Abstract: A method and system for detecting the location of a surface defect on a transparent film with respect to whether the surface defect is at a front or back surface of the film. By illuminating the surface defect with a light source from an oblique angle and capturing an image of the surface defect using a camera which is positioned along an axis where the light illuminates after unobstructedly reflected from the test surface of the film, and using the reflected light, an image of the surface defect is obtained. A computer executes an evaluation logic to determine whether the image of the defect contains any dark area. If there is a dark area present, the defect is judged to be on the front surface of the film. If there is no dark area present, the defect is judged to be on the back surface of the film.

Abstract: A detection method and system for inspecting a defect on a semi-reflective film by way of different light sources illuminated on the semi-reflective film along the same axis. More specifically, a P-polarized light source and an S-polarized light source are used to illuminate the defect on the semi-reflective film, with an illumination direction that is between 5-45 degrees relative to the semi-reflective film. A camera module captures an image to be inspected through the phenomenon that the P-polarized light will partially pass through the semi-reflective film, and the S-polarized light will be almost completely reflected by the semi-reflective film. During the detection, the defect is determined to be located on the front surface of the semi-reflective film when the S-polarized light is present in the image, and the defect is determined to be located on the back surface of the semi-reflective film when the P-polarized light is present in the image and no S-polarized light has entered the camera module.