US 12,254,645 B2
Shape invariant method for accurate fiducial finding
Umesh Adiga, Portland, OR (US); and Mark Biedrzycki, Beaverton, OR (US)
Assigned to FEI Company, Hillsboro, OR (US)
Filed by FEI Company, Hillsboro, OR (US)
Filed on Dec. 3, 2021, as Appl. No. 17/457,622.
Prior Publication US 2023/0177715 A1, Jun. 8, 2023
Int. Cl. G06T 7/70 (2017.01); G06T 3/40 (2024.01); G06T 7/00 (2017.01); G06T 7/13 (2017.01); G06T 7/30 (2017.01); G06V 10/25 (2022.01); H01J 37/22 (2006.01); H01J 37/31 (2006.01)
CPC G06T 7/70 (2017.01) [G06T 3/40 (2013.01); G06T 7/0004 (2013.01); G06T 7/13 (2017.01); G06T 7/30 (2017.01); G06V 10/25 (2022.01); H01J 37/222 (2013.01); H01J 37/31 (2013.01); G06T 2207/10061 (2013.01); G06T 2207/30164 (2013.01); G06T 2207/30204 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method, comprising:
obtaining an image of a workpiece at a first resolution and identifying a workpiece fiducial in the image;
selecting a portion of the image of the workpiece at the first resolution that includes a workpiece fiducial image as a region of interest (ROI) image;
processing the ROI image so that the ROI image has a second resolution that is greater than the first resolution;
masking the ROI image with a template based on the workpiece fiducial, the template including at least one aperture; and
processing a portion of the masked ROI image within an area defined by the at least one aperture to establish at least one workpiece coordinate associated with the workpiece fiducial, wherein the at least one workpiece coordinate is established by summing image intensity values of the portion of the masked ROI image within the area defined by the at least one aperture along at least one template axis and processing the sums of the image intensity values to obtain the workpiece coordinate associated with a direction perpendicular to the at least one template axis.