Geodetic referencing of point clouds

• US 9,594,167 B2
• Filed: 04/04/2014
• Issued: 03/14/2017
• Est. Priority Date: 04/05/2013
• Status: Active Grant

• Current Assignee: Leica Geosystems AG (Hexagon AB)
• Original Assignee: Leica Geosystems AG (Hexagon AB)
• Inventors: Zogg, Hans-Martin, Kotzur, Norbert
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US14/245,799
• Publication Number:
  US 20140300886A1
• Time in Patent Office: 1,075 Days
• Field of Search: 356/4.01
• US Class Current: 1/1
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

A geodetic surveying method includes deriving surface information for an object and geodetically accurate individual point measuring to at least one reference point. A position reference to an external coordinate system may also be provided by the at least one reference point. The method may also include aligning measurement radiation on the at least one reference point. The method may also include determining at least one direction to the reference point in an internal coordinate system. A method for reference point-independent scanning is also disclosed for deriving the surface information, the method may comprise scanning by continuously changing the alignment of the measurement radiation, determining a respective distance and a respective alignment of the measurement radiation emitted for a distance measurement for scanning points lying within the specified scanning region, and producing a point cloud representing the surface information and having the scanning points, in the internal coordinate system.

Claims

1. A geodetic surveying method for referencing a coordinate system of a geodetic surveying device, the method comprising:

deriving surface information for an object in respect to an internal coordinate system of the geodetic surveying device; and

geodetically accurate individual point measuring to at least one reference point, wherein

a position reference to an external coordinate system is provided by the at least one reference point,

measurement radiation is aligned precisely on the at least one reference point and

at least one direction to the reference point is determined in the internal coordinate system when the measurement radiation is aligned on the at least one reference point,

wherein reference point-independent scanning for deriving the surface information comprises;

scanning of a scanning region, specified in respect of the object, by continuously changing the alignment of the measurement radiation;

determining a respective distance and a respective alignment of the measurement radiation emitted for a distance measurement for scanning points lying within the specified scanning region, in particular with a predetermined scanning point resolution; and

producing a point cloud, representing the surface information and having the scanning points, in the internal coordinate system and

wherein referencing of the internal coordinate system in relation to the external coordinate system is made on the basis of at least;

the position reference to the external coordinate system provided by the reference point, and

the specified direction to the reference point in the internal coordinate system, so that at least one orientation of the point cloud is determined in the external coordinate system.

2. The geodetic surveying method according to claim 1, wherein an absolute position of the at least one reference point is known in the external coordinate system and the referencing is brought about on the basis of the known absolute position of the at least one reference point.

3. The geodetic surveying method according to claim 1, wherein the at least one reference point is provided in the external coordinate system by at least one of the following:

a geodetically referenced calibration point,

a retroreflector, and

a geodetic surveying device set up with known positioning or alignment.

4. The geodetic surveying method according to claim 1, wherein a distance to the at least one reference point and a position of the reference point are determined in the internal coordinate system and the referencing is brought about on the basis of the determined position of the reference point in the internal coordinate system.

5. The geodetic surveying method according to claim 1, wherein, within the scope of scanning, when determining the respective distance and the respective alignment of the measurement radiation, the alignment of the measurement radiation is modified continuously within the specified scanning region.

6. The geodetic surveying method according to claim 1, wherein, within the scope of referencing, the internal coordinate system is adapted in such a way that the internal coordinate system coincides with the external coordinate system, in particular corresponds to the external coordinate system.

7. The geodetic surveying method according to claim 5, wherein the internal coordinate system is adapted in respect of position and scaling of the internal coordinate system.

8. The geodetic surveying method according to claim 1, wherein the internal coordinate system is referenced in relation to the external coordinate system on the basis of further reference information.

9. The geodetic surveying method according to claim 1, wherein the internal coordinate system is referenced in relation to additional GNSS position information.

10. The geodetic surveying method according to claim 1, wherein the internal coordinate system is referenced on the basis of an additional point common to both the internal and external coordinate system.

11. The geodetic surveying method according to claim 1, wherein atmospheric state information is detected and/or geometric measurement information is defined within the scope of the surveying method, wherein

the atmospheric state information and/or geometric measurement information is processed when determining the distance for the respective scanning points and/or when determining the distance to the at least one reference point and there is a distance correction for determining the respective distance on the basis thereof and/or

the scanning points determined within the scope of the scanning are adapted in respect of the position thereof in the external coordinate system, in particular the orientation of the point cloud in the internal coordinate system, on the basis of the atmospheric state information and/or geometric measurement information.

