Measuring system with panoramic image acquisition functionality

Patent metadata

Field	Value
Publication number	US-12356077-B2
Application number	US-202217706349-A
Country	US
Kind code	B2
Filing date	Mar 28, 2022
Priority date	Mar 30, 2021
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

A measuring system for acquiring three-dimensional measuring points, comprising a base unit, a support unit mounted on the base unit and rotatable relative to the base unit around an azimuth axis, an emitting unit, a receiving unit, a directing unit mounted in the support unit, and configured for directing a transmission beam from the emitting unit towards a scene, directing a reception beam from the scene to the receiving unit, a first actuator configured for rotating the support unit relative to the base unit around the azimuth axis, a second actuator configured for rotating the directing unit relative to the support unit around the elevation axis, a first angle encoder configured for measuring a rotatory position of the support unit, a second angle encoder configured for measuring a rotatory position of the directing unit, a camera comprising an image sensor.

First claim

The invention claimed is:

1. A measuring system for acquiring three-dimensional measuring points, comprising
a base unit,
a support unit mounted on the base unit and rotatable relative to the base unit around an azimuth axis,
an emitting unit configured for providing a transmission beam,
a receiving unit configured for detecting a reception beam,
a directing unit mounted in the support unit, rotatable relative to the support unit around an elevation axis, and configured for
directing the transmission beam from the emitting unit towards a scene,
directing the reception beam from the scene to the receiving unit,

a first actuator configured for rotating the support unit relative to the base unit around the azimuth axis,
a second actuator configured for rotating the directing unit relative to the support unit around the elevation axis,
a first angle encoder configured for measuring a rotatory position of the support unit,
a second angle encoder configured for measuring a rotatory position of the directing unit,
a camera comprising an image sensor, wherein the camera is configured for capturing an image of at least part of the scene,
a computer connected to the first actuator, the second actuator, the first angle encoder, the second angle encoder, and the camera, wherein the computer is configured for
controlling a rotatory speed of the support unit via the first actuator, and
controlling a rotatory speed of the directing unit via the second actuator,

the computer is configured for generating a first panoramic image with the camera, comprising:
controlling the image sensor to sample frames with a frame rate,
controlling the first actuator to rotate the support unit with a rotatory speed that is adapted to the frame rate of the image sensor in such a way that n consecutive frames are overlapping, wherein n≥3, and wherein the n consecutive overlapping frames comprise an overlapping region common to all of the n consecutive overlapping frames and

processing at least some of the sampled frames to form the first panoramic image by accumulation, the accumulation comprising mapping the overlapping sample frames onto the first panoramic image by taking at least the first angle encoder reading into account,
wherein controlling the image sensor to sample frames comprises controlling the image sensor to sample frames with an image aspect ratio of between 1:5 and 1:40,
wherein a long extent of the frames are aligned parallel to the azimuth axis and a shorter extent are aligned parallel to the elevation axis.

2. The measuring system according to claim 1 , comprising a display unit configured for
displaying the first panoramic image on a graphical user interface (GUI) and
augmenting the first panoramic image on the GUI with an indicator, the indicator in particular representing the current field of view of the camera or the current pointing direction of the camera.

3. The measuring system according to claim 1 , wherein, for generating the first panoramic image with the camera, the computer is further configured for controlling the image sensor to sample the frames with an alternating exposure time.

4. The measuring system according to claim 1 , wherein processing the sampled frames comprises stitching and averaging the overlapping consecutive frames.

5. The measuring system according to claim 1 , wherein the computer is configured for
comparing the overlapping parts of the overlapping consecutive frames with each other and
discarding abnormal overlapping parts when processing the sampled frames to form the first panoramic image.

6. The measuring system according to claim 1 , comprising a flicker sensor configured for detecting power-line flicker caused by a lamp illuminating the scene, wherein the computer is configured for adapting, based on the detected power-line flicker, at least one of
the frame rate and
the amount of overlapping consecutive frames n.

7. The measuring system according to claim 1 , wherein the computer is configured for
generating a second panoramic image covering the same part of the scene as the first panoramic image,
detecting moving obstacles in the first and second panoramic images based on an analysis of object contours, and,
in case a moving obstacle is detected in at least one of the first and second panoramic images, generating an obstacle-freed panoramic image by processing the first and second panoramic image such that the obstacle-freed panoramic image is at least in part freed from the detected moving obstacle.

8. The measuring system according to claim 1 , further comprising
a visual-spectrum (VIS) flash unit configured for emitting VIS flash light towards the scene and connected to the computer, or
an infrared (IR) flash unit configured for emitting IR flash light towards the scene and connected to the computer.

9. The measuring system according to claim 1 , wherein the camera further comprises a Time-Of-Flight (TOF) sensor or the image sensor is embodied as a Time-Of-Flight (TOF) sensor, said TOF sensor configured for capturing a TOF image, said TOF image comprising range data and image data, wherein the image data are either generated by the detection of visual-spectrum (VIS) light or IR light.

10. The measuring system according to claim 1 , wherein the computer is configured for adapting:
an exposure time of the sensor and
the rotatory speed of the support unit

based on an exposure time as detected necessary by the camera due to respective light conditions detected by the camera at the corresponding rotatory position of the support unit.

11. The measuring system according to claim 1 , wherein, for identifying a target which is located in the scene and emitting a modulated light pattern, the computer is configured for detecting the modulated light pattern based on the overlapping frames and relative times of capture of these overlapping frames.

12. The measuring system according to claim 1 , wherein the image sensor comprises a central crop region, and wherein the sample frames corresponding to the central crop region of the image sensor.

13. The measuring system according to claim 1 , wherein each pixel of the first panorama image is based on an averaging and blending of n-frames.

14. The measuring system according to claim 1 ,
wherein the mapping the overlapping sample frames onto the first panoramic image further taking the camera's intrinsic and extrinsic calibration into account, and
wherein the accumulation further comprising
normalized by dividing by the number of samples accumulated in each pixel of the first panoramic image.

15. The measuring system according to claim 1 , wherein processing at least some of the sampled frames to form the first panoramic image is embodied as
for n=3, processing every second of the sampled frames to form the first panoramic image, or
for n>3, processing at least every m-th of the sampled frames to form the first panoramic image, wherein m=(n−1).

16. The measuring system according to claim 15 , further comprising a flash unit configured for emitting a flash light towards the scene, the computer connected to the flash unit, the camera configured for detecting a reflection of the flash light, wherein, for generating a target location panoramic image with the camera, the computer is configured for:
for n=3, processing every respective other second of the sampled frames to form a fourth panoramic image, or for n>3, processing at least every r-th of the sampled frames to form a fourth panoramic image, wherein r=(n−1) and wherein the at least every r-th

Assignees

• Hexagon Technology Ct Gmbh

Inventors

• Stigwall Johan
• Schwendener Andreas
• Jensen Thomas
• Schröder Marco
• Yang Zheng

Classifications

• H04N23/695

  Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects · CPC title

• G01C11/025

  by scanning the object · CPC title

• G06V10/143

  Sensing or illuminating at different wavelengths · CPC title

• G06V10/145

  Illumination specially adapted for pattern recognition, e.g. using gratings · CPC title

• G06V20/64

  Three-dimensional [3D] objects · CPC title