Patent ID: 7697724

Claim:
A system comprising: a data acquisition system configured to capture a first reference frame that includes a first feature in a first imaging area on a substrate prior to a relative position between the data acquisition system and the substrate being adjusted by approximately a predetermined distance during a first time period, capture a first comparison frame that includes the first feature in a second imaging area on the substrate and a second reference frame that includes a second feature in the first imaging area on the substrate subsequent to the first time period, capture a second comparison frame that includes the second feature in the second imaging area on the substrate subsequent to the relative position being adjusted by approximately the predetermined distance during a second time period that is subsequent to the first time period, the second imaging area being separated from the first imaging area by the predetermined distance; and a processing system configured to determine a displacement sum using a first displacement between the first feature in the first reference frame and the first feature in the first comparison frame and a second displacement between the second feature in the second reference frame and the second feature in the second comparison frame.