Automated extended depth of field imaging apparatus and method

• US 9,313,417 B2
• Filed: 12/15/2014
• Issued: 04/12/2016
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Applied Minds LLC
• Original Assignee: Applied Minds LLC
• Inventors: Ferren, Bran
• Primary Examiner(s): AGGARWAL, YOGESH K
• Application Number:
  US14/570,594
• Publication Number:
  US 20150097987A1
• Time in Patent Office: 484 Days
• Field of Search: 348/335, 348/340, 348/345, 348/348, 348/350, 348/352
• US Class Current: 1/1
• 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;

a processor;

a user interface that enables a specification by a user of a range of distances external to the imaging apparatus to be in focus for a composite, extended depth-of-field image; and

a memory embodying program logic for automatically acquiring a stack of images having depths of field covering the specified range of distances;

wherein the processor is configured to execute the program logic; and

wherein the system is configured to acquire the stack of images based upon the execution of the program logic.

2. The system of claim 1, wherein the imaging apparatus includes any of a digital camera or a film camera.

3. The system of claim 1, wherein the specification of the specified range of distances includes any of:

a direct specification of the specified range of distances by the user;

or

a specification by the user of boundaries of an out-of-focus range of distances, wherein an inverse of the out-of-focus range of distances comprises the specified range of distances.

4. The system of claim 1, wherein the user interface is operative to enable the user to specify the specified range of distances either before or after image acquisition.

5. The system of claim 1, wherein the user interface includes any of:

a mechanical element configured for specification by the user of near and far distances defining the specified range of distances;

a graphical user interface configured for specification by the user of near and far distances defining the specified range of distances by interacting with one or more elements displayed within the graphical user interface; and

an auto-focus system integrated within the apparatus configured for specification by the user of the specified range of distances by pointing a range finder at successive points of interest.

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

7. The system of claim 6, wherein the system is configured to create the extended depth-of-field image from at least the portion of the stack of images based on execution of the program logic by either the processor or a processing element external to the imaging apparatus.

8. The system of claim 1, wherein the program logic for acquiring the stack of images includes 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 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 a storage embodying program logic for adjusting the focus distance of a terminal image in the specified range of distances so that a depth of field limit for the terminal image corresponds to a specified limit of the specified range of distances.

11. The system of claim 1, further comprising a storage 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 the depths of field covering the 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:

a mechanism configured for a user to specify any of;

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

specific f-numbers for individual stack images; and

a maximum permissible circle of confusion.

14. The system of claim 1, further comprising:

a mechanism configured for a user to select an auto-EDOF mode from a plurality of modes, wherein acquisition of the stack of images proceeds automatically after shutter activation.

15. The system of claim 1, further comprising:

a retraction mechanism configured for retracting a reflex mirror during image acquisition.

16. The system of claim 1, further comprising

a temporary cache configured to offer faster write times than permanent memory, to enable 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;

a user interface that enables a specification by a user of a range of distances external to the imaging apparatus to be in focus for a composite, extended depth-of-field image; and

a mechanism integrated with the imaging apparatus for automatically acquiring a stack of images having depths of field covering the specified range of distances.

19. The system of claim 18, further comprising:

a mechanism for creating the composite, extended depth-of-field image from at least a portion of the stack of images.

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

receiving from a user a specified range of distances external to the apparatus to be in focus for a composite, extended depth-of-field image;

upon activation of a control element, a processor within the apparatus for extended depth-of-field imaging executing stored program logic for automatically acquiring a stack of images having depths of field covering the specified range of distances; and

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

21. The method of claim 20, further comprising:

receiving from a user, either before or after image acquisition, either;

a direct specification of the specified range of distances;

or

a specification of boundaries of an out-of-focus range of distances, wherein an inverse of the out-of-focus range of distances comprises the specified range of distances.

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

23. The method of claim 20, further comprising:

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

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

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:

inputting a user specification to have exactly the specified range of distances in focus.

26. The method of claim 25, further comprising:

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

27. The method of claim 20, further comprising any 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:

receiving from a user a specification of any of;

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

specific f-numbers for individual stack images; and

a maximum permissible circle of confusion.

29. The method of claim 20, further comprising:

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

30. The method of claim 20, further comprising:

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