Surveying system

Patent metadata

Field	Value
Publication number	US-10371518-B2
Application number	US-201816197071-A
Country	US
Kind code	B2
Filing date	Nov 20, 2018
Priority date	May 5, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 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, particularly wherein the surveying system further comprising a hand-carried surveying pole and the position measuring resource being mounted on the hand-carried surveying pole:
the camera module comprising at least one camera for capturing images, particularly wherein the camera module is designed to be attached to the hand-carried surveying pole,
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 reference point field is built up comprising a plurality of reference points of the surrounding, wherein coordinates of the reference points are derived, and
the poses for the images are determined,

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,
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 and
the point cloud is scaled, and particularly geo-referenced, with help of the received determined positions.

2. A subsystem according to claim 1 , wherein,
the control and evaluation unit is configured so that the spatial representation generation functionality is controlled and executed in such a way, that the point cloud is generated:
spatially inclusive and comprehensive across the whole surrounding and/or
with comparatively low resolution of the 3d-information across the surrounding, thus providing comparatively fast processing of the point cloud.

3. The subsystem according to claim 1 , wherein:
the control and evaluation unit is configured so that the spatial representation generation functionality is controlled and executed in such a way, that a graphical reproduction is generated for the scaled point cloud, the graphical reproduction being displayable by display means of the surveying system, thus providing for a direct feedback to a user about already acquired data, so that the already acquired data can be checked regarding its completeness.

4. The subsystem according to claim 1 , wherein,
the control and evaluation unit is configured so that the spatial representation generation functionality is controlled and executed in such a way, that position information is derived for a single point selected in at least one image of the series of images, wherein a subset of images with determined poses related to the selected point is automatically identified from the series of images, particularly all images in which the selected point appears, and the position information is calculated based on the subset, particularly after the point was manually selected by a user.

5. The subsystem according to claim 1 , wherein,
the control and evaluation unit is configured so that the spatial representation generation functionality is controlled and executed in such a way, that the point cloud is processed covering:
the surrounding as a whole as commonly appearing at least in pairs of images of series of images, thus providing for a global representation with comparatively low point-to-point resolution, and/or
a defined region of the surrounding as commonly appearing at least in pairs of images of series of images, thus providing for a regional representation with higher point-to-point resolution compared to the global representation, particularly wherein the point-to-point resolution of the point cloud is automatically adapted depending on the size of the region so that processing time fulfils a defined threshold.

6. The subsystem according to claim 1 , wherein,
the position measuring resource comprises a GNSS-antenna or a retro-reflector.

7. The subsystem according to claim 1 , wherein,
orientations of the at least one camera, particularly in all three rotational degrees of freedom, in particular position and orientation in six degrees of freedom, are derived based on one or more of the determined poses and further based on:
data from an inertial measuring unit of the camera module, and/or
a multitude of determined positions of the position measuring resource, particular a travelling history for the moved path.

8. 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, and
a surveying subsystem according to claim 1 .

9. A surveying subsystem comprising a camera module and a control and evaluation unit to be used as part of a surveying system that is adapted to determine positions with use of a surveying pole:
the camera module being designed to be attached to the surveying pole in a known distance to a bottom end of the pole and 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 scaling 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, a surrounding ground appearing in the images, 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 reference point field is built up comprising a plurality of reference points of the surrounding, wherein coordinates of the reference points are derived, and
the poses for the images are determined;

based on the determined poses, a point cloud comprising 3D-positions of points of the surrounding is computed by forward intersection using the series of images, particularly by using dense matching algorithm;
a distance from the camera to the ground is determined based on the known distance from the camera to the bottom end; and
the point cloud is scaled based on the determined distance.

10. The subsystem according to claim 9 , wherein:
scaling the point cloud comprises determining 3D-positions of points on the ground based on the determined distance.

11. The subsystem according to claim 9 , wherein,
determining the distance from the camera to the ground comprises deriving an orientation of the camera.

12. The subsystem according to claim 9 , wherein,
the orientation, particularly in all three rotational degrees of freedom, in particular position and orientation in six

Assignees

• Hexagon Technology Ct Gmbh

Inventors

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

Classifications

• H04N23/635

  Region indicators; Field of view indicators · CPC title

• H04N23/63

  by using electronic viewfinders · CPC title

• H04N23/55

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• H04N23/57

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