U.S. patent application number 15/984874 was filed with the patent office on 2018-12-13 for ingestible endoscopic optical scanning device.
This patent application is currently assigned to Innurvation, Inc.. The applicant listed for this patent is Innurvation, Inc.. Invention is credited to Michael R. ARNESON, William Robert BANDY, Brian Glenn JAMIESON, Kevin James POWELL, Kenneth Edward SALSMAN, Robert Charles SCHOBER, John WEITZNER.
Application Number | 20180353058 15/984874 |
Document ID | / |
Family ID | 41530891 |
Filed Date | 2018-12-13 |
United States Patent
Application |
20180353058 |
Kind Code |
A1 |
BANDY; William Robert ; et
al. |
December 13, 2018 |
INGESTIBLE ENDOSCOPIC OPTICAL SCANNING DEVICE
Abstract
An ingestible scanning device includes, in an embodiment, a
capsule housing having a transparent window and sized so as to be
ingestible, a photo-sensing array located within the capsule
housing, a mirror located within the housing and oriented to direct
an image from a surface outside the transparent window to the
photo-sensing array, and a light source for illuminating the
surface outside the transparent window.
Inventors: |
BANDY; William Robert;
(Gambrills, MD) ; JAMIESON; Brian Glenn; (Severna
Park, MD) ; POWELL; Kevin James; (Annapolis, MD)
; SALSMAN; Kenneth Edward; (Pleasanton, CA) ;
SCHOBER; Robert Charles; (Huntington Beach, CA) ;
WEITZNER; John; (Coto de Caza, CA) ; ARNESON; Michael
R.; (Finksburg, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Innurvation, Inc. |
Hermosa Beach |
CA |
US |
|
|
Assignee: |
Innurvation, Inc.
Hermosa Beach
CA
|
Family ID: |
41530891 |
Appl. No.: |
15/984874 |
Filed: |
May 21, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14020110 |
Sep 6, 2013 |
9974430 |
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15984874 |
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12370509 |
Feb 12, 2009 |
8529441 |
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14020110 |
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61028102 |
Feb 12, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 1/041 20130101;
A61B 1/0684 20130101; A61B 1/0607 20130101 |
International
Class: |
A61B 1/04 20060101
A61B001/04; A61B 1/06 20060101 A61B001/06 |
Claims
1. An ingestible scanning device, comprising: an ingestible capsule
housing having a transparent window; a photo-sensing array located
within the ingestible capsule housing; and a stationary conical
reflector, located within the ingestible capsule housing,
configured to deflect an image into a circular band to project a
toroidal shaped image onto the photo-sensing array.
2. The ingestible scanning device of claim 1, wherein the
photo-sensing array comprises a two dimensional photodetector
array.
3. The ingestible scanning device of claim 1, wherein the
stationary conical reflector is arranged to be oriented along a
center axis of the ingestible scanning device.
4. The ingestible scanning device of claim 1, further comprising: a
lens, situated between the photo-sensing array and the stationary
conical reflector, configured to focus the image onto the
photo-sensing array.
5. The ingestible scanning device of claim 4, wherein the lens
comprises a cylindrical lens.
6. The ingestible scanning device of claim 5, wherein the circular
band is approximately centered at ninety degrees to an axis of the
cylindrical lens.
7. The ingestible scanning device of claim 1, further comprising: a
light source configured to illuminate a surface corresponding to
the image with light.
8. The ingestible scanning device of claim 7, wherein the image is
associated with the light being reflected from the surface.
9. The ingestible scanning device of claim 7, wherein the light
source comprises one or more light emitting diodes.
10. The ingestible scanning device of claim 1, further comprising:
a mirror, arranged to be at an angle to the photo-sensing array,
configured to view the image through an aperture of the ingestible
capsule housing.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/020,110, filed Sep. 6, 2013, which is a
continuation of U.S. patent application Ser. No. 12/370,509, filed
Feb. 12, 2009, now U.S. Pat. No. 8,529,441, which is incorporated
by reference herein in its entirety. The present application also
claims the benefit of U.S. Provisional Patent Appl. No. 61/028,102,
filed Feb. 12, 2008, which is incorporated by reference herein in
its entirety.
BACKGROUND
Field
[0002] Embodiments of the present invention relate to optical
scanners, specifically optical scanners located on an ingestible
endoscopic device
Related Art
[0003] Modern electronic imaging systems typically utilize a two
dimensional focal plane array (FPA). However, this requires the use
of a single optical lens element with a stop that is circularly
symmetrical in two dimensions to focus the image onto all of the
imaging FPA. Currently, small imaging systems such as those used in
camera pills for biomedical cameras, as well as for security and
industrial applications, are limited in resolution by the pixels in
their FPA chip. As a result, the current camera pills for gastric
intestinal (also referred to herein as endoscopic) examination have
a relatively low resolution of, for example, 300.times.300 pixels.
This results in images that provide extremely limited details and
cannot be enlarged significantly for improved diagnostic
analysis.
[0004] These systems are further impaired with the orientation of
the array such that the field of view of the camera pill is
continuous and fixed. For example, a camera pill may only look down
the central axis of the pill and GI tract thereby presenting the
center of the field of view as having very little to no useful
image data. Additionally, these camera pills typically require
extremely wide angle "fish-eye" lenses to image the tissue along
the intestinal wall with the result that the images are distorted
and non-uniformly illuminated.
[0005] Further, use of a fish-eye lens generates images where the
information of the condition of the inside wall of the GI tract is
only contained in a ring of pixels at the peripheral region of the
image. In this situation the center region of the image shows a
view down the length of the intestine and contains little or no
useful information. This results in images where the most important
data is presented on a small fraction of the pixels in a focal
plane imaging array such as a CCD or CMOS imager. This reduction in
the effective resolution is exacerbated by the presentation of the
image in a distorted circular appearance with the most outer edge
visible being brightly lit and close to the imaging array while the
rest of the intestinal wall surface is progressively further away
from the camera and progressively dimmer in illumination.
[0006] Additionally, the images of interest to a physician are
images of the intestinal wall, not the forward-looking view down
the GI tract. The ability to scan the intestinal walls is thus
preferred over traditional camera pill imaging. The ability for the
capsule to image the entire tubular wall and the size and
electrical connections required for the focal plane array define
that the image array be set so that the imaging surface is
perpendicular to the axis of the pill.
