Patent ID: 7226797
Filing Date: 2007-06-05
Classification: G06T

Abstract:
1. An apparatus for facilitating positioning of a plurality of substantially parallel layers having an initial alignment state, comprising: an imaging system having an optical axis extending through said layers, a first of said layers at least partially obscuring a second of said layers with respect to said imaging system when in said initial alignment state; a positioning system displacing said first layer from a first position corresponding to said initial alignment state to a second position out of a field of view of the imaging system, said first layer being maintained out of said field of view as a first image is being acquired by said imaging system including at least a portion of said second material layer having a second-layer alignment marker thereon, said positioning system subsequently moving said first layer back to said first position to restore the initial alignment state; a memory storing said first image; and a processor retrieving said first image from said memory and receiving a second image acquired by said imaging system, the second image including at least a portion of said first layer having a first-layer alignment marker thereon, said processor processing said second image and said stored first image to determine said initial alignment state according to positions of said first-layer and second-layer alignment markers.