Method and system for determining shutter fluttering sequence

• US 9,332,191 B2
• Filed: 04/09/2009
• Issued: 05/03/2016
• Est. Priority Date: 03/02/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: McCloskey, Scott, Jelinek, Jan, Au, Kwong Wing
• Primary Examiner(s): TANG, KAREN C
• Application Number:
  US12/421,296
• Publication Number:
  US 20100220896A1
• Time in Patent Office: 2,581 Days
• US Class Current: 1/1
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/80 Camera processing pipelines; Components thereof

Abstract

A method, system and computer-usable medium for determining 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 has several desired properties. These properties can be expressed in the context of a fitness function: given a fluttering pattern and the target subject'"'"'s velocity, it produces the equivalent Modulation Transfer Function (MTF), measures three attributes, and produces a fitness score. These attributes are the minimum contrast, the variance in contrast across spatial frequencies, and the mean contrast. The objective of the disclosed approach is to determine the fluttering pattern that maximizes the fitness score.

Claims

1. A method for fluttering a shutter according to a determined shutter fluttering sequence, said method comprising:

determining a modulation transfer function based on a particular shutter fluttering pattern and at least two properties associated with a target subject, said particular shutter fluttering pattern associated with a flutter shutter camera;

determining a minimum allowable open shutter duration for said flutter shutter camera;

measuring a plurality of attributes associated with said modulation transfer function, said measured attributes being combined to produce a fitness score;

identifying a fluttering pattern that maximizes said fitness score;

selecting a shutter fluttering sequence with respect to said shutter flutter and said target subject according to said fluttering pattern that maximizes said fitness score; and

communicating said shutter fluttering sequence to said flutter shutter camera in order to flutter said shutter of said flutter shutter camera according to said shutter fluttering sequence.

2. The method of claim 1 wherein identifying a fluttering pattern that maximizes said fitness score, further comprises specifying said fluttering pattern by sequentially:

first determining a number and a duration of each open shutter period with respect to at least one constraint associated with said flutter shutter camera; and

second identifying a start time of each open shutter period.

3. The method of claim 1 wherein said at least one property associated with said target subject comprises a velocity of said target subject.

4. The method of claim 1 wherein at least one attribute among said plurality of attributes comprises a minimum contrast.

5. The method of claim 1 wherein at least one attribute among said plurality of attributes comprises a variance in contrast across a plurality of spatial frequencies.

6. The method of claim 1 wherein at least one attribute among said plurality of attributes comprises a mean contrast.

7. The method of claim 1 further comprising:

capturing an image of said target subject from among a plurality of subjects in said image via said flutter shutter camera.

8. The method of claim 7 further comprising:

utilizing said shutter fluttering sequence with respect to said flutter shutter camera and said target subject; and

biometrically identifying said target subject among said plurality of subjects.

9. A system for fluttering a shutter according to a determined shutter fluttering sequence, said system comprising:

a flutter shutter camera;

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;

determining a modulation transfer function based on a particular shutter fluttering pattern and at least two properties associated with a target subject, said particular shutter fluttering pattern associated with said flutter shutter camera;

determining a minimum allowable open shutter duration for said flutter shutter camera;

measuring a plurality of attributes associated with said modulation transfer function, said measured attributes being combined to produce a fitness score;

identifying a fluttering pattern that maximizes said fitness score;

selecting a shutter fluttering sequence with respect to said shutter flutter and said target subject according to said fluttering pattern that maximizes said fitness score; and

communicating said shutter fluttering sequence to said flutter shutter camera in order to flutter said shutter of said flutter shutter camera according to said shutter fluttering sequence.

10. The system of claim 9 wherein said instructions for identifying a fluttering pattern that maximizes said fitness score are further configured to specify said fluttering pattern by sequentially:

first determining a number and a duration of each open shutter period with respect to at least one constraint of said flutter shutter camera; and

second identifying a start time of each open shutter period.

11. The system of claim 9 wherein said at least one property associated with said target subject comprises a velocity of said target subject.

12. The system of claim 9 wherein at least one attribute among said plurality of attributes comprises a minimum contrast.

13. The system of claim 9 wherein at least one attribute among said plurality of attributes comprises a variance in contrast across a plurality of spatial frequencies.

14. The system of claim 9 wherein at least one attribute among said plurality of attributes comprises a mean contrast.

15. The system of claim 9 wherein said instructions are further configured for capturing an image of said target subject from among a plurality of subjects in said image via said flutter shutter camera.

16. The system of claim 15 wherein said instructions are further configured for utilizing said shutter fluttering sequence with respect to said flutter shutter camera and said target subject;

and

biometrically identifying said target subject among said plurality of subjects.

17. An apparatus for fluttering a shutter according to a determined shutter fluttering sequence, said apparatus comprising:

a shutter flutter camera; and

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;

determining a modulation transfer function based on a particular shutter fluttering pattern and at least two properties associated with a target subject, said particular shutter fluttering pattern associated with said flutter shutter camera;

determining a minimum allowable open shutter duration for said flutter shutter camera;

measuring a plurality of attributes associated with said modulation transfer function, said measured attributes being used to produce a fitness score;

identifying a fluttering pattern that maximizes said fitness score;

selecting a shutter fluttering sequence with respect to said shutter flutter and said target subject according to said fluttering pattern that maximizes said fitness score; and

communicating said shutter fluttering sequence to said flutter shutter camera in order to flutter said shutter of said flutter shutter camera according to said shutter fluttering sequence.

18. The apparatus of claim 17 wherein said embodied computer program code for identifying a fluttering pattern that maximizes said fitness score, further comprises computer executable, instructions for specifying said fluttering pattern by sequentially:

first determining a number and a duration of each open shutter period with respect to at least one constraint of said flutter shutter camera; and

second identifying a start time of each open shutter period.

19. The apparatus of claim 17 wherein said at least one property associated with said target subject comprises a velocity of said target subject.

20. The apparatus of claim 17 wherein at least one attribute among said plurality of attributes comprises at least one of the following types of attributes:

a minimum contrast, a variance in contrast across a plurality of spatial frequencies, and a mean contrast.