SUMMARY
[0007] An ingestible scanning device includes, in an embodiment, a
capsule housing having a transparent window and sized so as to be
ingestible, a photo-sensing array located within the capsule
housing, a mirror located within the housing and oriented to direct
an image from a surface outside the transparent window to the
photo-sensing array, and a light source for illuminating the
surface outside the transparent window.
[0008] Further features and advantages of the invention, as well as
the structure and operation of various embodiments of the
invention, are described in detail below with reference to the
accompanying drawings. It is noted that the invention is not
limited to the specific embodiments described herein. Such
embodiments are presented herein for illustrative purposes only.
Additional embodiments will be apparent to persons skilled in the
relevant art(s) based on the teachings contained herein.
BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
[0009] The accompanying drawings, which are incorporated herein and
form part of the specification, illustrate the present invention
and, together with the description, further serve to explain the
principles of the invention and to enable a person skilled in the
relevant art(s) to make and use the invention.
[0010] FIG. 1 illustrates an ingestible scanner according to an
embodiment of the present invention.
[0011] FIGS. 2A and 2B illustrate a lighting system for use in an
ingestible scanner, according to an embodiment of the present
invention.
[0012] FIG. 3 illustrates an exemplary endcap of an ingestible
scanner, according to an embodiment of the present invention.
[0013] FIG. 4 illustrates additional exemplary endcaps of an
ingestible scanner, according to an embodiment of the present
invention.
[0014] FIG. 5 illustrates a cross-section of an ingestible scanner
according to an embodiment of the present invention.
[0015] FIG. 6 illustrates a cross-section of another ingestible
scanner according to an embodiment of the present invention.
[0016] FIG. 7 illustrates a cross-section of another ingestible
scanner according to an embodiment of the present invention.
[0017] FIG. 8 illustrates exemplary scribes used in an embodiment
of the present invention.
[0018] FIG. 9A is a cross-section of a photodiode.
[0019] FIG. 9B is a top-down view of the photodiode of FIG. 9A.
[0020] FIGS. 10A and 10B illustrate construction of a back-lit
scanner according to an embodiment of the present invention.
[0021] FIG. 10C is a top-down view of a photosensor array using the
scanner of FIGS. 10A and 10B.
[0022] FIG. 11 illustrates an exemplary reflective element
according to an embodiment of the present invention.
[0023] FIG. 12 illustrates another exemplary reflective element
according to an embodiment of the present invention.
[0024] FIG. 13 illustrates an exemplary reflective and refractive
element according to an embodiment of the present invention.
[0025] The features and advantages of the present invention will
become more apparent from the detailed description set forth below
when taken in conjunction with the drawings, in which like
reference characters identify corresponding elements throughout. In
the drawings, like reference numbers generally indicate identical,
functionally similar, and/or structurally similar elements.
DETAILED DESCRIPTION
[0026] While specific configurations and arrangements are
discussed, it should be understood that this is done for
illustrative purposes only. A person skilled in the pertinent art
will recognize that other configurations and arrangements can be
used without departing from the spirit and scope of the present
invention. It will be apparent to a person skilled in the pertinent
art that this invention can also be employed in a variety of other
applications.
[0027] It is noted that references in the specification to "one
embodiment", "an embodiment", "an example embodiment", etc.,
indicate that the embodiment described may include a particular
feature, structure, or characteristic, but every embodiment may not
necessarily include the particular feature, structure, or
characteristic. Moreover, such phrases are not necessarily
referring to the same embodiment. Further, when a particular
feature, structure, or characteristic is described in connection
with an embodiment, it would be within the knowledge of one skilled
in the art to effect such feature, structure, or characteristic in
connection with other embodiments whether or not explicitly
described.
[0028] An ingestible sensor device may be swallowed by a patient,
such as a human, to diagnose one or more conditions of the patient.
The ingestible sensor device may include a sensor configured to
receive a stimulus inside the gastrointestinal tract of the
patient, wherein the sensor is configured to output a signal having
a characteristic proportional to the received stimulus. The
ingestible sensor device may further include a communications
module that transmits an acoustic signal modulated with the sensor
output signal and a housing configured to have a size that is
swallowable, wherein the housing substantially encloses the sensor
and communications module. The patient using the ingestible sensor
devices may be any type of animal, including a human. In addition,
these same sensor devices may be temporarily implanted into patient
for the purpose of continuous monitoring, such as with a several
hour to several day diagnostic period at `home` or at a
professional care center. A sensor link module may be located on
the surface of the patient to receive the acoustic signal output by
the sensor. An example ingestible sensor is further described in
U.S. patent application Ser. No. 11/851,221, filed Sep. 6, 2007,
and U.S. patent application Ser. No. 11/851,214, filed Sep. 6,
2007, each of which is incorporated by reference herein in its
entirety.
[0029] An ingestible sensor device may benefit from an optical
scanner coupled to the ingestible sensor device. Although the
present invention will be described with respect to an ingestible
endoscopic sensor device, one of skill in the art will recognize
that an optical scanner as described herein may be coupled to any
type of ingestible device, or may be used on its own, without
departing from the spirit and scope of the present invention.
Scanned image data from the ingestible sensor device may be
transmitted outside the body through use of acoustic data
transmission, or using any other type of data transmission known to
one of skill in the art. Additional embodiments and features of a
radial scanner that may be used in conjunction with the present
invention are described in U.S. Prov. Patent Appl. No. 61/030,453,
filed Feb. 21, 2008, which is hereby incorporated by reference in
its entirety. Additionally, although the present invention is
described in conjunction with scanning inside the gastrointestinal
tract, one of skill in the art will recognize that a similar
scanner may also be used inside vasculature, urinary tract,
reproductive tract, lung, nasal or internal ear cavity, or any
other cavity of an animal as also described in U.S. Prov. Patent
Appl. No. 61/030,453.
[0030] Unlike typical camera pills, in an ingestible endoscopic
scanner, the need for a focal plane to generate a two dimensional
image can be eliminated by the use of a single axis or single
element photo-sensor that is coupled with an optical scanning
element or is physically scanned over the desired field of view.
Whereas the image taken by a focal plane array is simultaneous over
the entire field of view and must be scanned out to a memory for
transmission, the single axis sensing array is capable of being
read a line at a time. With the combination of a scanner, a
broadband source, and a linear array, a point-by-point spectrum can
be produced using diffractive optics.
