Geodetic surveying device with a microlens array

• US 10,107,624 B2
• Filed: 08/07/2014
• Issued: 10/23/2018
• Est. Priority Date: 08/08/2013
• Status: Active Grant

• Current Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Original Assignee: Hexagon Technology Center GmbH (Hexagon AB)
• Inventors: Hinderling, Jurg, Metzler, Bernhard
• Primary Examiner(s): Patel, Jayanti K
• Assistant Examiner(s): Haghani, Shadan E
• Application Number:
  US14/454,395
• Publication Number:
  US 20150042790A1
• Time in Patent Office: 1,538 Days
• Field of Search: None
• CPC Class Codes: G01C 1/04 combined with cameras
• CPC Class Codes: G01C 11/02 Picture taking arrangements specially adapted for photogrammetry or photographic surveying, e.g. controlling overlapping of pictures
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors

Abstract

Some embodiments relate to a geodetic surveying device having a beam source for generating measurement radiation, a base defining a vertical axis, a support carrying a targeting unit and defining a tilt axis, the support being arranged on the base and rotatable relative to the base about the vertical axis, and the targeting unit being arranged rotatable relative to the support about the tilt axis, and an angle- and distance-measuring functionality. Moreover, the geodetic surveying device has an image acquisition unit for acquiring images of an object in a field of view defined by the image acquisition unit, and a control and processing unit. The image acquisition unit has at least an image sensor and a microlens array with a multiplicity of diffractive and/or refractive optical elements arranged in a defined two-dimensional manner.

Claims

1. A theodolite device comprising:

a beam source for generating measurement radiation defining a measurement axis,

a base defining a vertical axis,

a telescopic sight for targeting an object by aligning the telescopic sight on the object,

a support carrying the telescopic sight and defining a tilt axis, the support being arranged on the base and rotatable relative to the base about the vertical axis, and the telescopic sight being arranged rotatable relative to the support about the tilt axis,

an angle- and distance-measuring functionality, and

a control and processing unit,

wherein the telescopic sight comprises an image acquisition unit for acquiring images of an object in a field of view;

defined by the image acquisition unit, and

directed parallel to the measurement axis, and

wherein the image acquisition unit at least comprises;

an image sensor; and

a microlens array with a plurality of diffractive and/or refractive optical elements arranged in a defined two-dimensional manner,

wherein, during a measurement process by means of the image sensor, the image acquisition unit is configured to;

acquire image pieces respectively generated by the diffractive and/or refractive optical elements and representing at least parts of the object, and

generate an image data record representing the image pieces and comprising image information with a distance/focusing relation in respect of the field of view,

wherein an image corresponding to a currently measured distance is generated based on the currently measured distance by the control and processing unit from the image data record in such a way that objects situated at the measured distance are depicted in the image with a first degree of sharpness and objects at a different distance are depicted with a lower degree of sharpness, wherein the currently measured distance is measured with the measurement radiation of the beam source.

2. The theodolite device according to claim 1, wherein the microlens array is arranged with a fixed position and alignment relative to the image sensor and a respective beam entry direction for light beams incident on the image sensor can be derived from the image data record.

3. The theodolite device according to claim 1, wherein the diffractive and/or refractive optical elements have at least two different focal lengths.

4. The theodolite device according to claim 3, wherein the image sensor and the microlens array are arranged and interact in such a way that, as a result of the arrangement and the focal lengths of the diffractive and/or refractive optical elements, the generated image pieces in each case represent at least part of the field of view and can be projected onto the image sensor with a defined offset.

5. The theodolite device according to claim 3, wherein the microlens array is embodied and arranged in such a way that image pieces of objects at different object distances can be projected onto a common image plane by the groups of optical elements, the image sensor being arranged for acquiring the image pieces generated in the image plane.

