U.S. patent application number 13/329293 was filed with the patent office on 2012-06-21 for capsule endoscope.
This patent application is currently assigned to STMICROELECTRONICS R&D (BEIJING) CO. LTD. Invention is credited to Hong Xia Sun, Kai Feng Wang, Yong Qiang Wu, Peng Fei Zhu.
Application Number | 20120157769 13/329293 |
Document ID | / |
Family ID | 46235258 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120157769 |
Kind Code |
A1 |
Zhu; Peng Fei ; et
al. |
June 21, 2012 |
CAPSULE ENDOSCOPE
Abstract
An embodiment comprises and apparatus having an image capture
device with an image axis and a gyroscope operable to indicate the
orientation of the image axis. An embodiment of a capsule endoscopy
system comprises an imaging capsule and an external unit. The
imaging capsule may comprise an image capture device having an
image axis and a gyroscope operable to indicate the orientation of
the image axis. The external unit may comprise a gyroscope operable
to indicate an orientation of a subject and a harness wearable by a
subject and operable to align the gyroscope with the subject. The
imaging capsule may send and image to an external unit for
processing and display, and the external unit may provide for
calculation of the image-axis orientation relative to the body.
Inventors: |
Zhu; Peng Fei; (Beijing,
CN) ; Wu; Yong Qiang; (Beijing, CN) ; Wang;
Kai Feng; (Beijing, CN) ; Sun; Hong Xia;
(Beijing, CN) |
Assignee: |
STMICROELECTRONICS R&D
(BEIJING) CO. LTD
Beijing
CN
|
Family ID: |
46235258 |
Appl. No.: |
13/329293 |
Filed: |
December 18, 2011 |
Current U.S.
Class: |
600/109 |
Current CPC
Class: |
A61B 1/0661 20130101;
A61B 1/0002 20130101; A61B 1/00057 20130101; A61B 1/00158 20130101;
A61B 1/041 20130101; A61B 1/00032 20130101; G01C 19/02 20130101;
G01C 19/00 20130101; A61B 1/00016 20130101 |
Class at
Publication: |
600/109 |
International
Class: |
A61B 1/04 20060101
A61B001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2010 |
CN |
201010603106.2 |
Claims
1. An apparatus comprising: an image capture device having an image
axis; and a gyroscope operable to indicate the orientation of the
image axis.
2. The apparatus of claim 1, further comprising: a housing; and
wherein the image capture device and gyroscope are disposed within
the housing.
3. The apparatus of claim 2, wherein the housing is ingestible.
4. The apparatus of claim 2, wherein the housing is operable to be
ingested and to pass through the gastrointestinal tract of a
subject.
5. The apparatus of claim 4, wherein the image capture device is
operable to capture an image within the gastrointestinal tract.
6. The apparatus of claim 2, wherein at least a portion of the
housing is transparent.
7. The apparatus of claim 1, further comprising a wireless module
operable to send an indication of the orientation of the image
axis.
8. The apparatus of claim 7, wherein the wireless module is
operable to send the indication of the orientation of the image
axis to an external unit.
9. The apparatus of claim 2, further comprising a light source
disposed within the housing.
10. The apparatus of claim 9, wherein the light source is operable
to illuminate during image capture.
11. The apparatus of claim 1, wherein the image capture device
comprises a pixel array and a lens assembly.
12. The apparatus of claim 1, wherein the gyroscope and image
capture device are disposed on a single integrated circuit die.
13. The apparatus of claim 1, further comprising a power
supply.
14. An apparatus comprising: a gyroscope operable to indicate an
orientation of a subject; and a harness wearable by a subject and
operable to maintain an alignment of the gyroscope with the
subject.
15. The apparatus of claim 14, further comprising a wireless module
operable to receive an indication of the orientation of an image
axis.
16. The apparatus of claim 15, wherein the wireless module is
operable to receive the indication of the orientation of the image
axis from an imaging apparatus located within the gastrointestinal
tract of a human subject.
17. The apparatus of claim 14, wherein the gyroscope and wireless
module are disposed on a single integrated circuit die.
18. The apparatus of claim 15, further comprising a processor
operable to compare an indicated orientation of the subject and an
indicated orientation of the image axis.
19. The apparatus of claim 15, wherein the processor is further
operable to determine the orientation of the image axis relative to
the frame of reference of the wearer.
20. A system comprising: a first apparatus comprising: a housing;
an image capture device disposed within the housing and having an
image axis; and a first gyroscope disposed within the housing and
operable to indicate the orientation of the image axis; and a
second apparatus comprising: a gyroscope operable to indicate an
orientation of a subject; and a harness wearable by a subject and
operable to align the gyroscope with the subject.
21. The system of claim 20, wherein the housing is ingestible.
22. The system of claim 20, wherein the housing is operable to be
ingested and to pass through the gastrointestinal tract of a
subject.
