Registration of three-dimensional coordinates measured on interior and exterior portions of an object

Patent metadata

Field	Value
Publication number	US-10126116-B2
Application number	US-201815880878-A
Country	US
Kind code	B2
Filing date	Jan 26, 2018
Priority date	Dec 30, 2015
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A dimensional measuring device includes an overview camera and a triangulation scanner. A six-DOF tracking device tracks the dimensional measuring device as the triangulation scanner measures three-dimensional (3D) coordinates on an exterior of the object. Cardinal points identified by the overview camera are used to register in a common frame of reference 3D coordinates measured by the triangulation scanner on the interior and exterior of the object.

First claim

What is claimed is:

1. A method for measuring three-dimensional (3D) coordinates comprising:
providing a dimensional measuring device having a triangulation scanner coupled to the body, the triangulation scanner having an operably coupled camera, the dimensional measuring device having a device frame of reference;
in a first instance:
determining with a six degree-of-freedom (six-DOF) tracking system a first position and a first orientation of the dimensional measuring device, the six-DOF tracking system being separate from the dimensional measuring device, the six-DOF tracking system having a system frame of reference; and
determining, with the triangulation scanner, in the device frame of reference first 3D coordinates of a first 3D-coordinates point on the object;

in a second instance:
determining with the six-DOF tracking system a second position and a second orientation of the dimensional measuring device;
capturing with the camera a second overview image of a second portion of the object and in response determining second 2D coordinates of a first cardinal point in the second overview image; and
determining, with the triangulation scanner, in the device frame of reference second 3D coordinates of a second 3D-coordinates point on the object;

in a third instance:
positioning the dimensional measuring device in a location so as to be not measurable by the six-DOF tracking system;
capturing with the camera a third overview image of a third portion of the object and in response determining third 2D coordinates of the first cardinal point in the third overview image and third 2D coordinates of a second cardinal point in the third overview image; and
determining, with the triangulation scanner, in the device frame of reference third 3D coordinates of a third 3D-coordinates point on the object;

determining in the system frame of reference first system 3D coordinates of the first 3D-coordinates point, second system 3D coordinates of the second 3D-coordinates point and third system 3D coordinates of the third 3D-coordinates point, the determining based at least in part on the second 2D coordinates of the first cardinal point, the third 2D coordinates of the first cardinal point, and the third 2D coordinates of the second cardinal point; and
storing the first system 3D coordinates of the first 3D-coordinates point, the second system 3D coordinates of the second 3D-coordinates point, and the third systems 3D coordinates of the third 3D-coordinates point.

2. The method claim 1 , wherein the camera is a triangulation camera integral with the triangulation scanner.

3. The method of claim 2 , wherein the measurement device includes an overview camera separate from the triangulation camera, wherein the second overview image and the third overview image are acquired by the overview camera.

4. The method claim 1 , wherein the camera is separate from the triangulation scanner.

5. The method of claim 1 , wherein the six-DOF tracking system includes a six-DOF laser tracker.

6. The method of claim 5 , wherein the triangulation scanner further includes a six-DOF target configured for measurement by the six-DOF laser tracker.

7. The method of claim 1 , wherein the six-DOF tracking system includes a camera bar having a plurality of camera-bar cameras.

8. The method of claim 7 , wherein in providing a dimensional measuring device that includes a body and a triangulation scanner, the triangulation scanner further includes a collection of marks visible to the plurality of camera-bar cameras.

9. The method of claim 8 , wherein in providing a dimensional measuring device that includes a body and a triangulation scanner, a first mark in the collection of marks is selected from the group consisting of: a light source and a reflective spot.

10. The method of claim 8 , wherein the camera bar is coupled to a plurality of retroreflector targets fixed in a camera-bar frame of reference of the camera bar, the laser tracker configured to measure 3D coordinates of the plurality of retroreflector targets.

11. The method of claim 1 , wherein the six-DOF tracking system includes a plurality of rotating cameras, each rotating camera in the plurality of rotating cameras having an angular transducer configured to measure an angle of rotation.

12. The method of claim 11 , wherein the triangulation scanner further includes a collection of marks visible to the plurality of rotating cameras.

13. The method of claim 1 , wherein, in the second instance, the first cardinal point is selected from the group consisting of: a natural feature, an artificial mark, and a projected spot of light.

14. The method of claim 13 , wherein, in the third instance, the second cardinal point is selected from the group consisting of: a natural feature, an artificial mark, and a projected spot of light.

15. The method of claim 14 , wherein, in the second instance and the third instance, the first cardinal point and the second cardinal point are interest points.

16. The method of claim 15 , wherein, in the second instance and the third instance, the interest points are determined based on a method selected from the group consisting of: edge detection, blob detection, ridge detection, corner detection, and scale invariant feature transform (SIFT) detection.

17. The method of claim 1 , wherein the triangulation scanner further includes a tactile probe having a probe tip.

18. The method of claim 17 , further comprising determining 3D coordinates of the probe tip touched to a surface of the object, the determining further based on a position of the probe tip in the device frame of reference.

19. A system for measuring three-dimensional (3D) coordinates, the system comprising:
a triangulation scanner having a camera, the triangulation scanner operable to determine three-dimensional coordinates of points on a surface of the object in a device frame of reference;
a six degree-of-freedom (six-DOF) tracking system operable to determining a position and an orientation of the triangulation scanner in a system frame of reference; and
one or more processors responsive to nontransitory executable instructions for performing a method comprising:
in a first instance:
determining a first position and a first orientation of the triangulation scanner with the six-DOF tracking system; and
determining, with the triangulation scanner, in the device frame of reference first 3D coordinates of a first 3D-coordinates point on the object;

in a second instance:
determining with the six-DOF tracking system a second position and a second orientation of the dimensional measuring device;
capturing with the camera a second overview image of a second portion of the object and in response determining second 2D coordinates of a first cardinal point in the second overview image; and
determining, with the triangulation scanner, in the device frame of reference second 3D coordinates of a second 3D-coordinates point on the object;

in a third instance:
causing the triangulation scanner to be positioned in a location so as to be not measurable by the six-DOF tracking system;
capturing with the camera a third overview image of a third portion of the object and in response determining third 2D coordinates of the first cardinal point in the third overview image and third 2D coordinates of a second cardinal point in the third overview image; and
determining, with the triangulation scanner, in the device frame of reference third 3D coordinates of a third 3D-coordinates point on the object;

determining in the system

Assignees

• Faro Tech Inc

Inventors

• Becker Bernd-Dietmar
• Bridges Robert E
• Stiebeiner Ariane
• Heidemann Rolf
• Wolke Matthias

Classifications

• G01S17/86

  Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders · CPC title

• G01S17/66

  Tracking systems using electromagnetic waves other than radio waves · CPC title

• G01B11/25

  by projecting a pattern, e.g. {one or more lines,} moiré fringes on the object (G01B11/255 takes precedence {; image analysis for depth or shape recovery G06T7/50}) · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01S17/48

  Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves · CPC title