U.S. patent application number 12/550798 was filed with the patent office on 2010-02-04 for receiving apparatus, transmitting apparatus and transmitting/receiving system.
This patent application is currently assigned to OLYMPUS CORPORATION. Invention is credited to Manabu Fujita, Seiichiro Kimoto, Akira Matsui, Ayako Nagase, Kazutaka Nakatsuchi, Toshiaki Shigemori.
Application Number | 20100029236 12/550798 |
Document ID | / |
Family ID | 34754007 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100029236 |
Kind Code |
A1 |
Kimoto; Seiichiro ; et
al. |
February 4, 2010 |
RECEIVING APPARATUS, TRANSMITTING APPARATUS AND
TRANSMITTING/RECEIVING SYSTEM
Abstract
A receiving apparatus is for selecting and receiving a radio
signal in a frame structure having an information body part
including at least information body and an additional part
including information for receiving field intensity measurement by
using a plurality of antennas. The apparatus includes a controller
that measures a receiving field intensity of not a first antenna
which has received the information body in a transmission period of
the additional part in a current frame but a second antenna, and
measures a receiving field intensity of the first antenna in a
transmission period of the information body part in the current
frame, and if the receiving field intensity of the second antenna
exceeds the receiving field intensity of the first antenna, selects
and changes to the second antenna as the first antenna of a next
frame.
Inventors: |
Kimoto; Seiichiro; (Tokyo,
JP) ; Shigemori; Toshiaki; (Tokyo, JP) ;
Nagase; Ayako; (Tokyo, JP) ; Fujita; Manabu;
(Tokyo, JP) ; Matsui; Akira; (Tokyo, JP) ;
Nakatsuchi; Kazutaka; (Tokyo, JP) |
Correspondence
Address: |
SCULLY SCOTT MURPHY & PRESSER, PC
400 GARDEN CITY PLAZA, SUITE 300
GARDEN CITY
NY
11530
US
|
Assignee: |
OLYMPUS CORPORATION
Tokyo
JP
|
Family ID: |
34754007 |
Appl. No.: |
12/550798 |
Filed: |
August 31, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11483355 |
Jul 7, 2006 |
7596359 |
|
|
12550798 |
|
|
|
|
PCT/JP2005/000115 |
Jan 7, 2005 |
|
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11483355 |
|
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Current U.S.
Class: |
455/226.2 |
Current CPC
Class: |
H04N 7/083 20130101;
A61B 1/00016 20130101; H04B 7/0808 20130101; A61B 1/00036 20130101;
A61B 1/041 20130101; A61B 5/073 20130101 |
Class at
Publication: |
455/226.2 |
International
Class: |
H04B 17/00 20060101
H04B017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2004 |
JP |
2004002423 |
Feb 3, 2004 |
JP |
2004026875 |
Mar 4, 2004 |
JP |
2004061277 |
Mar 12, 2004 |
JP |
2004071579 |
Mar 12, 2004 |
JP |
2004071580 |
Mar 12, 2004 |
JP |
2004071581 |
Claims
1. A receiving apparatus for selecting and receiving a radio signal
in a frame structure having an information body part including at
least information body and an additional part including information
for receiving field intensity measurement by using a plurality of
antennas, the apparatus comprising: a controller that measures a
receiving field intensity of not a first antenna which has received
the information body in a transmission period of the additional
part in a current frame but a second antenna, and measures a
receiving field intensity of the first antenna in a transmission
period of the information body part in the current frame, and if
the receiving field intensity of the second antenna exceeds the
receiving field intensity of the first antenna, selects and changes
to the second antenna as the first antenna of a next frame.
2. The receiving apparatus according to claim 1, wherein when the
receiving field intensity of the second antenna does not exceed the
receiving field intensity of the first antenna, the controller
sequentially changes to other second antenna.
3. The receiving apparatus according to claim 1, wherein the
controller provides a timing of the receiving field intensity
measurement of the second antenna near the start of the
transmission period of the information body part.
