1. A surface inspection system for inspecting a surface of a workpiece, the surface inspection system comprising: an illumination subsystem that projects a beam to the surface of the workpiece, the illumination subsystem comprising a plurality of lenses, each of the lenses having a known surface roughness, the plurality of lenses having a total surface roughness that does not exceed a selected amount; a collection subsystem for collecting scattered portions of the beam scattered from the surface of the workpiece, and a processing subsystem operatively coupled to the collection subsystem for processing signals received from the collection subsystem to provide information about the surface of the workpiece.