Method and apparatus for determining a contour of a frame groove

Patent metadata

Field	Value
Publication number	US-12072179-B2
Application number	US-202217719489-A
Country	US
Kind code	B2
Filing date	Apr 13, 2022
Priority date	Oct 15, 2019
Publication date	Aug 27, 2024
Grant date	Aug 27, 2024

Abstract

A method for determining a contour of a frame groove in a rim of a spectacle frame includes illuminating the rim, capturing a plurality of images of the illuminated rim from different predetermined perspectives, evaluating the captured images, and determining a spatial curve of the frame groove based on the evaluated images. The rim is illuminated along the entire circumference of the rim by directed illumination. Moreover, the evaluation of the captured images includes assigning each portion contained in the captured images to a respective surface element of the frame groove on the basis of at least one of the following properties: shadowing of the respective portion, brightness of the respective portion and phase angle of the illumination of the respective portion. Moreover, an apparatus, a computer program, a method for grinding a spectacle lens, and a computer-implemented method for determining a geometry of a spectacle lens are disclosed.

First claim

What is claimed is:

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.

2. The method as claimed in claim 1 , wherein the completion of the edges comprises collectively triangulating lines of sight for all spatial points of a spatial curve of the contour.

3. The method as claimed in claim 1 , wherein the rim is illuminated such that the illumination is incident on the rim from the outside.

4. The method as claimed in claim 1 , wherein the directed illumination is incident on the spectacle frame from only one direction relative to an image capturing device.

5. The method as claimed in claim 1 , wherein directed illumination is incident as incident light from one direction on the spectacle frame, in which direction an image evaluation unit is arranged relative to the spectacle frame.

6. The method as claimed in claim 1 , wherein the directed illumination is provided by an illumination device having one or more point light sources, the illumination device illuminating the rim from a predetermined direction and creating shadowing which is as precise as possible on the frame groove.

7. The method as claimed in claim 1 , wherein the directed illumination is selected from collimated illumination, transmitted light illumination, incident light illumination, ultraviolet illumination, or polarized illumination.

8. The method as claimed in claim 1 , wherein the plurality of images are captured such that the image capturing device captures two rims of a spectacle frame in the image region.

9. A method for grinding a spectacle lens into a spectacle frame, wherein a contour of a frame groove in a rim of the spectacle frame is determined with the method as claimed in claim 1 .

10. A computer-implemented method for determining a geometry of a spectacle lens, comprising determining a contour of a frame groove in a rim of a spectacle frame with the method as claimed in claim 1 .

11. An apparatus for contactless determination of a contour of a frame groove in a rim of a spectacle frame, the apparatus comprising:
an illumination device configured to illuminate the rim of the spectacle frame;
an image capturing device configured to capture a plurality of images of the illuminated rim from different predetermined perspectives;
an image evaluation unit configured to evaluate the plurality of captured images, to determine the spatial curves describing the frame groove on the basis of the evaluated images, and to determine the contour of the frame groove based on the spatial curves,
wherein the illumination device is configured to illuminate the rim 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 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
the image evaluation unit is further configured such that the determination of the spatial curves includes:
to determine 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
to determine 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 and a criterion of a smallest distance as an optimization goal in the form of a term of a cost function is included in an iterative optimization with a second optimization method.

12. The apparatus as claimed in claim 11 , wherein the image evaluation unit is further configured such that the completion of the edges comprises collectively triangulating lines of sight for all spatial points of a spatial curve of the contour.

13. The apparatus as claimed in claim 11 , wherein the apparatus is configured such that the illumination is incident on the rim from the outside when the rim is illuminated.

14. The apparatus as claimed in claim 11 , wherein the apparatus is configured such that the directed illumination is incident on the spectacle frame from only one direction relative to an image capturing device when the rim is illuminated.

15. The apparatus as claimed in claim 11 , wherein the apparatus is configured such that the directed illumination is incident as incident light on the spectacle frame when illuminating the rim, the incidence being from a direction in which an image evaluation unit is arranged relative to the spectacle frame.

16. The apparatus as claimed in claim 11 , wherein the illumination device comprises one or more point light sources for providing the directed illumination and wherein the illumination device is configured to illuminate the rim from a predetermined direction and to create shadowing which is as precise as possible on the frame groove.

17. The apparatus as claimed in claim 16 , wherein the one or more point light sources are each in the form of one of the following elements: an incandescent lamp, an LED, a laser diode, and a laser.

18. The apparatus as claimed in claim 16 , further comprising one or more light sources which facilitate transmitted light illumination for t

Assignees

• Zeiss Carl Vision Int Gmbh

Inventors

• Carls Jörg
• Schwarz Oliver

Classifications

• G02C13/003

  Measuring during assembly or fitting of spectacles · CPC title

• B24B9/144

  the spectacles being used as a template · CPC title

• G06V10/44

  Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components · CPC title

• G06T7/97

  Determining parameters from multiple pictures (depth or shape recovery from multiple images G06T7/55; stereo camera calibration G06T7/85) · CPC title

• G06T7/11

  Region-based segmentation · CPC title