Automated Determination of Cross-Stream Wind Velocity from an Image Series

• US 20090154771A1
• Filed: 12/13/2007
• Published: 06/18/2009
• Est. Priority Date: 12/13/2007
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: Cichiello, James M.
• Granted Patent: US 8,000,499 B2
• Time in Patent Office: Days
• US Class Current: 382/107
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20104 Interactive definition of region of interest [ROI]
• CPC Class Codes: G06T 2207/20132 Image cropping
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51

Abstract

Systems and methods are provided for determining the cross-stream component of wind velocity near a target location. A modal-decomposition of a first series of images is conducted to obtain a plurality of contribution functions representing the first set of images. A second series of images is mapped to a selected subset of the plurality of contribution functions to create a set of reconstructed images. At least one characteristic of the set of reconstructed images is measured to estimate the cross-stream component of the wind velocity near the target location.

Claims

1. A method for determining a cross-stream component of wind velocity near a target location, comprising:

conducting a modal-decomposition of a first series of images to obtain a plurality of contribution functions representing the first series of images;

mapping a second series of images onto a selected subset of the plurality of contribution functions to create a set of reconstructed images; and

measuring at least one characteristic of the set of reconstructed images to estimate the cross-stream component of the wind velocity near the target location.

2. The method of claim 1, wherein measuring the at least one characteristic of the set of reconstructed images comprises a frame-to-frame correlation of the set of reconstructed images and calculating a change in a position of at least one tracer between each correlated pair.

3. The method of claim 2, wherein measuring the at least one characteristic of the set of reconstructed images comprises translating the change in position of the at least one tracer to a velocity according to a known scale of the reconstructed images and a known frame rate.

4. The method of claim 1, wherein conducting the modal-decomposition of the first series of images comprises conducting a proper-orthogonal decomposition over the first series of images.

5. The method of claim 1, wherein mapping the second series of images onto the selected subset of the plurality of contribution functions comprises projecting each image from the second series of images onto the selected subset of contribution functions to produce a corresponding reconstructed image comprising a linear combination of the selected subset of contribution functions.

6. The method of claim 1, further comprising acquiring the first series of images at a sensor and stabilizing the first series of images to reduce jitter across the first series of images.

7. The method of claim 1, further comprising:

acquiring a set of images;

selecting a portion of the set of images, represented as a selected window of pixels having a common position on each of the acquired set of images; and

segmenting the selected window of each image from the remainder of the image to provide the first series of images.

8. The method of claim 1, further comprising displaying the estimated cross-stream component of the wind velocity at an associated display.

9. The method of claim 1, wherein conducting the modal-decomposition of the first series of images comprises selecting a group of contribution functions that represent the greatest contribution to a determined wind energy as the selected subset.

10. A system for monitoring a cross-stream component of wind velocity near a target location, comprising:

a sensor that captures a first series of images and a second series of images of the target location;

a modal-decomposition component that generates a set of contribution functions representing at least a portion of wind energy represented by distortion within the first series of images; and

a mapping component that maps the second series of images to the set of contribution functions to create a series of reconstructed images that facilitate the estimation of the cross-stream component of the wind.

11. The system of claim 10, further comprising a parameter-measurement component that determines the cross-stream component of the wind velocity from the series of reconstructed images.

12. The system of claim 11, the parameter-measurement component comprising an image-correlation component that correlates pairs of images in the series of reconstructed images and calculates a change in a position of at least one tracer between each correlated pair.

13. The system of claim 10, the sensor comprising a camera that images the target location in one of the visible spectrum and the infrared spectrum.

14. The system of claim 13, the sensor further comprising a window-selection component that selects a portion of each of a plurality of images provided by the camera to produce the first series of images and the second series of images.

15. A spotter scope comprising the system of claim 10.

16. A system for monitoring a cross-stream component of wind velocity near a target location, comprising:

a sensor that captures a first series of images of the target location;

a mapping component that maps the first series of images onto a set of contribution functions to create a series of reconstructed images containing at least one tracer feature that illustrates the cross-stream component of the wind velocity; and

a parameter-measurement component that determines the cross-stream component of the wind velocity from the at least one tracer feature.

17. The system of claim 16, further comprising a modal-decomposition component that generates the set of contribution functions from a second series of images.

18. The system of claim 16, further comprising an image stabilization component that provides a frame-by-frame alignment the first series of images to reduce mechanical jitter.

19. The system of claim 16, the sensor comprising a camera that images the target location in the infrared spectrum.

20. A sniper scope comprising the system of claim 16.