Camera using beam splitter with micro-lens image amplification

• US 6,801,719 B1
• Filed: 03/14/2003
• Issued: 10/05/2004
• Est. Priority Date: 03/14/2003
• Status: Active Grant

• Current Assignee: Monument Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Eastman Kodak Company
• Inventors: Szajewski, Richard P., Irving, Lyn M.
• Primary Examiner(s): Mathews, Alan A.
• Assistant Examiner(s): Smith, Arthur A
• Application Number:
  US10/389,464
• Publication Number:
  US 20040179834A1
• Time in Patent Office: 571 Days
• Field of Search: 396/322, 396/333, 396/429, 348/64
• US Class Current: 396/333
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/0062 Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• CPC Class Codes: H04N 23/51 Housings
• CPC Class Codes: H04N 23/957 Light-field or plenoptic cameras or camera modules

Abstract

In one aspect, an imaging system is provided. The imaging system has a taking lens unit adapted to focus light from a scene, and a beam splitter receiving light from the scene with a portion of the received light traveling from the beam splitter to a first imaging surface and a portion of the received light traveling from the beam splitter to a second imaging surface. A first image capture system is provided for capturing an image based upon the light traveling to the first imaging surface, and a second image capture system is provided for capturing a second image based upon the image formed at the second imaging surface. An array of micro-lenses is in optical association with the first imaging surface, with each micro-lens in the array concentrating a first fraction of the light from the beam splitter onto concentrated image areas of the first imaging surface. Wherein the first image capture system forms an image based upon the light concentrated onto the concentrated image areas.

Claims

1. An imaging system comprising:

a taking lens unit adapted to focus light from a scene;

a beam splitter receiving light from the scene with a portion of the received light traveling from the beam splitter to a first imaging surface and a portion of the received light traveling from the beam splitter to a second imaging surface;

a first image capture system for capturing an image based upon the light traveling to the first imaging surface;

a second image capture system for capturing a second image based upon the image formed at the second imaging surface; and

an array of micro-lenses in optical association with the second imaging surface, with each micro-lens in the array concentrating a first fraction of the light from the beam splitter onto concentrated image areas of the second imaging surface;

wherein the second image capture system forms an image based upon the light concentrated onto the concentrated image areas.

2. The imaging system of claim 1, wherein the array of micro-lenses also permits a second fraction of the light to form a residual image in areas of the associated imaging surface that surround the concentrated image areas.

3. The imaging system of claim 2, wherein the array of micro-lenses concentrates the first fraction of the light to form an image in the concentrated image areas of the second imaging surface when light from the scene is within a first range of exposure and wherein the second fraction of the light from the beam splitter forms an image in a residual image area surrounding the concentrated image areas of the second imaging surface when light from the scene is within a second, higher, range of exposures.

4. The imaging system of claim 3, wherein the second image capture system forms an image based upon the pattern of concentrated image elements and the image formed in the residual image area.

5. The imaging system of claim 4, wherein the first image capture system captures an image when light from the scene is within a third range of exposures, and wherein micro-lenses are selected so that the first range of exposures and the second range of exposures generally coincide with the third range of exposures.

6. The imaging system of claim 4, wherein the first image capture system captures an image when light from the scene is within a third range of exposures, and wherein micro-lenses are selected so that the first range of exposures and the second range of exposures coincide with at least 60% of the third range of exposures.

7. The imaging system of claim 1, wherein the micro-lenses concentrate light so that the appearance of the image captured by the second image capture system based upon the pattern of concentrated light generally corresponds to the appearance of the image captured by the first image capture system.

8. The imaging system of claim 1, wherein the micro-lenses concentrate light so that the second image capture system can capture images when the scene illumination is above a first lower response threshold and wherein the first image capture system is adapted to capture images when the scene illumination is at least above a second lower response threshold with the first lower response threshold being at least as low as the second lower response threshold.

9. The imaging system of claim 8, wherein first image capture system and second image capture system are optically associated with, respectively, a first array of micro-lenses and a second array of micro-lenses that are adapted so that the first image capture system and second image capture system are capable of capturing similar appearing images of a scene when exposed to a scene having a predefined range of illumination intensities.

10. The imaging system of claim 1, wherein a second array of micro-lenses is optically associated with the first image capture system, with each micro-lens in the second array concentrating a first fraction of the light traveling to the first imaging surface onto concentrated image areas of the first imaging surface and wherein the second image capture system forms an image based upon the concentrated image areas.

11. The imaging system of claim 1, wherein the fraction of light traveling to the second imaging surface is less than the fraction of light traveling to the first imaging surface.

12. The imaging system of claim 1, wherein the fraction of the light traveling to the second imaging surface is between 5%-95% of the light received by the beam splitter.

13. The imaging system of claim 1, wherein the beam splitter comprises at least one of a prism or a mirror.

14. The imaging system of claim 1, wherein the second imaging surface comprises an image sensor and the second image capture system comprises a processor and a display, wherein the processor collects image information from the image sensor, processes the image information and presents the images captured by the second image capture system on the display.