23. The system of claim 22, wherein the image capture device is
operable to capture an image within the gastrointestinal tract.
24. The system of claim 20, wherein at least a portion of the
housing is transparent.
25. The system of claim 20, wherein the first apparatus comprising
a wireless module disposed within the housing and operable to send
an indication of the orientation of the image axis to the second
apparatus.
26. The system of claim 20, wherein the first apparatus further
comprises a light source disposed within the housing.
27. The system of claim 26, wherein the light source is operable to
illuminate during image capture.
28. The system of claim 20, wherein the image capture device
comprises a pixel array and a lens assembly.
29. The system of claim 20, wherein the first gyroscope and image
capture device are disposed on a single integrated circuit die.
30. The system of claim 20, wherein the first apparatus further
comprises a power supply.
31. The system of claim 20, wherein the second apparatus further
comprises a wireless module operable to receive an indication of
the orientation of an image axis.
32. The system of claim 31, wherein the second gyroscope and
wireless module are disposed on a single integrated circuit
die.
33. The system of claim 20, further comprising a processor operable
to compare an indicated orientation of the subject and an indicated
orientation of the image axis.
34. The system of claim 33, wherein the processor is further
operable to determine the orientation of the image axis relative to
the frame of reference of the subject.
35. The system of claim 20 further comprising a memory operable to
store a plurality of image axis indications, a plurality of subject
orientation indications, and a plurality of images.
36. A method comprising: determining the orientation of a body axis
relative to a first frame of reference; determining the orientation
of an image axis relative to the first frame of reference; and
determining the orientation of the image axis relative to the body
axis.
37. The method of claim 36, comprising determining the orientation
of a body axis relative to a first frame of reference via a
gyroscope.
38. The method of claim 36, comprising determining the orientation
of an image axis relative to the first frame of reference via a
gyroscope.
39. The method of claim 36, comprising subtracting the determined
orientation of the body axis from the determined orientation of the
image axis.
40. The method of claim 36, comprising associating the determined
body axis orientation and image axis orientation with an image.
41. An apparatus comprising: a gyroscope operable to indicate the
frame of reference of a wearer; and a wireless module operable to
receive an indication of the orientation of an image axis relative
to a frame of reference.
42. The apparatus of claim 41, wherein the gyroscope and wireless
module are disposed on a single integrated circuit die.
Description
PRIORITY CLAIM
[0001] The instant application claims priority to Chinese Patent
Application No. 201010603106.2, filed Dec. 17, 2010, which
application is incorporated herein by reference in its
entirety.
SUMMARY
[0002] An embodiment of an image capture device comprises an image
axis and a gyroscope operable to indicate the orientation of the
image axis.
[0003] An embodiment of a capsule endoscopy system comprises an
imaging capsule and an external unit. The imaging capsule may
include an image capture device having an image axis and a
gyroscope operable to indicate the orientation of the image axis.
The external unit may include a gyroscope operable to indicate an
orientation of a subject and a harness wearable by the subject, and
is operable to align the gyroscope with an axis of the subject. The
imaging capsule may send an image to the external unit for
processing and display, and the external unit may calculate the
image-axis orientation relative to the body.
[0004] For example, in such an embodiment, the imaging capsule may
be ingested and images of a subject's gastrointestinal system, and
the external unit may determine the orientation of the imaging
capsule's image axis relative to the subject's body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The present disclosure is presented by way of at least one
non-limiting exemplary embodiment, illustrated in the accompanying
drawings in which like references denote similar elements, and in
which:
[0006] FIG. 1 is a cross-sectional view of a human subject and of
an embodiment of a capsule endoscopy system that includes an
imaging capsule and an external unit.
[0007] FIGS. 2 and 3 are side views of the human subject of FIG. 1
in standing and supine positions, respectively.
[0008] FIG. 4 is a block diagram of an embodiment of the imaging
capsule of FIG. 1.
[0009] FIG. 5 is a block diagram of an embodiment of the external
unit of FIG. 1 operatively connected with a computer.
[0010] FIG. 6 is diagram of the human subject of FIGS. 1-3 and of a
coordinate system for the subject's frame of reference.
[0011] FIG. 7 is a diagram of the imaging capsule of FIGS. 1 and 4
and of coordinate system for the capsule's frame of reference.
[0012] FIG. 8 is a diagram of a coordinate system for a frame of
reference within which the human subject of FIG. 6 and the imaging
capsule of FIG. 7 may be located.
DETAILED DESCRIPTION
[0013] Endoscopy, or internal examination of a living subject such
as a human, may be performed with an endoscope that is inserted
into a body opening (e.g., mouth or anus) and that allows a
physician to internally view a body cavity (e.g., esophagus,
stomach, colon, or intestine) that is accessible via the opening.
Examination of the gastrointestinal tract ("GI tract"), for
example, includes inserting the endoscope into the mouth, down the
esophagus, and into the stomach and/or intestines. Similarly,
examination of the colon (e.g., a colonoscopy), for example,
includes inserting the endoscope through the anus into the
colon.
