Articulated arm coordinate measurement machine having a 2D camera and method of obtaining 3D representations

• US 10,060,722 B2
• Filed: 10/26/2016
• Issued: 08/28/2018
• Est. Priority Date: 01/20/2010
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Bridges, Robert E., Atwell, Paul C.
• Primary Examiner(s): FULTON, CHRISTOPHER W
• Application Number:
  US15/334,961
• Publication Number:
  US 20170102224A1
• Time in Patent Office: 671 Days
• Field of Search: 33503
• CPC Class Codes: G01B 11/005 coordinate measuring machines
• CPC Class Codes: G01B 11/2509 Color coding
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G01B 21/047 Accessories, e.g. for positioning, for tool-setting, for measuring probes
• CPC Class Codes: G01B 2210/58 Wireless transmission of information between a sensor or probe and a control or evaluation unit
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G01B 5/012 Contact-making feeler heads therefor
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37193 Multicoordinate measuring system, machine, cmm
• CPC Class Codes: G05B 2219/40233 Portable robot
• CPC Class Codes: G05B 2219/45061 Measuring robot
• CPC Class Codes: G06T 2200/04 involving 3D image data
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 7/13 Edge detection
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06T 7/73 using feature-based methods
• 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 portable articulated arm coordinate measuring machine includes a noncontact 3D measuring device that has a projector configured to emit a first pattern of light onto an object, a scanner camera arranged to receive the first pattern of light reflected from the surface of the object, an edge-detecting camera arranged to receive light reflected from an edge feature of the object, and a processor configured to determine first 3D coordinates of an edge point of the edge feature based on electrical signals received from the scanner camera and the edge-detecting camera.

Claims

1. A portable articulated arm coordinate measuring machine (AACMM) for measuring three-dimensional (3D) coordinates of an object in space, comprising:

a processor;

a noncontact 3D measuring device operably coupled to the processor, the noncontact 3D measuring device having a projector and a scanner camera, the projector configured to emit a first pattern of light onto the object, the scanner camera arranged to receive the first pattern of light reflected from the object and to send a first electrical signal to the processor in response;

an edge-detecting camera operably coupled to the processor, the edge-detecting camera being one of the scanner camera or a second camera different than the scanner camera, the edge-detecting camera positioned to receive during operation a second light reflected from an edge feature of the object and to send a second electrical signal to the processor in response; and

the processor being responsive to non-transitory computer readable instructions, the computer readable instructions comprising;

determining a first 3D coordinates of first points on a surface of the object based at least in part on the first pattern of light from the projector and the first electrical signal;

determining a first ray from the edge-detecting camera to the object, the first ray based at least in part on the second electrical signal; and

determining a second 3D coordinates of an edge point of the edge feature, the second 3D coordinates based at least in part on an intersection of the first ray with the first 3D coordinates of the surface.

2. The AACMM of claim 1 wherein the first pattern of light is a line of light.

3. The AACMM of claim 1 wherein the first pattern of light is a coded structured light pattern.

4. The AACMM of claim 1 wherein the second light reflected from the object is in response to ambient light that falls on the object.

5. The AACMM of claim 1 wherein the second light reflected from the object is in response to light provided by the a light source, the light provided by the light source being substantially uniform.

6. The AACMM of claim 1 wherein the projector has a projector perspective center and the scanner camera has a scanner camera perspective center, rays of light from the projector passing through the projector perspective center, rays from a second pattern of light reflected off the object passing through the scanner camera perspective center, a baseline distance being a distance from the projector perspective center to the scanner camera perspective center, wherein the first 3D coordinates are further based on the baseline distance.

7. A method for measuring an edge point with a portable articulated arm coordinate measuring machine (AACMM), the method comprising:

providing the AACMM, the AACMM including a processor, a noncontact 3D measuring device operably coupled to the processor, the noncontact 3D measuring device having a projector and a scanner camera, the AACMM further including and an edge-detecting camera operably coupled to the processor, the edge-detecting camera being one of the scanner camera or a second camera different than the scanner camera;

emitting from the projector a first pattern of light onto object;

receiving with the scanner camera the first pattern of light reflected from the object and sending a first electrical signal to the processor in response;

receiving with the edge-detecting camera a second light reflected from an edge feature of the object and sending a second electrical signal to the processor in response, the edge feature having an edge point, the edge point being a point on the edge feature;

determining with the processor first 3D coordinates of first points on a surface of the object, the first 3D coordinates based at least in part on the first pattern of light from the projector and the first electrical signal;

further determining with the processor a first ray from the edge-detecting camera to the object, the first ray based at least in part on the second electrical signal;

further determining with the processor second 3D coordinates of the edge point based at least in part on an intersection of the first ray with the first 3D coordinates of the surface; and

storing the second 3D coordinates of the edge point.