Abstract:
A wide angle HDTV endoscope includes at least two optical imaging channels. Lenses close each channel at the distal end of the endoscope. The imaging channels each have a different field of view in complementary directions, and have overlapping or cross-over field of view areas. Received images are transmitted along the longitudinal axis of the imaging channels of the endoscope to a camera head that contains a wide screen image sensing device. An external light source provides the required lighting and an image processing device can provide necessary software algorithms to format the images and to control any overlapping or cross-over field of view areas to obtain a single display image. In another arrangement, optical blocking elements provided at the proximal end of the endoscope or within the imaging channels eliminate portions of one or more images from the imaging channels so that at the cross-over areas only a single image is provided to the imaging device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/007,002, filed Dec. 10, 2007, which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the endoscopy field, and primarily endoscopes used in minimally invasive surgeries. This invention allows a true wide screen endoscopic image to be created that is sent to a display screen to provide a 16:9 aspect ratio HDTV image with a wide angle view that shows more of an observed surface of an anatomical structure to viewers. 
     BACKGROUND OF THE INVENTION 
     In today&#39;s minimally invasive surgeries, imaging devices are used to help a surgeon visualize the interior of a patient&#39;s body. Depending on the type of procedure, an endoscope is typically inserted into the patient&#39;s abdominal area, knee joint, shoulder joint or some other part of the body that requires surgical treatment. As shown in prior art  FIG. 1 , the endoscope  12  is usually connected at its proximal end to a camera  14  which is connected to an image processing device  16  either via a connecting cable  18  or wirelessly through a radio frequency transmitter and receiver (not shown). The camera  14  usually contains image sensors, such as CCD, CMOS or other kinds of imaging devices. As shown in  FIG. 1 , an external light source  20  is also usually connected to the endoscope  12  by a fiber optic cable  22 . The processing device  16  and light source  20  are shown on shelf unit  23 . 
     As shown in  FIG. 2 , the endoscopes  12  used in today&#39;s minimally invasive surgeries have a circular outer shield  24  and a circular optical system  26  inside the outer shield  24  to transmit an image from a distal end  28  to a proximal end  30 . The outer shield  24  is typically stainless steel or a flexible plastic material. The circular optical system  26  generally is either a series of rigid rod lenses or a flexible optical fiber inserted along the longitudinal axis of the endoscope  12 . These endoscopes have not changed much over the last decade or so in terms of the way they pick up and transmit an image of a target object from the distal end  28  of the endoscope  12  through the optical system  26  and an optics coupler  34  to image sensors  36  of the camera  14  at the proximal end  30  of the endoscope  12 . The circular optical system  26  views objects in the field of view  38  as shown in  FIG. 2 . An image enters the distal end  38  of the endoscope  12  and travels through circular optical system  26  and optics coupler  34  to the image sensor  36  at the proximal end  30  of the endoscope. Fiber optic cable  22  provides light from light source  20  to a light transmitting optic fiber  40  that outputs illuminating light at the distal end  28  of the endoscope  12 . While a single optic fiber  40  is shown, a plurality of optic fibers may output light at the distal end  28  of the endoscope  12 . 
     Prior art endoscopes are initially designed to be used with imaging elements of standard definition (SD) aspect ratio. Such an aspect ratio is also known as 4:3 or 5:4, which is the fraction of the horizontal width of a video image to the vertical height of the image on a display device. Imaging technology and consumer demand, however, have significantly changed recently and the aspect ratio requirement for such endoscope video systems has shifted from the standard definition (SD) aspect ratio to wide screen (also known as high definition (HD) aspect ratio which is typically a width to height ratio of 16:9. 