[0014] Unfortunately, such a procedure may be invasive and
uncomfortable for a subject, and may necessitate general
anesthesia. Moreover, such a procedure may require sterile
endoscopy equipment and a sterile environment. Accordingly, an
endoscopy procedure is generally performed in a hospital setting,
which may increase the cost of such a procedure.
[0015] FIG. 1 is a cross-sectional view of a human subject 100 and
an embodiment of a capsule endoscopy system 105 that includes an
imaging capsule 110 and an external unit 115. As discussed in
further detail herein, the imaging capsule 110 may be swallowed,
and thereafter may pass through the esophagus 120, through the
stomach 125, through the intestines 130 (the esophagus, stomach,
and intestines may be collectively referred to as the GI tract
140), and out the anus 135 as depicted in FIG. 1. As it makes its
journey through the subject's GI tract 140, the imaging capsule 110
may be operable to capture images of the GI tract 140 along an
imaging axis 145 and to transmit the captured images to the
external unit 115. The imaging capsule 110 may be recovered when it
leaves the body of the subject 100, or may be disposed as part of
the subject's waste (e.g., via a toilet during a bowel
movement).
[0016] Compared to conventional endoscopy as discussed above, the
endoscopy system 105 described herein is non-invasive because a
subject 100 need only swallow the imaging capsule 110 and wear the
external unit 115 as the imaging capsule travels through his/her GI
tract 140. Therefore, no anesthesia is believed to be required in
most cases, and imaging via the endoscopy system 105 need not be
performed in a sterile hospital setting, or even at a doctor's
office. In fact, once the subject 100 swallows the imaging capsule
110, the subject may move about normally as the imaging capsule
captures images of the subject's GI tract 140. This may
significantly reduce the cost of endoscopy procedures and may
significantly reduce the discomfort and inconvenience of the
subject 100.
[0017] The imaging capsule 110 may assume numerous orientations
relative to the subject 100 while traveling through the GI tract
140, such that the image axis 145 may be pointing in any direction
at any given time. Therefore, images captured by the imaging
capsule 110 may be taken from numerous orientations within the GI
tract. As described further herein, because a physician may want to
know the relative orientation of each image relative to the GI
tract 140 for purposes of analysis and diagnosis, the external unit
115 and imaging capsule 110 may be operable to indicate, for each
image, the orientation of the imaging capsule 110 relative to a
frame of reference of the subject 100. For example, for images of
the subject's stomach, a doctor may wish to know if the image is
of, e.g., the back of the stomach, the front of the stomach, the
top of the stomach, or the bottom of the stomach.
[0018] FIGS. 2 and 3 are side views of the human subject 100
respectively standing and lying down, with an embodiment of the
imaging capsule 110 inside the subject 100 and an embodiment of an
external unit 115 being worn by the subject 100.
[0019] The external unit 115 is coupled to the subject 100 with a
harness 210, which may be a belt or strap of a suitable material
that encircles the subject 100 and maintains an axis 245 of the
frame of reference of the external unit 115 in alignment with an
axis 250 of the subject's frame of reference regardless of how the
subject 100 may move. That is, the harness 210 maintains the unit's
axis 245 approximately parallel to or approximately co-linear with
the subject axis 250. For example, the subject 100 in FIG. 2 is
shown standing with the body axis 250 aligned with a gravity vector
{right arrow over (G)}, and the subject in FIG. 3 is laying down
with the body axis 250 perpendicular to the gravity vector {right
arrow over (G)}. In both subject orientations, the harness 210
maintains the external-unit axis 245 in approximate alignment with
the body axis 250.
[0020] Additionally, FIGS. 2 and 3 depict the imaging capsule 110
in two different orientations relative to the frame of reference of
the subject 100. Although both FIGS. 2 and 3 depict the image axis
145 of the capsule 110 oriented in the same direction relative to
the earth's frame of reference, i.e., aligned with the gravity
vector {right arrow over (G)}, the orientation of the image axis
relative to the frame of reference of the subject 100, and thus
relative to the body axis 250, is different. FIG. 2 depicts the
image axis 145 pointing toward the distal inferior extremities of
the subject 100 (e.g. down toward the legs, etc.) in parallel with
the body axis 250. However, FIG. 3 depicts the image axis 145
pointing toward the posterior of the subject 100, perpendicular to
the body axis 250. As discussed herein, the orientation of the
image axis 145 relative to the body axis 250, and thus to the
subject's frame of reference, 100 may be determined based on
orientation indications provided by the imaging capsule 110 and the
external unit 115. The orientation of images captured by the
imaging capsule 110 may thereby be determined relative to the body
axis 250 as further discussed herein so that a physician, such as a
radiologist, may determine the orientation of each image relative
to the subject's GI tract. That is, an image's orientation may be
toward the front of the subject, toward the back of the subject,
etc. Knowing an image's orientation relative to the subject may
facilitate the physician's analysis of the image, and may
facilitate the physician formulating a diagnosis of the
subject.
