Method for measuring spatial points

Patent metadata

Field	Value
Publication number	US-9529085-B2
Application number	US-201214361264-A
Country	US
Kind code	B2
Filing date	Nov 29, 2012
Priority date	Nov 29, 2011
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

Some embodiments of the invention relate to a method for measuring spatial points with a laser scanner. The method may include: scanning multiple spatial points on an object; determining coordinates of the respective spatial point, determining a close range about a central spatial point with at least two spatial points whose angle coordinates are in a defined angular space adjacent to those of the central spatial point; aggregating coordinates of the spatial points in the specific close range; and replacing coordinates of the central spatial point by aggregating coordinates of the spatial points in the specific close range. In some embodiments, the laser scanner forms the origin of the coordinates, and the coordinates comprise a distance and at least one angle.

First claim

What is claimed is:

1. A method for measuring spatial points using a laser scanner, the method comprising:
scanning a plurality of spatial points of an object,
ascertaining coordinates of a respective spatial point, wherein the laser scanner forms the coordinate origin and the coordinates comprise a distance and two angles;
defining a two-dimensional vicinity around a central spatial point, having spatial points which are less than or equal to two scanning step sizes of an angle around the central spatial point, aggregating coordinates of the spatial points in the defined vicinity; and
replacing coordinates of the central spatial point by the aggregation of coordinates of the spatial points in the defined vicinity.

2. The method according to claim 1 , wherein the spatial points are scanned by the laser scanner using a scanning step size of an angle.

3. The method according to claim 2 , wherein, while using these scanned spatial points, a vicinity is defined, wherein at least those scanned spatial points, which are less than or equal to two scanning step sizes of the angle around the central spatial point, are considered to be adjacent to the central spatial point.

4. The method according to claim 1 , wherein
the spatial points are scanned by the laser scanner in at least three region segments having the scanning step size of a first angle; and
while using these region segments, a vicinity is defined, wherein at least those region segments, which are less than or equal to two scanning step sizes of a second angle around the central spatial point are considered to be adjacent to the central spatial point.

5. The method according to claim 1 , wherein a vicinity which is symmetrical in the angle space is defined, wherein a number of spatial points arranged symmetrically in relation to the central spatial point is defined as the vicinity in the angle space.

6. The method according to claim 1 , wherein respectively the distance of the spatial points is aggregated in the defined vicinity.

7. The method according to claim 1 , wherein respectively three coordinates of the spatial points are aggregated in the defined vicinity.

8. The method according to claim 1 , wherein coordinates of the central spatial point are replaced by a mean value of coordinates in the defined vicinity, wherein at least the distance of the central spatial point is replaced.

9. The method according to claim 1 , wherein the aggregation of coordinates in the defined vicinity is weighted by a settable filter.

10. The method according to claim 9 , wherein the spatial points in the vicinity are equally weighted by the filter.

11. The method according to claim 9 , wherein the spatial points in the vicinity are unequally weighted by the filter.

12. The method according to claim 1 , wherein only coordinates of those spatial points are aggregated, the measured distances of which differ from the distance measured in the central spatial point by not more than a defined threshold value.

13. The method as claimed in claim 12 , wherein a threshold value is used, which has a sum of a constant displacement value and a measured value, wherein a measured value is used, which
is inversely proportional to a measured amplitude of the registered light,
is proportional to a power of a measured amplitude of the registered light having a real exponent, and/or
is derived from the signal-to-noise ratio of the registered light.

14. The method according to claim 1 , wherein
the aggregation of coordinates in the defined vicinity is weighted by a settable filter, and
scanned spatial points, the measured distances of which differ from the distance measured in the central spatial point by more than a defined threshold value, are filtered out by an adapted filter.

15. The method according to claim 1 , wherein the vicinity is defined with the use of three spatial points scanned in chronological sequence by the laser scanner, wherein at least one scanned spatial point has been scanned chronologically before the central spatial point and at least one scanned spatial point has been scanned chronologically after the central spatial point.

16. A system comprising:
a laser scanner configured to:
scan a plurality of spatial points of an object; and
ascertain coordinates for each of the spatial points, wherein the laser scanner forms the coordinate origin and the coordinates comprise a distance and at least two angles; and

an computer configured to:
define a two-dimensional vicinity around a central spatial point, having spatial points which are less than or equal to two scanning step sizes of an angle around the central spatial point,
aggregate coordinates of the spatial points in the defined vicinity, and
replace coordinates of the central spatial point by the aggregation of coordinates of the spatial points in the defined vicinity are executable.

17. A non-transitory computer program product having program code, which is stored on a machine-readable carrier, for executing the method comprising:
reading in data representing a plurality of spatial points of an object gathered through scanning the object with a laser scanner;
defining a two-dimensional vicinity around a central spatial point, having spatial points which are less than or equal to two scanning step sizes of an angle around the central spatial point, aggregating coordinates of the spatial points in the defined vicinity, and
replacing coordinates of the central spatial point by the aggregation of coordinates of the spatial points in the defined vicinity, when the program is executed in an analysis unit; and
storing the replaced coordinates of the plurality of spatial points as a modified 3D point cloud.

18. A method for measuring spatial points by means of a laser scanner, the method comprising:
scanning a plurality of spatial points of an object;
ascertaining coordinates of the respective spatial point, wherein the laser scanner forms the coordinate origin and the coordinates comprise a distance and at least one angle;
defining a vicinity around a central spatial point, having at least two spatial points,
the angle coordinates of which in a defined angle space are adjacent to that of the central spatial point, and
the measured distances of which differ from the distance measured in the central spatial point by not more than a defined threshold value;

aggregating coordinates of the spatial points in the defined vicinity; and
replacing coordinates of the central spatial point by the aggregation of coordinates of the spatial points in the defined vicinity.

19. The method according to claim 18 , wherein a threshold value is used, which has a sum of a constant displacement value and a measured value, wherein a measured value is used, which:
is inversely proportional to a measured amplitude of the registered light,
is proportional to a power of a measured amplitude of the registered light having a real exponent, and/or
is derived from the signal-to-noise ratio of the registered light.

20. The method according to claim 18 , wherein a vicinity is defined with the use of three spatial points scanned in chronological sequence by the laser scanner, wherein at least one scanned spatial point has been scanned chronologically before the central spatial point and at least one scanned spatial point has been scanned chronologically after the central spatial point.

21. The method according to claim 18 , wherein a vicinity which is symmetrical in the angle space is defined, wherein a

Assignees

• Hexagon Technology Ct Gmbh

Inventors

• Stutz Reto
• Aebischer Beat
• Rohner Marcel
• Bednarek Ingo

Classifications

• G01B11/005

  coordinate measuring machines · CPC title

• G01S17/42 Primary

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title

• G01S17/89 Primary

  for mapping or imaging · CPC title

• G01S13/06

  Systems determining position data of a target · CPC title

• G01B11/00

  Measuring arrangements characterised by the use of optical techniques · CPC title