6. The theodolite device according to claim 5, wherein the image sensor is arranged in the image plane.

7. The theodolite device according to claim 1, wherein the diffractive and/or refractive optical elements of the microlens array are assigned to a number of groups, with the optical elements assigned to a group in each case having the same focal length and a first group differing from a second group in terms of the focal length of the assigned optical elements.

8. The theodolite device according to claim 1, wherein the image acquisition unit comprises an objective lens arranged in such a way that

incident light from the field of view is projected onto the microlens array by the objective lens or

light incident through the microlens array is projected onto the image sensor by the objective lens.

9. The theodolite device according to claim 1, wherein the image sensor comprises a plurality of sub-sensors arranged in two dimensions, with the image pieces generated by the microlens array being projectable onto the sub-sensors and it being possible to generate the image data record by means of the plurality of sub-sensors.

10. The theodolite device according to claim 1, wherein the image acquisition unit is embodied as an overview camera, the overview camera defining a field of view separate from the telescopic sight and being arranged separately from the telescopic sight.

11. The theodolite device according to claim 1, wherein the image acquisition unit is arranged in the telescopic sight in such a way that the field of view of the image acquisition unit substantially corresponds to the field of view of a telescopic sight for targeting the target of the telescopic sight.

12. The theodolite device according to claim 1, wherein the control and processing unit is configured to:

generate a plurality of image pieces, respectively imaging the object at least in part with at least two different depth of field ranges,

acquire the image pieces and

generate an image data record representing the image pieces.

13. A method for image acquisition using a theodolite device comprising:

a beam source for generating measurement radiation for distance measuring, wherein the measurement radiation defines a measurement axis,

a base defining a vertical axis,

a telescopic sight for targeting an object by aligning the telescopic sight on the object,

a support carrying the telescopic sight and defining a tilt axis, the support being arranged on the base and rotatable relative to the base about the vertical axis, and the telescopic sight being arranged rotatable relative to the support about the tilt axis,

an angle- and distance-measuring functionality, and

a control and processing unit,

wherein the telescopic sight comprises an image acquisition unit for acquiring images of an object in a field of view

defined by the image acquisition unit and

directed parallel to the measurement axis;

the method comprising;

generating a plurality of image pieces, respectively imaging the object at least in part with at least two different depth of field ranges,

acquiring the image pieces and

generating an image data record representing the image pieces and comprising image information with a distance/focusing relation in respect of the field of view,

wherein an image corresponding to a currently measured distance is generated based on the currently measured distance from the image data record in such a way that objects situated at the measured distance are depicted in the image with a first degree of sharpness and objects at a different distance are depicted with a lower degree of sharpness, wherein the currently measured distance is measured with the measurement radiation of the beam source.

14. The method according to claim 13, wherein distance information for the object is derived from the image data record.

15. The method according to claim 13, wherein distance information for the object is derived from the image data record using triangulation for each image piece with a 3D point cloud being generated.

16. The method according to claim 13, wherein a sub-image data record is derived from the image data record, the former representing a sub-image with at least one image region which can be depicted in focus, with image elements within the at least one image region being generated substantially on the basis of a single image piece or a defined number of image pieces from the plurality of image pieces generated together, on the basis of the different depth of field ranges for the image pieces with the image elements being acquired with a common object distance.

17. The method according to claim 13, wherein a sub-image data record is derived from the image data record, the former representing a sub-image with at least one image region which can be depicted in focus, with image elements within the at least one image region being generated substantially on the basis of a single image piece or a defined number of image pieces from the plurality of image pieces generated together, on the basis of the different depth of field ranges for the image pieces, the image region being selected by a user input.

18. The method according to claim 13, wherein an in-focus image with a depth of field which is as large as possible corresponding to the different depth of field ranges for the image pieces, is calculated from the image data record.

19. A tangible, non-transitory computer program product, stored on a machine-readable medium that when executed by a processor causes the processor to perform the method of claim 13, the method comprising:

controlling the generation of a plurality of image pieces;

controlling the acquisition of image pieces; and

controlling the generation of the image data record, representing the image pieces.