[0021] FIG. 4 is a block diagram of an embodiment of the imaging
capsule 110 of FIGS. 1-3. The imaging capsule 110 includes a
housing or capsule shell 405, and disposed within the housing is an
imaging-module integrated circuit (IC) 410, which may be formed
from one or more integrated-circuit dies. For example, the
imaging-module IC 410 may be a system on a chip.
[0022] The imaging module chip 410 includes a processor 420, a
gyroscope 430, a wireless transceiver module 440, a light source
450, a power source 460, a lens assembly 470, and a pixel array
480. The focal axis of the lens assembly 470 and the array axis
normal to the center of the pixel array 480 are approximately
aligned along the image axis 145. That is, the pixel array 480 is
operable to capture an image of an object toward which the image
axis 145 points.
[0023] The shell 405 may be formed of any suitable material, and
may be any suitable size and shape. For example, in an embodiment,
the shell 405 may be operable to be ingested and to pass through
the gastrointestinal tract of the subject 100 (FIGS. 1-3).
Therefore, the shell 405 may be of a size (e.g., pill or
medicinal-capsule size) suitable for ingestion by the subject 100,
and may be formed from a material that is resilient to the
conditions experienced within the gastrointestinal tract of the
subject such that the imaging capsule may remain functional for its
entire journey through the subject's GI tract 140. Additionally, at
least the portion of the shell 405 through which the image axis 145
extends may be transparent so that images may be captured through
the shell. For example, if the pixel array 480 is sensitive to
electromagnetic energy having wavelengths in the visible portion of
the electromagnetic spectrum, then this portion of the shell 405
may be transparent to these visible wavelengths. Likewise, if the
pixel array 480 is sensitive to electromagnetic energy having
wavelengths in the infrared portion of the electromagnetic
spectrum, then this portion of the shell 405 may be transparent to
these infrared wavelengths. Additionally, the shell 405 and other
components of the imaging capsule 110 may be made of
environmentally friendly material so that if the imaging capsule is
intended to be disposable (i.e., not recovered when leaving the
subject 100), the imaging capsule would have little or no negative
environmental impact as waste.
[0024] The imaging-module IC 410 may be an integrated circuit, a
hybrid integrated circuit, a micro-electro-mechanical system
(MEMS), or any suitable system. Furthermore, as discussed above,
the components of the imaging-module IC 410 may be disposed on a
single IC die or on multiple IC dies. Additionally, the
imaging-module IC 410 may include more or fewer components than are
described herein, and such components may be configured in any
suitable arrangement.
[0025] The processor 420 may be any suitable processor, processing
system, controller, or module, and may be programmable to control
one or more of the other components of the imaging capsule 110.
Furthermore, the processor 420 may perform image processing on
images captured by the pixel array 480 before the images are
transmitted to the external unit 115 (FIG. 1-3).
[0026] The gyroscope 430 may be any suitable device operable to
indicate a degree of rotation about one or more coordinate axes of
the gyroscope's frame of reference. For example, the gyroscope 430
may be operable to detect "yaw", "pitch", and "roll" (i.e.,
rotation) about coordinate X, Y, and Z axes, respectively. Examples
of gyroscopes suitable for the gyroscope 430 include the
STMicroelectronics L3G4200DH and the L3G4200D. In an embodiment,
there may be a plurality of gyroscopes 430.
[0027] The wireless module 440 may be any suitable device that is
operable to send and receive wireless communications. For example,
the wireless module 440 may be operable to send to the external
unit 115 (FIGS. 1-3 & 5) images captured by the pixel array 480
and indications of rotation from the gyroscope 430; the external
unit may use these indications of rotation to calculate the
orientation of the image axis 145 for each received image.
Furthermore, the wireless module 440 may allow one to control the
operation of one or more components of the imaging capsule 110, and
may allow one to program the processor 420. Moreover, the wireless
module 440 may send status information to the external unit 115,
such as the level of power remaining in the power source 460, or
the intensity of the illumination provided by the light source 460
(the imaging capsule 110 may include a sensor, not shown in FIG. 4,
to measure the intensity of the light source).
[0028] The light source 450 may be any suitable device (e.g., one
or more light-emitting diodes) operable to provide illumination to
aid in capturing images. For example, the light source may be
operable to provide sufficient illumination while in the
gastrointestinal tract of the subject 100 such that the pixel array
480 may capture an image. The light source 450 may provide
continuous illumination, or may provide flash illumination as is
suitable for the application, for example, under the control of the
processor 420. Additionally, the intensity of illumination may be
modified, e.g., by the processor 420 (the light source 450, or the
image capsule 110, may include an intensity sensor (not shown in
FIG. 4) that is coupled to the processor). Alternatively, the light
source 450 may be omitted, for example, if the pixel array 480 is
sensitive to infrared wavelengths. In an embodiment, there may be a
plurality of light sources 450.
