In vivo camera with multiple sources to illuminate tissue at different distances

• US 8,636,653 B2
• Filed: 05/29/2009
• Issued: 01/28/2014
• Est. Priority Date: 06/09/2008
• Status: Active Grant

• Current Assignee: CapsoVision, Inc.
• Original Assignee: CapsoVision, Inc.
• Inventors: Wilson, Gordon C.
• Primary Examiner(s): Leubecker, John P
• Assistant Examiner(s): COLQUE, RONALD DAVID
• Application Number:
  US12/475,435
• Publication Number:
  US 20090306474A1
• Time in Patent Office: 1,705 Days
• Field of Search: 600/177, 600/178, 600/179, 600/180, 600/181, 600/182, 600/22, 600/425, 600/473, 600/476, 600/310, 600/32, 600/109, 600/459, 600/160, 348/68, 348/280, 348/223.1, 348/222.1, 362/574, 356/436, 356/301, 607/92, 607/110, 607/90, 607/2, 607/88, 607/89, 250/461.1
• US Class Current: 600/160
• CPC Class Codes: A61B 1/00006 of control signals
• CPC Class Codes: A61B 1/00009 of image signals during a use of endoscope
• CPC Class Codes: A61B 1/00016 using wireless means
• CPC Class Codes: A61B 1/0002 provided with data storages
• CPC Class Codes: A61B 1/00032 internally powered
• CPC Class Codes: A61B 1/00114 Electrical cables in or with an endoscope
• CPC Class Codes: A61B 1/00177 for 90 degrees side-viewing
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 1/0607 for annular illumination
• CPC Class Codes: A61B 1/0623 for off-axis illumination
• CPC Class Codes: A61B 1/0625 for multiple fixed illumination angles
• CPC Class Codes: A61B 1/0661 Endoscope light sources
• CPC Class Codes: A61B 1/0684 using light emitting diodes [LED]

Abstract

An in vivo endoscope illuminates tissue using multiple sources. Light from a short-range source exits a tubular wall of the endoscope through a first illumination region that overlaps an imaging region, and the light returns through the imaging region after reflection by tissue, to form an image in a camera. Light from a long-range source exits the tubular wall through a second illumination region that does not overlap the imaging region. The endoscope of some embodiments includes a mirror, and light from an emitter for the short-range source is split and reaches the first illumination region from both sides of an optical axis of the camera. Illuminating the first illumination region with split fractions of light results in greater uniformity of illumination, than illuminating directly with an un-split beam. The energy generated by each source is changed depending on distance of the tissue to be imaged.

Claims

1. An endoscope comprising:

a housing sufficiently small to travel through a gastrointestinal tract of a human, the housing comprising a tubular wall;

a transmitter enclosed within said housing, to transmit image data to an external device;

a set of one or more sensors enclosed within said housing and coupled to said transmitter, said set supplying said image data to said transmitter;

a first source enclosed within said housing, to generate first electromagnetic radiation exiting said housing;

wherein said first source is positioned at a first location whereby said first electromagnetic radiation passes through a first region of the housing defined by a first intersection of said first electromagnetic radiation with a surface of the housing;

a second source enclosed within said housing, to generate second electromagnetic radiation exiting said housing;

wherein said second source is positioned at a second location whereby the second electromagnetic radiation passes through a second region of the housing defined by a second intersection of said second electromagnetic radiation with the surface of the housing;

wherein the first region is larger than the second region;

wherein a third electromagnetic radiation enters said housing through said tubular wall, to form said image data; and

wherein at least a portion of said third electromagnetic radiation arises from reflection of a fraction of said first and second electromagnetic radiation.

2. The endoscope of claim 1 wherein:

the endoscope further comprises an additional wall enclosed within the housing;

a plurality of paths correspond to a plurality of rays originating from a specific source in a group consisting of the first source and the second source, the plurality of paths pass through the additional wall to reach the housing and reflect therefrom to form within said housing, a mirror image of the specific source, in the absence of the additional wall; and

wherein the additional wall is opaque and positioned adjacent to the specific source, to block passage of the plurality of rays along said paths to prevent said formation of said mirror image by said plurality of rays.