     In addition to a wider aspect ratio, advancements in imaging technology have led to higher native acquisition resolutions in both interlaced and progressive scanning modes. Interlaced or progressive scanning usually refers to the way an image is acquired by the image sensor. If the horizontal lines of image are scanned one after another consecutively, then the system is called a progressive scan system. If the horizontal lines of image are scanned by skipping every other line in the first scan followed by a second scan to scan the skipped lines, then the system is called an interlaced scanning system. Whether an interlaced or a progressive scan, the HD resolution includes at least one of the following three well known standards: 1280×720p, 1920×1080i, and 1920×1080p, where i stands for interlaced and p stands for progressive. Although these three formats may have different horizontal and vertical lines of resolution, they all maintain a 16:9 horizontal to vertical aspect ratio. Also known as HDTV standards, these three standards are perceived to show more picture and better picture quality on a display screen. Typically, however, progressive scan systems provide a superior image quality compared to interlaced scan systems. Movies and sports events primarily benefit from these HDTV standards, especially the progressive scan ones, which give a unique viewing angle and feel to their viewers. 
     Since the imaging and display technologies have advanced from standard definition (SD) resolutions (with 4:3 or 5:4 aspect ratio) to high definition (HD) resolutions (with 16:9 aspect ratio), almost all consumer-grade imaging equipment has shifted over to using a 16:9 aspect ratio. The same technological change has also been affecting the medical markets including endoscopic imaging equipment. The image sensor devices (primarily CCD and CMOS sensors or devices performing a similar function) and the displays (LCDs and plasma screens) have slowly shifted toward a 16:9 aspect ratio in endoscopic imaging applications. 
     Existing scopes, as used with the existing 4:3 aspect ratio imaging sensors as described above, cause significant loss of viewing area as shown in  FIG. 3 . The magnified scope image  42  shown in  FIG. 3  covers and extends beyond the usable surface area of the generally rectangular imaging device  44  due to the simple geometrical mismatch of the endoscope&#39;s circular optical element with a rectangular 4:3 aspect ratio imaging element. Thus, this arrangement shows a problem that already existed with 4:3 aspect ratio imaging elements  44 . The mismatch, however, becomes much more unacceptable and undesirable with the use of a HD imaging device  46  having a 16:9 aspect ratio as shown in  FIG. 4 . Although a 16:9 rectangular imaging device  46  can cover more of the scope&#39;s circular image  42  from side to side as compared to a 4:3 imaging device, the 16:9 imaging device  46  receives much less of the scope&#39;s circular image  42  vertically upwardly and downwardly compared to the 4:3 imaging device  44  as shown by comparison of  FIG. 4  with  FIG. 3 . In other words, an imaging device  46  having a 16:9 aspect ratio does not maximize the amount of a circular image  42  that can be viewed from an endoscope imaging arrangement. Instead, less of the vertical portions of the image  42  are viewable. This invention offers a solution to minimize or eliminate the problem. 
     One device that addresses the problem is disclosed in U.S. Pat. No. 6,498,884 to Colvin, et al., whose disclosure is incorporated herein by reference. In the &#39;884 system, multiple rectangular optical channels (lens elements) are used to create an overall rectangular lens system. This arrangement also requires all sides of the individual rectangular lenses to be coated or blackened to minimize glare and refractive errors. Besides the excessively high cost of manufacturing rectangular lenses, such designs usually continue to have optical image quality problems due to the natural corners of the rectangular lens elements no matter what kind of coating is provided for the rectangular lenses. In fact, perfectly coating such lens corners in practical systems is almost impossible. The invention described herein does not require any of the above special requirements and uses readily available rounded optical rod elements and optical fibers or the like. 
     Another wide viewing endoscope is taught in U.S. Patent Publication 2006/0235276 A1. The &#39;276 publication discloses an endoscope having a plurality of illumination lenses and one objective viewing lens having a wide angle. 
     SUMMARY OF THE INVENTION 
     The invention relates to a wide viewing angle endoscope having at least two rounded optical imaging channels for sensing images and providing the images to an image sensor. The invention fits the images from the imaging channels to a rectangular image sensor to increase the field of view of the endoscope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a prior art endoscope system utilized in an operating-room setting. 
         FIG. 2  shows the prior art endoscope illustrated in  FIG. 1 . 
         FIG. 3  shows an image from an endoscope projected on a rectangular image sensor having a 4:3 aspect ratio. 
