Measuring system for determining 3D coordinates of an object surface

Patent metadata

Field	Value
Publication number	US-9482524-B2
Application number	US-201214002657-A
Country	US
Kind code	B2
Filing date	Apr 13, 2012
Priority date	Apr 14, 2011
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A measuring system for determining 3D coordinates of measurement points on an object surface which has a scanning apparatus for measuring the measurement points on the object surface and for determining inner measurement point coordinates in an inner scanning coordinate system. Furthermore, a referencing arrangement for producing referencing information for referencing the inner measurement point coordinates in the outer object coordinate system and an evaluation unit for determining the 3D coordinates of the measurement points in the outer object coordinate system on the basis of the inner measurement point coordinates and the referencing information are provided such that the inner measurement point coordinates are in the form of 3D coordinates in the outer object coordinate system. The scanning apparatus is in this case carried in an unmanned, controllable, automotive air vehicle.

First claim

What is claimed is:

1. A measuring system for determining 3D coordinates of measurement points of an object surface in an outer object coordinate system, the measuring system comprising:
an optical scanning device based on a triangulation principle for point by point optical measurement of the measurement points of the object surface and for determining inner measurement point coordinates in an inner scanning coordinate system;
a referencing arrangement for generating referencing information for referencing the inner measurement point coordinates in the outer object coordinate system;
an evaluation unit for determining 3D coordinates of the measurement points in the outer object coordinate system depending on the inner measurement point coordinates and referencing information, so that the inner measurement point coordinates are present as 3D coordinates in the outer object coordinate system;
an unmanned, controllable, automotive air vehicle carrying the optical scanning device; and
a control unit configured such that the air vehicle is moved relative to the object surface under automatic control while maintaining a predefined range of measuring distances, wherein a measuring distance takes into account at least one of:
respective current inner measurement point coordinates determined with the optical scanning device; and
a digital model object surface predefined by a digital model along a flight path defined by the digital model;

wherein at least one of
the control unit is configured to move and orient the air vehicle while being automatically controlled relative to the object surface depending on the measuring distance to the object surface that is determined with the optical scanning device;
a position and a target profile of the object surface is pre-determinable by a digital CAD model and, based on a predefined object surface, respective target surface coordinates are comparable with the respective 3D coordinates and the referencing arrangement is referenced to the object surface by referencing predefined reference points; and
the optical scanning device comprises at least one of:
an optical scanning apparatus generating scanning strips during a movement of the air vehicle,
the measuring system configured to use image sequences for determining at least one of the inner measurement point coordinates in the inner scanning coordinate system and the inner measurement point coordinates in the outer scanning coordinate system,
a line scanner,
a strip projection scanner, and
a camera.

2. The measuring system as claimed in claim 1 , wherein the 3D coordinates of the measurement points comprise a plurality of 3D coordinates of measurement points of the object surface and the object surface is a surface of an industrial product.

3. The measuring system as claimed in claim 1 , wherein the inner measurement point coordinates comprise 3D coordinates in the outer object coordinate system as a scatter plot.

4. The measuring system as claimed in claim 1 , wherein the unmanned, controllable, automotive air vehicle carrying the optical scanning device is configured to be oriented and moved while hovering.

5. The measuring system as claimed in claim 1 , wherein at least one of:
the control unit is configured to move and orient the air vehicle while being automatically controlled relative to the object surface depending on at least one of
a measuring position and a measuring orientation of the optical scanning device are continuously being determined with the referencing arrangement;
the measuring distance to the object surface that is determined with the optical scanning device; and
at least one of the position, and the target profile of the object surface is defined and the scanning strips are generated during a movement of the air vehicle.

6. The measuring system as claimed in claim 1 , wherein:
the flight path is automatically determined depending on a surface position, a target surface profile, and the flight path;
a flight speed is optimized with regard to at least one of a scanning travel, a scanning time, a scanning accuracy, a stability of motion of the air vehicle, determination of a position and orientation of the air vehicle, and collision avoidance; and
a distance to an obstruction is determined with a distance measurement sensor, the scanning strips being at least partly overlapped depending on the flight path, wherein at least one of:
the scanning accuracy, the scanning travel, and the scanning time is adjusted; and
a movement and the orientation of at least one of the air vehicle and the optical scanning device is determined with an analysis of an overlap area of the scanning strips by image processing.

7. The measuring system as claimed in claim 1 , wherein the referencing arrangement comprises at least one of:
a position determining arrangement, which is designed such that an outer measuring position of the optical scanning device is determined in relation to the object coordinate system; and
an orientation determination arrangement, which is designed such that a measuring orientation of the optical scanning device is determined in relation to either or both the inner object coordinate system and the outer object coordinate system.

8. The measuring system as claimed in claim 1 , wherein:
at least one of the optical scanning device and the air vehicle comprise a reflector;
the referencing arrangement comprises at least one of a geodetic measuring device, a total station, and a laser tracker, with at least:
a radiation source for generating an optical measurement beam for distance measurement;
a base defining a vertical axis;
a beam deflection unit for emitting the measurement beam and for receiving at least part of the measurement beam reflected at the reflector, wherein for orientation of an optical target axis the beam deflection unit is configured to pivot by a motor relative to the base about the vertical axis and an inclination axis essentially orthogonal to the vertical axis;
angle measuring functionality for high precision recording of an orientation of a target axis; and
evaluation means for data storage and controlling an orientation of the beam deflection unit, and

wherein the measurement beam is configured to orient to the reflector continuously so that a measuring position of at least one of the optical scanning device and an air vehicle position is determined.

9. The measuring system as claimed in claim 8 , wherein at least one of:
the measuring system is configured to send a signal to at least one of the optical scanning device and to the air vehicle, the signal comprising at least one of:
position information, wherein the position information is convertible into control data for controlling the air vehicle in a first processing unit associated with the air vehicle; and
the control data for controlling the air vehicle, wherein the control data is determinable from the position information with a second processing unit associated with the referencing arrangement.

10. The measuring system as claimed in claim 9 , wherein:
at least one of the optical scanning device and the air vehicle comprises a GNSS antenna, configured to receive GNSS signals and determine the measuring position of the optical scanning device from the GNSS signals;
the referencing arrangement comprises a pseudo satellite module for transmitting positioning signals; and
a receiver unit of at least one of the optical scanning device and of the air vehicle is designed to receive positioning signals and to determine at least one of the measuring position and a measuring orientation of the scanner from the received positioning signals.

11. The measuring

Assignees

• Metzler Bernhard
• Siercks Knut
• Hexagon Technology Ct Gmbh

Inventors

• Metzler Bernhard
• Siercks Knut

Classifications

• B64U2201/10

  autonomous, i.e. by navigating independently from ground or air stations, e.g. by using inertial navigation systems [INS] · CPC title

• B64U2101/30

  for imaging, photography or videography · CPC title

• G01C15/004

  Reference lines, planes or sectors · CPC title

• G01B21/04 Primary

  by measuring coordinates of points · CPC title

• B64C2201/123

  Operations & Transport · mapped topic