[0029] The power source 460 may be any suitable source of power
such as a battery, and may provide power to one or more components
of the imaging capsule 110. The power source 460 may be recharged
via a wired technique, or may be recharged wirelessly (e.g., via RF
energy). In an embodiment, there may be a plurality of power
sources 460.
[0030] The lens assembly 470 may be operable to focus, or otherwise
to modify electromagnetic energy (e.g., visible light) such that
the energy may be sensed by the pixel array 480 to capture an
image. Collectively, the lens assembly 470 and pixel array 480 may
constitute an image-capture apparatus, and may be arranged as a
single imaging module, assembly, or unit. As discussed above, the
normal to the center of the pixel array 480 and the focal axis of
the lens assembly 470 are approximately aligned along the image
axis 145, which "points" in the direction of an object (or portion
of an object) whose image the pixel array may capture. The lens
assembly 470 may be any suitable type of imaging lens assembly,
such as a macro lens, process lens, fisheye lens, or stereoscopic
lens.
[0031] In an embodiment, the pixel array 480 and lens assembly 470
may be operable to capture images in various regions of the
electromagnetic spectrum, including infrared, ultraviolet, or
within visible light. In an embodiment, the pixel array 480, lens
assembly 470, or both the pixel array and the lens assembly, may be
separate from the imaging module chip 410. Additionally, in an
embodiment, the lens assembly 470 may be omitted. In an embodiment,
there may be a plurality of pixel arrays 480 lens assemblies
470.
[0032] FIG. 5 is a block diagram of an embodiment of an external
system 500, which includes an embodiment of the external unit 115
and an embodiment of an optional computer 510 coupled to the
external unit. The external unit 115 includes a processor 520, a
gyroscope 530, a wireless module 550, and a power source 560.
[0033] The processor 520 may be any suitable processor, processing
system, controller, or module, and may be programmable to control
one or more of the other components of the imaging capsule 110.
Furthermore, the processor 520 may perform image processing on
images captured by the pixel array 480.
[0034] The gyroscope 530 may be any suitable device operable to
indicate a degree of rotation about one or more coordinate axes of
the gyroscope's frame of reference. For example, the gyroscope 530
may be operable to detect "yaw", "pitch", and "roll" (i.e.,
rotation) about coordinate X, Y, and Z axes, respectively.
[0035] The wireless module 540 may be operable to send and receive
wireless communications. For example, the wireless module 540 may
be operable to receive from the imaging capsule 110 (FIGS. 1-4)
images captured by the pixel array 480 and indications of rotation
from the gyroscope 430. The wireless module 540 may also be
operable to wirelessly communicate with the computer 510. The
wireless module 540 may be any suitable device that is operable to
send and receive wireless communications. Furthermore, the wireless
module 540 may allow one to control the operation of one or more
components of the external unit 115, and may allow one to program
the processor 520 via, e.g., the computer 510. Moreover, the
wireless module 540 may send status information to the computer
510, such as the level of power remaining in the power source 560.
Furthermore, the wireless module 540 may act as a "go-between" for
the capsule 110 (FIG. 4) and another device such as the computer
510.
[0036] The computer 510 may be any suitable computing device (e.g.,
a laptop or desktop computer) that is directly or wirelessly
coupled with the external unit 510, and may be operable to program
the external unit 115, obtain stored data from the external unit
115, process data obtained from the external unit 115, and the
like. The computer 510 may also be operable to program the
processor 420 of the imaging capsule 110 (FIG. 4) either directly
or via the external unit 115. Furthermore, the computer 510 may be
operable to process image data received from the imaging capsule
110 directly or via the external unit 115, and to recover one or
more images from this data, to determine the orientation of the
image axis 145 (FIG. 4) for each recovered image as discussed below
in conjunction with FIGS. 6-8, and to display each recovered image.
The computer 510 may also be able to send the recovered images and
other related information to a remote location, such as a doctors'
office, via the internet. Accordingly, the subject 100 (FIGS. 1-3
and 6) may be able to go about his/her normal activities such as
working or sleeping as the imaging capsule 110 travels through the
subject's GI tract 130 (FIG. 1), and images captured by the imaging
capsule could be sent in real time to the doctor's office over the
Internet. The power source 560 may be any suitable source of power
such as a battery, and may provide power to one or more components
of the external unit 115. The power source 560 may be recharged via
conventional wired methods, or may be recharged wirelessly (e.g.,
via RF energy). In an embodiment, there may be a plurality of power
sources 560.
[0037] In an embodiment, the endoscopy system 105 described herein
may also be used to capture images within a non-human subject 100.
Additionally, the endoscopy system 105 or components thereof may be
used to capture images within non-living systems, such as systems
of pipes, a moving body of water, or the like.