12. The geodetic surveying method according to claim 1 wherein the geometric measurement information includes either particular meteorological data or measurement axis error, and atmospheric state information includes at least one of ambient temperature, air pressure and atmospheric humidity.

13. The geodetic surveying method according to claim 1, wherein

at least one further instance of scanning of further scanning points,

deriving a further point cloud having the further scanning points in a further coordinate system,

geodetically accurate individual point measuring in respect of the at least one reference point and/or in respect of a further reference point, with determination of at least the direction to the reference point and/or to the further reference point in the further coordinate system and

referencing the further coordinate system in relation to the external coordinate system on the basis of at least the determined direction to the reference point coordinate system, in particular wherein in the further the scanning and the at least one further instance of scanning is brought about from different setup points, wherein the orientations of the respective point clouds are determined in the external coordinate system and hence the orientations of the respective point clouds are determined relative to one another.

14. The geodetic surveying method according to claim 13, wherein there is at least partial, mutual adapting of positions of the specified scanning points and/or of the further scanning points in the external coordinate system on the basis of the referencing of the internal coordinate system and the further coordinate system in relation to the external coordinate system.

15. The geodetic surveying method according to claim 1 wherein the geodetic surveying method is carried out by and using the geodetic surveying device, wherein the surveying device comprises at least:

one scanning functionality for detecting the scanning points by scanning and producing the point cloud; and

one individual point measuring functionality for highly precisely determining the direction to the reference point.

20. A computer program product with computer-executable instructions, which is stored on a machine-readable medium, that when executed by a computer performs the following method:

controlling the scanning and the individual point measuring; and

carrying out the referencing of the internal coordinate system in relation to the external coordinate system of the geodetic surveying method according to claim 1.

16. A geodetic surveying device, comprising

a base defining a pivot axis;

a structure which is arranged on the base and can pivot relative to the base about the pivot axis, wherein the structure defines a tilt axis which is substantially orthogonal to the pivot axis;

a sighting unit arranged such that it can pivot relative to the structure about the tilt axis and has an emission unit with a beam source for generating and emitting measurement radiation;

a distance measuring functionality for measuring distances to points;

an angle measuring functionality for measuring an alignment of the measurement radiation;

a control and processing unit for data processing and for controlling the surveying device; and

an individual point measuring functionality, wherein the individual point measuring functionality can be carried out by the control and processing unit in such a way that;

at least one reference point can be surveyed in a geodetically accurate fashion by aligning the measurement radiation in a highly precise fashion therewith, wherein a position reference to an external coordinate system is provided by the at least one reference point, and

at least one direction to the reference point can be determined in an internal coordinate system of the surveying device when aligning the measurement radiation on the at least one reference point,

wherein the geodetic surveying device comprises;

a reference point-independent scanning functionality, wherein the scanning functionality can be carried out by the control and processing unit in such a way that

the scanning points can be surveyed with a predetermined scanning point resolution by continuously changing the alignment of the measurement radiation on scanning points lying within a specified scanning region, and

a point cloud with the scanning points can be produced in the internal coordinate system of the surveying device; and

a referencing functionality, wherein there is, when the latter is carried out by the control and processing unit, referencing of the internal coordinate system in relation to the external coordinate system on the basis of at least;

the position reference to the external coordinate system provided by the reference point and

the direction to the reference point in the internal coordinate system, which can be determined by the individual point measuring functionality, such that at least one orientation of the point cloud is determined in the external coordinate system.

17. The geodetic surveying device according to claim 16, wherein the surveying device comprises a remote control unit and/or a display unit, wherein the remote control unit includes an evaluation unit, wherein the referencing functionality can be carried out by the evaluation unit, and wherein the a display unit is used for depicting measurement information.

18. The geodetic surveying device according to claim 17 wherein a scanning progress can be depicted by at least partial depiction of scanning points of a point cloud.

19. The geodetic surveying device according to claim 16, wherein the geodetic surveying device comprises a GNSS module for detecting GNSS position information for correcting the position of the scanning points and/or of the point cloud in the external coordinate system and/or for adapting measured values during the scanning point survey and/or reference point survey.