[0031] The scan line images may be generated without the two
dimensional circular lens and stop element used in existing
ingestible cameras. In this manner, the single line array of pixels
can scan a region such that in one axis, the linear line array
provides the resolution while in the opposing axis a scanning
system is utilized. In this manner, as will be described further
below, the scanning element can be composed of any of a variety of
opto-mechanical configurations composed of, for example, an
oscillating mirror, a prism, a cylindrical lens, etc. This allows
the achievable resolution of the scanned axis and the speed of
imaging to be adjustable. Also, this scanning approach can be used
with illumination or in combination with a joint illumination and
imaging optical configuration producing a highly efficient optical
imaging system. In embodiments, this construction may lead to the
pixel area on the surface being imaged being defined by the spot
size generated by the light source. Color images can be generated
either by sequential scans with switching color light sources, or
by using pixel rows on the photo-sensor array each with a color
filter assigned to each row.
[0032] FIG. 1 illustrates an exemplary ingestible scanner 100
according to an embodiment of the present invention. A single axis
photo-sensing array 102 is located such that it extends across the
diameter of a capsule housing 104 and is perpendicular to the axis
of the capsule and the axis of housing 104. Array 102 may be, for
example and without limitation, a single photosensing diode (also
referred to herein as a photosensor or photodetector) or a
one-dimensional array of multiple photosensors. Housing 104 may be,
for example, a tubular housing. A mirror 106 within the pill is
placed such that it is at an angle to array 102 that allows array
102 to view the intestinal wall surface 108 through the side wall
of housing 104 through a clear aperture 110 in housing 104. Mirror
106 may be, for example, an elliptical mirror. Alternatively,
mirror 106 may be a rectangular mirror that deflects on only one
axis. Mirror 106 may be placed at an angle of, for example, 90
degrees to array 102. Mirror 106 may be a two-sided mirror, to
capture twice the data in a single revolution. Aperture 110 may
extend for 360 degrees around housing 104. Mirror 106 may be
coupled to a micro-motor 112 such that an electrical signal causes
mirror 106 to rotate. The axis of rotation of mirror 106 is
approximately parallel to the axis of capsule 100. The rotation of
mirror 106 results in array 102 scanning, in a 360 degree field,
the region surrounding capsule 100. In an alternative embodiment
(not shown), mirror 106 may be attached to a rod having two
conductors and suspended in an electrical coil, such that the rod
rotates as electricity is applied to the coil.
[0033] In an embodiment, a cylindrical lens 114 is placed over
array 102 to focus light from surface 108 reflected by mirror 106
onto array 102. Because array 102 is imaging surface 108 through
aperture 110 on the side of capsule 100, rather than through the
end of capsule 100, resolution of array 102 is approximately
uniform at any given scan rate. Resolution may be increased in the
rotational axis by adjusting the speed of rotation of mirror
106.
[0034] Array 102 is used to generate one or more images of surface
108 by scanning. This is accomplished in one embodiment by moving
cylindrical lens 114, which is placed down the length of array 102
such that the curvature of cylindrical lens 114 is perpendicular to
the length of array 102. Scanning of the region to be imaged (such
as surface 108) is achieved by movement of the relative position of
cylindrical lens 114 to array 102. In an embodiment, either of
array 102 or cylindrical lens 114 can be moved. In this manner,
light from different regions of the image are focused sequentially
onto the pixels of array 102 as the movement occurs. By use of
cylindrical lens 114 (or a more complex lens surface, in an
embodiment) extremely wide angle images can be achieved on the axis
of the image that is scanned.
[0035] In an embodiment, cylindrical lens 114 is replaced with a
scanning mirror or prism. The prism may have either a transmissive
or reflective function depending upon the scanning optical
design.
[0036] Illumination of the imaged wall region, such as surface 108,
may be accomplished by placing LED light sources adjacent to array
102, to create a light distribution ring, or "light pipe" 116. In
an embodiment, light pipe 116 evenly outputs light around
approximately the entire perimeter of housing 104. In an
embodiment, light from light pipe 116 is output at multiple
frequencies. In this manner individual scans or frames of different
frequencies can be captured and integrated into full color images,
partial color images or false color images. Light sources may
include, for example and without limitation, narrow band emitters
in the visible range, white light emitters, ultraviolet emitters
and infrared or near infrared emitters. Imaging arrays comprising,
for example, three rows of photo-sensors, each with a specific
color filter, may be used to generate full visible color images. In
this manner the imaging system can be utilized to detect reflection
differences in tissue over a spectral range far exceeding the
abilities of the human eye. In an embodiment, a pixel size of array
102 may be controlled through the use of mechanical shutters or a
shutter wheel. The shutter wheel may include one or more color
filters.
[0037] In an embodiment, light pipe 116 is located within housing
104. In another embodiment, light pipe 116 is external to housing
104. In an embodiment where light pipe 116 is located external to
housing 104, light pipe 116 acts to space the scanning optics off
the intestinal wall. Further, positioning light pipe 116 outside
housing 104 ensures that the light source path is separated from
the received light path, with no internal reflecting surfaces.
[0038] In one embodiment, the entire light pipe 116 may be
illuminated at a given time, providing illumination for the entire
circumference of the intestinal wall at the same time. In another
embodiment, in order to preserve power, light pipe 116 may direct
light only to the portion of surface 108 being imaged at a given
time by array 102. FIGS. 2A and 2B illustrate an exemplary lighting
system for focusing illumination light on intestinal wall surface
108. FIG. 2A illustrates a cross-sectional view of the directional
lighting system. As shown in FIG. 2A, a toroidal lens 202 surrounds
array 102. The relationship between toroidal lens 202 and array 102
is further illustrated in FIG. 2B. Returning to FIG. 2A, toroidal
lens 202 directs illumination light from light source 204 (which
may be, for example, an LED) to mirror 106. Mirror 106 further
focuses the illumination light onto surface 108. Mirror 106 may be
positioned such that surface 108 is approximately located at a
focal point of mirror 106. Alternatively, a collimating lens (not
shown) may be included between surface 108 and mirror 106 to
account for any focal length variability of surface 108. An image
from surface 108 is then returned to array 102.
[0039] Alternatively, illumination may be provided to a small
portion of surface 108 using an optical fiber to direct the
illumination light accordingly. In yet another alternative, a
photosensor in array 102 may include a hole that allows light to
pass through array 102 to mirror 106, and then be reflected onto
surface 108.
[0040] Illuminating only a small portion of the surface preserves
power in the ingestible capsule, because light produced by the
light source is focused onto a specific spot rather than
distributed across many spots. This allows the amount of radiation
output by the light source to be decreased without changing the
radiation per pixel received.
