US 12,205,264 B2
System and method for extracting and measuring shapes of objects having curved surfaces with a vision system
Hongwei Zhu, Natick, MA (US); and Daniel Moreno, Northbridge, MA (US)
Assigned to Cognex Corporation, Natick, MA (US)
Filed by Cognex Corporation, Natick, MA (US)
Filed on Oct. 15, 2021, as Appl. No. 17/503,220.
Claims priority of provisional application 63/092,438, filed on Oct. 15, 2020.
Prior Publication US 2022/0148153 A1, May 12, 2022
Int. Cl. G06T 7/00 (2017.01); G06T 3/067 (2024.01); G06V 10/46 (2022.01)
CPC G06T 7/0004 (2013.01) [G06T 3/067 (2024.01); G06V 10/46 (2022.01); G06T 2207/10028 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A system for detecting features relative to curved surfaces from a 3D point cloud imaged by a 3D vision system camera assembly comprising:
an extraction process that identifies a curved surface in 3D space and provides a reference model relative to the curved surface;
a flattening process that flattens the curved surface, including a feature thereof, into a flattened, planar shape in accordance with the reference model, wherein a portion of the curved surface is represented as a height image having values representative of distances of the points on the curved surface from a central element of the reference model, wherein the curved surface comprises one or more regions that are monotonic with respect to an outward radial direction from the central element of the reference model;
a feature location process that locates the feature on the planar shape represented in the height image by processing the planar shape produced from the flattening process with respect to the height image;
a mapping process that converts the feature located by processing the planar shape into the 3D space; and
a feature output process that reports, relative to the curved surface, the feature converted to the 3D space.