15. The imaging system of claim 14, wherein the display has a predefined display resolution that is less than an imaging resolution of the first imaging sensor and the array micro-lenses comprises an array of micro-lenses that concentrates light to form a pattern of concentrated image elements on the image sensor that corresponds to the display resolution of the display.

16. The imaging system of claim 1, wherein the second imaging surface comprises an image sensor having a plurality of photosensitive photosites and wherein there are fewer micro-lenses in the array of micro-lenses than there are photosites in the plurality of image sensing photosites.

17. The imaging system of claim 1, wherein the second imaging surface comprises an image sensor having an array of spaced photosensor areas and wherein each micro-lens in the array of micro-lenses receives light directed at more than one of the photosensors and concentrates a portion of the received light onto less than all of the photosensors at which the received light is directed.

18. The imaging system of claim 1, wherein the first imaging surface and the second imaging surface comprise image sensors that use photosensors to convert incident light into electrical charge.

19. The imaging system of claim 1, wherein at least one of the imaging surfaces comprises a photosensitive element having chemicals generate a latent image when exposed to light.

20. An image capture system comprising:

a taking lens unit adapted to focus light toward a beam splitter with the beam splitter receiving light from the taking lens unit and passing a portion of light to form an image at a first imaging surface and a portion of the light to form an image at a second imaging surface;

a photosensitive element image capture system having a shutter assembly for controlling the passage of light to at least one imaging surface and a photosensitive element positioning system having gate positioning a photosensitive element having the first imaging surface thereon to receive light controlled by the shutter assembly;

an electronic image capture system having an image sensor with the second imaging surface thereon said electronic image capture system adapted to capture an image based upon the light incident on the second imaging surface;

a micro-lens array in optical association with the second imaging surface imaging plane concentrating light directed at concentrated image areas of the second imaging surface; and

a controller for determining a capture time and for enabling the shutter assembly and electronic image capture system to capture an image representative of scene conditions during the capture time.

21. The image capture system of claim 20 wherein the shutter assembly is positioned so that the shutter controls the passage of light to every imaging surface.

22. The image capture system of claim 21 wherein the array of micro-lenses optically downsamples the image.

23. The image capture system of claim 21 wherein the controller determines a sensitivity for the photosensitive element, determines a capture time and causes the shutter assembly to open for the capture time and further causes the electronic image to capture an image based upon the scene conditions during the capture time.

24. The image capture system of claim 21, wherein the controller determines a sensitivity for the photosensitive element, determines a desired effective sensitivity for the photosensitive element image capture system based at least in part upon the sensitivity of the photosensitive element, and further causes the electronic image capture system to capture images in a manner that has an effective sensitivity that corresponds to the effective sensitivity of the photosensitive element image capture system.

25. The image capture system of claim 21 wherein the photosensitive element image capture system is adapted to receive a set of different types of photosensitive elements with each type of photosensitive element in the set having a different sensitivity, wherein the array of micro-lenses comprises an array having a set of different types of micro-lenses with each type of micro-lens concentrating light in a manner adapted to correspond to one type of the photosensitive elements so that the sensitivity of each different one of the photosensitive elements in the set can be matched by selectively forming an image based upon the light concentrated by the set of micro-lenses corresponding to a particular photosensitive element.

26. The image capture system of claim 25 wherein the processor is adapted to determine the sensitivity of a photosensitive element and to cause the electronic image capture system to capture images based upon light concentrated by micro-lenses that are associated with the type of micro-lens associated with the sensitivity of the photosensitive element.

27. The image capture system of claim 21 wherein the electronic image capture system begins an image capture sequence only when light from the scene strikes the image sensor.

28. The image capture system of claim 20 wherein the electronic image capture system incorporates a display and the electronic image capture system processes the captured image for presentation on the display.

29. The image capture system of claim 28, wherein the electronic image capture system resamples the captured image for presentation on the display.

30. The image capture system of claim 29, wherein the electronic image capture system incorporates a display and the electronic image capture system processes the captured image into a form that has an appearance that is adapted to generally correspond to the appearance of the image captured on the photosensitive element.

31. The imaging system of claim 28, wherein the display has a predefined display resolution that is less than an imaging resolution of the first imaging sensor and the array micro-lenses comprises an array of micro-lenses that concentrates light to form a pattern of concentrated image elements on the first imaging sensor with the pattern having a number of concentrated image elements that corresponds to the number of display elements.

32. The imaging system of claim 20, wherein the micro-lens array also permits a residual image of non-concentrated light to be formed on residual areas of the second imaging surface with the electronic image capture system comprising:

a display processor adapted to collect image information from concentrated images areas and from residual image areas of the image sensor to process the image information to form a captured image and to present the captured image on the display.

