A polarization image method for lens decentration measurement

The tilt and decenter error of lens is usually induced by lens manufacturing process, injection molding or glass molding. The paper presents a polarization image method for measuring the tilt and decenter of lens. At first, to put the lens under test between two linear polarizers, and then a focused or divergent polarized beam will pass through a half-wave plate, once the lens has a shape error, the polarization image pattern and color will be change. Finally, the lens shape error can be computed by image processing.