AUTOMATED EXTENDED DEPTH OF FIELD IMAGING APPARATUS AND METHOD

• US 20090225199A1
• Filed: 03/04/2009
• Published: 09/10/2009
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Applied Minds LLC
• Original Assignee: Applied Minds, Inc.
• Inventors: FERREN, Bran
• Granted Patent: US 8,154,647 B2
• Time in Patent Office: Days
• US Class Current: 348/240.990
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: H04N 23/62 Control of parameters via user interfaces
• CPC Class Codes: H04N 23/64 Computer-aided capture of images, e.g. transfer from script file into camera, check of taken image quality, advice or proposal for image composition or decision on when to take image
• CPC Class Codes: H04N 23/743 Bracketing, i.e. taking a series of images with varying exposure conditions
• CPC Class Codes: H04N 23/951 by using two or more images to influence resolution, frame rate or aspect ratio
• CPC Class Codes: H04N 23/959 by adjusting depth of field during image capture, e.g. maximising or setting range based on scene characteristics
• CPC Class Codes: H04N 5/2625 for obtaining an image which is composed of images from a temporal image sequence, e.g. for a stroboscopic effect sequence generated by event triggered capturing H04N7/188

Abstract

An imaging apparatus and method enables an automated extended depth of field capability that automates and simplifies the process of creating extended depth of field images. An embodiment automates the acquisition of an image “stack” or sequence and stores metadata at the time of image acquisition that facilitates production of a composite image having an extended depth of field from at least a portion of the images in the acquired sequence. An embodiment allows a user to specify, either at the time of image capture or at the time the composite image is created, a range of distances that the user wishes to have in focus within the composite image. An embodiment provides an on-board capability to produce a composite, extended depth of field image from the image stack. One embodiment allows the user to import the image stack into an image-processing software application that produces the composite image.

Claims

1. A system for extended depth-of-field imaging, comprising:

an imaging apparatus;

at least one processing element integrated on said imaging apparatus; and

storage means embodying program logic for automatically acquiring at least one stack of images having depths of field covering at least one specified range of distances, wherein execution of said program logic by said at least one processing element causes said system to acquire said at least one stack of images.

2. The system of claim 1, wherein said imaging apparatus comprises either a digital camera or a film camera.

3. The system of claim 1, further comprising a control element that enables a user to specify said range of distances, said control element comprising means for any of:

specifying said at least one range of distances directly; and

specifying boundaries of at least one out-of-focus range of distances, wherein an inverse of said at least one out-of-focus range of distances comprises said at least one specified range of distances.

4. The system of claim 3, wherein said control element is operative to enable said user to specify said at least one range of distances either before or after image acquisition.

5. The system of claim 3, wherein said control element is selected from the group consisting of:

one or more mechanical elements by which the user specifies near and far distances defining said at least one range of distances;

an integrated user interface wherein the user specifies said near and far distances defining said at least one range of distances by interacting with one or more elements within said user interface; and

an auto-focus system integrated within said apparatus that includes means for said user to specify said at least one range of distances by pointing a range finder at successive points of interest.

6. The system of claim 1, further comprising storage means embodying program logic for creating at least one composite, extended depth-of-field image from at least a portion of said at least one stack of images.

7. The system of claim 6, wherein execution of said program logic for creating said at least one composite, extended depth-of-field image by either said processing element integrated on said imaging apparatus or a processing element external to said imaging apparatus causes said system to create said at least one extended depth-of-field image from at least a portion of said at least one stack of images.

8. The system of claim 1, wherein said program logic for acquiring a stack of images having depths of field covering at least a specified range of distances comprises program logic for:

iteratively computing a focus distance for each stack image based on a hyperfocal distance and the near and far limits of the at least one specified range of distances until at least the specified range of distances is covered.

9. The system of claim 8, wherein a user is enabled to specify that the user wants to have exactly the specified range of distances in focus.

