Two-camera triangulation scanner with detachable coupling mechanism

• US 9,964,402 B2
• Filed: 04/21/2016
• Issued: 05/08/2018
• Est. Priority Date: 04/24/2015
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Tohme, Yazid, Heidemann, Rolf, Grau, Markus, Bridges, Robert E.
• Primary Examiner(s): BARNES, TED W
• Application Number:
  US15/134,838
• Publication Number:
  US 20160313114A1
• Time in Patent Office: 747 Days
• Field of Search: None
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence
• CPC Class Codes: G01B 11/25 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 Class Codes: G01B 11/2518 Projection by scanning of the object
• CPC Class Codes: G01B 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/257 Colour aspects

Abstract

A three-dimensional (3D) scanner having two cameras and a projector is detachably coupled to a device selected from the group consisting of: an articulated arm coordinate measuring machine, a camera assembly, a six degree-of-freedom (six-DOF) tracker target assembly, and a six-DOF light point target assembly.

Claims

1. A device for measuring three-dimensional (3D) coordinates of an object surface comprising:

a processor; and

a triangulation scanner including a projector, a first scanner camera, a second scanner camera, and a scanner connector, the scanner connector configured to detachably couple to an arm connector of an articulated arm coordinate measurement machine (AACMM), the projector configured to project a scanner pattern onto the object surface, the projector having a projector perspective center and a projector optical axis, the first scanner camera configured to form a first image of the scanner pattern and to send a first electrical scanner signal to the processor in response, the first scanner camera having a first-camera perspective center and a first-camera optical axis, the second scanner camera configured to form a second image of the scanner pattern and to send a second electrical scanner signal to the processor in response, the second camera having a second-camera perspective center and a second-camera optical axis, the projector perspective center, the first-camera perspective center, and the second-camera perspective center being arranged in a triangular pattern on a first plane, the first plane not including the projector optical axis, the first-camera optical axis, or the second-camera optical axis;

wherein the processor is configured to determine the 3D coordinates of the object surface when the triangulation scanner is coupled to the AACMM and when uncoupled from the AACMM, the 3D coordinates measured by the triangulation scanner being in a scanner frame of reference, the determining of the 3D coordinates being based at least in part on the scanner pattern, the first electrical scanner signal, and the second electrical scanner signal; and

a six degree-of-freedom (six-DOF) tracker target assembly including a retroreflector and an assembly connector, the retroreflector configured to return light received from a laser tracker, the six-DOF tracker target assembly further configured to cooperate with the laser tracker and the processor to determine six degrees of freedom of the triangulation scanner while the triangulation scanner is moving, the assembly connector configured to detachably couple to the scanner connector, the processor being configured to determine the 3D coordinates of the object surface further based on the determined six degrees of freedom of the triangulation scanner in a frame of reference of the laser scanner.

2. The device of claim 1 wherein the processor is further configured to determine the 3D coordinates of the object surface based on a first baseline distance from the first-camera perspective center to the projector perspective center, a second baseline distance from the second-camera perspective center to the projector perspective center, and a third baseline distance from the first-camera perspective center to the second-camera perspective center.

3. The device of claim 1 wherein the triangulation scanner includes a first set of epipolar constraints between the first camera and the projector, a second set of epipolar constraints between the second camera and the projector, and a third set of epipolar constraints between the first camera and the second camera, the processor being configured to determine the 3D coordinates of the object surface further based on the first set of epipolar constraints, the second set of epipolar constraints, and the third set of epipolar constraints.

4. The device of claim 1 wherein the projector is configured to produce the scanner pattern by sending light through a diffractive optical element.

5. The device of claim 1 wherein the projector comprises a scanner light source and a scanner digital micromirror device (DMD), the scanner light source and the scanner DMD being configured to produce the scanner pattern.

6. The device of claim 1 wherein the triangulation scanner further comprises a battery.

7. The device of claim 1 further comprising a display.

8. The device of claim 7 wherein the display includes a touch screen.

9. The device of claim 1 further comprises a color camera configured to produce a color image, the color camera configured to produce an electrical signal of the color image, the processor being configured to add color to the 3D coordinates of the object surface based at least in part on the electrical signal of the color image.

10. The device of claim 1 wherein the device further comprises a battery.

11. The device of claim 10 further comprising a display operably coupled to the processor.

12. The device of claim 11 wherein the display includes a touch screen.