Surveying system

Patent metadata

Field	Value
Publication number	US-10495461-B2
Application number	US-201916398101-A
Country	US
Kind code	B2
Filing date	Apr 29, 2019
Priority date	May 5, 2014
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

A system is disclosed that comprises a camera module and a control and evaluation unit. The camera module is designed to be attached to the surveying pole and comprises at least one camera for capturing images. The control and evaluation unit has stored a program with program code so as to control and execute a functionality in which a series of images of the surrounding is captured with the at least one camera; a SLAM-evaluation with a defined algorithm using the series of images is performed, wherein a reference point field is built up and poses for the captured images are determined; and, based on the determined poses, a point cloud comprising 3D-positions of points of the surrounding can be computed by forward intersection using the series of images, particularly by using dense matching algorithm.

First claim

The invention claimed is:

1. A surveying subsystem comprising:
a camera module; and
a control and evaluation unit,
wherein:
the surveying subsystem is adapted to be used as part of a surveying system that is adapted to determine positions of a position measuring resource,
the camera module comprising at least one camera for capturing images,
the control and evaluation unit having stored a program with program code so as to control and execute a spatial representation generation functionality in which, when moving along a path through a surrounding:
a series of images of the surrounding is captured with the at least one camera, the series comprising an amount of images captured with different poses of the camera, the poses representing respective positions and orientations of the camera,
a SLAM-evaluation with a defined algorithm using the series of images is performed, wherein a plurality of respectively corresponding image points are identified in each of several sub-groups of images of the series of images and, based on resection and forward intersection using the plurality of respectively corresponding image points,
(a) a reference point field is built up comprising a plurality of reference points of the surrounding, wherein coordinates of the reference points are derived, and
(b) the poses for the images are determined, and

a quality indicative output is generated concerning the measurement uncertainty of a 3D-position for at least one point of the surrounding to be computable by forward intersection using the images of the series of images and the determined poses.

2. The subsystem according to claim 1 , wherein the forward intersection implies using a variance-covariance-matrix, and the quality indicative output is derived from the variance-covariance-matrix.

3. The subsystem according to claim 1 , wherein:
the quality indicative output represents an uncertainty regarding the precision with which the 3D-position for the at least one point is computable or computed, wherein the quality indicative output is influenced by at least one of the following:
a precision with which image-positions for the image points within the images is determinable,
an amount of images which are usable out of the series of images for the computation of the 3D-position for at least one point of the surrounding, and
a length of the baselines of the poses of the usable images.

4. The subsystem according to claim 1 , wherein:
based on the determined poses, a point cloud comprising 3D-positions of points of the surrounding is computed by forward intersection using the images of the series of images, and
the quality indicative output is generated for at least one of the computed points of the point cloud.

5. The subsystem according to claim 4 , wherein:
a graphical reproduction is generated for the point cloud representing the quality indicative output, the graphical reproduction being displayable by display means of the surveying system, thus providing for a feedback to a user about already acquired data, so that the already acquired data can be checked regarding its quality.

6. The sub system according to claim 4 , wherein:
the quality indicative output is represented by a coloured point cloud, a scaled indication or a specific sign displayable on display means of the surveying system.

7. The subsystem according to claim 1 , wherein
the camera module comprises a camera-arrangement being built and designed in such a way that a field of view of 360° at least in azimuthal direction are coverable, wherein the camera-arrangement comprises at least two cameras arranged in a common housing of the camera module.

8. The subsystem according to claim 7 , wherein a sensor unit is fixedly integrated into the common housing, the sensor unit comprising at least one of the following sensors:
inertial measuring unit,
gyroscope,
tilt sensor, and
magnetic compass.

9. A surveying system comprising:
a hand-carried surveying pole,
a position measuring resource being mounted on the surveying pole, wherein positions of the position measuring resource are determinable by the surveying system, wherein the position measuring resource comprises a GNSS-antenna or a retro-reflector, and
a surveying subsystem according to claim 1 , wherein the camera module of the surveying subsystem is designed to be attached to the hand-carried surveying pole.

10. A surveying subsystem comprising:
a camera,
a profiler, and
a control and evaluation unit,
wherein:
the surveying subsystem is adapted to be used as part of a surveying system that is adapted to determine positions of a position measuring resource,
the camera module is designed to be brought into a fixed mechanical connection with the position measuring resource, and comprising at least one camera for capturing images,
the profiler is designed to be brought into a fixed mechanical connection with the position measuring resource, in particular by being attached to the surveying pole, and is adapted for:
emission of a rotating laser beam, and
reception and detection of a returning part of the emitted laser beam being scattered back from points of a surrounding,

the profiler is further provided with an electronic distance measuring functionality as well as an angle measuring functionality for the rotating laser beam so that profiler measurement data comprising distance and angle information is gatherable, and
the control and evaluation unit has stored a program with program code so as to control and execute a spatial representation generation functionality in which, when moving along a path through the surrounding:
a series of images of the surrounding is captured with the camera, the series comprising a plurality of images captured with different poses of the camera, i.e. from different points on the path and with different orientations of the camera,
a SLAM-evaluation with a defined algorithm using the series of images is performed, wherein a plurality of respectively corresponding image points are identified in each of several sub-groups of images of the series of images and, based on resection and forward intersection using the plurality of respectively corresponding image points,
(a) a reference point field is built up comprising a plurality of reference points of the surrounding, wherein coordinates of the reference points are derived, and
(b) the poses for the images are determined,

determined positions of the position measuring resource for points that have been adopted on the path are received by the control and evaluation unit from the surveying system,
a 6-dof-travelling-history including translational and rotational information in 6 degrees of freedom is derived for the moved path based at least on the poses determined within the SLAM-evaluation and the received determined positions, particularly by use of a Kalman filter, and
coordinates for points of the surrounding are determined as the spatial representation, based on the profiler measurement data in combination with the derived 6-dof-travelling-history.

11. The subsystem according to claim 10 , wherein:
the surveying subsystem further comprises an inertial measurement unit designed to be brought into a fixed mechanical connection with the position measuring resource and designed for gathering IMU measurement data, and
the control and evaluation unit is configured so that the spatial representation generation functionality is controlled and executed in such a way, that the 6-dof-travelling-history is derived further based on the IMU measurement data, particularly wherein the IMU measurement data and the SLAM-evaluation are taken into account for deriving the rotatio

Assignees

• Hexagon Technology Ct Gmbh

Inventors

• Siercks Knut
• Metzler Bernhard
• Van Der Zwan Elmar Vincent
• Fidler Thomas
• Parys Roman
• Velizhev Alexander
• Scheja Jochen

Classifications

• H04N23/698

  for achieving an enlarged field of view, e.g. panoramic image capture · CPC title

• H04N23/57

  Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices · CPC title

• H04N23/51

  Housings · CPC title

• H04N23/69

  Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming · CPC title

• H04N23/63

  by using electronic viewfinders · CPC title