Method and device for determining 3D coordinates of an object

• US 9,995,567 B2
• Filed: 12/06/2012
• Issued: 06/12/2018
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Inventors: Pettersson, Bo, Siercks, Knut, Voit, Eugen, Hinderling, Jrg, Zebhauser, Benedikt, Schneider, Klaus
• Primary Examiner(s): Vaughn, Jr., William C
• Assistant Examiner(s): Towe, Joseph A
• Application Number:
  US14/363,269
• Publication Number:
  US 20140320603A1
• Time in Patent Office: 2,014 Days
• Field of Search: 348 46
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar

Abstract

The invention relates to a method for determining 3D coordinates of an object (2) by a handheld laser-based distance measuring device (1), the method comprising determining an object point (20) at the object (2); measuring a distance (100) from the handheld laser-based distance measuring device (1) to the determined object point (20) by means of an EDM (10); capturing a 3D image (110) of the object (2), the 3D image (110) includes the determined object point (20); identifying the determined object point (20) in the captured 3D image (110); and linking the measured distance (100) with the identified object point (20) in the 3D image (110). The invention also relates to a handheld laser-based distance measuring device (1) and a computer program product for execution of said method.

Claims

1. A method for determining 3D coordinates of an object by a handheld laser-based distance measuring device, the method being performed by the handheld laser-based distance measuring device comprising:

determining an object point at the object with the handheld laser-based distance measuring device;

measuring a distance from the handheld laser based distance measuring device to the determined object point by means of an electronic distance meter (EDM) of the handheld laser-based distance measuring device;

capturing a 3D image of the object, the 3D image including the determined object point with a time-of-flight (TOF) camera of the handheld laser-based distance measuring device;

holding the handheld laser-based distance measuring device over ground supported only with a hand of the user during the measuring and capturing;

identifying the determined object point in the captured 3D image with the handheld laser-based distance measuring device; and

linking the measured distance measured by the electronic distance meter with the identified object point in the 3D image with the handheld laser-based distance measuring device.

2. The method according to claim 1, wherein

the electronic distance meter (EDM) aims at the determined object point along an emission axis;

the emission axis forms a fixed geometric relationship with an optical axis of the TOF camera; and

the determined object point is identifiable in a coordinate system of the TOF camera with respect to the optical axis,

the method further comprising simultaneously aiming the EDM and the TOF camera at the determined object point by hand.

3. The method according to claim 1, wherein

a 2D image of the object is captured, the 2D image includes the determined object point;

the determined object point is determined in the captured 2D image; and

the measured distance is linked with the identified object point in the 2D image.

4. The method according to claim 3, wherein

the electronic distance meter (EDM) aims at the determined object point along an emission axis;

a photo sensor array (PSA) camera captures the 2D image with determined object point;

the emission axis forms a fixed geometric relationship with an optical axis of the PSA camera; and

the determined object point is identifiable in a coordinate system of the PSA camera with respect to the optical axis.

5. The method according to claim 3, wherein

the captured 3D image of the determined object point and the captured 2D image of the determined object point are superposed;

and

the superposed images of the determined object point are displayed.

6. The method according to claim 1, wherein

the electronic distance meter (EDM) aims at the determined object point along an emission axis and issues a cursor data signal indicating the emission axis;

a time-of-flight (TOF) camera issues for a captured 3D image an 3D data signal;

or

a photo sensor array (PSA) camera captures a 2D image with the determined object point and issues for a captured 2D image an 2D data signal; and

a position of the cursor data signal is linked to the 3D data signal or 2D data signal.

7. The method according to claim 1, wherein

at least one of a further object point is determined or a geometric element is recognized.

8. The method according to claim 7, wherein

the determined further object point or recognized geometric element is hooked relative to the measured object point.

9. The method according to claim 1, wherein

a further object point in a 3D data signal or 2D data signal being displayed is determined through selection of at least one characteristic point of the displayed 3D data signal or 2D data signal, said characteristic point being the further object point.

10. The method according to claim 1, wherein

geometric element recognition with at least one of a 3D data signal of a captured 3D image or a 2D data signal of a captured 2D image is performed;

a geometric element in at least one of the 3D data signal or the 2D data signal is recognized; and

/or

a geometric element in at least one of the 3D data signal or the 2D data signal is recognized, and at least one characteristic point of the geometric element is determined, said characteristic point being the further object point.

