Stereo particle image velocimetry (PIV) system for long term coastal ocean deployment

Patent metadata

Field	Value
Publication number	US-11047873-B2
Application number	US-201916428781-A
Country	US
Kind code	B2
Filing date	May 31, 2019
Priority date	May 31, 2018
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

Systems and methods are provided for making in-situ measurements of the sea bed 3 component fluid velocity field and sediment motion across a range of real ocean conditions using particle image velocimetry (PIV). A PIV system in accordance with an embodiment of the present disclosure can include a camera to capture images of the particles in motion, a laser to generate a laser sheet for illuminating the particles, and a synchronizer to act as an external trigger for the laser and the camera.

First claim

What is claimed is:

1. A particle image velocimetry (PIV) device, the PIV device comprising:
a plurality of legs;
a turntable coupled to the plurality of legs;
a laser enclosure coupled to the turntable, wherein the laser enclosure is configured to enclose:
a multi-faceted rotating mirror configured to generate a laser sheet based on a first reflected laser beam, wherein the laser sheet is configured to illuminate a plurality of particles in a medium surrounding the PIV device,
a laser configured to generate a first laser beam,
a first mirror configured to reflect the first laser beam to the multi-faceted rotating mirror, thereby generating the first reflected laser beam,
a second mirror configured to receive a portion of the laser sheet and to generate a second reflected laser beam, and
a sensor device configured to receive the second reflected laser beam;

a camera enclosure coupled to the turntable, wherein the camera enclosure is configured to enclose a camera, and wherein the camera is configured to:
detect backscatter reflected from the plurality of particles, and
generate an image based on the backscatter; and

a control module enclosure configured to enclose a control module, wherein the control module is coupled to the sensor device and the camera, and wherein the control module is configured to synchronize the laser and the camera.

2. The PIV device of claim 1 , further comprising:
a second camera enclosure coupled to the turntable, wherein the second camera enclosure is configured to enclose a second camera, and wherein the control module is configured to synchronize the laser, the camera, and the second camera.

3. The PIV device of claim 1 , wherein the control module is further configured to control a rotation of the turntable.

4. The PIV device of claim 1 , wherein the control module comprises a synchronizer, wherein the synchronizer is coupled to the sensor device and the camera, and wherein the synchronizer is configured to synchronize the laser and the camera.

5. The PIV device of claim 1 , wherein the sensor device is configured to send a signal to the control module based on the second reflected laser beam, wherein the camera is configured to transmit the image to the control module, and wherein the control module is configured to synchronize the laser and the camera based on the signal and the image.

6. The PIV device of claim 1 , wherein the camera comprises a plurality of lenses, and wherein the control module is configured to control operation of the plurality of lenses.

7. The PIV device of claim 6 , wherein the plurality of lenses comprise an aperture lens and a focus lens.

8. The PIV device of claim 1 , wherein the control module is configured to:
instruct the laser to generate the first laser beam; and
instruct the camera to detect the backscatter.

9. A device, comprising:
a laser, enclosed by a first pressure vessel, wherein the laser is configured to generate a laser beam that illuminates a plurality of particles in a medium surrounding the device;
a camera, enclosed by a second pressure vessel, wherein the camera is configured to:
detect backscatter reflected from the plurality of particles, and
generate an image based on the backscatter; and

a control module, coupled to the laser and the camera, wherein the control module is enclosed by a third pressure vessel, and wherein the control module is configured to synchronize the laser and the camera.

10. The device of claim 9 , wherein the laser beam is a two dimensional laser sheet.

11. The device of claim 9 , wherein the medium is water.

12. The device of claim 9 , further comprising a second camera coupled to the control module, wherein the control module is further configured to synchronize the camera, the second camera, and the laser.

13. The device of claim 9 , further comprising a rotating mirror coupled to the laser, wherein the laser is configured to generate a first laser beam, wherein the first laser beam is reflected off the rotating mirror to generate the laser beam that illuminates the plurality of particles in the medium surrounding the device.

14. The device of claim 9 , wherein the device is located underwater, and wherein the device further comprises:
an umbilical cable coupled to the control module and to a source above water, wherein the umbilical cable is configured to deliver power and data to the device from the source.

15. A system for particle image velocimetry (PIV), the system comprising:
an particle image velocimetry (PIV) device located below water, the PIV device comprising:
a plurality of legs;
a turntable coupled to the plurality of legs;
a laser enclosure coupled to the turntable, wherein the laser enclosure is configured to enclose:
a multi-faceted rotating mirror configured to generate a laser sheet based on a first reflected laser beam, wherein the laser sheet is configured to illuminate a plurality of particles in a medium surrounding the PIV device,
a laser configured to generate a first laser beam,
a first mirror configured to reflect the first laser beam to the multi-faceted rotating mirror, thereby generating the first reflected laser beam,
a second mirror configured to receive a portion of the laser sheet and to generate a second reflected laser beam, and
a sensor device configured to receive the second reflected laser beam;

a camera enclosure coupled to the turntable, wherein the camera enclosure is configured to enclose a camera, and wherein the camera is configured to:
detect backscatter reflected from the plurality of particles, and
generate an image based on the backscatter; and

a control module enclosure configured to enclose a control module, wherein the control module is coupled to the sensor device and the camera, and wherein the control module is configured to synchronize the laser and the camera;

an umbilical cord coupled to the PIV device, wherein the umbilical cord is configured to send power and data to the PIV device; and
a command center device, coupled to the umbilical cord, wherein the command center device is located above water.

16. The system of claim 15 , wherein the command center device is configured to receive the image from the camera via the umbilical cord.

17. The system of claim 15 , wherein the command center device is configured to send a signal, via the umbilical cord, to the control module, wherein the signal instructs the control module to control an operation of the PIV device.

18. The system of claim 17 , wherein the signal instructs the control module to focus the camera.

19. The system of claim 17 , wherein the signal instructs the control module to rotate the first mirror, the second mirror, or the multi-faceted rotating mirror.

20. The system of claim 17 , wherein the PIV device further comprises:
a second camera enclosure coupled to the turntable, wherein the second camera enclosure is configured to enclose a second camera, and wherein the control module is configured to synchronize the laser, the camera, and the second camera.

Assignees

• Us Gov Sec Navy

Inventors

• Calantoni Joseph
• Braithwaite Edward
• Gray Callum
• Griffin Sean

Classifications

• G01P5/20 Primary

  using particles entrained by a fluid stream (G01P5/22 takes precedence) · CPC title

• G06T7/292

  Multi-camera tracking · CPC title

• G01P5/001

  Full-field flow measurement, e.g. determining flow velocity and direction in a whole region at the same time, flow visualisation · CPC title

• G06T7/246

  using feature-based methods, e.g. the tracking of corners or segments · CPC title

• G06T2207/30181

  Earth observation · CPC title