         FIG. 4  shows an image from an endoscope projected on a rectangular high definition imaging sensor having a 16:9 aspect ratio. 
         FIG. 5  shows a longitudinal side view of an endoscope system according to the invention. 
         FIG. 6  shows an enlarged front end view of the distal tip end of the endoscope of  FIG. 5 . 
         FIG. 7  shows an enlarged top view of the distal tip end of the endoscope of  FIG. 5 . 
         FIG. 8  shows a cross-sectional view of the tip end of the endoscope taken at  8 - 8  in  FIG. 6 . 
         FIG. 9  shows a perspective view of the endoscope of  FIG. 5 . 
         FIG. 10  shows an enlarged perspective view of the proximal end of the endoscope of  FIG. 5  and the areas of images projecting therefrom. 
         FIG. 11  shows the images from the proximal end of the endoscope projected onto an image sensor. 
         FIG. 12  shows a front view of the distal end tip of another embodiment of the endoscope. 
         FIG. 13  shows an enlarged front end view of another embodiment of the endoscope. 
         FIG. 14  shows a cross-sectional view of the tip end of the endoscope taken at  14 - 14  of  FIG. 13 . 
         FIG. 15  shows an enlarged top end view of the distal tip end of another embodiment of the endoscope. 
         FIG. 16  shows the images projected from the proximal end of the endoscope onto an image sensor. 
         FIG. 17  shows the rotatable images from the proximal end of the endoscope projected onto an image sensor. 
         FIG. 18  shows another embodiment having four images from the proximal end of the endoscope projected onto an image sensor. 
     
    
    
     Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the tool arrangement and designated parts thereof. The words “forwardly” and “distally” will refer to the direction toward the end of the tool arrangement which is closest to the patient, and the words “rearwardly” and “proximally” will refer to the direction away from the end of the tool arrangement which is furthest from the patient. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     DETAILED DESCRIPTION 
       FIGS. 5-9  illustrate one embodiment of the invention. In this embodiment, the distal tip end  48  of the endoscope  50  has a flat circular tip and is rounded or tapered in a longitudinal direction to join with a cylindrical portion of the endoscope  50 . As in the prior art, the endoscopic system includes a fiber optic cable  22  connected to external light source  20 . A lens coupler  51  is provided at the proximal end of the endoscope  50 . Further, the system includes a camera  14  having an image sensor  46  connected by a cable  18  to an image processing device  49 . 
     A front view of the distal tip end  48  of the imaging endoscope  50  is shown in  FIG. 6 . The tip end  48  includes a first frontwardly directed central lens  52  and second and third sidewardly oriented lenses  54 ,  56  symmetrically provided on opposing sides of the center lens  52 . While lenses  54 ,  56  appear elliptical in  FIG. 6 , the lenses  54 ,  56  are actually circular in shape, as is central lens  52 . In  FIG. 7 , the lenses  54 ,  56  are oriented at an outward angle as compared to the central lens  52 . The lenses are oriented and shaped so that central lens  52  has a central field of view θ 1  projecting longitudinally outwardly from the distal tip end  48  of the endoscope  50 . Lens  56  has a field of view θ 2  as shown in  FIG. 7 , and lens  54  has a field of view defined by θ 3  in  FIG. 7 . The fields of view θ 2 , θ 3  have the same size and are symmetric with respect to a longitudinal axis  57  of the endoscope  50 . 
       FIG. 7  also shows an overlap or cross-over in the fields of view θ 2 , θ 3  of the side lenses  54 ,  56  with respect to the field of view θ 1  of the central lens  52 . In  FIG. 7  the overlap of the field of view of lenses  52 ,  56  is defined by angle α 1  and the cross-over or overlap for the lenses  52 ,  54  is defined by the angle α 2 . 
     The lenses  52 ,  54 ,  56 , preferably are concave to obtain the desired field of view. 