4. The receiving apparatus according to claim 1, wherein the
controller measures receiving field intensities of a plurality of
second antennas in the transmission period of the additional part,
and when the receiving field intensity of a second antenna having
the largest receiving field intensity out of the field intensities
of the plurality of second antennas exceeds the receiving field
intensity of the first antenna, selects and changes to the second
antenna as the first antenna of a next frame.
5. The receiving apparatus according to claim 1, comprising an
antenna changeover unit that is connected to each antenna in
correspondence to arrangement positions of the plurality of
antennas and detects a connection state of each antenna to change
over the connected antennas according to an instruction, wherein
the controller selects and changes to an antenna whose connection
is detected by the antenna changeover unit.
6. A receiving apparatus for receiving a radio signal, transmitted
from the inside of a subject, in a frame structure having a video
signal part for transmitting at least a video signal and an
additional part including information for receiving field intensity
measurement by using a plurality of antennas provided outside the
subject, the apparatus comprising: a changeover unit that selects
and changes over the plurality of antennas; a field intensity
measurement unit that measures a receiving field intensity of not a
first antenna which has received the radio signal in a transmission
period of the additional part in a current frame but a second
antenna, and measures a receiving field intensity of the first
antenna in a transmission period of the video signal part in the
current frame; a selection controller that, when the receiving
field intensity of the second antenna measured by the field
intensity measurement unit exceeds the receiving field intensity of
the first antenna, selects the second antenna as the first antenna
of a next frame; and a changeover controller that sequentially
changes over and connects an antenna other than the first antenna
selected by the selection controller in a transmission period of
the additional part of the next frame, and changes to and connects
the selected first antenna in a transmission period of the video
signal part.
7. A receiving apparatus for selecting and receiving a radio signal
in a frame structure having an information body part including at
least information body and an additional part including information
for receiving field intensity measurement by using a plurality of
antennas, the apparatus comprising: a controller that measures
receiving field intensities of more than two antennas in the
additional part in a current frame, and selects and changes to an
antenna having the largest receiving field intensity out of the
more than two antennas as an antenna for receiving the information
body part in a current frame.
8. The receiving apparatus according to claim 7, wherein the more
than two antennas are all of the plurality of antennas.
9. The receiving apparatus according to claim 7, wherein the more
than two antennas are an antenna group in which the plurality of
antennas are grouped.
10. The receiving apparatus according to claim 7, wherein the more
than two antennas are an antenna group near an antenna which has
received the information body in a previous frame.
11. The receiving apparatus according to claim 7, wherein the
plurality of antennas each have a serial number for a moving path
of a transmitting apparatus communicating with the receiving
apparatus, and the more than two antennas are an antenna group of
the antenna which has received the information body in a previous
frame and subsequent antennas.
12. The receiving apparatus according to claim 7, comprising an
antenna changeover unit that is connected to each antenna in
correspondence to arrangement positions of the plurality of
antennas and detects a connection state of each antenna to change
over the connected antennas according to an instruction, wherein
the controller selects and changes to an antenna whose connection
has been detected by the antenna changeover unit.
13. A receiving apparatus for selecting and receiving a radio
signal in a frame structure having an information body part
including at least information body and an additional part
including information for receiving field intensity measurement by
using a plurality of antennas, the apparatus comprising: a
controller that compares a first receiving field intensity of an
antenna which has received the information body in a previous frame
with a second receiving field intensity being the largest receiving
field intensity out of a result of measurement of receiving field
intensities of more than two antennas other than the antenna in the
additional part of a current frame, and selects and changes to the
antenna having the larger receiving field intensity as an antenna
for receiving the information body part in the current frame.
14. The receiving apparatus according to claim 13, wherein the more
than two antennas are antennas other than the antenna having the
first receiving field intensity.
15. The receiving apparatus according to claim 13, wherein the more
than two antennas are an antenna group in which the plurality of
antennas are grouped.
16. The receiving apparatus according to claim 13, wherein the more
than two antennas are an antenna group near an antenna which has
received the information body in a previous frame.
17. The receiving apparatus according to claim 13, wherein the
plurality of antennas each have a serial number for a moving path
of a transmitting apparatus communicating with the receiving
apparatus, and the more than two antennas are an antenna group of
the antenna which has received the information body in a previous
frame and subsequent antennas.
