Vision based projector geometric correction involves complicated geometrical transforms and calibration procedures,and is susceptible to poor illumination and background or o ther external environmental factors.In order to improve the efficiency and robustness of the geometric corr ection procedure,a new method based on structured light and homography is proposed.The proposed method levera ges the light sensors distributed at those points of interest (POI) to capture the structured light pa tterns projected by projector and converts them to the coordinates relative to the projector′s image plane,and t hen calculates the homography matrix between the target projection surface plane and the projector image plane.After that,the homography matrix is exploited to perform the perspective transform on the images to be projected,to pre-warp the image and maximize the display area.Experiments are carried out under various environmental condit ions,indicating that the coordinates of the POI could be precisely attained,thus projecting the images correctly to the target projection surface,and achieving high precision.The proposed approach is simple,fast and robust,not vulnerable to the external environment factors,which means that it could be complementary to those vision- based methods.