     Returning to  FIG. 6 , in one embodiment the surface at the distal tip end  48  of the endoscope  50 , not including the lenses  52 ,  54 ,  56 , includes a plurality of fiber optics (only some of which are shown) represented by numeral  58  projecting light outwardly from the distal end of the endoscope. The fiber optics  58  are connected to the light source  20 . Light projecting outwardly from the fiber optics  58  provides illumination so that the lenses  52 ,  54 ,  56  may view an anatomical structure in the interior of a patient&#39;s body. 
     The cross-sectional view of  FIG. 8  shows corresponding image channels  62 ,  64 ,  66  within the endoscope for each of the image receiving lenses  52 ,  54 ,  56 . The imaging channels  62 ,  64 ,  66  in the illustrated embodiment have a circular cylindrical shape along the longitudinal lengths thereof and are defined by cylindrical walls  68 . The imaging channels  62 ,  64 ,  66  extend the length of the endoscope  50  and open at the proximal end  70  of the endoscope. Openings  72 ,  74 ,  76  shown at the proximal end  70  in  FIG. 9  correspond to the imaging channels  62 ,  64 ,  66 , respectively. As shown in  FIG. 5 , in one embodiment the imaging channels  62 ,  64 ,  66  join with optical coupler  51  to provide images to the imaging device  46 . 
     Operation 
     Light source  20  provides light that passes through fiber optics  58  and outwardly from the distal tip end  48  of the endoscope  50  to illuminate an anatomical structure in a patient&#39;s body. Reflected light images pass through the lenses  52 ,  54 ,  56  at the distal tip end  48  of the endoscope  50  and into the imaging channels  62 ,  64 ,  66  shown in  FIG. 8 . The images pass through the imaging channels  62 ,  64 ,  66  and are refocused by lens coupler  51  (not shown in  FIG. 10 ) to form corresponding images  82 ,  84 ,  86 . Image  82  is the central image.  FIG. 11  shows how the images  82 ,  84 ,  86  coact with a 16:9 aspect ratio imaging device  46  of a camera  14 . The image sensor  46  converts the images to electrical signals. The electrical signals are provided to the image processing device  49 . 
     In  FIG. 11 , the projected images  82 ,  84 ,  86  completely cover the entirety of the image sensor  46 , but also contain overlapping regions  92 ,  94  wherein the side images  84 ,  86  from the side imaging channels  64 ,  66  share a portion of the field of view of the central image  82 . 
     In a first embodiment of the invention, the overlap or cross-over of the images in regions  92 ,  94  is prevented by optical blocking elements  90  in the lens coupler  51  as shown in  FIG. 5 . The optical blocking elements  90  can comprise secondary optics, mechanical stoppers, mechanical blockers, or optical image stoppers located at the proximal end  70  of the endoscope  50  for eliminating the image from one or more of the imaging channels  62 ,  64 ,  66  only in the cross-over areas  92 ,  94  so that only one image is provided thereat. In some embodiments, the stoppers are formed by light absorbing coatings. The image sensed by imaging device  46  is then sent to the image processing device  49  and forwarded to a video display. 
     While the blocking elements  90  are a part of the lens coupler  51  at the proximal end  70  of the endoscope  50  in  FIG. 5 , in some embodiments the blocking elements are located within one or more of the channels  62 ,  64 ,  66  to provide the blocking effect. 
     In another embodiment of the invention, the image processing device  49  connected to the camera  14  processes the scanned images  82 ,  84 ,  86  captured by the image sensor  46  and utilizes image correction algorithms or software filters to eliminate the effect of the multiple images applied in the cross-over areas  92 ,  94  to provide an accurate image for display in the cross-over areas. In yet another embodiment, the algorithms or software filters are provided by a separate processor device located within the camera  14 . 
     The above embodiments prevent blurry outcomes when two images are mapped over one another in the cross-over areas  92 ,  94 . The blurriness is due to the adjacent channels  62 ,  64 ,  66  viewing the same point of an object from a different angle at the distal tip end  48  of the endoscope  50 . 