18. The receiving apparatus according to claim 13, comprising an
antenna changeover unit that is connected to each antenna in
correspondence to arrangement positions of the plurality of
antennas and detects a connection state of each antenna to change
over the connected antennas according to an instruction, wherein
the controller selects and changes to an antenna whose connection
has been detected by the antenna changeover unit.
19. A receiving apparatus for selecting and receiving a radio
signal in a frame structure having an information body part
including at least information body and an additional part
including information for receiving field intensity measurement by
using a plurality of antennas according to each receiving field
intensity, wherein part of a synchronization period of the
information body part is set at part or all of a receiving field
intensity measurement period of the additional part to use a
synchronization signal of the synchronization period as a signal
for receiving field intensity measurement.
20. The receiving apparatus according to claim 19, comprising an
antenna changeover unit that is connected to each antenna in
correspondence to arrangement positions of the plurality of
antennas and detects a connection state of each antenna to change
over the connected antennas according to an instruction, wherein
the controller selects and changes to an antenna whose connection
has been detected by the antenna changeover unit.
21. A receiving apparatus for selecting and receiving a radio
signal in a frame structure having an information body part
including at least information body and an additional part
including information for receiving field intensity measurement by
using a plurality of antennas according to each receiving field
intensity, wherein part of a synchronization period of the
information body part is set at part or all of a receiving field
intensity measurement period of the additional part to use a
synchronization signal of the synchronization period as a signal
for receiving field intensity measurement, and the antenna for
receiving field measurement and the antenna for receiving the
information body part are changed over in the synchronization
period according to a measurement result of a receiving field
intensity to each of the plurality of antennas.
22. The receiving apparatus according to claim 21, wherein the
antenna for receiving field measurement is changed over in the
receiving field intensity measurement period to measure a receiving
field intensity of each antenna.
23. The receiving apparatus according to claim 21, comprising an
antenna changeover unit that is connected to each antenna in
correspondence to arrangement positions of the plurality of
antennas and detects a connection state of each antenna to change
over the connected antennas according to an instruction, wherein
the controller selects and changes to an antenna whose connection
has been detected by the antenna changeover unit.
24. A receiving apparatus for receiving a radio signal in a frame
structure having an information body part including at least
information body as a radio signal transmitted from a moving
transmitting apparatus and an additional part including information
for receiving field intensity measurement, the receiving apparatus
comprising: an antenna changeover unit that is connected to each
antenna in correspondence to arrangement positions of the plurality
of antennas and detects a connection state of each antenna to
change over the connected antennas according to an instruction, and
a controller that sequentially changes to an antenna whose
connection has been detected by the antenna changeover unit on
reception of the additional part to detect a receiving field
intensity, and changes to an antenna having the largest receiving
field intensity to cause the antenna to receive a radio signal of
the information body part.
25. The receiving apparatus according to claim 24, wherein a number
of the plurality of antennas is less than a number of the plurality
of connecting portions, and the plurality of antennas are used by
replacing part of a plurality of already connected antennas with
other connecting portions.
26. The receiving apparatus according to claim 24, wherein the
controller measures receiving field intensities of a plurality of
antennas in a receiving period of the additional part.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/483,355, filed Jul. 7, 2006, which is the National Stage of
International Application No. PCT/JP2005/000115, filed Jan. 7,
2005, and which claims priority from Japanese Patent Applications
No. 2004-002423, filed Jan. 7, 2004; No. 2004-026875, filed Feb. 3,
2004; No. 2004-061277, filed Mar. 4, 2004; No. 2004-071579, filed
Mar. 12, 2004; No. 2004-071580, filed Mar. 12, 2004; and No.
2004-071581, filed Mar. 12, 2004, all of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a transmitting apparatus
for transmitting an imaged video signal, a receiving apparatus for
receiving the video signal by using a plurality of antennas, and a
transmitting/receiving system having the transmitting apparatus and
the receiving apparatus, and particularly to a
transmitting/receiving system for receiving a radio video signal
transmitted from a capsule endoscope within a subject by using a
plurality of antennas outside the subject.
