Abstract: An apparatus for determining the surface characteristics of a flat transparent article which includes a light beam source, a scanner to deflect the light beam to produce a line scan, a lens to collimate the light beam of the line scan, a locator for the flat transparent article to enable the article to be exposed to the collimated light, a grating through which the portion of collimated light reflected by the surface of the located article passes, another lens to focus the collimated light passing through the grating onto a sample detector which generates an intensity indicative signal, and a base reference signal generator. The signals are processed by a microprocessor to indicate the surface characteristics.