33. An imaging system comprising:

a taking lens unit adapted to focus light from a scene;

an image capture system for capturing an image based upon the light traveling to an imaging surface;

a stacked array magnifier positioned to alter the effective magnification of the light traveling to the imaging surface; and

an array of micro-lenses in optical association with the imaging surface, with each micro-lens in the array concentrating a first fraction of the light onto concentrated image areas of the imaging surface;

wherein the image capture system forms an image based upon the light concentrated onto the concentrated image areas.

34. A method for capturing an image of a scene using a first imaging surface having a first sensitivity and a second imaging surface having a second sensitivity, the method comprising the steps of:

focusing light from the scene;

dividing the focused light from the scene into a first portion traveling to a first imaging surface and a second portion traveling to a second imaging surface;

capturing a first image based upon the light reaching the first imaging surface;

concentrating a fraction of the light traveling to the second imaging surface to form a pattern of concentrated image elements on the second imaging surface; and

capturing a second image based upon the pattern of concentrated image elements formed on the second imaging surface.

35. The method of claim 34 wherein a second fraction of the light traveling to the second imaging surface is not concentrated and forms a residual image on areas of the first imaging surface that surround the concentrated image areas.

36. The method of claim 35 wherein the step of concentrating the light traveling to the second imaging surface comprises concentrating the light traveling to the second imaging surface so an image that is formed based upon the pattern of concentrated image elements appears to have been captured using an image capture surface having the sensitivity of the first image capture surface.

37. The method of claim 36, wherein the second image is formed based upon the pattern of concentrated image elements and the image formed in the residual image area.

38. The method of claim 36, wherein the first image comprises an image formed from light the scene that is within a third range of exposures, and wherein light is concentrated so that the first range of exposures and the second range of exposures generally coincide with the third range of exposures.

39. The method of claim 36, wherein the first images comprises an image formed from light from the scene that is within a third range of exposures, and wherein degree of light concentration is selected so that the first range of exposures and the second range of exposures coincide with at least 60% of the third range of exposures.

40. The method of claim 34 wherein the first fraction of the light traveling to the second imaging surface is concentrated to form an image in the concentrated image areas of the imaging surface when light from the scene is within a first range of exposure and wherein a second fraction of the light traveling to the second imaging surface forms an image in a residual image area surrounding the concentrated image areas of the second imaging surface when light from the scene is within a second, higher, range of illumination intensities.

41. The method of claim 34, wherein the micro-lenses concentrate light so that the appearance of the image captured by the second image capture system based upon the pattern of concentrated light generally corresponds to the appearance of the image captured by the first image capture system.

42. The method of claim 34, wherein light traveling to the second imaging surface is concentrated so that a first image can be captured using the concentrated light when the scene illumination is above a first lower response threshold and wherein the first image is captured when the scene illumination is at least above a second lower response threshold, with the first response threshold being at least as low as the second lower response threshold.

43. The method of claim 42, wherein the first image and second image have a similar appearance when exposed to a scene having a predefined range of illumination intensities.

44. The method of claim 34, wherein a fraction of the light traveling to the second imaging surface is concentrated onto concentrated image areas of the second imaging surface and wherein the second image is based upon the concentrated fraction of the light.

45. The method of claim 34, wherein the portion of light traveling to the second imaging surface is less than the portion of light traveling to the first image capture system.

46. The method of claim 34, wherein the portion of the light traveling to the second imaging surface is between 5%-95% of the light traveling to the second imaging surface.

47. The method of claim 34, wherein the second imaging surface comprises an electronic image sensor and the step of capturing a first image comprises capturing a second image by using the electronic image sensor to covert light incident on the first imaging surface into electronic signals.

48. The method of claim 47, further comprising the steps of processing the electronic signals into an image that can be presented on a display and presenting the image on the display.

49. The method of claim 48, wherein the display has a predefined display resolution defined by a number of display elements that is less than an imaging resolution of the electronic imaging sensor and the light traveling to the second imaging surface is concentrated to form a pattern of concentrated image elements on the electronic imaging sensor having a number of concentrated image elements that corresponds to the number of display elements.

50. The imaging system of claim 34, wherein the second imaging surface comprises an image sensor having a plurality of photosensitive photosites and wherein there are fewer micro-lenses in the array of micro-lenses than there are photosites in the plurality of image sensing photosites.

51. The method of claim 34, wherein the second imaging surface comprises an image sensor having an array of spaced photosensor areas and wherein light directed at the second imaging surface at an area containing more than one of the photosensors is concentrated onto less than all of the photosensors in the area at which the received light is directed.

52. The method of claim 34, wherein at least one of the steps of forming a first image and forming a second image comprise forming by converting light incident on one of the first and second imaging surfaces into electrical charge and processing the electrical charge to form a electronic signal representing the image.

53. The method of claim 34, wherein at least one of the imaging surfaces comprises a photosensitive element having chemicals that generate a latent image when exposed to light.