[0041] Illuminating a small portion of a surface also allows image
processing of the imaged surface such that very accurate
colorimetry measurements may be made, according to an embodiment of
the present invention. Color information may be obtained through
use of an array having more than one photodetector element, such as
a two- or four-element array. In one embodiment, the array may be
separated into subcategories of traditional red, blue, and/or
green. Alternatively, a single photodetector element may be used
with multiple color light emitting diodes (LEDs), as use of a
single photodetector element maximizes the sensitivity of the
aperture size. This allows inspection of tissue for regions which
have a slight loss of oxygen or are just becoming infected or
inflamed. This technique provides higher accuracy of these
conditions than that capable with white light and the human
eye.
[0042] In an embodiment, the illumination intensity can be varied
for different views. For example, illumination intensity may be
increased when scanning points of particular interest, such as a
surface of the intestinal wall. Similarly, illumination intensity
may be decreased when scanning across points of lesser interest,
such as down the intestine where less light will be reflected back
to the detector.
[0043] Returning to FIG. 1, the scan rate, as determined by the
rotational rate of mirror 106, may be adjusted to match a desired
frame rate. This requires less memory and allows more flexibility
of the imaging rate. The ability to scan the image with an optical
mechanical device also allows the elimination of a complex lens.
Although FIG. 1 illustrates mirror 106 as coupled to motor 112 for
rotating mirror 106, scanning can alternatively or additionally be
accomplished by moving array 102, tilting mirror 106 to view 360
degrees around the sides of capsule 100, or by moving cylindrical
lens 114 to scan a region. The rate of motion of array 102, mirror
106, or lens 114 defines the rate of the scan in one axis. For
example, mirror 106 may not only be rotatable around a capsule axis
118, but it may also be tiltable, having a pivot line perpendicular
to axis 118. Such a tiltable, rotatable mirror provides a two-axis
range of motion of mirror 106.
[0044] In an embodiment, light pipe 116 homogenizes the intensity
and converts the light into a ring which illuminates the optical
scanning region with a highly uniform ring of light. In a specific
example, not intended to limit the present invention, mirror 106 is
oriented at 45 degrees with respect to array 102. Motor 112 rotates
mirror 106 and a lens is placed so that array 102 images a 0.5
degree instantaneous field of view. The start of each scan line may
be identified by the use of an occlusion in the field of view, such
as wires attaching array 102 to its supporting electronics. In this
specific example, the system provides approximately 720 pixels per
scan with a pixel size of 55 microns. In this example, data may be
captured at 16 bits per color giving a 48 bit full color data per
pixel. In this example, scan rates may vary from, for example, 1000
rpm to 10,000 rpm. This provides an example resolution of
720.times.405 pixel full color image comprising 875,000 pixels,
which is approximately 1/3 the resolution of a high-definition
television. In another example, the axial scan may include a full
720 pixel resolution of 720.times.1280 pixels.
[0045] In an embodiment, the scanner may use feedback from other
sensors in the capsule to enter into a single color mode when a
full color scan is not substantially different from a previous
scan. Similarly, the scanner may enter into a multi-color mode
(using two or more colors) when a single color scan is different
from previous scans. In another embodiment, such color selection
instructions may be received from an operator external to the
capsule instead of other sensors within the capsule.
[0046] Various additional embodiments are possible using tilting
and/or rotating mirrors and/or arrays. As shown in FIG. 1, a second
optical system may be located on the opposite end of capsule 100
from array 102 and mirror 106. This allows a 360 degree field of
view for capsule 100. FIGS. 3-7 each illustrate a different
exemplary configuration for capsule 100.
[0047] In FIG. 3, the end of capsule 300 containing the imaging
optics includes a globe-shaped housing 302. This allows a very wide
angle field to be imaged by photodetector 304.
[0048] In FIG. 4, ends 402a and 402b of capsule 400 are shaped like
a truncated cone, so that light enters the imaging optics through a
flat surface. This increases the simplicity of optics required to
counteract distortion caused by light passing through housing
404.
[0049] FIG. 5 illustrates a cross-section of a capsule 500, wherein
the imaging optics are not located at the ends of the capsule, but
instead are located in the central portion of the capsule. Mirror
502 is located on a central cylinder 504. At least a portion of
housing 506 is transparent, such that an image from intestinal wall
surface 508 is reflected by mirror 502 to photodetector 510.
Central cylinder 504 may be rotatable, such that mirror 502 can
image around the full perimeter of capsule 500. In an embodiment,
mirror 502 is a dish mirror to direct light to photodetector 510
when mirror 502 is tilted. In an embodiment, central cylinder 504
includes an illuminator. The illuminator may be located inside
central cylinder 504 with light exiting through a slit in central
cylinder 504 (not shown) in order to illuminate intestinal wall
surface 508.
[0050] FIG. 6 illustrates a cross-section of a capsule 600, wherein
the imaging optics are located in the central portion of the
capsule. In this embodiment, photodetector 602 is located on a
central cylinder 604. Central cylinder 604 may be made from a
reflective material, such that an image from intestinal wall
surface 610 enters through transparent housing 606 and reflects off
central cylinder 604 to a mirror 608. The image is further
reflected by mirror 608 to photodetector 602. Central cylinder 604
may be rotatable, such that photodetector 602 can image around the
full perimeter of capsule 600.
[0051] FIG. 7 illustrates a cross-section of a capsule 700, wherein
the imaging optics are surrounded by hemispherical lenses 702a and
702b on either end of capsule 700. In an embodiment, hemispherical
lenses 702a and 702b may be organized in conjunction with a
pre-distorted lens to scan a respective hemisphere of the GI tract
with high resolution on the side walls and graduated lower
resolution toward the centerline of the scanner field of view.
[0052] In an embodiment where a 2 dimensional photodetector array
is used, a conical reflector 1102 may be oriented along the center
axis of the optical lens system, as illustrated in FIG. 11. In a
similar embodiment, a parabolic mirror or other cylindrically
symmetrical reflector, as illustrated in FIG. 12, may be used in
place of the conical reflector. In still another embodiment, this
mirror element may be composed of one or more reflective and
refractive surfaces, as illustrated in FIG. 13. An image may be
taken of the inside of the GI tract that maximizes the number of
pixels in an imaging array that present a useful image of the
internal wall. In addition, illumination of the wall perpendicular
to the orientation of the scanner presents a field of view with the
tissues at nearly a constant distance from the scanner lens. This
improves the ability to capture scan images at a uniform focus,
resolution and illumination intensity.