11. The method according to claim 1, wherein

at least one 3D coordinate data of the object point is calculated, said 3D coordinate data being from at least one of a multi-point distance calculation, an area calculation, or a volume calculation;

and

the 3D coordinate data is calculated based on at least one radial measured distance of a range image of the 3D image and the measured distance.

12. The method according to claim 1, wherein

at least one 3D coordinate data of the further object point is calculated, said 3D coordinate data being from at least one of a multi-point distance calculation, an area calculation, or a volume calculation;

and

the 3D coordinate data is calculated based on at least one radial measured distance of a range image of the 3D image and the measured distance.

16. A computer program product comprising:

a non-transitory tangible machine-readable storage medium that includes computer-executable instructions for determining 3D coordinates of an object by a handheld laser-based distance measuring device while holding the handheld laser-based distance measuring device over ground supported only with a hand of the user during measuring and capturing, which when executed by a processor performs the method of claim 1.

17. The computer program product according to claim 16, wherein

the electronic distance meter (EDM) aims at the determined object point along an emission axis;

the emission axis forms a fixed geometric relationship with an optical axis of the TOF camera; and

the determined object point is identifiable in a coordinate system of the TOF camera with respect to the optical axis.

18. The computer program product according to claim 17, wherein

a 2D image of the object is captured, the 2D image includes the determined object point;

the determined object point is determined in the captured 2D image; and

the measured distance is linked with the identified object point in the 2D image.

19. The computer program product according to claim 18, wherein

the electronic distance meter (EDM) aims at the determined object point along an emission axis;

a photo sensor array (PSA) camera captures the 2D image with determined object point;

the emission axis forms a fixed geometric relationship with an optical axis of the PSA camera; and

the determined object point is identifiable in a coordinate system of the PSA camera with respect to the optical axis.

20. The method according to claim 16, wherein

a 2D image of the object is captured, the 2D image includes the determined object point;

the determined object point is determined in the captured 2D image; and

the measured distance is linked with the identified object point in the 2D image.

13. A handheld laser-based distance measuring device, comprising:

an electronic distance meter (EDM) for measuring a distance from the handheld laser-based distance measuring device to the determined object point;

a time-of-flight (TOF) camera for capturing a 3D image of the object; and

a computer having a central processing unit with a tangible machine-readable carrier with at least one computer program for executing the method comprising;

determining an object point at the object;

measuring a distance from the handheld laser based distance measuring device to the determined object point by means of an EDM;

capturing a 3D image of the object, the 3D image including the determined object point;

identifying the determined object point in the captured 3D image; and

linking the measured distance with the identified object point in the 3D image; and

a housing having the EDM, TOF camera and computer, the housing being configured to be supported off of ground only by a hand of a user during the measuring and capturing and simultaneously aiming the EDM and the TOF camera at the determined object point by hand.

14. The handheld laser-based distance measuring device according to claim 13, wherein

the electronic distance meter (EDM) and the time-of-flight (TOF) camera are mounted in the housing of the handheld laser-based distance measuring device in a rigid manner;

and

an optical axis of the TOF camera forms a fixed geometrical relationship with an emission axis of the EDM.

15. The handheld laser-based distance measuring device according to claim 14, wherein

a photo sensor array (PSA) camera for capturing a 2D image of the object;

and

a display for displaying at least one of a measured distance, a cursor data signal indicative of an emission axis, a 3D data signal for a captured 3D image, a 2D data signal for a captured 2D image, an inclination data signal for a measured inclination, a determined object point, a determined further object point, a recognized geometric element, a 3D coordinate data of the object point, or a 3D coordinate data of the further object point.

21. The handheld laser-based distance measuring device according to claim 13, wherein

a photo sensor array (PSA) camera for capturing a 2D image of the object;

and

a display for displaying at least one of a measured distance, a cursor data signal indicative of an emission axis, a 3D data signal for a captured 3D image, a 2D data signal for a captured 2D image, an inclination data signal for a measured inclination, a determined object point, a determined further object point, a recognized geometric element, a 3D coordinate data of the object point, or a 3D coordinate data of the further object point.