Three-dimensional coordinate scanner and method of operation

• US 10,267,619 B2
• Filed: 08/25/2016
• Issued: 04/23/2019
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Tohme, Yazid, Bridges, Robert E.
• Primary Examiner(s): Hallenbeck-Huber, Jeremiah C
• Assistant Examiner(s): Shahnami, Amir
• Application Number:
  US15/246,619
• Publication Number:
  US 20160364874A1
• Time in Patent Office: 971 Days
• Field of Search: 348 47
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G01B 11/2531 using several gratings, projected with variable angle of incidence on the object, and one detection device
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence
• CPC Class Codes: G01B 5/004 for measuring coordinates of points
• CPC Class Codes: G01C 3/10 using a parallactic triangle with variable angles and a base of fixed length in the observation station, e.g. in the instrument
• CPC Class Codes: G01S 17/003 Bistatic lidar systems; Multistatic lidar systems
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• 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 7/593 from stereo images
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: H04N 13/204 using stereoscopic image cameras stereoscopic photography G03B35/00
• 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 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 13/275 from 3D object models, e.g. computer-generated stereoscopic image signals

Abstract

A noncontact optical three-dimensional measuring device that includes a first projector, a first camera, and a second camera; a processor electrically coupled to the first projector, the first camera and the second camera; and computer readable media which, when executed by the processor, causes the first digital signal to be collected at a first time and the second digital signal to be collected at a second time different than the first time and determines three-dimensional coordinates of a first point on the surface based at least in part on the first signal and the first distance and determines three-dimensional coordinates of a second point on the surface based at least in part on the second signal.

Claims

1. A method of determining three-dimensional (3D) coordinates of points on a surface of an object, the method comprising:

providing a 3D coordinate measurement device that includes a projector and a camera, the projector having a light source operable to emit projected light, the projected light having at least one pattern, the camera having a lens and a photosensitive array, the camera having a camera field of view;

providing a moveable apparatus operable to cause relative movement between the object and the device;

providing a position sensing mechanism operably coupled to the moveable apparatus, the position sensing mechanism operable to determine a position of the moveable apparatus;

providing a processor electrically coupled to the projector, the camera, the moveable apparatus, and the position sensing mechanism;

emitting from the projector onto the surface a first projected light having a first pattern;

acquiring with the camera a first image of the first projected light and producing a first electrical signal in response;

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

determining with the processor a simulation in which the processor projects first rays from the projector in the first position to the first points and calculates for each first ray an angle of reflection of a secondary ray from each of the first points and determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

moving the device with the moveable apparatus from the first position to a second position based at least in part on the determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

with the projector in the second position, emitting from the projector onto the surface a second projected light having a second pattern;

acquiring with the camera a second image of the second projected light and producing a second electrical signal in response;

determining with the processor a second set of 3D coordinates of a second point on the surface, the second set based at least in part on the second pattern and the second electrical signal; and

storing the second set of 3D coordinates.

2. The method of claim 1, wherein the first pattern and the second pattern are the same.

3. The method of claim 1, wherein the first pattern is different than the second pattern.

4. The method of claim 1, further including steps of:

combining the first set of 3D coordinates and the second set of 3D coordinates into a third set of 3D coordinates;

eliminating a portion of the third set of 3D coordinates to obtain a fourth set of 3D coordinates based at least in part on the determining that the angle of reflection of at least one of the secondary rays intersects the object within the field of view of the camera in the first position; and

storing the fourth set of 3D coordinates.

5. The method of claim 1, wherein:

the determining with the processor a simulation in which the processor projects first rays further includes steps of emitting from the projector onto the surface a first collection of epipolar lines, reflecting into the camera a portion of the first collection of epipolar lines;

reflecting into the camera a portion of the first collection of epipolar lines as a first diagnostic reflected light;

forming with the lens a first diagnostic image of the first diagnostic reflected light on the photosensitive array and producing a first diagnostic electrical signal in response;

determining with the processor whether the first diagnostic image includes a collection of straight lines; and

determining with the processor that the first diagnostic image includes lines that are not straight lines; and

in the selecting by the processor the second pattern, the second pattern is further based on the determining that the first diagnostic image includes lines that are not straight lines.

6. The method of claim 1, wherein in the selecting with the processor the second pattern, the second pattern is a single line stripe or a single spot, the second pattern being based at least in part on the determining that the angle of reflection of at least one of the secondary rays intersects the object within the field of view of the camera in the first position.

7. A method of object measurement to determine three-dimensional (3D) coordinates of points on a surface of the object, the method comprising:

providing a 3D coordinate measurement device that includes a projector and a camera, the camera having a lens and a photosensitive array, the camera having a camera field of view;

providing a moveable apparatus operable to cause relative movement between the object and the device;

providing a position sensing mechanism operably coupled to the moveable apparatus, the position sensing mechanism configured to determine a position of the moveable apparatus;

providing a processor electrically coupled to the projector, the camera, the moveable apparatus, and the position sensing mechanism;

providing a CAD model of the object, the CAD model operable to provide computer-readable information for determining a 3D representation of the surface of the object;

providing computer readable media having computer readable instructions which when executed by the processor calculates 3D coordinates of points on the surface based at least in part on the CAD model;

determining with the processor a first set of 3D coordinates of first points on the surface, the first set based at least in part on the computer-readable information in the CAD model;

determining with the processor a simulation in which the processor projects first rays from the projector to the first points and calculates for each first ray an angle of reflection of a secondary ray from each of the first points and determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

moving the movable apparatus to a first location based at least in part on the determining that the angle of reflection of at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

selecting with the processor a first pattern based at least in part on the determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

with the projector in the first location, emitting from the projector onto the surface a first projected light having the first pattern;

acquiring with the camera a first image of the first projected light and producing a first electrical signal in response;

determining with the processor a second set of 3D coordinates of at least one second point on the surface, the second set based at least in part on the first pattern and the first electrical signal; and

storing the second set of 3D coordinates.

