Aerial device that cooperates with an external projector to measure three-dimensional coordinates

Patent metadata

Field	Value
Publication number	US-9989357-B2
Application number	US-201615250324-A
Country	US
Kind code	B2
Filing date	Aug 29, 2016
Priority date	Sep 9, 2015
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A three-dimensional (3D) coordinate measuring system includes an external projector that projects a pattern of light onto an object and an aerial drone attached to a 3D imaging device, the 3D imaging device and the external projector cooperating to obtain 3D coordinates of the object.

First claim

What is claimed is:

1. A three-dimensional (3D) coordinate measuring system, comprising:
an external projector operable to operate while stationary and to project a first projected pattern of light onto an object; and
an aerial measuring device that includes an aerial drone and a 3D imaging device, the 3D imaging device being attached to the aerial drone, the 3D imaging device having a projector that emits a second pattern of light onto the object, the aerial measuring device being separate from the external projector, the aerial measuring device being operable to cooperate with the external projector to determine 3D coordinates of the object based at least in part on the first projected pattern of light and the second pattern of light.

2. A three-dimensional (3D) coordinate measuring system, comprising:
an external projector operable to operate while stationary and to project a first projected pattern of light onto an object; and
an aerial measuring device that includes an aerial drone and a 3D imaging device, the 3D imaging device being attached to the aerial drone, the aerial measuring device being separate from the external projector, the aerial measuring device being operable to cooperate with the external projector to determine 3D coordinates of the object, the aerial drone is movable from a first position to a second position, and wherein the 3D imaging device further comprises a first two-dimensional (2D) camera operable to capture a first 2D image from the first position and a second 2D image from the second position; and
one or more processors configured to execute nontransitory computer readable instructions, the computer readable instructions comprising:
identifying with the 3D imaging device three cardinal points common to the first image and the second image;
deriving each of the three cardinal points from the first projected pattern of light on the object or from natural features of the object, at least one of the three cardinal points being derived from the first projected pattern of light;
determining a first 3D coordinates of a first object point;
determining a second 3D coordinates of a second object point; and
determining a third 3D coordinates of a third object, the determined first 3D coordinates, determined second 3D coordinates, and determined third 3D coordinates based at least in part on the three cardinal points in the first image and the three cardinal points in the second image.

3. The 3D coordinate measuring system of claim 2 wherein the computer readable instructions further comprising:
configuring the external projector to project a first collection of spots of light onto the object, wherein the external projector comprises a source of laser light and a diffraction grating;
projecting with the external projector laser light through the diffraction grating and onto the object; and
adjusting power of the laser light according to an amount of light received by pixels of the first 2D camera.

4. The 3D coordinate measuring system of claim 2 , further comprising:
an internal projector operable to project a second pattern of projected light through a projector perspective center onto the object, the internal projector being configured to project a pulsed pattern of light, the second pattern of projected light being a line of light;
a second 2D camera operable to form a second camera image of the second pattern of projected light on the object, the second 2D camera having a camera perspective center, there being a baseline between the projector perspective center and the camera perspective center, the length of the baseline being a baseline distance, wherein the first 2D camera is a color camera;
wherein the aerial drone device further includes a second mechanism operable to steer the 3D imaging device into a plurality of directions, the second mechanism being operable to steer the 3D imaging device about two orthogonal axes and an angular transducer is provided to measure an angle of rotation of the second mechanism; and
wherein the computer readable instructions further comprise determining the 3D coordinates of the object based at least in part on the second pattern of projected light, the second camera image, and the baseline distance.

5. The 3D coordinate measuring system of claim 1 wherein the external projector is further configured to be moved by a motorized device, the motorized device, the motorized device being one of a mobile platform having motorized wheels or an aerial drone.

6. The 3D coordinate measuring system of claim 1 wherein:
the external projector includes a first mechanism operable to steer light from the external projector into a plurality of directions;
the first mechanism is operable to steer the light from the external projector about two orthogonal axes; and
a projector angular transducer is provided to measure an angle of rotation of the first mechanism.

7. The 3D coordinate measuring system of claim 2 wherein the computer readable instructions further comprise:
detecting motion of the external projector relative to the object, the determination based at least in part on movement of the first projected pattern of light relative and on cardinal points that are based on natural features of the object; and
determining a pose of the external projector based at least in part on the first projected pattern of light and on those cardinal points that are obtained from natural features of the object.

8. The 3D coordinate measuring system of claim 4 wherein the computer readable instructions further comprise:
detecting motion of the external projector relative to the object, the relative motion determined based at least in part on the first projected pattern of light, an observed movement of the first projected pattern of light, the second pattern of projected light, the second camera image, and the baseline distance; and
determining a pose of the external projector based at least in part on the first projected pattern of light, the observed movement of the first projected pattern of light, the second pattern of projected light, the second camera image, and the baseline distance.

9. A three-dimensional (3D) coordinate measuring system, comprising:
an external projector operable to project a first projected pattern of light onto an object;
an aerial measuring device in a device frame of reference, the aerial measuring device including a triangulation scanner and a registration camera, the triangulation scanner including an internal projector and a first camera; and
one or more processors configured to execute nontransitory computer readable instructions, the computer readable instructions comprising:
determining with the triangulation scanner 3D coordinates of the object in the device frame of reference in a first instance and a second instance;
acquiring an image with the registration camera of the first projected pattern of light in the first instance and the second instance; and
registering in a common frame of reference the determined 3D coordinates in the first instance and in the second instance based at least in part on the registration camera image of the first projected pattern of light in the first instance and the second instance.

10. The 3D coordinate measuring system of claim 9 wherein the first projected pattern of light is projected from the external projector while the external projector is stationary.

11. The 3D coordinate measuring system of claim 9 wherein
the external projector is attached to a motorized mobile platform operable to move the external projector to multiple positions, the motorized mobile platform being selected from a group comprising an apparatus having motorized wheels, a drone

Assignees

• Faro Tech Inc

Inventors

• Heidemann Rolf
• Wohlfeld Denis
• Bridges Robert E
• Kramer Helmut

Classifications

• B64U2101/30

  for imaging, photography or videography · CPC title

• G01C15/00

  Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00 · CPC title

• G01B11/24 Primary

  for measuring contours or curvatures · CPC title

• B64C39/00

  Aircraft not otherwise provided for · CPC title

• G01B11/254

  Projection of a pattern, viewing through a pattern, e.g. moiré · CPC title