Method and system for designing optimal flutter shutter sequence

• US 8,537,272 B2
• Filed: 11/17/2010
• Issued: 09/17/2013
• Est. Priority Date: 03/02/2010
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Jelinek, Jan, McCloskey, Scott
• Primary Examiner(s): Pasiewicz, Daniel M
• Application Number:
  US12/948,015
• Publication Number:
  US 20110216211A1
• Time in Patent Office: 1,035 Days
• Field of Search: 348/208.4, 348/208.6, 348/208.12, 348/241, 348/248, 348/362, 348/367, 382/115, 382/190, 382/191
• US Class Current: 348/367
• CPC Class Codes: H04N 23/683 performed by a processor, e.g. controlling the readout of an image memory
• CPC Class Codes: H04N 23/6845 by combination of a plurality of images sequentially taken

Abstract

A method, system and computer-usable medium for determining an optimal shutter fluttering sequence. The disclosed approach is based on the use of shutter flutter technology, which means that an image can be acquired in such a manner as to encode all information about the moving subject. The disclosed approach involves determining a shutter'"'"'s fluttering pattern that optimally encodes information at all frequencies. The disclosed approach involves an optimization method for finding a shutter fluttering pattern that maximizes the minimum value of a function defining the plurality of flutter shutter sequences over a frequency domain. The disclosed approach involves eliminating all flutter shutter sequences that contain lost frequencies. The objective of the disclosed approach is to select an optimal flutter shutter sequence for implementation with a flutter shutter camera.

Claims

1. A method for determining an optimal flutter shutter sequence, said method comprising:

defining a total required exposure time for a flutter shutter camera, wherein said total required exposure time is determined by an amount of energy required to create an exposed image;

generating a plurality of flutter shutter sequences, wherein said plurality of flutter shutter sequences includes a plurality of on chops which sum to said total required exposure time, said plurality of flutter shutter sequences associated with said flutter shutter camera; and

searching said plurality of flutter shutter sequences for optimal flutter shutter sequences, wherein said optimal flutter shutter sequences maximize a minimum value of a function defining said plurality of flutter shutter sequences over a particular frequency domain in order to thereafter implement said optimal flutter shutter sequences via said flutter shutter camera; and

wherein searching said plurality of flutter shutter sequences further comprises;

eliminating flutter shutter sequences among said plurality of flutter shutter sequences, which include a root on a unit circle in said particular frequency domain, which correspond to lost frequencies, utilizing a Jury algorithm.

2. The method of claim 1 further comprising implementing said optimal flutter shutter sequences via said flutter shutter camera.

3. The method of claim 1 wherein searching said plurality of flutter shutter sequences further comprises:

eliminating flutter shutter sequences among said plurality of flutter shutter sequences which include a root on a unit circle in said particular frequency domain, and which correspond to lost frequencies, utilizing a Schur-Cohn algorithm.

4. The method of claim 1 further comprising:

resealing a radius of said unit circle to eliminate flutter shutter sequences among said plurality of flutter shutter sequences, which have values corresponding to frequencies near zero.

5. The method of claim 1 further comprising:

evaluating remaining flutter shutter sequences among said plurality of flutter shutter sequences for smoothness; and

selecting a smoothest remaining flutter shutter sequence among said plurality of flutter shutter sequences as said optimal flutter shutter sequence.

6. The method of claim 1 further comprising:

capturing an image of a target subject from among a plurality of subjects via said flutter shutter camera, wherein a shutter of said flutter shutter camera is opened according to said optimal flutter shutter sequence.

7. The method of claim 6 further comprising:

utilizing said optimal flutter shutter sequence with respect to said flutter shutter camera and said target subject to biometrically identify said target subject among said plurality of subjects.