[0004] 2. Description of the Related Art
[0005] In recent years, in the field of endoscope, there has
appeared a swallow type capsule endoscope. This capsule endoscope
is provided with an imaging function and a wireless communication
function. The capsule endoscope has a function of, after being
swallowed from the mouth of a patient for observation (inspection),
moving and sequentially imaging inside the body cavity, for
example, inside the organs such as stomach and small intestine
according to their peristalses before being discharged from a human
body.
[0006] While moving inside the body cavity, image data imaged
inside the human body by the capsule endoscope is sequentially
transmitted to the outside via wireless communication, and is
accumulated in a memory provided in an external receiving
apparatus. A patient brings the receiving apparatus comprising the
wireless communication function and the memory function with
him/her, and consequently the patient can freely act even in the
period after he/she swallowed the capsule endoscope until it is
discharged. Thereafter, a doctor or nurse can display the organs'
images on a display based on the image data accumulated in the
memory, thereby making a diagnosis.
[0007] Generally, the receiving apparatus is constituted so that a
plurality of antennas for receiving a video signal transmitted from
the capsule endoscope are distributed outside the human body and
one antenna which is less erroneously receives the video signal is
selected and changed for reception. Japanese Patent Application
Laid-Open No. 2003-19111 describes a receiving apparatus which
performs receiving changeover of a plurality of antennas arranged
outside the human body and retrieves the position of the capsule
endoscope inside the human body as a video signal originating
source based on a field intensity received by each antenna.
SUMMARY OF THE INVENTION
[0008] A receiving apparatus according to one aspect of the present
invention is for selecting and receiving a radio signal in a frame
structure having an information body part including at least
information body and an additional part including information for
receiving field intensity measurement by using a plurality of
antennas. The apparatus includes a controller that measures a
receiving field intensity of not a first antenna which has received
the information body in a transmission period of the additional
part in a current frame but a second antenna, and measures a
receiving field intensity of the first antenna in a transmission
period of the information body part in the current frame, and if
the receiving field intensity of the second antenna exceeds the
receiving field intensity of the first antenna, selects and changes
to the second antenna as the first antenna of a next frame.
[0009] A receiving apparatus according to another aspect of the
present invention is for receiving a radio signal, transmitted from
the inside of a subject, in a frame structure having a video signal
part for transmitting at least a video signal and an additional
part including information for receiving field intensity
measurement by using a plurality of antennas provided outside the
subject. The apparatus includes a changeover unit that selects and
changes over the plurality of antennas; a field intensity
measurement unit that measures a receiving field intensity of not a
first antenna which has received the radio signal in a transmission
period of the additional part in a current frame but a second
antenna, and measures a receiving field intensity of the first
antenna in a transmission period of the video signal part in the
current frame; a selection controller that, when the receiving
field intensity of the second antenna measured by the field
intensity measurement unit exceeds the receiving field intensity of
the first antenna, selects the second antenna as the first antenna
of a next frame; and a changeover controller that sequentially
changes over and connects an antenna other than the first antenna
selected by the selection controller in a transmission period of
the additional part of the next frame, and changes to and connects
the selected first antenna in a transmission period of the video
signal part.
[0010] A receiving apparatus according to still another aspect of
the present invention is for selecting and receiving a radio signal
in a frame structure having an information body part including at
least information body and an additional part including information
for receiving field intensity measurement by using a plurality of
antennas. The apparatus includes a controller that measures
receiving field intensities of more than two antennas in the
additional part in a current frame, and selects and changes to an
antenna having the largest receiving field intensity out of the
more than two antennas as an antenna for receiving the information
body part in a current frame.
[0011] A receiving apparatus according to still another aspect of
the present invention is for selecting and receiving a radio signal
in a frame structure having an information body part including at
least information body and an additional part including information
for receiving field intensity measurement by using a plurality of
antennas. The apparatus includes a controller that compares a first
receiving field intensity of an antenna which has received the
information body in a previous frame with a second receiving field
intensity being the largest receiving field intensity out of a
result of measurement of receiving field intensities of more than
two antennas other than the antenna in the additional part of a
current frame, and selects and changes to the antenna having the
larger receiving field intensity as an antenna for receiving the
information body part in the current frame.
