a scatterometric measurement system for measuring an object under test is disclosed . the scatterometric measurement system generates a beam of light from a light source sending the generated beam to illumination optics for transforming the beam and sending this transformed beam to a beam splitter . the beam splitter redirects the transformed beam to a first detector while deflecting the transformed light beam to the object under test which produces scattered light . collection optics then receives this scattered light from the object under test and processes and sends the scattered light to a second detector through the beam splitter . the second detector generates a signal based on this processed scattered light and sends this result to a computation unit that calculates using the second detectors signal a desired output according to an algorithm for a given measurement for the object under test .