3. The endoscope of claim 2 wherein:

the additional wall is annular.

4. The endoscope of claim 1 wherein:

the housing has an aspect ratio greater than one;

a longitudinal plane passes through a longitudinal axis of the housing;

the longitudinal plane passes through each of said first source and said second source; and

said first source is offset from said second source in a direction of said longitudinal axis.

5. The endoscope of claim 4 wherein:

a majority of the first electromagnetic radiation exiting the housing passes through the third region.

6. The endoscope of claim 5 wherein:

said set is coupled to said transmitter by a processor comprised in the endoscope and enclosed within said housing;

additional electromagnetic radiation enters said housing to form additional data also supplied by said set to said processor; and

said processor excludes said additional data to obtain said image data supplied to said transmitter.

7. The endoscope of claim 6 wherein:

at least a portion of said additional electromagnetic radiation arises from reflection by said surface, of a fourth electromagnetic radiation from at least one of the first source or the second source.

8. The endoscope of claim 4 wherein:

a portion of the first electromagnetic radiation is reflected by a mirror in the endoscope before passing through the first region of the housing; and

another portion of the first electromagnetic radiation passes through the first region of the housing without reflection by said mirror.

9. The endoscope of claim 8 wherein:

a sensor in said set is comprised in a camera configured to capture at least a portion of the third electromagnetic radiation entering the housing; and

a first distance between the first source and an optical axis of the camera is smaller than a second distance between the first source and the minor.

10. The endoscope of claim 4 further comprising:

a baffle enclosed within the housing;

wherein the baffle is positioned to block rays originating in at least one of the first source and the second source from forming a virtual image that can be captured by the set of sensors.

11. The endoscope of claim 1 wherein:

a third region of the housing is defined by an intersection of the surface of the housing with said third electromagnetic radiation; and

a majority of the second electromagnetic radiation passes through a portion of the second region not overlapping the third region.

12. The endoscope of claim 11 wherein:

almost all of the second electromagnetic radiation passes through said portion of the second region.

13. The endoscope of claim 11 wherein:

a majority of the first region overlaps the third region.

14. The endoscope of claim 11 wherein:

the endoscope further comprises an additional wall enclosed within the housing;

a plurality of paths correspond to a plurality of rays originating from a specific source in a group consisting of the first source and the second source, the plurality of paths pass through the additional wall to reach the housing and reflect therefrom to form within said housing, a minor image of the specific source, in the absence of the additional wall;

wherein the additional wall is opaque and positioned adjacent to the specific source, to block passage of the plurality of rays along said paths to prevent said formation of said mirror image by said plurality of rays.

15. The endoscope of claim 11 wherein:

at least a portion of the first electromagnetic radiation and at least a portion of the second electromagnetic radiation are provided in a same radial direction.

16. The endoscope of claim 1 wherein:

a majority of the first electromagnetic radiation exiting the housing passes through a third region defined by an intersection of the surface of the housing with said third electromagnetic radiation.

17. The endoscope of claim 1 wherein:

the first region is at least several times larger than the second region.

18. The endoscope of claim 1 wherein:

a portion of the first electromagnetic radiation is reflected by a mirror in the endoscope before passing through the first region of the housing; and

another portion of the first electromagnetic radiation passes through the first region of the housing without reflection by said mirror.

19. The endoscope of claim 18 wherein:

a sensor in said set is comprised in a camera configured to capture at least a portion of the third electromagnetic radiation entering the housing; and

a first distance between the first source and an optical axis of the camera is smaller than a second distance between the first source and the mirror.

20. The endoscope of claim 18 wherein:

a sensor in said set is comprised in a camera configured to capture at least a portion of the third electromagnetic radiation entering the housing;

the housing has an aspect ratio greater than one; and

a first offset in a direction of a longitudinal axis of the housing, between the first source and an optical axis of the camera, is less than a second offset in said direction, between the first source and a minor in the endoscope.

