Device for optically scanning and measuring an environment

• US 9,599,455 B2
• Filed: 02/14/2013
• Issued: 03/21/2017
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Heidemann, Rolf, Ossig, Martin, Becker, Reinhard
• Primary Examiner(s): Yenke, Brian
• Assistant Examiner(s): Khalid, Omer
• Application Number:
  US13/767,154
• Publication Number:
  US 20140168379A1
• Time in Patent Office: 1,496 Days
• Field of Search: 348/136, 348/47, 348/135, 348/48, 356/614
• US Class Current: 1/1
• 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 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: H04N 13/243 using three or more 2D image sensors
• CPC Class Codes: H04N 13/25 using two or more image sensors with different characteristics other than in their location or field of view, e.g. having different resolutions or colour pickup characteristics; using image signals from one sensor to control the characteristics of another sensor
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects

Abstract

A device for optically scanning and measuring an environment is provided. The device includes at least one projector for producing at least one uncoded pattern on an object in the environment. A first camera is provided for recording at least one first image of the object provided with the pattern, the first camera having a first image plane. A second camera is provided for recording at least one second image of the object provided with the uncoded pattern, the second camera being spaced apart from the first camera in order to acquire the uncoded pattern on a second image plane. A controller is provided having a processor configured to determine the three-dimensional coordinates of points on the surface of the object based at least in part on the uncoded pattern, the at least one first image and the at least one second image.

Claims

1. A system for optically scanning and measuring an object in an environment, the system comprising:

a scanner device that includes a projector, a first camera, and a second camera,

the projector configured to project a first pattern of light from a projector plane, the first pattern of light being a first multivalued uncoded structured light pattern, the first pattern of light including a collection of illuminated points, the projector having a projector optical axis, each of the illuminated points having an identical shape,

the first camera configured to record in a first time instance a first image of the first multivalued pattern of light projected onto the object, the first image being recorded on a first image plane of the first camera, the first camera having a first camera optical axis,

the second camera configured to record in the first time instance a second image of the first multivalued pattern of light projected onto the object, the second image being recorded on a second image plane of the second camera, the second camera having a second camera optical axis,

the projector optical axis, the first camera optical axis, and the second camera optical axis are oriented in a non-collinear triangular arrangement,

each of the illuminated points on the projector plane, the first image plane, and the second image plane corresponding to and lying on an epipolar line in each of the other two of the projector plane, the first image plane, and the second image plane, the correspondence among epipolar lines and the illuminated points of the first pattern of light on the three planes determined by geometrical epipolar relations among the projector plane, the first image plane, and the second image plane; and

a processor configured to determine the correspondence among each of the illuminated points on the projector plane, the first image plane, and the second image plane, the correspondence determined at least in part by the geometrical epipolar relations among the three planes, the processor further configured to determine three-dimensional coordinates of each of the illuminated points on the object at the first time instance based at least in part on the illuminated points in the first multivalued pattern of light, the first image of the first multivalued pattern of light on the object, the second image of the first multivalued pattern of light on the object, and the geometry of the triangle.

2. The system of claim 1 wherein the collection of illuminated points includes at least three illuminated spots, each of the illuminated spots including a bright region surrounded by a dark region, each illuminated spot being unattached to any other illuminated spot.

3. The system of claim 2 wherein the collection of illuminated points further includes an illuminated line, the illuminated line including a continuous linear region of illumination.

4. The system of claim 1 wherein the collection of illuminated points includes a collection of illuminated spots falling on a regular grid pattern in the projector plane.

5. The system of claim 1, wherein:

the projector includes a laser that emits a first wavelength to create the first pattern of light; and

the first camera and the second camera include bandpass filters that transmit at the first wavelength.

6. The system of claim 1 wherein the scanner device further comprises a third camera, the third camera being a color camera that records images of the object at visible wavelengths, the third camera being fixed on the scanner device.

7. The system of claim 1, wherein the scanner device generates a second pattern of light, the second pattern of light being different than the first pattern of light, the second pattern of light being a second multivalued uncoded structured light pattern.