     While the lenses  52 ,  54 ,  56  illustrated in  FIG. 6  are all circular relative to the surrounding surface of the distal tip end  48 , in some embodiments the lenses  52 ,  54 ,  56  and the imaging channels  62 ,  64 ,  66  have an elliptical shape. An important factor is that the image sensor  46  is completely enclosed by the images  82 ,  84 ,  86  received through the lenses  52 ,  54 ,  56  and the imaging channels  62 ,  64 ,  66 . While the image sensor  46  is illustrated as a single rectangular element in  FIGS. 5 and 11 , plural elements, such as three elements defining a rectangular shape are also contemplated. 
       FIG. 12  shows another embodiment of the endoscope  50 .  FIG. 12  corresponds to the distal tip end  48  illustrated in  FIG. 6  having lenses  52 ,  54 ,  56 . Also included at the distal tip end  48 , however, are additional lenses  97 ,  98  and corresponding image channels. Thus each lens  52 ,  54 ,  56 ,  97 ,  98  each have their own image channel. 
     The endoscope of  FIG. 12  is rotatable relative to the imaging device  46  of the camera  14 . When rotated 90°, the central lens  52  transfers an image through the imaging channel  62 . This results from the additional lenses  97 ,  98  transferring images through respective imaging channels similar to the images transferred through lenses  54 ,  56  to create the images  82 ,  84 ,  86  at the proximal end of the endoscope  50  as shown in  FIG. 11 . Thus, a cross-sectional view of the distal end taken in a perpendicular plane across the channels of lenses  52 ,  97 , and  98  would appear substantially the same as the cross-sectional view of  FIG. 8 . 
       FIGS. 13 and 14  show another embodiment of the endoscope  50 . In this embodiment the circular lenses  52 ,  54 ,  56  are provided at a flat distal tip end  48  of the endoscope  50 . Thus the tip end  48  has a cylindrical shape. The lenses  52 ,  54 ,  56  have fields of view that provide overlapping images that can be similar to the fields of view shown in the earlier embodiment illustrated in  FIGS. 7 and 9 . Further, in some embodiments the fields of view need not extend sidewardly and outwardly to the extent of the fields of view θ 2  and θ 3  in  FIG. 7 . 
       FIGS. 15 and 16  show an additional embodiment of the endoscope  50 .  FIG. 15  shows side lenses  102 ,  104 ,  106  spaced on the distal tip end  48  of the endoscope. No central lens is present in this embodiment. Illuminating fibers  58  (only some of which are shown) are provided on the surface at the distal tip end  48  of the endoscope, except for the lenses  102 ,  104 ,  106 . The plurality of fiber optics  58  are connected to a light source  20  and project light outwardly from the distal end  48  of the endoscope. The light provides illumination so that the endoscope  50  may view an anatomical structure in the interior of a patient&#39;s body. 
     As in the earlier embodiments, reflected light images pass through the lenses  102 ,  104 ,  106  at the distal tip end  48  of the endoscope and into imaging channels (not shown). The images pass through the imaging channels and are refocused by a lens coupler to form corresponding images  112 ,  114 ,  116  as shown in  FIG. 16 . The projected images  112 ,  114 ,  116  overlap respective adjacent images in cross-over areas  122 ,  124 ,  126 . Further, at overlapping region  128 , the three images completely overlap each other. The images  112 ,  114 ,  116  cover the entirety of the image sensor  46 . In this embodiment, the images  112 ,  114 ,  116  and the endoscope  50  are fixed relative to the image sensor  46 . 
     In one embodiment, optical blocking elements  90  block portions of the images  112 ,  114 ,  116  at overlapping cross-over areas  122 ,  124 ,  126 ,  128  so that the image sensor  46  shown in  FIG. 16  receives a single image thereon without overlapping images. 
     In another embodiment, the image processing device  49  can include image correction algorithms or software filters instead of blocking elements  90  to eliminate the effect of the multiple images applied in the cross-over areas  122 ,  124 ,  126 , and the triple cross-over area  128 . 
