Method for coupling co-ordinate systems, and computer-assisted system

Patent metadata

Field	Value
Publication number	US-12118745-B2
Application number	US-202117526007-A
Country	US
Kind code	B2
Filing date	Nov 15, 2021
Priority date	May 15, 2019
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

A method for coupling a relative coordinate system of a relative automatic position finding system to an absolute coordinate system of an absolute localization system includes capturing optically identifiable identifiers of the localization system using a light sensor of a mobile apparatus of the relative automatic position finding system. The method further includes ascertaining a relative position for each of the captured optically identifiable identifiers in the relative coordinate system of the relative automatic position finding system, retrieving absolute positions of the optically identifiable identifiers in the absolute coordinate system, determining a position of the light sensor in the absolute coordinate system, and coupling, based on the determined position of the light sensor, the relative coordinate system to the absolute coordinate system.

First claim

The invention claimed is:

1. A method for coupling a relative coordinate system of a relative automatic position finding system, which is based on scanning of surroundings, to an absolute coordinate system of an absolute localization system, which is based on signal interchange with at least temporarily stationary components of the absolute localization system, the method comprising:
capturing optically identifiable identifiers of the localization system using a light sensor attached to a mobile apparatus of the relative automatic position finding system,
ascertaining a relative position for each of the captured optically identifiable identifiers in the relative coordinate system of the relative automatic position finding system,
retrieving absolute positions of the optically identifiable identifiers in the absolute coordinate system, the optically identifiable identifiers being attached to the at least temporarily stationary components of the absolute localization system,
determining an absolute position of the light sensor in the absolute coordinate system by comparing the relative positions of the optically identifiable identifiers in the relative coordinate system with the absolute positions of the optically identifiable identifiers in the absolute coordinate system, wherein the comparing comprises size scaling of the relative coordinate system in one or more axes and alignment of the relative coordinate system with respect to the absolute coordinate system, and
coupling, based on the absolute position of the light sensor, the relative coordinate system to the absolute coordinate system by recording a relationship between the relative coordinate system and the absolute coordinate system based on the size scaling and the alignment,
determining a relative position of the mobile apparatus in the relative coordinate system, by the relative automatic position finding system, as part of a computer-aided system, and
compensating a drift of the determination of the relative position of the mobile apparatus using the coupling of the relative coordinate system to the absolute coordinate system.

2. The method as claimed in claim 1 , wherein the relative automatic position finding system determines relative changes of position by performing a simultaneous localization and mapping algorithm (SLAM), which involves detecting objects in the surroundings in the relative coordinate system and assigning the detected objects positions in the relative coordinate system, wherein the SLAM algorithm is based on image processing of image data captured using the light sensor.

3. The method as claimed in claim 1 , wherein the optically identifiable identifiers comprise light sources that transmit unique light signals associated with respective optically identifiable identifiers, and wherein the light sensor captures the light signals,
wherein the light sources comprise flashing lights that emit symbols represented in flash sequences, the information content of which symbols permits a unique inference of the light source and hence of the position of the light source in the absolute coordinate system.

4. The method as claimed in claim 1 , wherein the optically identifiable identifiers comprise one-dimensional or two-dimensional code structures, and wherein the code structures represent symbols that comprise unique data associated with respective optically identifiable identifiers, and wherein the light sensor captures the code structures.

5. The method as claimed in claim 1 , wherein the optical identifiers comprise retroreflectors that reflect incident light in such a way that the light sensor captures reflected light.

6. The method as claimed in claim 1 , wherein the light sensor is in the form of:
a camera, and the relative position of the optically identifiable identifiers is ascertained by distance determination via two-dimensional or three-dimensional object detection in the image data of the camera, or
a light detection and ranging (LIDAR) sensor, and the relative position of the optically identifiable identifiers is ascertained by distance determination via a propagation delay measurement.

7. The method as claimed in claim 1 , wherein the computer-aided system further comprises a light signal source on the mobile apparatus for generating light signals that can be captured using the light sensor of the relative automatic position finding system, as a result of which the optically identifiable identifiers are captured and the relative positions are ascertained by using a camera with a projection system or a camera with laser-based time-of-flight measurement for relative position finding, and
wherein light signals in the infrared, visible and/or ultraviolet spectral range are sent by the mobile apparatus.

8. The method as claimed in claim 1 , wherein the absolute positions of the optically identifiable identifiers are transmitted to the computer-aided system via a wireless communication channel by communication with the absolute localization system.

9. The method as claimed in claim 1 , wherein the absolute localization system is incorporated in a data network that covers the localization area of the absolute localization system for the purposes of data interchange, the method further comprising:
moving the mobile apparatus into the localization area; and
transmitting the absolute positions of the optically identifiable identifiers present in the localization area to the mobile apparatus.

10. The method as claimed in claim 1 , wherein the relative coordinate system is coupled to the absolute coordinate system by using the known absolute positions of the at least temporarily stationary components.

11. The method as claimed in claim 1 , wherein the optically identifiable identifiers are in the form of light signal units and the light sensor is in the form of a camera, the method further comprising:
initiating sending of light signals by the light signal units in a signal sequence predetermined for each of the light signal units;
capturing the light signals using the camera, wherein the light signals form an arrangement of signal points associated with the respective light signal units in a camera image; and
determining the position of the camera in the absolute coordinate system by comparing the arrangement of signal points against the absolute positions of the light signal units in the absolute coordinate system that are associated with the signal points of the arrangement,
wherein the relative coordinate system is coupled to the absolute coordinate system in view of the position of the camera in the absolute coordinate system by adjusting an attitude of the relative coordinate system with reference to the camera.

12. The method as claimed in claim 11 , wherein the light signals are sent in the infrared, visible and/or ultraviolet spectral range and the camera is designed to detect infrared, visible and/or ultraviolet light.

13. The method as claimed in claim 11 , wherein the comparison of the arrangement of signal points involves the detected light signals being made to coincide with the known local reference of the related light signal units by coordinate transformation.

Assignees

• Trumpf Werkzeugmaschinen Gmbh Co Kg
• Trumpf Tracking Tech Gmbh

Inventors

• Bossert Daniel
• Wahl Eberhard
• Beuttler Manuel

Classifications

• G06T2207/30244

  Camera pose · CPC title

• G01S17/08

  for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) · CPC title

• G01S17/931

  of land vehicles · CPC title

• G06F3/011

  Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00) · CPC title

• G01S5/16

  using electromagnetic waves other than radio waves · CPC title