[0053] In this embodiment, the conical reflector is designed to
match the field of view of the lens and deflect the image into a
circular band that is centered at or near 90 degrees to the
original axis of the lens. In this manner the lens is provided with
an image region where optical path lengths from one edge of the
cylindrically imaged region are approximately equidistant to the
path length of the opposing edge of the imaged region. A moderate
field of view may thus be obtained with a normal lens. This allows
simple optical elements to be used with minimal focal or distortion
issues. Nearly all the pixels within the imaging array are
presented with useful information. This maximizes the usable
resolution in the resulting image. It is also easier to illuminate
the imaged region in a near uniform manner. The images may then be
processed to remove the circular distortion and produce panoramic
images that represent an unwrapped and undistorted image of the
interior wall.
[0054] Another embodiment whereby effects of a variable focal
distance are mitigated includes changing the focus position of the
lens to bring any specific distance of the imaged surface into
focus. Oscillating the focus from a close position to a distant
position creates a temporally focused image. This approach can then
be used to determine the distance between any region of the imaged
surface and the lens. By further incorporating software that can
selectively capture regions of the image when they are in focus, it
is possible to generate a composite image where the entire image is
in focus or to generate a depth map of the surface. Once a depth
map of the surface is created, additional image processing can
provide a parallax calculation to be made, and images can thereby
be created which represent the surface in three dimensions.
[0055] More particularly, the distance between the imaging lens and
the film or image sensing array (such as a CCD or CMOS focal plane
array) may vary depending upon the distance at which the imaged
surface is in focus. This results in the spacing of the lens
varying as various distances of the imaged surface are brought into
focus. By smoothly oscillating the lens between its minimal and
maximum spacing above the film or imaging array, it is possible to
generate a series of images or frames where each surface region is
progressively brought into focus from the closest to the farthest
from the lens. Sharp objects or markings on the surfaces which
represent high contrast regions (such as edges of shadows or sharp
edged color differences) are sharp and high contrast only when they
are in focus. The contrast of these objects drops rapidly when the
lens position is changed even slightly. In this manner, it is
possible to utilize software that analyzes pixel values and
identifies adjacent pixels having sharp intensity variations when
the lens is in other spacing positions. By capturing these regions
in a sequential manner, it is possible to generate a composite
image where the entire image surface is presented in sharp focus.
The lens spacing information corresponding to each image may be
used to create a depth profile map of the surface. This profile may
then be used to generate a pseudo three dimensional image by
generation of images representative of a parallax pair of images,
where the position of near field surfaces is shifted more than the
background surfaces.
[0056] By utilizing image processing algorithms that capture
regions of an image at their highest contrast and incorporating a
rapidly dynamic focusing lens system that has a narrow depth of
field, the focus position may be used to generate a depth profile
of the image. This depth profile may then be utilized to generate a
topographic map of the imaged region. The depth profile can
additionally be utilized to generate a pseudo-parallax perspective
of the imaged region and present the processed image in three
dimensions utilizing head-mounted stereoscopic displays or other
similar devices. In addition, distortions to the image may be
created to enhance the representation of depth on a single display
monitor.
[0057] This allows presentation of a fully focused image of tissues
which vary greatly in distance from the imaging lens, while
utilizing an optical lens system designed for the highest light
efficiency possible. In addition, the ability to generate depth
profiles and pseudo three dimensional images can assist a physician
in visualizing the relative position of the tissues, further
assisting in diagnosis.
[0058] In another embodiment, a scanner having multiple
photodetectors in its array enables not only spot detection but
also the level of light diffused from the coherent signal sent out.
The diffusion may be important, because rough tissue scatters light
much more than smooth tissue. Having multiple photodetectors in the
array not only offers a gain advantage in that it is more sensitive
to reflected light, but it also offers an opportunity to determine
a relative amount of light in the center of the image versus the
outside of the image, and gives an approximate correlation to
smooth tissue as opposed to rough tissue.
[0059] As has been discussed, an ingestible optical scanner may
include a tiltable and/or rotatable mirror for capturing a wide
angle field of view. In an embodiment of the present invention, as
introduced with respect to FIG. 1, a capsule may contain two
scanning systems, one on each end of the capsule. As discussed
above, FIG. 7 is an illustration of an exemplary capsule 700 having
scanning optics located in two hemispherical lenses 702a and 702b.
Depending on the field of view, it may be possible for each
scanning system 702a and 702b to image the same feature 704 on an
intestinal wall surface 706. Because of the effects of parallax
caused by the distance d separating optics 708a and 708b, a
three-dimensional image of feature 704 may be obtained. Although
this three-dimensional feature is described with respect to
hemispherical lenses 702a and 702b, one of skill in the art will
recognize that any type of lenses may be used without departing
from the spirit and scope of the present invention.
[0060] In another embodiment, a single scanning system may image a
feature such as feature 704 from two different locations within the
GI tract. In this embodiment, parallax due to the distance between
the two locations may be used to provide a three-dimensional image
of the feature.
[0061] In an embodiment of the present invention, the mirror used
to reflect images to the capsule's imaging sensor may have scribes
located on the mirror's surface in predetermined equal distances
from each other. An example set of scribes is illustrated in FIG.
8. Although FIG. 8 illustrates the distance between scribes in
terms of micrometers, the distance between scribes could
alternatively be fractions of mm, fractions of an inch etc. This
provides accurate reference dimensions to aid a physician in
identifying size of objects in view on the picture. The scribes on
the mirror may result in pictures having the scribe lines always
showing as a reference on each and every frame.
[0062] The mirror may also be a magnifying mirror, where the
magnification is, for example and without limitation, 2.times.,
3.times., or 4.times. as desired for a given purpose. This enhances
the scanning capsule endoscope by increasing resolution using
optical magnification. When the scribes are designed for the
magnifying mirror, the magnification should be appropriately
considered.
2. Variable Resolution and/or Variable Magnification Scanning
[0063] In an embodiment, the resolution of an axis can be
controlled by the scanning optical system. This allows for higher
resolution images to be generated than with existing FPA chips
within the size range required of the applications. In addition,
for many applications, the imaging rate (frame rate) and resolution
of the images does not need to be at a fixed (e.g., video) rate.
This allows the scan system to operate at variable speeds such that
when triggers within the image are activated, from, for example,
additional sensors within the capsule or from an operator external
to the capsule, the speed of the image generation can be changed.
