Investigation of light scattering for scratch detection

In this study, a simple experimental setup was established and experiments were carried out to investigate light scattering for scratch detection. Many factors would affect the scratch line detection based on light scattering, such as the size and orientation of the scratches, state of the polarizer, light incident angle, detecting angle of light scattering, and light spot size. It is found that the scattered light intensity depends on the orientation of the scratch lines. The intensity power of scattered light would increase with increasing lines per millimeter on the test plate surface. The detection at the zerodegree detecting angle is more sensitive than that at other detecting angles. It is also found that the scratch detection based on light scattering may be performed using S polarization.