Devices for refractive field visualization

Patent metadata

Field	Value
Publication number	US-10636149-B2
Application number	US-201715819791-A
Country	US
Kind code	B2
Filing date	Nov 21, 2017
Priority date	May 15, 2013
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

An apparatus according to an embodiment of the present invention enables measurement and visualization of a refractive field such as a fluid. An embodiment device obtains video captured by a video camera with an imaging plane. Representations of apparent motions in the video are correlated to determine actual motions of the refractive field. A textured background of the scene can be modeled as stationary, with a refractive field translating between background and video camera. This approach offers multiple advantages over conventional fluid flow visualization, including an ability to use ordinary video equipment outside a laboratory without particle injection. Even natural backgrounds can be used, and fluid motion can be distinguished from refraction changes. Embodiments can render refractive flow visualizations for augmented reality, wearable devices, and video microscopes.

First claim

What is claimed is:

1. An augmented reality apparatus comprising:
a video camera with an imaging plane, the video camera configured to capture video of a scene including a textured background, the video including captured light that passes from the textured background to the imaging plane through a refractive field; and
an augmented reality display configured to render the video of the scene with a visualization of actual motions of the refractive field, the actual motions determined by correlating, over time, representations of apparent motions of the textured background observed at the imaging plane in the video from frame to frame by modelling translations of the refractive field as causing the apparent motions.

2. The apparatus of claim 1 , wherein the visualization includes representations of velocities of the refractive field based upon the correlated representations of the apparent motions.

3. The apparatus of claim 1 , wherein the refractive field is a fluid.

4. The apparatus of claim 1 , further including a processor configured to determine the actual motions by correlating the representations of the apparent motions through an assumption of frame-to-frame changes in at least one of intensity and phase resulting from the motions alone.

5. The apparatus of claim 1 , further including a processor configured to determine the actual motions by correlating the representations of the apparent motions using an approximation that the apparent motions are constant from one video frame to another video frame.

6. The apparatus of claim 1 , wherein the visualization of actual motions of the refractive field is a visualization of a fluid turbulence, updraft, downdraft, or vortex.

7. The apparatus of claim 1 , wherein the actual motions of the refractive field arise from motion of one or more refractive objects in a fluid, and wherein the representations of the apparent motions are representations of motions of the one or more refractive objects.

8. The apparatus of claim 7 , wherein the one or more refractive objects include at least one of a smoke particle, molecule, region of the fluid differing in temperature from a surrounding region, region of fluid differing in pressure from a surrounding region, droplet, bubble, exhaust, hydrocarbon, or volatile substance.

9. The apparatus of claim 1 , wherein the textured background is a natural background.

10. The apparatus of claim 1 , wherein the display is wearable and further configured to render the video of the scene with a visualization of actual motions of the refractive field for viewing by a wearer's eye.

11. The apparatus of claim 10 , further comprising a processor configured to determine the actual motions.

12. The apparatus of claim 10 , wherein the video camera and the augmented reality display form part of an air traffic control system, an onboard airplane system, a weather monitoring system, a leak detection system, a civil engineering system, an aeronautical engineering system, or a ballistics or combustion monitoring system.

13. A wearable device comprising:
a video camera with an imaging plane, the video camera configured to capture video of a scene including a textured background, the video including captured light that passes from the textured background to the imaging plane through a refractive field; and
an augmented reality display configured to render a visualization of actual motions of the refractive field in a wearer's eye, the actual motions determined by correlating, over time, representations of apparent motions of the textured background observed at the imaging plane in the video from frame to frame by modelling translations of the refractive field as causing the apparent motions.

14. A video microscope comprising:
a video camera with a microscopic field of view and an imaging plane, the video camera configured to output video by capturing light that passes from a textured background to the imaging plane through a refractive field in the microscopic field of view; and
a display configured to show a visualization of actual motions of the refractive field in the microscopic field of view, the actual motions determined by correlating, over time, representations of apparent motions observed at the imaging plane in the video from frame to frame by modelling translations of the refractive field as causing the apparent motions.

15. The video microscope of claim 14 , wherein the visualization includes representations of velocities of the refractive field based upon the correlated representations of the apparent motions.

16. The video microscope of claim 14 , wherein the refractive field is a fluid.

17. The video microscope of claim 14 , further including a processor configured to determine the actual motions by correlating the representations of the apparent motions using an assumption of frame-to-frame changes in at least one of intensity and phase resulting from the motions alone.

18. The video microscope of claim 14 , further including a processor configured to determine the actual motions by correlating the representations of the apparent motions using an approximation that the apparent motions are constant from one video frame to another video frame.

19. The video microscope of claim 14 , wherein the motions of the refractive field arise from motion of one or more refractive objects in a fluid, and wherein the representations of the apparent motions are representations of motions of the one or more refractive objects.

20. The apparatus of claim 19 , wherein the one or more refractive objects include at least one of a molecule, region of the fluid differing in temperature from a surrounding region, region of fluid differing in pressure from a surrounding region, droplet, bubble, hydrocarbon, or volatile substance.

21. The video microscope of claim 14 , wherein the textured background is a natural background.

22. The video microscope of claim 14 , wherein the textured background is an artificial textured background having microscopic features.

23. The video microscope of claim 14 , wherein the microscopic field of view includes at least a partial view of a chemical sample or a cell culture or other biological sample.

Assignees

• Massachusetts Inst Technology

Inventors

• Freeman William T
• Durand Frederic
• Xue Tianfan
• Rubinstein Michael
• Wadhwa Neal

Classifications

• G06T2207/10056

  Microscopic image · CPC title

• G02B27/54

  Schlieren-optical systems · CPC title

• G06T7/246

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

• G01P5/26

  by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave · CPC title

• G06T7/20 Primary

  Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) · CPC title