guide plate based on multi-directional Gabor filtering and sub-pixel analysis is proposed.Firstly, in order to highlight the defect area,a multi-directional Gabor filter is designed.Furthermore,the sub-pixel image ana lysis method is used to accurately segment the suspected defect area from the background image.Finally,the area sha pe feature is analyzed to accurately extract the slight line scratch defects.The experimental results sho w that the algorithm has high efficiency and accuracy,strong stability and robustness,and can effectively dete ct slight line scratches.