21. The endoscope of claim 1 wherein:

a sensor in said set is comprised in a camera configured to capture at least a portion of the third electromagnetic radiation entering the housing;

a first distance between the first source and an optical axis of the camera is larger than a second distance between the first source and a mirrored surface in the endoscope; and

a portion of the first electromagnetic radiation is reflected by the mirrored surface before passing through the first region of the housing.

22. The endoscope of claim 1 further comprising:

a mirrored surface oriented to reduce angular divergence of a portion of the first electromagnetic radiation incident thereon.

23. The endoscope of claim 1 wherein:

wherein said third electromagnetic radiation enters said housing to form said image data.

24. The endoscope of claim 1 further comprising:

a baffle and a lens enclosed within the housing;

wherein a first virtual image of the baffle blocks a line-of-sight between a pupil and a second virtual image of at least one of the first source and the second source, the second virtual image being formed within a field of view of the lens in the absence of the first virtual image.

25. The endoscope of claim 1 further comprising:

a baffle enclosed within the housing;

wherein the baffle is positioned to block rays originating in at least one of the first source and the second source from forming a virtual image that can be captured by the set of sensors.

26. The endoscope of claim 1 wherein further comprising:

a pair of domes capping the tubular wall at opposite ends thereof, to form a capsule; and

a baffle positioned between a window in the tubular wall and at least one of the first source and the second source.

27. The endoscope of claim 1 further comprising:

a mirror enclosed within the housing;

wherein the minor block rays originating in at least one of the first source and the second source from forming a virtual image that can be captured by the set of sensors.

28. The endoscope of claim 1 wherein:

said image data represents a diagnosable image at a specific location in a gastrointestinal tract and excludes additional data which represents an unduly bright region.

29. The endoscope of claim 1 wherein:

the first region is at least 1.2 times larger than the second region.

30. The endoscope of claim 1 wherein:

the first region is at least 1.5 times larger than the second region.

31. The endoscope of claim 1 wherein:

the first region is at least 2 times larger than the second region.

32. The endoscope of claim 1 wherein:

at least a portion of the first electromagnetic radiation and at least a portion of the second electromagnetic radiation are provided in a same radial direction.

33. The endoscope of claim 1 wherein:

a majority of said first and second electromagnetic radiation exits from the endoscope through the tubular wall.

34. The endoscope of claim 1 wherein:

the housing comprises a pair of domes capping the tubular wall at opposite ends thereof, to form a capsule; and

the domes do not receive the third electromagnetic radiation that forms said image data.

35. The endoscope of claim 1 wherein:

the housing comprises a pair of domes capping the tubular wall at opposite ends thereof, to form a capsule; and

the domes do not transmit the first and second electromagnetic radiation exiting the endoscope.

36. The endoscope of claim 1 further comprising:

a pupil having an optical axis that intersects with an internal surface of the housing;

wherein the housing has an aspect ratio greater than one;

wherein the first source is offset from the optical axis in a longitudinal direction of the endoscope; and

wherein the second source is offset from the optical axis in the longitudinal direction opposite to the first source.

37. The endoscope of claim 1 wherein:

the first source and the second source generate different amounts of energy relative to each other depending on a distance of tissue from the endoscope.

38. The endoscope of claim 1 wherein:

an imaging region on the housing is defined by a field of view of the set of one or more sensors;

the imaging region at least partially overlaps the first region; and

the imaging region does not overlap the second region.

39. The endoscope of claim 1 wherein the first source comprises:

an emitter; and

an optical element that splits electromagnetic radiation received from the emitter.

40. The endoscope of Claim 1 further comprising:

an optical element;

wherein the optical element reduces angular dispersion of at least one fraction of the first electromagnetic radiation.

41. The endoscope of Claim 1 further comprising:

an optical element surrounded by the tubular wall;

wherein the optical element is of an annular shape comprising a plurality of spokes between an inner wall and an outer wall that face each other.

42. The endoscope of Claim 1 further comprising:

an optical element surrounded by the tubular wall;

wherein a surface of the optical element is a surface of a truncated compound parabolic concentrator.

43. The endoscope of Claim 1 further comprising:

an optical element;

wherein;

the first source comprises an emitter encapsulated within a cavity; and

an aperture of the cavity is located only partially under an input aperture of the optical element.

