In Vivo CAMERA WITH MULTIPLE SOURCES TO ILLUMINATE TISSUE AT DIFFERENT DISTANCES

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.

What is claimed is: 
     
         1 . An endoscope comprising:
 a housing sufficiently small to travel through a gastrointestinal tract of a human;   a transmitter enclosed within said housing, to transmit image data to an external device;   a set comprising at least one sensor enclosed within said housing and coupled to said transmitter, said set supplying said image data to said transmitter;   wherein a first region of the housing is defined by an intersection of a surface of the housing with a first electromagnetic radiation entering the housing to form said image data;   a source enclosed within said housing, to generate second electromagnetic radiation exiting said housing;   wherein said source is positioned at a location whereby a majority of the second electromagnetic radiation exiting the housing passes through a second region of the housing not overlapping the first region;   wherein a portion of said first electromagnetic radiation arises from reflection of a fraction of said second electromagnetic radiation by said gastrointestinal tract.   
     
     
         2 . The endoscope of  claim 1  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. 
 
     
     
         3 . The endoscope of  claim 1  wherein:
 said set is coupled to said transmitter by a processor comprised in the endoscope and enclosed within said housing; and 
 said processor supplies said image data to said transmitter without any cropping. 
 
     
     
         4 . The endoscope of  claim 1  wherein:
 the housing comprises a tubular wall and a pair of domes capping the tubular wall at opposite ends thereof, to form a capsule; 
 the source is surrounded by the tubular wall and each of the first region and said second region is on a surface of the tubular wall. 
 
     
     
         5 . The endoscope of  claim 1  wherein:
 the source is hereinafter referred to as a first source; 
 the endoscope further comprises a second source enclosed within the housing; 
 the endoscope further comprises an annular wall enclosed within the housing; 
 a plurality of paths correspond to a plurality of rays originating from the second source, the plurality of paths pass through the annular wall to reach the housing and reflect therefrom to form within said housing, a mirror image of the second source in the absence of the annular wall; and 
 wherein the annular wall is opaque and positioned adjacent to the second 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. 
 
     
     
         6 . The endoscope of  claim 1  wherein:
 the source is hereinafter referred to as a first source; 
 the housing has an aspect ratio greater than one; 
 a longitudinal plane passes through a longitudinal axis of the housing; 
 the endoscope further comprises a second source; and 
 the longitudinal plane passes through each of said first source and said second source. 
 
     
     
         7 . The endoscope of  claim 6  wherein:
 said first source is offset from said second source in a direction of said longitudinal axis; 
 the endoscope has a pupil through which the first electromagnetic radiation enters the housing to form the image data; and 
 said pupil is located between said first source and said second source. 
 
     
     
         8 . A device comprising:
 a housing sufficiently small to travel through a gastrointestinal tract of a human;   a source enclosed within said housing, said source comprising a pair of terminals with current passing therebetween and at least one emitter of electromagnetic radiation, said at least one emitter being powered through said pair of terminals;   an optical element enclosed within said housing and offset from said source, the optical element being located in a path of a portion of electromagnetic radiation emitted by the source, the optical element being located in said housing such that at least a fraction of said portion of electromagnetic radiation becomes incident on a surface of the housing from the optical element;   wherein the optical element is on a first side of a plane and the source is on a second side of said plane and all electromagnetic radiation from the source is emitted on the second side of said plane; and   at least one camera enclosed within said housing, wherein at least one image is formed in said at least one camera by reflection from the gastrointestinal tract of at least a fraction of said majority of said portion of said electromagnetic radiation.   
     
     
         9 . The device of  claim 8  wherein:
 a first distance between the source and the camera is smaller than a second distance between the source and the optical element; and 
 the optical element comprises a reflective surface. 
 
     
     
         10 . The device of  claim 9  wherein:
 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 source and the camera, is less than a second offset in said direction, between the source and the optical element. 
 
     
     
         11 . The device of  claim 8  wherein:
 a first distance between the source and the camera is larger than a second distance between the source and the optical element; and 
 the optical element limits angular divergence of said fraction of light incident thereon from said source. 
 
     
     
         12 . The device of  claim 8  wherein:
 the optical element has an input aperture facing the source and an output aperture separated from and opposite to the input aperture; and 
 angular divergence of electromagnetic radiation exiting the output aperture is less than angular divergence of electromagnetic radiation entering the input aperture. 
 
     
     
         13 . A method of in vivo imaging, comprising:
 an endoscope emitting first electromagnetic radiation from a first region of a housing to illuminate a gastrointestinal tract;   said endoscope emitting second electromagnetic radiation from a second region of said endoscope to further illuminate said gastrointestinal tract;   wherein said first region is larger than said second region; and   said endoscope storing inside a memory at least a portion of an image formed by reflections, received through said first region, of said first electromagnetic radiation and said second electromagnetic radiation by said gastrointestinal tract.   
     
     
         14 . The method of  claim 13  wherein said emittings and said storing 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 Δd 1  resulting from said movement, in a first distance d 1  of the first region from the gastrointestinal tract is greater than a second increase Δd 2  resulting from said movement, in a second distance d 2  of the second region from the gastrointestinal tract when measured in a common direction, said endoscope automatically increasing radiant energy E 2  emitted in the second electromagnetic radiation from said second region by a second amount ΔE 2  while increasing radiant energy emitted in the first electromagnetic radiation by a first amount ΔE 1 , said first amount ΔE 1  being smaller than said second amount ΔE 2 ; and 
 subsequent to said increasings, said endoscope storing in said memory another portion of another image of said tract from said second location. 
 
     
     
         15 . The method of  claim 13  further comprising:
 said endoscope generating the first electromagnetic radiation using a first source; 
 at least a first fraction of the first electromagnetic radiation from the first source being 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 being incident on the first region without reflection by the optical element, said first fraction being greater than said second fraction; 
 wherein the optical element is on a first side of a plane and the first source is on a second side of said plane and all electromagnetic radiation from the first source is emitted on the second side of said plane; and 
 said endoscope generating the second electromagnetic radiation using a second source, a majority of the second electromagnetic radiation from the second source being incident on the second region without reflection between the second source and the housing; 
 wherein each source is enclosed within a housing of said endoscope and each source comprises a pair of terminals with current passing therebetween and at least one emitter of electromagnetic radiation powered through said pair of terminals. 
 
     
     
         16 . The method of  claim 13  wherein:
 said endoscope transmits a majority of the first electromagnetic radiation after reflection by an optical element within said endoscope; 
 wherein the optical element is on a first side of a plane and a first source of the first electromagnetic radiation is on a second side of said plane and all electromagnetic radiation from the first source is emitted on the second side of said plane; and 
 said endoscope transmits a majority of the second electromagnetic radiation without reflection by said optical element. 
 
     
     
         17 . The method of  claim 16  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. 
 
     
     
         18 . The method of  claim 17  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. 
 
     
     
         19 . The method of  claim 18  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.