8. The system of claim 1, wherein the projector includes an element from a group consisting of a diffractive optical element, a collection of microlenses, a plurality of single lasers, and a projected mask.

9. The system of claim 1, wherein the processor is configured to select the first pattern of light from among a plurality of patterns of light.

10. The system of claim 9 wherein the scanner device is further configured to project a second pattern of light, the second pattern of light being offset with respect to time to the first pattern of light, the second pattern of light being a second uncoded pattern.

11. The system of claim 1, wherein the first pattern of light further comprises a second pattern of light, the first pattern of light having a first optical wavelength and the second pattern of light having a second optical wavelength different than the first wavelength, the second pattern of light being a second uncoded pattern.

12. The system of claim 1, wherein the scanner device further comprises a second projector, the second projector configured to project a second pattern of light different than the first pattern of light, the second pattern of light being a second multivalued uncoded structured light pattern.

13. The system of claim 1 wherein the scanner device is a handheld device.

14. The system of claim 1, wherein the scanner device further comprises:

a base member, the projector being arranged in the base member;

a grip member protruding from the base member;

a trigger switch disposed on the grip member; and

a head end on an opposite end of the grip member from the base member, wherein the first camera and the second camera are disposed in the head end.

15. The system of claim 1 wherein the processor is an integral part of the scanner device.

16. The system of claim 1, wherein the collection of illuminated points includes a first plurality of light points having a first intensity and a second pattern of light having a second plurality of light points having a second intensity different than the first intensity, wherein the first plurality of light points and the second plurality of light points each define a multivalued uncoded structured light pattern.

17. A system for optically scanning and measuring an object in an environment, the system comprising:

a scanner device that includes a projector, a first camera, and a second camera,

the projector configured to project a first pattern of light from a projector plane, the first pattern of light being a first multivalued uncoded structured light pattern, the first pattern of light including a collection of illuminated points, the projector having a projector optical axis,

the first camera configured to record in a first time instance a first image of the first multivalued pattern of light projected onto the object, the first image being recorded on a first image plane of the first camera, the first camera having a first camera optical axis,

the second camera configured to record in the first time instance a second image of the first multivalued pattern of light projected onto the object, the second image being recorded on a second image plane of the second camera, the second camera having a second camera optical axis,

the projector optical axis, the first camera optical axis, and the second camera optical axis are oriented in a non-collinear triangular arrangement,

each of the illuminated points on the projector plane, the first image plane, and the second image plane corresponding to and lying on an epipolar line in each of the other two of the projector plane, the first image plane, and the second image plane, the correspondence among epipolar lines and the illuminated points of the first pattern of light on the three planes determined by geometrical epipolar relations among the projector plane, the first image plane, and the second image plane;

a processor configured to determine the correspondence among each of the illuminated points on the projector plane, the first image plane, and the second image plane, the correspondence determined at least in part by the geometrical epipolar relations among the three planes, the processor further configured to determine three-dimensional coordinates of each of the illuminated points on the object at the first time instance based at least in part on the illuminated points in the first multivalued pattern of light, the first image of the first multivalued pattern of light on the object, the second image of the first multivalued pattern of light on the object, and the geometry of the triangle;

a second projector arranged separate and apart from the scanner device, the second projector being configured to project a stationary pattern of light on the object;

wherein the first camera is configured to record a first plurality of images when the scanner device is moved relative to the second projector;

wherein the second camera is configured to record a second plurality of images when the scanner device is moved relative to the second projector; and

wherein the processor is further configured to register images within the first plurality of images to each other and to register images within the second plurality of images to each other based at least in part on the stationary pattern of light.

18. The device according to claim 17, wherein the at least one second projector is configured to produce the stationary pattern with a wavelength in the infrared or ultraviolet range.

19. The device according to claim 17 wherein the stationary pattern is different than the first pattern of light.

20. The device according to claim 17 wherein the stationary pattern is selected from group consisting of:

a pattern of light points, a pattern of lines and a pattern of points and lines.

21. The device according to claim 17 wherein elements of the stationary pattern may vary with regard to geometry or time or spectrum.