8. A system of determining three-dimensional (3D) coordinates of points on a surface of an object, the system comprising:

a 3D coordinate measurement device having a projector and a camera, the projector having a light source operable to emit projected light, the projected light having at least one pattern, the camera having a lens and a photosensitive array, the camera having a camera field of view;

a moveable apparatus operable to cause relative movement between the object and the device;

a position sensing mechanism operably coupled to the moveable apparatus, the position sensing mechanism operable to determine a position of the moveable apparatus;

one or more processors responsive to executable computer instructions, the one or more processors electrically coupled to the projector, the camera, the moveable apparatus, and the position sensing mechanism, the executable computer instructions comprising;

emitting from the projector onto the surface a first projected light having a first pattern;

acquiring with the camera a first image of the first projected light and producing a first electrical signal in response;

determining a first set of 3D coordinates of first points on the surface, the first set based at least in part on the first pattern and the first electrical signal;

determining a simulation in which first rays are projected from the projector in the first position to the first points;

calculating for each first ray an angle of reflection of a secondary ray from each of the first points;

determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

moving the device with the moveable apparatus from the first position to a second position based at least in part on the determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

emitting from the projector onto the surface, with the projector in the second position, a second projected light having a second pattern;

acquiring with the camera a second image of the second projected light and producing a second electrical signal in response;

determining a second set of 3D coordinates of a second point on the surface, the second set based at least in part on the second pattern and the second electrical signal; and

storing the second set of 3D coordinates.

9. The system of claim 8, wherein the first pattern and the second pattern are the same.

10. The system of claim 8, wherein the first pattern is different than the second pattern.

11. The system of claim 8, wherein the executable computer instructions further comprise:

combining the first set of 3D coordinates and the second set of 3D coordinates into a third set of 3D coordinates;

eliminating a portion of the third set of 3D coordinates to obtain a fourth set of 3D coordinates based at least in part on the determining that the angle of reflection of at least one of the secondary rays intersects the object within the field of view of the camera in the first position; and

storing the fourth set of 3D coordinates.

12. The system of claim 8, wherein:

in the of determining a simulation in which the first rays are projected, further includes steps of emitting from the projector onto the surface a first collection of epipolar lines, reflecting into the camera a portion of the first collection of epipolar lines;

reflecting into the camera a portion of the first collection of epipolar lines as a first diagnostic reflected light;

forming with the lens a first diagnostic image of the first diagnostic reflected light on the photosensitive array and producing a first diagnostic electrical signal in response;

determining with the processor whether the first diagnostic image includes a collection of straight lines; and

determining with the processor that the first diagnostic image includes lines that are not straight lines; and

in the selecting the second pattern, the second pattern is further based on the determining that the first diagnostic image includes lines that are not straight lines.

13. The system of claim 8, wherein, in the step of selecting with the processor the second pattern, the second pattern is a single line stripe or a single spot, the second pattern being based at least in part on the determining that the angle of reflection of at least one of the secondary rays intersects the object within the field of view of the camera in the first position.

14. A system of object measurement to determine three-dimensional (3D) coordinates of points on a surface of the object, the system comprising:

a 3D coordinate measurement device having a projector and a camera, the camera having a lens and a photosensitive array, the camera having a camera field of view;

a moveable apparatus operable to cause relative movement between the object and the device;

a position sensing mechanism operably coupled to the moveable apparatus, the position sensing mechanism operable to determine a position of the moveable apparatus;

one or more processors responsive to executable computer instructions, the one or more processors being electrically coupled to the projector, the camera, the moveable apparatus, and the position sensing mechanism, the executable computer instructions comprising;

receiving a CAD model of the object, the CAD model configured to provide computer-readable information for determining a 3D representation of the surface of the object;

determining 3D coordinates of points on the surface based at least in part on the CAD model;

determining a first set of 3D coordinates of first points on the surface, the first set based at least in part on the computer-readable information in the CAD model;

determining a simulation in which first rays are projected from the projector to the first points;

calculating for each first ray an angle of reflection of a secondary ray from each of the first points;

determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

moving the movable apparatus to a first location based at least in part on the determining that the angle of reflection of at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

selecting a first pattern based at least in part on the determining that at least one of the secondary rays intersects the object within the field of view of the camera in the first position;

emitting from the projector onto the surface, with the projector in the first location, a first projected light having the first pattern;

acquiring with the camera a first image of the first projected light and producing a first electrical signal in response;

determining with the processor a second set of 3D coordinates of at least one second point on the surface, the second set based at least in part on the first pattern and the first electrical signal; and

storing the second set of 3D coordinates.