Method for operating a geodetic instrument, and related geodetic instrument

Patent metadata

Field	Value
Publication number	US-12596005-B2
Application number	US-202318116119-A
Country	US
Kind code	B2
Filing date	Mar 1, 2023
Priority date	Sep 30, 2020
Publication date	Apr 7, 2026
Grant date	Apr 7, 2026

Abstract

The present inventive concept relates to a method for operating a geodetic instrument comprising an optical source for assisting a user in aiming at a target in a scene by emitting optical pulses forming a spot at the target, and an imaging device, wherein the imaging device and the optical source share a common optical channel within the geodetic instrument, the method comprising: capturing a first image of a scene with the optical source turned on; obtaining a reference image from at least the first image, wherein contribution from the scene is suppressed, the reference image representing crosstalk occurring in the common optical channel; capturing a second image with the optical source turned on; and processing the second image with the reference image for removing crosstalk from the second image.

First claim

The invention claimed is:

1 . A method for operating a geodetic instrument comprising an optical source for assisting a user in aiming at a target in a scene by emitting optical pulses forming a spot at the target, and an imaging device, wherein the imaging device and the optical source share a common optical channel within the geodetic instrument, the method comprising:
capturing a first image of a scene with the optical source turned on; obtaining a reference image from at least the first image, wherein contribution from the scene is suppressed, the reference image representing crosstalk occurring in the common optical channel; capturing a second image with the optical source turned on; and processing the second image with the reference image for removing crosstalk from the second image.

2 . The method according to claim 1 , wherein contribution from the spot is suppressed in the reference image by aiming the geodetic instrument such that the optical source is directed towards a target which does not reflect light emitted by the optical source back towards the imaging device when capturing the first image.

3 . The method according to claim 1 , wherein contribution from the scene is suppressed by providing a dark scene or a scene which does not reflect ambient light towards the imaging device.

4 . The method according to claim 1 , further comprising:
capturing a third image of the scene with the optical source turned off; and generating a difference image based on the first and third images, wherein contribution from the scene is suppressed; wherein the reference image is based on the difference image.

5 . The method according to claim 1 , further comprising
capturing additional images with the optical source turned on, the additional images and the first image forming a plurality of images; wherein obtaining the reference image comprises:
determining a lowest registered intensity level of each pixel of the imaging device among the plurality of images; and
obtaining the reference image using said determined lowest registered intensity level for each respective pixel of the imaging device.

6 . A method for operating a geodetic instrument comprising an optical source for assisting a user in aiming at a target in a scene by emitting optical pulses forming a spot at the target, and an imaging device, wherein the imaging device and the optical source share a common optical channel within the geodetic instrument, the method comprising:
capturing a plurality of images with the optical source turned on; determining a lowest registered intensity level of each pixel of the imaging device among the plurality of images; obtaining a reference image using said determined lowest registered intensity level for each respective pixel of the imaging device, the reference image representing crosstalk occurring in the common optical channel; capturing a to-be processed image with the optical source turned on; and processing the captured to-be processed image with the reference image for removing crosstalk from the to-be processed image.

7 . A geodetic instrument comprising:
an optical source for assisting a user in aiming at a target in a scene by emitting optical pulses forming a spot at the target; an imaging device configured to capture images of the scene using a frame sequence; wherein the imaging device and the optical source share a common optical channel within the geodetic instrument; and a processing unit configured to operate the geodetic instrument in accordance with a method as defined in claim 1 .

8 . The geodetic instrument according to claim 7 , wherein the optical source is an infrared laser, and wherein the imaging device is an infrared camera or a thermal imaging camera.

9 . The geodetic instrument according to claim 7 , wherein the optical source is a laser in the visible spectrum, and wherein the imaging device is configured to detect visible light.

Assignees

• Trimble Inc

Inventors

• Svanholm Set

Classifications

• G01C1/04

  combined with cameras · CPC title

• G01C15/002 Primary

  Active optical surveying means (optical plumbing G01C15/105) · CPC title