[0038] FIG. 6 is a coordinate system 600 of a frame of reference of
the subject 100, the coordinate system having the axes X.sub.BODY,
Y.sub.BODY, and Z.sub.BODY, interposed on the subject, wherein the
Z.sub.BODY axis is aligned with the body axis 250 of the subject.
Given that the spine 605 of the subject 100 is not typically linear
within the coronal plane of the subject, the Z.sub.BODY and the
body axis 250 may be aligned with a hypothetically straightened
spine, or may only be aligned with the spine along the sagittal
plane. As the subject 100 changes position the X.sub.BODY,
Y.sub.BODY, and Z.sub.BODY remain stationary relative to the
subject. In other words, the X.sub.BODY, Y.sub.BODY, and Z.sub.BODY
are fixed relative to the subject's 100 frame of reference. For
example, if the subject 100 lies down, then the Z.sub.BODY axis
will maintain the same alignment with the body axis 250.
[0039] As depicted in FIG. 6, the X.sub.BODY axis extends along the
mid-sagittal plane of the subject 100 perpendicular to the frontal
plane of the subject, and the Y.sub.BODY axis is perpendicular to
the mid-sagittal plane of the subject or co-linear with and along
the frontal plane of the subject. The Z.sub.BODY axis extends in
alignment with the body axis (i.e., parallel to the body axis 250
superiorly from the axis origin).
[0040] In an embodiment, the external unit axis 245 (FIGS. 2 and 3)
(i.e., the orientation of the external unit 115) is assumed to
represent the body frame of reference 600. Because external unit
115 may be worn on the outside of the subject 100, the body frame
of reference 600 and the external unit axis 245 may not be directly
aligned. Therefore, an assumption may be made that the external
unit axis 245 is aligned with the body axis 250, and that the
external unit 115 frame of reference is the same as the subject 100
frame of reference 600. Accordingly, the external unit 115 worn by
the subject 100 may be assumed to be detecting changes in the
orientation of the body axis 250 within the subject frame of
reference.
[0041] Although the X.sub.BODY, Y.sub.BODY, and Z.sub.BODY are
depicted as having specific orientations relative to the body of
the subject 100, in another embodiment, the X.sub.BODY, Y.sub.BODY,
and Z.sub.BODY axes may have different orientations relative to the
subject, and need not be aligned with a plane, the spine 605, or
other part of the body. Therefore, the alignments of the
X.sub.BODY, Y.sub.BODY, and Z.sub.BODY axes shown in FIG. 6 merely
represent one possible configuration of the axes. Additionally, the
X.sub.BODYY.sub.BODY plane may be moved up and down relative to the
Z.sub.BODY axis.
[0042] FIG. 7 is a coordinate system 700 frame of reference for the
capsule 110 having the axes X.sub.CAP, Y.sub.CAP, and Z.sub.CAP,
interposed on the imaging capsule, wherein the Z.sub.CAP axis is
aligned (i.e., parallel to or co-linear) with the image axis 145 of
the imaging capsule. As the imaging capsule 110 changes position,
the X.sub.BODY, Y.sub.BODY, and Z.sub.BODY axes remain stationary
relative to the imaging capsule. In other words, the X.sub.CAP,
Y.sub.CAP, and Z.sub.CAP are fixed relative to the imaging
capsule's frame of reference. Additionally, as discussed above in
conjunction with FIG. 6, the alignment of X.sub.CAP, Y.sub.CAP, and
Z.sub.CAP may be in any desired orientation; for example, the
Z.sub.CAP axis need not be aligned with the imaging axis 145,
although such alignment may make easier the calculations for
determining the orientation of the imaging axis 145 relative to the
subject's frame of reference 600.
[0043] FIG. 8 is a terrestrial coordinate system 800 having the
axes X.sub.EARTH, Y.sub.EARTH, and Z.sub.EARTH, wherein the
Z.sub.EARTH axis is aligned with vector {right arrow over (G)},
which represents the direction of the gravitational force of the
earth. Depicted within the coordinate system 800 are a body
orientation Z.sup.N.sub.BODY, and a cap orientation
Z.sup.N.sub.CAP. The terrestrial coordinate system 800 is fixed to
the earth's frame of reference. Additionally, the body orientation
Z.sup.N.sub.BODY, and the cap orientation Z.sup.N.sub.CAP
respectively represent the orientation of the subject's 100 frame
of reference and the imaging capsule's 110 frame of reference at a
given time N relative to the origin of terrestrial coordinate
system 800.
[0044] The Z.sup.N.sub.BODY orientation represents an orientation
of the Z.sub.BODY axis (FIG. 6) relative to the terrestrial
coordinate system 800 at a given time N, e.g., Z.sup.1.sub.BODY,
Z.sup.2.sub.BODY, Z.sup.3.sub.BODY, etc. For example, as the
subject 100 changes position (e.g., lies down, bends over,
reclines, etc.) the orientation of the Z.sub.BODY axis of the
subject 100 would change relative to the terrestrial coordinate
system 800.
