Computational imaging using variable optical transfer function

• US 9,002,138 B2
• Filed: 12/30/2012
• Issued: 04/07/2015
• Est. Priority Date: 12/19/2011
• Status: Active Grant

• Current Assignee: Ziva Corporation
• Original Assignee: Ziva Corporation
• Inventors: Ranalli, Eliseo, Saperstein, Robert
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): Niu, Feng
• Application Number:
  US13/731,067
• Publication Number:
  US 20130329094A1
• Time in Patent Office: 828 Days
• Field of Search: None
• US Class Current: 382/280
• CPC Class Codes: G06T 2207/10004 Still image; Photographic image
• CPC Class Codes: G06T 2207/20024 Filtering details
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 5/10 using non-spatial domain filtering
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/75 by influencing optical camera components
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation
• CPC Class Codes: H04N 23/951 by using two or more images to influence resolution, frame rate or aspect ratio
• CPC Class Codes: H04N 25/60 Noise processing, e.g. detecting, correcting, reducing or removing noise
• CPC Class Codes: H04N 25/615 involving a transfer function modelling the optical system, e.g. optical transfer function [OTF], phase transfer function [PhTF] or modulation transfer function [MTF]
• CPC Class Codes: H04N 5/265 Mixing
• CPC Class Codes: H04N 9/646 for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters

Abstract

In selected embodiments, improved image restoration is realized using extensions of Wiener filtering combined with multiple image captures acquired after simple, fast reconfigurations of an optical imaging system. These reconfigurations may yield distinct OTF responses for each capture. The optical imaging system may reduce fabrication cost, power consumption, and/or system weight/volume by correcting significant optical aberrations. The system may be configured to perform independent correction of fields within the total field-of-regard. The system may also be configured to perform independent correction of different spectral bands.

Claims

1. An imaging method, comprising:

capturing a plurality of M captured images of an object through an optical system, the optical system comprising a configurable optical component, the configurable optical component being capable of being configured in a plurality of configurations, wherein each captured image of the plurality of M captured images is captured with the configurable optical component being in a different corresponding configuration of the plurality of configurations;

transforming each captured image of the plurality of M captured images using a selected spatial transform to obtain a corresponding transformed captured image, thereby obtaining a plurality of M transformed captured images;

weighting each transformed captured image of the plurality of M transformed captured images by a weighting coefficient (1−

η

)×

B_m wherein η

is a predetermined constant less than 1 and greater than 0, and B_m is computed using the formula

2. The imaging method of claim 1, wherein the selected spatial transform is a spatial Fourier Transform, and the inverse transform is an inverse spatial Fourier Transform.

3. The imaging method of claim 2, wherein the configurable optical component comprises a deformable mirror and the method further comprises configuring the deformable mirror in the plurality of different configurations using one or more control parameters of the deformable mirror.

4. The imaging method of claim 2, wherein:

the configurable optical component is a deformable mirror;

each of the steps of capturing, transforming, weighting, summing, and inverse transforming is performed at least in part by at least one processor of at least one computer system; and

one or more zeroes of the optical transfer function of the optical system differ for at least two configurations of the plurality of different configurations corresponding to at least two images of the plurality of M captured images.

5. The imaging method according to claim 1, further comprising configuring the configurable optical component in at least two configurations of the plurality of configurations.

6. The imaging method according to claim 5, wherein the step of configuring the configurable optical component comprises causing the optical system to wait for the object to move to a different field of the optical system.

7. The imaging method according to claim 5, wherein the step of configuring the configurable optical component causes at least one change in an optical axis of the optical system.

8. The imaging method according to claim 5, wherein the step of configuring the configurable optical component comprises providing relative motion between the configurable optical component and the object.

9. The imaging method according to claim 5, wherein the step of configuring the configurable optical component comprises changing at least one control parameter of a deformable mirror of the optical system.

10. The imaging method according to claim 5, wherein the step of configuring the configurable optical component comprises moving a focal plane array of the optical system.

11. The imaging method according to claim 5, wherein the step of configuring the configurable optical component effects at least one alteration in focus of the optical system.

12. The imaging method according to claim 5, wherein the step of configuring the configurable optical component comprises changing dioptric power of a lens of the optical system.

13. The imaging method according to claim 5, wherein the step of configuring the configurable optical component effects at least one change in size of an aperture of the optical system.

14. The imaging method according to claim 5, wherein the step of configuring the configurable optical component causes at least one change in zoom setting of the optical system.

15. The imaging method according to claim 5, wherein the step of configuring the configurable optical component comprises panning the optical system.

16. The imaging method according to claim 5, further comprising performing field correction of the plurality of M captured images.

17. The imaging method according to claim 5, further comprising performing spectral band correction of the plurality of M captured images.

18. An apparatus for processing images, the apparatus comprising:

an optical system comprising a configurable optical component, the configurable optical component being capable of being configured in a plurality of different configurations;

a storage device storing program code instructions; and

at least one processor, wherein the at least one processor is coupled to the optical system to enable the at least one processor to control configuration of the configurable optical component and to capture images in a focal plane of the optical system, and wherein the at least one processor is configured to execute the program code instructions to cause the apparatus to perform steps comprising;

capturing a plurality of M captured images of an object through the optical system, wherein each captured image of the plurality of M captured images is captured with the configurable optical component being in a different corresponding configuration of the plurality of configurations;

transforming each captured image of the plurality of M captured images using a selected spatial transform to obtain a corresponding transformed captured image, thereby obtaining a plurality of M transformed captured images;

weighting each transformed captured image of the plurality of M transformed captured images by a weighting coefficient (1−

η

)×

B_m wherein η

is a predetermined constant less than 1 and greater than 0, and B_m is computed using the formula

19. The apparatus of claim 18, wherein the selected spatial transform is a spatial Fourier Transform, and the inverse transform is an inverse spatial Fourier Transform.

20. The apparatus of claim 19, wherein the configurable optical component comprises a deformable mirror configurable in the plurality of different configurations using at least one control parameter of the deformable mirror.

21. The apparatus of claim 19, wherein:

the configurable optical component comprises a deformable mirror; and

one or more zeroes of the optical transfer function of the optical system differ for at least two configurations of the plurality of different configurations corresponding to at least two images of the plurality of M captured images.

22. The apparatus according to claim 21, wherein the configurable optical component comprises a variable aperture, and the at least one processor is configured to execute the program code instructions to change size of the variable aperture of the optical system from image to image.

23. The apparatus according to claim 21, wherein the at least one processor is further configured to execute the program code instructions to perform field-based correction of the plurality of M captured images.

24. The apparatus according to claim 21, wherein the at least one processor is further configured to execute the program code instructions to perform spectral band correction of the plurality of M captured images.

25. The imaging apparatus according to claim 21, wherein the configurable optical component comprises a configurable liquid-crystal based spatial light modulator.

26. The apparatus according to claim 21, wherein the configurable optical component comprises a configurable liquid lens.

27. The apparatus according to claim 21, wherein the configurable optical component comprises a movable detector array.