[0012] A receiving apparatus according to still another aspect of
the present invention is for selecting and receiving a radio signal
in a frame structure having an information body part including at
least information body and an additional part including information
for receiving field intensity measurement by using a plurality of
antennas according to each receiving field intensity. Part of a
synchronization period of the information body part is set at part
or all of a receiving field intensity measurement period of the
additional part to use a synchronization signal of the
synchronization period as a signal for receiving field intensity
measurement.
[0013] A receiving apparatus according to still another aspect of
the present invention is for selecting and receiving a radio signal
in a frame structure having an information body part including at
least information body and an additional part including information
for receiving field intensity measurement by using a plurality of
antennas according to each receiving field intensity. Part of a
synchronization period of the information body part is set at part
or all of a receiving field intensity measurement period of the
additional part to use a synchronization signal of the
synchronization period as a signal for receiving field intensity
measurement, and the antenna for receiving field measurement and
the antenna for receiving the information body part are changed
over in the synchronization period according to a measurement
result of a receiving field intensity to each of the plurality of
antennas.
[0014] A receiving apparatus according to still another aspect of
the present invention is for receiving a video signal transmitted
as a radio signal from a moving transmitting apparatus by using a
plurality of antennas. The receiving apparatus includes a
controller that sequentially changes over each antenna in a
vertical blanking period of the video signal added with a dummy
signal for receiving intensity measurement in the vertical blanking
period to detect a receiving field intensity of the each antenna,
and changes to an antenna having the largest receiving field
intensity to cause the antenna to receive a video signal other than
in the vertical blanking period.
[0015] A transmitting apparatus according to still another aspect
of the present invention is for transmitting an imaged video signal
as a radio signal to cause a receiving apparatus having a plurality
of antennas to receive the video signal. A dummy signal for
receiving field intensity measurement, which sequentially changes
over each antenna of the receiving apparatus to receive the video
signal and detects a receiving field intensity of each antenna, is
added and transmitted in a vertical blanking period in the imaged
video signal.
[0016] A transmitting/receiving system according to still another
aspect of the present invention includes a transmitting apparatus
for transmitting an imaged video signal as a radio signal and a
receiving apparatus for receiving the video signal by using a
plurality of antennas. The transmitting apparatus includes a dummy
signal adder that adds and transmits a dummy signal in a vertical
blanking period in the video signal. The receiving apparatus
includes a controller that sequentially changes over each antenna
in the vertical blanking period to detect a receiving field
intensity of each antenna from the dummy signal, and changes to an
antenna having the largest receiving field intensity to cause the
antenna to receive a video signal other than in the vertical
blanking period.
[0017] A receiving apparatus according to still another aspect of
the present invention is for receiving a radio signal in a frame
structure having an information body part including at least
information body as a radio signal transmitted from a moving
transmitting apparatus and an additional part including information
for synchronization by using a plurality of antennas. The receiving
apparatus includes a controller that sequentially changes over each
antenna in a blank of the radio signal in which a dummy signal for
receiving intensity measurement is added in the blank of the
information body part whose arrangement position is previously
determined to detect a receiving field intensity of each antenna,
and changes to an antenna having the largest receiving field
intensity to cause the antenna to receive a radio signal of the
information body part other than in the blank.
[0018] A transmitting apparatus according to still another aspect
of the present invention is for transmitting an imaged video signal
as a radio signal to cause a receiving apparatus having a plurality
of antennas to receive the video signal. Each antenna of the
receiving apparatus is sequentially changed and received in a
horizontal blanking period in the video signal to add and transmit
a dummy signal for receiving field intensity measurement for
detecting a receiving field intensity of each antenna.
[0019] A transmitting/receiving system according to still another
aspect of the present invention includes a transmitting apparatus
for transmitting an imaged video signal as a radio signal and a
receiving apparatus for receiving the video signal by using a
plurality of antennas. The transmitting apparatus includes a dummy
signal adder that adds and transmits a dummy signal in a horizontal
blanking period in the video signal. The receiving apparatus
includes a controller that sequentially changes over each antenna
in the horizontal blanking period to detect a receiving field
intensity of the each antenna from the dummy signal, and changes to
an antenna having the largest receiving field intensity to cause
the antenna to receive a video signal other than in the horizontal
blanking period.
