a method is used for detecting a tilt of an optical pickup head . the method includes the steps of : capturing a plurality of images ; converting the images to bitmap images ; superposing the bitmap images together to form an superimposed bitmap image ; setting a two - dimensional coordinating system of the superimposed bitmap image ; determining coordinates of a first static spot , a second static spot , and dynamic spot ; calculating a first distance between the first static spot and the dynamic spot , and a second distance between the second static spot and the dynamic spot based on the coordinates to determine a maximum distance ; and comparing the maximum distance with a first standard distance to attain a conclusion whether the tilt is in an acceptable range .