10. The system of claim 9, further comprising storage means embodying program logic for adjusting the focus distance of a terminal image in said range of distances so that a depth of field limit for said terminal image corresponds to a specified limit of said specified range of distances.

11. The system of claim 1, further comprising storage means embodying program logic for any of:

automatically determining f-number based on lens capabilities and light level; and

automatically selecting a maximum permissible circle of confusion.

12. The system of claim 1, wherein each of said depths of field covering at least one specified range of distances either overlap an adjacent depth of field or abut at least one adjacent depth of field.

13. The system of claim 1, further comprising at least one selected from a group consisting of:

control means for the user to specify a specific f-number at which stack images are to be acquired;

control means to specify specific f-numbers for individual stack images; and

control means to specify a maximum permissible circle of confusion.

14. The system of claim 1, further comprising:

selection means enabling said user to select an auto-EDOF mode from a plurality of modes, wherein acquisition of said stack of images proceeds automatically after shutter activation.

15. The system of claim 1, further comprising retraction means for retracting a reflex mirror during image acquisition.

16. The system of claim 1, further comprising a temporary cache offering faster write times than permanent memory, enabling faster image acquisition.

17. The system of claim 1, further comprising a processor programmed to

stabilize acquired images to compensate for subject or camera movement during image acquisition.

18. A system for extended depth-of-field imaging comprising:

an imaging apparatus;

means integrated on said imaging apparatus for automatically acquiring at least one stack of images having depths of field covering at least one specified range of distances.

19. The system of claim 18, further comprising:

means for creating at least one composite, extended depth-of-field image from at least a portion of said at least one stack of images.

20. A method of operating an apparatus for extended depth-of-field imaging comprising the steps of:

upon activation of a control element, at least one processing element within said apparatus for extended depth-of-field imaging executing stored program logic for automatically acquiring at least one stack of images having depths of field covering at least one specified range of distances;

responsive to said step of executing said stored program logic, said apparatus for extended depth-of-field imaging automatically acquiring said stack of images having depths of field covering at least said specified range of distances.

21. The method of claim 20, further comprising either of the steps of:

a user specifying said at least one range of distances directly, either before or after image acquisition; and

said user specifying boundaries of at least one out-of-focus range of distances, either before or after image acquisition, wherein an inverse of said at least one out-of-focus range of distances comprises said at least one specified range of distances.

22. The method of claim 20, wherein said apparatus comprises either a digital camera or a film camera.

23. The method of claim 20, further comprising the step of:

automatically creating at least one composite, extended depth-of-field image from at least a portion of said at least one stack of images.

24. The method of claim 20, wherein acquiring said stack of images having depths of field covering at least said specified range of distances comprises the steps of:

iteratively computing a focus distance for each stack image based on hyperfocal distance and the near and far limits of the specified range of distances until at least the specified range of distances is covered; and

acquiring at least one image at each computed focus distance.

25. The method of claim 24, further comprising the step of:

said user specifying that the user wants to have exactly the specified range of distances in focus.

26. The method of claim 25, further comprising the step of:

automatically adjusting the focus distance of a terminal image in said range of distances so that a depth of field limit for said terminal image corresponds to a specified limit of said specified range of distances.

27. The method of claim 20, further comprising the steps of:

automatically determining f-number based on lens capabilities and light level; and

automatically selecting a maximum permissible circle of confusion.

28. The method of claim 20, further comprising at least one step selected from a group consisting of:

a user specifying a specific f-number at which stack images are to be acquired;

said user specifying specific f-numbers for individual stack images; and

said user specifying a maximum permissible circle of confusion.

29. The method of claim 20, further comprising the step of:

a user selecting an auto-EDOF mode from a plurality of modes, wherein acquisition of said stack of images proceeds automatically after shutter activation.

30. The method of claim 20, further comprising the step of:

stabilizing acquired images to compensate for subject or camera movement during image acquisition.