[0045] The Z.sup.N.sub.CAP orientation represents an orientation of
the Z.sub.CAP axis (FIG. 7) relative to the terrestrial coordinate
system 800 at a given time N (e.g., Z.sup.1.sub.CAP,
Z.sup.2.sub.CAP, Z.sup.3.sub.CAP, etc.). For example, as the
imaging capsule 110 changes orientation within the GI tract 140 of
the subject 100 (as the image capsule moves through the
gastrointestinal tract) the orientation of the Z.sub.CAP axis may
change relative to the terrestrial coordinate system 800.
Additionally, the orientation of the Z.sub.CAP axis may change
relative to the Z.sub.BODY axis, and vice versa.
[0046] Z.sup.N.sub.CAP and Z.sup.N.sub.BODY may be defined within
the terrestrial coordinate system 800 by spherical coordinates
relative to the earth X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate
system 800. For example, .theta..sub.BODY and .phi..sub.BODY, are
depicted in FIG. 8 as spherical coordinates of Z.sup.N.sub.BODY,
where .theta..sub.BODY represents an angle from the positive
Y.sub.EARTH axis projected in the X.sub.EARTHY.sub.EARTH plane
(e.g., in radians from 0 to 2.pi.) with the vertex being the
origin, and where .phi..sub.BODY represents an angle from the
positive Z.sub.BODY axis (e.g., in radians from 0 to .pi.) with the
vertex being the origin. Accordingly, .theta..sub.BODY and
.phi..sub.BODY, for example, define the orientation
Z.sup.N.sub.BODY from the origin of the
X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate system 800. Similarly,
.theta..sub.CAP and .phi..sub.CAP (not shown in FIG. 8), define the
orientation Z.sup.N.sub.CAP from the origin of
X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate system 800.
[0047] As Z.sup.N.sub.CAP changes direction relative to the
terrestrial coordinate system 800 as the imaging capsule 110 moves
through the gastrointestinal tract capturing images, knowing the
orientation of Z.sup.N.sub.CAP relative to Z.sup.N.sub.BODY may be
important when interpreting the images captured by the image
capsule 110. For example, for a given image or a series of images,
it may be important to determine whether the image axis 145 is
pointing toward the back, legs, head, or front of the subject 100
so that the images may be properly interpreted or so that images
may be combined.
[0048] Given that the Z.sup.N.sub.CAP and Z.sup.N.sub.BODY
orientations may be both continuously and independently changing
relative to each other over time, the orientation of
Z.sup.N.sub.CAP relative to the body coordinate system 600 may be
calculated by synchronizing or calibrating the frame of reference
of the external unit 115 and the frame of reference of the imaging
capsule 110 (FIGS. 1-5) relative to each other, relative to the
terrestrial coordinate system 800, at Z.sup.0.sub.CAP and
Z.sup.0.sub.BODY and then tracking the orientations of the imaging
capsule 110 and external unit 115 (which is assumed to represent
the body frame of reference) over time as images are captured by
the imaging capsule 110. As depicted in FIG. 9, the frame of
reference of the external unit 115 can be assumed to have the same
origin as X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate system 800.
Also, the frame of reference of the imaging capsule 110 may not be
aligned with the frame of reference of the external unit 115;
however, the frame of reference of the imaging capsule 110 may also
be assumed to have the same origin as the
X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate system 800 as depicted
in FIGS. 10 and 11. Therefore, the external unit 115 frame of
reference and imaging capsule 110 frame of reference can be
translated into the X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate
system 800 so that the orientations Z.sup.N.sub.CAP and
Z.sup.N.sub.BODY are within a common frame of reference and these
orientations may be assumed to be relative to the origin of the
X.sub.EARTHY.sub.EARTHZ.sub.EARTH coordinate system 800, regardless
of the position of the external unit 115 (i.e., the subject 100) or
imaging capsule 110, relative to each other.
[0049] For example, a doctor may initially synchronize or calibrate
the external unit 115 and imaging capsule 110 by having the subject
100 stand while wearing the external unit coincident to or parallel
with the gravitational force of earth {right arrow over (G)} and
Z.sub.BODY, while the doctor holds the imaging capsule parallel
with the gravitational force of earth (e.g., away from the ground),
as depicted in FIG. 9. The external unit 115 and imaging capsule
110 may be calibrated or synchronized, e.g., by pressing a button
on the external unit, or via the computer 510 (FIG. 5). The
orientations of the external unit 115 and imaging capsule 110 may
thereafter be tracked in relation to each other over time as the
subject 100 swallows the imaging capsule and as the imaging capsule
travels through the subject's GI tract 140.
