US 12,072,179 B2
Method and apparatus for determining a contour of a frame groove
Jörg Carls, Altdorf (DE); and Oliver Schwarz, Ellwangen (DE)
Assigned to Carl Zeiss Vision International GmbH, Aalen (DE)
Filed by Carl Zeiss Vision International GmbH, Aalen (DE)
Filed on Apr. 13, 2022, as Appl. No. 17/719,489.
Application 17/719,489 is a continuation of application No. PCT/EP2020/079067, filed on Oct. 15, 2020.
Claims priority of application No. 19203172 (EP), filed on Oct. 15, 2019.
Prior Publication US 2022/0316870 A1, Oct. 6, 2022
Int. Cl. G01B 11/25 (2006.01); B24B 9/14 (2006.01); G02C 13/00 (2006.01); G06T 7/00 (2017.01); G06T 7/11 (2017.01); G06V 10/44 (2022.01)
CPC G01B 11/2545 (2013.01) [B24B 9/144 (2013.01); G02C 13/003 (2013.01); G06T 7/11 (2017.01); G06T 7/97 (2017.01); G06V 10/44 (2022.01)] 24 Claims
OG exemplary drawing
 
1. A method for determining a contour of a frame groove in a rim of a spectacle frame, the method comprising:
illuminating the rim of the spectacle frame;
capturing a plurality of images of the illuminated rim from different predetermined perspectives;
evaluating the plurality of captured images and determining spatial curves describing the frame groove based on the plurality of evaluated images; and
determining the contour of the frame groove based on the spatial curves,
wherein the rim is illuminated simultaneously along an entire circumference of the rim with directed illumination;
wherein the evaluation of the plurality of captured images includes recognizing portions of the spectacle frame contained in the captured images and an assignment of each portion contained in the captured images to a respective surface element of the frame groove based on a brightness and/or a shading of the respective portion, wherein recognizing the portions includes:
a rim segmentation;
a detection of edges, which bound the portions and surface elements within the segmented rim, with preference given to edges extending virtually parallel to the rim; and
a completion of the edges with a first optimization method in which a cost function is minimized, and
wherein determining the spatial curves includes:
determining spatial points, which describe the frame groove and through which the spatial curves extend, based on the surface elements, the spatial points being located on edges which bound the portions and the surface elements; and
determining a relative position of the spatial points in space by triangulation, the triangulation being carried out collectively for all spatial points of a spatial curve of the plurality of spatial curves, wherein a criterion of a smallest distance as an optimization goal in form of a term of the cost function is included in an iterative optimization with a second optimization method.