Measurement of surface orientations of transparent objects using polarization in highlight

There are no simple noncontact methods available to measure a transparent object's shape. In this context, the authors suggest highlight polarization analysis as a method for noncontact measurement of the transparent object's shape. Highlight is the light observed as specular reflection component, which is the part of reflected light that remains nearly unchanged (that is, very much similar to source light). Highlight, however, is only observed near the direction of regular reflection, which normally covers just a small part of the object's surface. As a solution, use of spherical area light source is offered; with such a light source, normal direction can be found across the whole object's surface without any contact.