[0050] For example, presuming that the external unit 115 and
imaging capsule 110 are initially synchronized or calibrated having
the orientations depicted in FIG. 9 (i.e., Z.sup.0.sub.CAP=(0,0)
and Z.sup.0.sub.BODY=(0,0)), the external unit 115 and imaging
capsule 110 will be assumed to both change orientation relative to
the earth coordinate system 800 from these respective initial
orientations. Any change in orientations of the external unit 115
and imaging capsule 110 may be tracked relative to these initial
orientations based on changes in orientation detected by the
respective gyroscopes 430, 530 (FIGS. 4 and 5). Roll, pitch and yaw
.phi., .theta., .psi. indicated by the gyroscopes 430, 530 may be
converted into spherical coordinates or other desirable orientation
indications by known methods. (Note the lower-case symbols .phi.,
.theta., .psi. of roll, pitch and yaw as opposed to the upper-case
symbols .theta. and .phi., in spherical coordinates).
[0051] Accordingly, as the subject 100 and external unit 115 change
orientation, and as the imaging capsule 110 changes orientation
within the subject 100 while capturing images, the orientation of
the image axis 145 may be determined relative to the subject
coordinate system 600 (FIG. 6) but independent of the orientation
of the external unit 115 (i.e., the subject 100) within the
terrestrial frame of reference 800.
[0052] For example, assume that the external unit 115 and imaging
capsule 110 are initially synchronized or calibrated having the
initial orientations depicted in FIG. 9, (i.e.,
Z.sup.0.sub.CAP=(0,0) and Z.sup.0.sub.BODY=(0,0)). Then assume that
the subject 100 and imaging capsule assume the orientations
depicted in FIG. 10, wherein the subject reclines such that
Z.sup.1.sub.BODY=(90.degree., 180.degree.) and that
Z.sup.1.sub.CAP=(45.degree., 135.degree.). Further assume that the
capsule gyroscope 430 reports a roll, pitch and yaw of
R.sup.1(-45.degree., 45.degree., -90.degree.).sub.CAP and that body
gyroscope 530 reports a roll, pitch and yaw of R.sup.1(-90.degree.,
0.degree., -90.degree.).sub.BODY.
[0053] To determine the normalized rotation (R.sup.N.sub.NORMAL)
and normalized orientation (O.sup.N.sub.NORMAL) of the image axis
145 (i.e., the orientation of the image axis relative to the body
coordinate system 600 frame of reference), one may use the
following equation: R.sup.1 (.phi., .theta.,
.psi.).sub.CAP-R.sup.1(.phi., .theta.,
.psi.).sub.BODY=R.sup.1(.phi., .theta., .psi.).sub.NORMAL. (i.e.,
R.sup.1.phi..sub.CAP-R.sup.1.phi..sub.BODY=R.sup.1.phi..sub.NORMAL;
R.sup.1.theta..sub.CAP-R.sup.1.theta..sub.BODY=R.sup.1.theta..sub.NORMAL;
R.sup.1.psi..sub.CAP-R.sup.1.psi..sub.BODY=R.sup.1.psi..sub.NORMAL).
Returning to the example above, (.phi., .theta., .psi.).sub.NORMAL
may be calculated as follows: R.sup.1(-45.degree., 45.degree.,
-90.degree.).sub.CAP-R.sup.1(-90.degree., 0.0.degree.,
-90.degree.).sub.BODY=R.sup.1(45.degree., 45.degree.,
-0.degree.).sub.NORMAL. As depicted in FIG. 11, this corresponds to
a normalized orientation O.sup.1.sub.NORMAL of O.sup.1(45.degree.,
-45.degree.).sub.NORMAL.
[0054] Images captured by the imaging capsule 110 may be associated
with a given time so that the image orientation (i.e., the
orientation of the image axis 145) may be determined at a number of
discrete times. For example, I.sup.1 (image 1) may be associated
with Z.sup.1.sub.CAP and Z.sup.1.sub.BODY and a determination of
O.sup.1.sub.NORMAL would therefore be an indication of the
normalized orientation of I.sup.1 relative to the body of the
subject 100 and the body coordinate system 600 frame of reference
(FIGS. 6 and 11) at T.sub.1. Additionally, I.sup.1 (image 1) may be
associated with R.sup.1.sub.CAP and R.sup.1.sub.BODY and a
determination R.sup.1.sub.NORMAL may be the normalized rotation of
I.sup.1 relative to the body of the subject 100 and the body
coordinate system 600 frame of reference.
[0055] Images and corresponding data may be captured at various
suitable intervals. For example, images and corresponding data may
be captured every second, tenth of a second, or five images every
tenth of a second, with one second between a set of such five
images.
[0056] From the foregoing it will be appreciated that, although
specific embodiments have been described herein for purposes of
illustration, various modifications may be made without deviating
from the spirit and scope of the disclosure. Furthermore, where an
alternative is disclosed for a particular embodiment, this
alternative may also apply to other embodiments even if not
specifically stated.
* * * * *