For example, the data rate generated can be lowered when
information is redundant or not of interest, and increased when
specific image information is critical to the application or
different from a previous scan. This increases the efficiency of
the information gathering and is similar in result to image
compression. In another example, a low resolution scan may be taken
when the ingestible capsule is moving through the GI tract, to
ensure that information regarding the portion of the GI tract
through which the capsule is passing is obtained. When the capsule
is not moving, the resolution can be ramped up to obtain higher
resolution images of the location. In yet another example, each
color may be imaged in either high resolution or low resolution
depending on a previous scan and a threshold of difference from the
previous scan.
[0064] Under the variable resolution scanning approach, a slower
scan can be used to produce a higher resolution image on the
scanning axis. The use of a cylindrical lens (such as cylindrical
lens 114) or other scanning mirror and/or prism optics provides
wide angle imaging without distortion and without requiring complex
optical surfaces. A radial resolution of the capsule is a function
of the scan rotation rate, and is approximately equal to the line
scan capture rate divided by the number of rotations per second of
the scanning optics. To obtain a high resolution, for example, the
capsule may capture a line scan image every degree around the
viewing field. One of skill in the art will recognize that other
rates of line scan image capture may be utilized without departing
from the spirit and scope of the present invention. A length
resolution of the capsule is a function of the linear velocity of
the capsule (such as the rate at which the capsule moves through
the GI tract), and is approximately equal to the number of
rotations per second of the scanning optics divided by the linear
velocity.
[0065] By using discrete frequency illumination, each scan can be
used to collect the different reflectivity of the target surface,
and therefore can be used to generate full color images and
spectral analysis data at various resolutions.
[0066] Such a technique may also be used to vary the magnification
of an image without any modifications to the detector. That is, if
the spot size decreases while resolution stays constant, an
increase in magnification results.
3. Photosensor Construction and Image Data Format
[0067] The top surface of a typical integrated circuit, including a
focal plane image sensor, has nearly complete metal coverage. This
metal is required to provide addressing, data readout, as well as
cell, or pixel, transistor circuit connections. Each pixel's
photodiode (that is, light sensor) must be placed in an area where
incoming light can reach it. FIG. 9A is an illustration of a
cross-section of a typical photodiode. A photosensor 902 is
implemented in CMOS. As the supporting electronics are designed
depending on the characteristics of photosensor 902, they are
implemented on the chip after the implementation of photosensor
902. Supporting electronics for photosensor 902 are illustrated as
electronics 904. Incoming light beam 906 enters through a hole in
electronics 904 so as to be incident on photosensor 902. Because of
the space needed for electronics 904, the majority of the pixel
area under electronics 904 cannot be used for light sensing. This
limits the available light sensitivity as well as the resolution of
photosensor 902. Dark current and coupled noise further limits the
sensitivity of the photosensor 902. This disparity between the size
of photosensor 902 and the size of a pixel containing photosensor
902 is illustrated in FIG. 9B, which is a top-down view of a
portion of an exemplary photosensor array.
[0068] Large image sensors for a given pixel density have been used
to provide image resolution and light sensitivity. However, the
dark current and coupled noise is a tradeoff limitation of current
image sensors. Additionally, this results in a significant amount
of illumination that must be supplied by LED light sources on the
pill, and thus a portion of the pill's battery capacity is required
for it.
[0069] In an embodiment, a Silicon-on-Insulator (SOI) CMOS image
scanner may be illuminated from the back of the integrated circuit
to achieve a maximum light sensitivity and finest image resolution,
while enabling a small image scanner integrated circuit. FIGS. 10A
and 10B illustrate how such a back-lit scanner may be constructed.
As shown in FIG. 10A, a base 1002 of silicon oxide (SiO.sub.2) is
implemented in place of traditional CMOS. A sacrificial metal layer
1004 is also included to provide support for base 1002. Photosensor
1006 and supporting electronics 1008 are implemented as usual, with
no hole being included in electronics 1008 for accessing
photosensor 1006.
[0070] As shown in FIG. 10B, once sacrificial layer 1004 is
removed, a light beam 1010 may be incident on photosensor 1006
through transparent base 1002. Because the size of photosensor 1006
is no longer limited by the area requirements for supporting
electronics 1008, photosensor 1006 can be made larger, as
illustrated in FIG. 10C, which is a top-down view of an exemplary
photosensor array. Indeed, photosensor 1006 can be made large
enough to have double digit electron sensitivity or less.
[0071] This integrated circuit technology makes it possible to
capture high resolution peripheral scanned images through
hemispherical optics with lower image data along the center line of
the optics, in accordance with an embodiment of the present
invention. On-chip image scanner circuitry may also be incorporated
with variable resolution in an embodiment of the present invention
to trade-off resolution with the quantity of data under electronic
control.
[0072] In an embodiment, optimized circuit design and layout is
performed in defining the electronic arrangement of the pixel
circuitry and pixel photo sensor diodes. The photosensor diodes may
be substantially arranged in a circular pattern for scanning the
illuminated hemispherical field of view. The hemispherical optics
(such as a fisheye lens or cylindrical lens) may work in
conjunction with the image scanner layout. This arrangement offers
scanning information capture and output of the image in a radial
data format. In an embodiment, the outer periphery of the scanning
radius contains a higher density of pixels than the center, which
has the lowest pixel count per unit area of silicon by simple
geometry. This provides the highest resolution on the sidewall of
the intestine at or near the endoscopic capsule, while lower
resolution is provided down the intestinal tract. The read-out
electronics may be located primarily in the center of the array
where the readout lines are the shortest for low power operation. A
low density of pixels may be located throughout the readout
electronic region for coverage in the center of the hemispherical
scanned image which looks down the intestinal tract. The four
corners may also used for image electronics, since there are no
pixels located there.
[0073] In an embodiment, three dimensional data is derived by
combining multiple images, especially those that form opposite ends
of the capsule. Post-processing of this combined data may be
performed for areas of interest by the physician's desk. Once an
area of interest is selected, the data may be processed and viewed
at the operator's command. Three dimensional viewing modes may be
similar to fly-over map viewing having controls for elevation and
azimuth.
[0074] Further regarding this embodiment, the primary data format
has 0 to 360 degrees around the pill plotted on the conventional
x-axis and distance down the intestine plotted on the conventional
y-axis. This data format may be presented on a single page so that
the entire intestine can be observed quickly as a full page
thumbnail. From this view, a mouse may be used to zoom in on areas
of interest (e.g., from operator observation or selection of areas
of interest can be computer-assisted). Higher resolution data may
be zoomed in for regions of interest. In these regions, three
dimensional enhancement that may be viewed in a fly-over mode
employs a similar effectiveness to fly-over map controls. Location
information can be presented in combination with selection of areas
of interest. These and many other data presentation modes are an
outcome of image scanning, as opposed to conventional movie picture
imaging. Post-processing may be employed to render this data into a
more conventional format of looking down the intestine so that
normal data output is available.
