Patent ID: 6509559
Filing Date: 2003-01-21
Classification: G01B

Abstract:
A machine-vision system for inspecting an object, comprising:an inspection station that support the object; a scanning mechanism positioned to scan the inspection station; an imager head coupled to the scanning mechanism, wherein the scanning mechanism moves the imager head in a linear motion to scan the object at the inspection station, the imager head including: a grating having a first region including a cyclic pattern of substantially clear stripes and substantially opaque stripes, wherein each cycle includes a first substantially clear stripe of a first width, a first substantially opaque stripe of second width, and between the first substantially clear stripe and the first substantially opaque stripe are a second substantially opaque stripe of a third width narrower than the first width and narrower than the second width, and a second substantially clear stripe of a fourth width narrower than the first width and narrower than the second width.