A novel polarimetric measurement based on hemispherical light-scattering for the assessment of
superficial screw is presented. The optical system is capable of capturing polarized light images. The
effect of the thread surface backscattering is estimated with the use of in-plane and out-of-plane
illumination. The angular distributions of polarized light scattered by the ISO metric screws are
measured for light incident from a green laser. A partial Stokes vector imaging detector is mounted
on a motorized rotating arm at an oblique angle to the sample normal and consists of a 10-bit scientific
camera, an object lens, and a polarizer. The partial Stokes vector images of light scattered towards the
camera are generated for each direction and a useful decomposition of the partial Stokes vector is
presented. The thread surface effects can be minimized using out-of-plane polarized illumination in
conjunction with polarized images. The experimental result may provide a new polarized imaging
technique for using visible light to inspect the key features of a screw in automated optical inspection
system.