     In another embodiment shown in  FIG. 17 , the endoscope  50  is rotatable relative to the image sensor  46  of the camera  14 . Rotation of the endoscope  50 , and thus the corresponding images  112 ,  114 ,  116 , allows the orientation of the images to change. The images  112 ,  114 ,  116  cover the entirety of the image sensor  46  within the dashed circle line  129  no matter what the angle of rotation is. This embodiment allows the orientation of the processed image viewed on a display screen to remain viewable during the entire rotation of the endoscope  50 . As in the earlier described embodiments, blocking elements or image correction algorithms eliminate the effect of the overlapping images in cross-over areas  122 ,  124 ,  126 ,  128 . 
     While the embodiments of  FIGS. 15-17  show three essentially circular shaped images  112 ,  114 ,  116  that overlap with each other, other embodiments including more than three lenses that provide more than three overlapping images are contemplated. For example, another embodiment has four lenses (not shown) that are preferably symmetrically located about a distal tip end  48  of an endoscope. The four lenses provide four images  130 ,  132 ,  134 ,  136  as shown in  FIG. 18  that project from the proximal end of the endoscope onto an image sensor  46 . 
     In  FIG. 18 , the projected images  130 ,  132 ,  134 ,  136  overlap adjacent images at cross-over areas  140 ,  142 ,  144 ,  146 . At a central point  148 , the images  130 ,  132 ,  134 ,  136  all meet each other, but are not intended to overlap with each other in most embodiments. The dashed circle line  150  in  FIG. 18  shows the innermost position of the outer edges of the images  130 ,  132 ,  134 ,  136  with respect to the image sensor  46  during rotation of the endoscope. Thus the images  130 ,  132 ,  134 ,  136  continue to cover the entirety of the image sensor  46  during rotation of the endoscope. 
     While an optical coupler  51  is disclosed, in some embodiments individual refocusing lenses or blockers are provided at the apertures  72 ,  74 ,  76  shown in the  FIG. 10  embodiment as a substitute for the coupler. Other embodiments of the invention may also use this arrangement. 
     While various arrangements with different corresponding lenses for the endoscope  50  are shown in the above embodiments, in an additional embodiment a pair of imaging lenses with a pair of corresponding imaging channels extending through the endoscope provide two images that cover the entire surface of an imaging sensor  46 . The imaging lenses preferably are equidistant from the longitudinal axis  57  of the endoscope. An overlapping area or cross-over region of the two images can be blocked, removed or accounted for by an optic coupler  51  having a blocking element or by an algorithm or software filter in an image processing device  49  as discussed above with respect to other embodiments. 
     The endoscope  50  can have a plurality of channels. The endoscope  50  preferably includes from two to five imaging channels, and most preferably three imaging channels  62 ,  64 ,  66  as discussed above. 
     While the imaging channels are shown as circular cylindrical shaped channels, the channels may be rounded and provided with elliptical shapes or other shapes. As discussed above, however, a square or rectangular shape for the image channels is generally undesirable. 
     In some embodiments the lenses  52 ,  54 ,  56  and the corresponding image channels  62 ,  64 ,  66  have the same size. In other embodiments, selected lenses and corresponding image channels have different dimensions relative to each other. Thus the projected images have different sizes. 
     While  FIG. 5  shows an external light source  20  providing light to fiber optics  58 , in some embodiments LEDs within the endoscope  50  provide illuminating light to the distal end  48  through fiber optics  58 . In other embodiments each LED provides light to a plurality of fiber optics  58  or the like. Further, in some embodiments LEDs are provided at the distal tip end  48  of the endoscope. 
     In another embodiment, a transmitter  99  shown in broken line in  FIG. 5  and located within the camera, sends a wireless signal of the sensed images. In one embodiment, the wireless signals are RF signals. In other embodiments, wireless signals are ultra-wide band (WWB), WiFi signals or the like. A receiver  100  illustrated in broken line within the image processing device  49  in  FIG. 5  receives the wireless signals. Thus, in this embodiment the cable  18  is not required. 
     The above described embodiments provide a high definition panoramic image for a display generally having an aspect ratio of 16:9. 
     Although particular preferred embodiments of the invention are disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.