[0075] To limit the data for lower resolution pictures and to
increase the light sensitivity, groups of pixels may be combined in
the low resolution mode. This pixel combination can be performed on
the array or during processing external to the array. For instance,
groups of four or more neighboring pixels may be combined.
Similarly, image data compression may be performed by examining the
neighboring pixels electronically. In a specific example not meant
to limit the present invention, a low resolution 320.times.320=100
k pixel frame may become a 640.times.640=400 k pixel frame with a
4.times. magnified image resolution. In this example, a 16.times.
image magnification is 1280.times.1280=1.6M pixel frame. Further
according to this example, a 64.times. magnification renders
2560.times.2560=6.5M pixel resolution. Due to the image scanning
technology described above, the data out before data compression is
about one-fourth that of a conventional imager. The excessively
high amount of data output for a full scan in the highest
resolution mode may be limited by smart sensor technology in the
capsule electronic controls.
[0076] In an embodiment of the present invention, electrical
potentials related to peristalsis may be sensed differentially from
electrodes near either end of the capsule. These electrodes may
also be used to load data, electronically test, sense ingestion,
and turn the capsule off or on independently. Additionally, as will
be described further below, intestinal pressure waveform data can
be used to determine movement of the capsule. In this manner and
according to a further embodiment of the present invention, under
program control the scanner may gather a low resolution image data
during peristalsis and progress to stages of higher resolution
scanning while the local area of the intestinal tract is quiet. The
use of these high resolution modes can be used to examine parts of
the intestine on the cellular level where some forms of pre-cancer
have been observed.
[0077] In an embodiment, after these engineering features are
implemented on the SOI CMOS semiconductor chip, completed wafers
may be fabricated on the semiconductor processing line. As an
additional final manufacturing step, the substrate on which the SOI
wafer is constructed may be removed down to the buried Oxide (BOX).
In an embodiment, this yields a cellophane-like semiconductor which
may be "flip-chip" mounted on the focal plane area of a PC-board or
flex circuit in the capsule.
[0078] For a full spherical image scanner, both ends of the capsule
may contain one of these image scanners with its respective
optics.
4. Arbitrary Sampling Scanner
[0079] Scanning systems such as facsimile machines have a
specifically defined resolution coordinating to the data they
acquire, which is typically defined by the spot size or pixel size
of the imaging array. It is possible to sub-sample the optical
pixel to acquire higher resolution. In digital systems, this is
typically done by utilizing more discrete pixels than optical
spots, thereby requiring a higher photodetection resolution than
optical resolution. This is a costly and inefficient use of the
pixels. The desire for higher resolution images with basic system
designs has pushed the need for higher pixel counts for starring
arrays such as focal plane array (FPA) CMOS or CCD imagers.
[0080] A scanner utilizing movement of the target or movement of
the sensors provides the ability to utilize high response speeds to
gain higher resolution data.
[0081] In an embodiment of the present invention, the analog
response of a photodetector can be utilized to capture image data
from an optical scanner so that the final resolution of the system
is described by a combination of the optical spot size on the
target surface being imaged and the amount of sub-sampling
accomplished by an analog to digital (A/D) converter. Since A/D
converters have the capability to sample at extremely high data
rates, this allows the scanner to be arbitrary in resolution within
the confines of the response speed of the photodetector and the
illumination spot size of the scanner optics. As the scanner's
illumination spot moves across the scanning range, its response can
be much faster than the scanning rate. In this manner, the value of
the signal from a high speed photodetector responds to changes in
the intensity of the scanned spot as it moves within the diameter
of the original spot. Plotting the response of the photodetector
shows changes in the value of the detected signal corresponding to
changes in the surface of the object that are much smaller than the
optical spot size. This allows a high speed A/D converter to
generate several sub-samples of the image before the spot has moved
to cover a completely new surface area adjacent to the initial
image spot. This sub-sampling ability allows higher resolution
details in the object to be detected and imaged. Mapping of the
changes in the sub-sampling data allows calculations of the
position, size, and intensity of surface features significantly
smaller than the optical spot size.
5. Video or Scanned Image Audio Content Indicator
[0082] Humans observing continuous visual data become numb to
sudden, short-lived, or unexpected changes in the image. This
psycho-physical reaction is part of the human eye-brain response
and is a known issue with monitoring security cameras as well as
reviewing continuous streams of data from instruments such as
medical monitoring equipment.
[0083] Because of this, reviewing long data streams of video images
from optical scanning systems for medical applications is
difficult, particularly when a majority of the scans have very
similar data showing normal tissue, while a small selection of
scans may have indications of disease or other medical issues of
key interest.
[0084] In cases where video or scanned image streams have a
majority of similar content and human monitoring or reviewing is
tedious, auditory signals may be used as indicators of sudden
change in the image content. For example, some modern security
systems utilize temporal difference filtering of images to set off
alarms when there are sudden changes in the scene so as to alert
security guards of possible intrusions. Similarly, medical image
data can be processed to generate cues to alert a physician or
observer when the scans show tissue abnormalities.
[0085] In an embodiment of the present invention, the overall
intensity profile of each line or frame may be determined by
utilizing the intensity of each of the color channels of the
scanner. When objects within the image change the parameters of
these levels, the change in intensity values may exceed the normal
range for the data stream. This intensity level data may be
assigned an acoustic tone value which may be for the sum of the
color values. In an embodiment, a tone may be assigned for each
color channel being imaged to generate a set of tones. When
multiple tones are used, a chord may be established to indicate
data that is within a normal specification range, while data that
exceeds the normal range may be assigned tone values to generate
discordant tones whose assignments may be made to indicate the
amount that the data exceeds the normal data range. Tone
intensities may also be used to indicate optical channel
intensities, range values outside of the normal data range, or the
percentage of a frame and/or region where values exceed the normal.
User selection may be made to eliminate the tones indicating normal
values so that data exceeding the normal data range will generate
alert tones. In addition, solid tones may be replaced with specific
types of music or other acoustic media where subtle changes in the
sound obtain the attention of the observer and alert the observer
of the event in the video image or data.
[0086] In an embodiment, the imaging system may include a feed of
the scanner video or data stream to a computer, where the value
setting of the feed is converted into audio signals via software.
