Patent ID: 7345751
Filing Date: 2008-03-18
Classification: G01B,G01N

Abstract:
1. A system for measuring a height of an object comprising: a first electromagnetic signal source for transmitting a first signal toward a first position on the object at a first angle; a second electromagnetic signal source for transmitting a second signal toward the first position on the object at a second angle; a first retro-reflection unit for reflecting a first single reflected signal toward the first position on the object, wherein the first single reflected signal is a portion of the first signal that reflects off of the object; a second retro-reflection unit for reflecting a second single reflected signal toward the first position on the object, wherein the second single reflected signal is a portion of the second signal that reflects off of the object; a polarizing beam combiner for combining the first and second double reflected signals and directing the combined beams to a position sensitive detector to receive both the first and second double reflected signals for generating an output in response to the first and second double reflected signals; a processor, that receives the output and generates a material independent signal representing at least one of a height of the first position and a slope of the first position, the material independent signal being independent of the type of material comprising the object.