44. The endoscope of Claim 1 further comprising:

an optical element; and

an annular minor configured to reflect out of the endoscope, one portion of the first electromagnetic radiation that exits an aperture of the optical element;

wherein another portion of the first electromagnetic radiation that exits the aperture, exits out of the endoscope directly from the aperture.

45. The endoscope of claim 1 further comprising an optical element, wherein:

the endoscope transmits a majority of the first electromagnetic radiation after reflection by said optical element; and

the endoscope transmits a majority of the second electromagnetic radiation without reflection by said optical element.

46. The endoscope of claim 1 further comprising an optical element located between the first source and the housing, wherein:

at least a first fraction of the first electromagnetic radiation from the first source is incident on the first region after reflection by the optical element;

at least a second fraction of the first electromagnetic radiation from the first source is incident on the first region without reflection by the optical element; and

said first fraction is greater than said second fraction.

47. A method comprising:

using a first source enclosed within a housing of an endoscope, to generate first electromagnetic radiation exiting the housing;

wherein the housing is sufficiently small to travel through a gastrointestinal tract of a human, the housing comprising a tubular wall;

wherein said first source is positioned at a first location in the housing whereby said first electromagnetic radiation passes through a first region of the housing defined by a first intersection of said first electromagnetic radiation with a surface of the housing;

using a second source enclosed within said housing, to generate second electromagnetic radiation exiting said housing;

wherein said second source is positioned at a second location in the housing whereby the second electromagnetic radiation passes through a second region of the housing defined by a second intersection of said second electromagnetic radiation with the surface of the housing;

using a transmitter enclosed within the housing, to transmit image data to an external device;

wherein a set of one or more sensors enclosed within said housing are coupled to said transmitter, said set supplying said image data to said transmitter;

wherein the first region is larger than the second region;

wherein a majority of a third electromagnetic radiation enters said housing through said tubular wall, to form said image data; and

wherein at least a portion of said third electromagnetic radiation arises from reflection of a fraction of said first and second electromagnetic radiation.

48. The method of claim 47 wherein said using the first source and said using the second source are performed when said endoscope is at a first location relative to the gastrointestinal tract, the method further comprising:

in response to movement of said endoscope to a second location at which a first increase Δ

dresulting from said movement, in a first distance dl of the first region from the gastrointestinal tract is greater than a second increase Δ

d2 resulting from said movement, in a second distance d2 of the second region from the gastrointestinal tract when measured in a common direction, said endoscope automatically increasing radiant energy E2 emitted in the second electromagnetic radiation from said second region by a second amount Δ

E2 while increasing radiant energy emitted in the first electromagnetic radiation by a first amount Δ

E1, said first amount Δ

E1 being smaller than said second amount Δ

E2; and

subsequent to said increasings, said endoscope storing in memory another portion of another image of said tract from said second location.

49. The method of claim 47 wherein:

at least a first fraction of the first electromagnetic radiation from the first source is incident on the first region after reflection by an optical element located between the first source and the housing and at least a second fraction of the first electromagnetic radiation from the first source is incident on the first region without reflection by the optical element, said first fraction being greater than said second fraction.

50. The method of claim 47 wherein:

a majority of the second electromagnetic radiation from the second source is incident on the second region without reflection between the second source and the housing.

51. The method of claim 47 wherein:

said endoscope transmits a majority of the first electromagnetic radiation after reflection by an optical element within said endoscope; and

said endoscope transmits a majority of the second electromagnetic radiation without reflection by said optical element.

52. The method of claim 47 further comprising:

said endoscope calculating an average luminance value for each sector in a plurality of sectors used to sense said image;

said endoscope calculating a difference between the average luminance value calculated for each sector and a target luminance value for said each sector; and

said endoscope computing a drive current for generating the second electromagnetic radiation, based at least partially on said difference.

53. The method of claim 52 wherein:

a change in said drive current is obtained based on a linear combination of a plurality of said differences individually calculated for each sector in said plurality of sectors.

54. The method of claim 53 wherein:

said linear combination comprises multiplication of a vector of said differences with a matrix of values, each value being selected to be one of a plurality of predetermined values based on drive current.