The value setting may then be passed to an audio system via cables
or wireless connections. This type of data processing may be
accomplished with, for example and without limitation, a
microcontroller or FPGA, which may be incorporated with other
components within the data stream handling electronics.
[0087] In the case of patient wearable systems such as wearable
monitors, this type of audio alarm may be used to notify the
patient and/or physician via, for example, cell phone or wireless
link, that the monitor has identified data exceeding the normal
data range limits.
[0088] In this manner, the system user can be assured to be
notified of the presence of the anomaly. With individual color tone
generation and anomaly size to intensity generation, unique
acoustic signatures may be associated with the nature of the
anomalies, further providing the physician or observer with
acoustic diagnostic information. Tonal shifts in the data values
provides the human observer with a second sensory input to prevent
missing important events in otherwise tedious data, and allows
review of data at high speeds. Further, this acoustic assignment
process may be used to highlight specific images in data prior to
human review, allowing the data stream to be filtered to show only
the images where the data has exceeded normal values.
6. Monitoring Peristalsis
[0089] During a peristalsis contraction, a select region of the GI
tract tissue is compressed by the muscle fiber contained within its
structure. This compression is how the body normally moves food and
waste products through the GI tract. Monitoring of peristalsis or
the muscle activity with the gastric intestinal tract is critical
to evaluation of the patients ability to process and move food
through the body. Damage caused by disease, nerve damage, rupture
or atrophy of the muscles lining the gastric intestinal tract
(including the stomach) are causes of serious conditions that can
be life threatening.
[0090] In an embodiment of the present invention, the ingestible
endoscopic capsule can utilize peristalsis, and other muscle
contractions of the GI tract, to provide data regarding the extent
and nature of the contraction. Additionally, the capsule may
utilize the contraction to control the functions of the pill such
as powering up, transmitting data, taking images, etc.
[0091] For example, pressure sensor(s) may be used within the
ingestible capsule such that these contractions are be monitored
and utilized to control the timing of acoustic transmission of data
and the collection of images and other sensor data. During these
contractions the tissue is squeezed against the external wall of
the capsule, providing the highest acoustic coupling possible and
thereby the most efficient time for acoustic signals to be sent
with minimal reflections from within the gastric intestinal
structure. This increase in coupling allows the capsule to utilize
minimal power for transmission as well as provide an enhancement in
the ability to locate the position of the capsule, for example, in
three dimensions from acoustic detectors placed on the patient's
skin. In addition, since the capsule is not in any significant
motion between contractions the continuous collection of data such
as images between contractions generates data redundancy with
little value to the examining physician. Therefore, the pressure
provided by the contraction can also be utilized to activate the
capsule's transmission system and/or initiate data collection.
Along with this, images of the tissue within the GI tract that is
in direct contact with the surface of the capsule provides the
ability to see the tissue with minimal distortion, unlike when the
tissue is relaxed and the distance from one region of the tissue is
significantly different from another region within the same
image.
[0092] In another embodiment of the present invention, monitoring
of the activity within the gastric system is accomplished using an
ingestible capsule sensor to detect electrical signals
corresponding to muscular contractions associated with peristalsis.
Detecting electrical emissions from nearby muscle activity and
communicating the information via an acoustical link to sensors
mounted on the skin of the patient allows both a detailed analysis
of the peristalsis function of the gastric intestinal tract and a 3
dimensional map of the location of the pill as it collects data to
be provided. This provides physicians with the location and extent
of functional anomalies within this system.
[0093] The capsule peristalsis sensor may contain electrical field
sensors such as those used in EKG and muscle activity sensors in
other biological monitors. The capsule may process these electrical
signals and use an onboard microcontroller to modulate a
piezoelectric crystal also contained along with a battery power
source within the capsule. As described above, the modulated
acoustic signal from the capsule containing the electrical muscle
activity data is then received by acoustic sensors contained within
patches on the skin of the patient. These patches may be
distributed across the body in such a manner as to provide a three
dimensional location of the pill as it is transmitting. An
exemplary method and system for locating an ingestible sensor is
further described in U.S. patent application Ser. No. 11/851,179,
filed Sep. 6, 2007, which is incorporated by reference herein in
its entirety. Various embodiments of this sensor approach can
combine other sensors including imaging.
[0094] Once the location is known, scanned images may be combined
with more traditional data to provide a more detailed understanding
of the scanned images. For example, scanned images may be combined
with data from a traditional magnetic resonance imaging (MRI)
procedure or from a traditional ultrasound.
CONCLUSION
[0095] While specific embodiments of the invention have been
described above, it will be appreciated that the invention may be
practiced otherwise than as described. For example, the invention
may take the form of a computer program containing one or more
sequences of machine-readable instructions describing a method as
disclosed above, or a data storage medium (e.g., semiconductor
memory, magnetic or optical disk) having such a computer program
stored therein.
[0096] The descriptions above are intended to be illustrative, not
limiting. Thus, it will be apparent to one skilled in the art that
modifications may be made to the invention as described without
departing from the scope of the claims set out below. It is to be
appreciated that the Detailed Description section, and not the
Summary and Abstract sections, is intended to be used to interpret
the claims. The Summary and Abstract sections may set forth one or
more but not all exemplary embodiments of the present invention as
contemplated by the inventor(s), and thus, are not intended to
limit the present invention and the appended claims in any way.
[0097] Embodiments of the present invention have been described
above with the aid of functional building blocks illustrating the
implementation of specified functions and relationships thereof.
The boundaries of these functional building blocks have been
arbitrarily defined herein for the convenience of the description.
Alternate boundaries can be defined so long as the specified
functions and relationships thereof are appropriately
performed.
[0098] The foregoing description of the specific embodiments will
so fully reveal the general nature of the invention that others
can, by applying knowledge within the skill of the art, readily
modify and/or adapt for various applications such specific
embodiments, without undue experimentation, without departing from
the general concept of the present invention. Therefore, such
adaptations and modifications are intended to be within the meaning
and range of equivalents of the disclosed embodiments, based on the
teaching and guidance presented herein. It is to be understood that
the phraseology or terminology herein is for the purpose of
description and not of limitation, such that the terminology or
phraseology of the present specification is to be interpreted by
the skilled artisan in light of the teachings and guidance.
[0099] The breadth and scope of the present invention should not be
limited by any of the above-described exemplary embodiments, but
should be defined only in accordance with the following claims and
their equivalents.
* * * * *