8. A system for determining a shutter fluttering sequence, said system comprising:

a processor;

a data bus coupled to the processor; and

a computer-usable medium embodying computer code, the computer-usable medium being coupled to the data bus, the computer program code comprising instructions executable by the processor and configured for;

defining a total required exposure time for a flutter shutter camera, wherein said total required exposure time is determined by an amount of energy required to create an exposed image;

generating a plurality of flutter shutter sequences, wherein said plurality of flutter shutter sequences includes a plurality of on chops which sum to said total required exposure time, said plurality of flutter shutter sequences associated with said flutter shutter camera; and

searching said plurality of flutter shutter sequences for optimal flutter shutter sequences, wherein said optimal flutter shutter sequences maximize a minimum value of a function defining said plurality of flutter shutter sequences over a particular frequency domain in order to thereafter implement said optimal flutter shutter sequences via said flutter shutter camera, wherein searching said plurality of flutter shutter sequences further comprises;

eliminating flutter shutter sequences among said plurality of flutter shutter sequences, which include a root on a unit circle in said particular frequency domain, which correspond to lost frequencies, utilizing a Jury algorithm.

9. The system of claim 8 wherein said instructions are further configured implementing said optimal flutter shutter sequences via said flutter shutter camera.

10. The system of claim 8 wherein searching said plurality of flutter shutter sequences further comprises:

eliminating flutter shutter sequences among said plurality of flutter shutter sequences which include a root on a unit circle in said particular frequency domain, and which correspond to lost frequencies, utilizing a Schur-Cohn algorithm.

11. The system of claim 8 wherein said instructions are further configured for resealing a radius of said unit circle to eliminate flutter shutter sequences among said plurality of flutter shutter sequences, which have values corresponding to frequencies near zero.

12. The system of claim 8 wherein said instructions are further configured for evaluating remaining flutter shutter sequences among said plurality of flutter shutter sequences for smoothness;

and selecting a smoothest remaining flutter shutter sequence among said plurality of flutter shutter sequences as said optimal flutter shutter sequence.

13. The system of claim 8 wherein said instructions are further configured for capturing an image of a target subject from among a plurality of subjects via said flutter shutter camera, wherein a shutter of said flutter shutter camera is opened according to said optimal flutter shutter sequence.

14. The system of claim 13 wherein said instructions are further configured for utilizing said optimal flutter shutter sequence with respect to said flutter shutter camera and said target subject to biometrically identify said target subject among said plurality of subjects.

15. The system of claim 9 wherein said instructions are further configured for utilizing said shutter fluttering sequence with respect to said flutter shutter camera and said target subject to biometrically identify said target subject among said plurality of subjects.

16. A non-transitory computer-usable medium for determining a shutter fluttering sequence, said computer-usable medium embodying computer program code, said computer program code comprising computer executable instructions configured for:

defining a total rewired erasure time for a flutter shutter camera, wherein said total required exposure time is determined by an amount of energy required to create an exposed image;

generating a plurality of flutter shutter sequences, wherein said plurality of flutter shutter sequences includes a plurality of on chops which sum to said total required exposure time, said plurality of flutter shutter sequences associated with said flutter shutter camera; and

searching said plurality of flutter shutter sequences for optimal flutter shutter sequences, wherein said optimal flutter shutter sequences maximize a minimum value of a function defining said plurality of flutter shutter sequences over a particular frequency domain in order to thereafter implement said optimal flutter shutter sequences via said flutter shutter camera, wherein searching said plurality of flutter shutter sequences further comprises;

eliminating flutter shutter sequences among said plurality of flutter shutter sequences, which include a root on a unit circle in said particular frequency domain, which correspond to lost frequencies, utilizing a Jury algorithm.

17. The non-transitory computer-usable medium of claim 16 wherein said optimal flutter shutter sequences are capable of being implemented by said flutter shutter camera.

18. The non-transitory computer-usable medium of claim 16 wherein said computer executable instructions are further configured for resealing a radius of said unit circle to eliminate flutter shutter sequences among said plurality of flutter shutter sequences, which values corresponding to frequencies near zero.

19. The non-transitory computer-usable medium of claim 16 wherein said computer executable instructions are further configured for evaluating remaining flutter shutter sequences among said plurality of flutter shutter sequences for smoothness;

and selecting a smoothest remaining flutter shutter sequence among said plurality of flutter shutter sequences as said optimal flutter shutter sequence.