[0020] A receiving apparatus according to still another aspect of
the present invention is for receiving a radio signal in a frame
structure having an information body part including at least
information body as a radio signal transmitted from a moving
transmitting apparatus and an additional part including information
for receiving field intensity measurement. The receiving apparatus
includes an antenna changeover unit that is connected to each
antenna in correspondence to arrangement positions of the plurality
of antennas and detects a connection state of each antenna to
change over the connected antennas according to an instruction, and
a controller that sequentially changes to an antenna whose
connection has been detected by the antenna changeover unit on
reception of the additional part to detect a receiving field
intensity, and changes to an antenna having the largest receiving
field intensity to cause the antenna to receive a radio signal of
the information body part.
[0021] The above and other objects, features, advantages and
technical and industrial significance of this invention will be
better understood by reading the following detailed description of
presently preferred embodiments of the invention, when considered
in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a schematic diagram showing the entire structure
of a wireless in-subject information acquiring system including a
receiving apparatus according to a first embodiment of the present
invention;
[0023] FIG. 2 is a block diagram showing a structure of the
receiving apparatus shown in FIG. 1;
[0024] FIG. 3 is a block diagram showing a detailed structure of a
sample hold circuit shown in FIG. 2;
[0025] FIG. 4 is a block diagram showing a detailed structure of a
changeover switch shown in FIG. 2;
[0026] FIG. 5 is a diagram showing a frame format of a radio signal
transmitted from a capsule endoscope shown in FIG. 1;
[0027] FIG. 6 is a time chart showing a receiving field intensity
measurement processing for each frame by the receiving apparatus
shown in FIG. 1;
[0028] FIG. 7 is a flowchart showing an antenna changeover
processing procedure by the receiving apparatus shown in FIG.
1;
[0029] FIG. 8 is a block diagram showing a structure of a receiving
apparatus according to a second embodiment of the present
invention;
[0030] FIG. 9 is a time chart showing a receiving field intensity
measurement processing for each frame by the receiving apparatus
shown in FIG. 8;
[0031] FIG. 10 is a block diagram showing a structure of a
receiving apparatus according to a third embodiment of the present
invention;
[0032] FIG. 11 is a timing chart for explaining an antenna
changeover processing by the receiving apparatus shown in FIG.
10;
[0033] FIG. 12 is a block diagram showing a structure of a
receiving apparatus according to a fourth embodiment of the present
invention;
[0034] FIG. 13 is a timing chart for explaining an antenna
changeover processing by the receiving apparatus shown in FIG.
12;
[0035] FIG. 14 is a block diagram showing a structure of a
receiving apparatus according to a fifth embodiment of the present
invention;
[0036] FIG. 15 is a diagram for explaining a frame format;
[0037] FIG. 16 is a timing chart for explaining an antenna
changeover processing by the receiving apparatus shown in FIG.
14;
[0038] FIG. 17 is a block diagram showing a structure of a capsule
endoscope according to a sixth embodiment of the present
invention;
[0039] FIG. 18 is a block diagram showing a structure of a
receiving apparatus according to the sixth embodiment of the
present invention;
[0040] FIG. 19 is a diagram showing a frame format of a radio
signal transmitted from the capsule endoscope shown in FIG. 17;
[0041] FIG. 20 is a time chart showing a processing for receiving
field intensity measurement and antenna changeover by the receiving
apparatus shown in FIG. 18;
[0042] FIG. 21 is a time chart showing a variant of the processing
for receiving field intensity measurement and antenna changeover by
the receiving apparatus shown in FIG. 18;
[0043] FIG. 22 is a block diagram showing a structure of a capsule
endoscope 3 according to a seventh embodiment of the present
invention;
[0044] FIG. 23 is a block diagram showing a structure of a
receiving apparatus according to the seventh embodiment of the
present invention;
[0045] FIG. 24 is a diagram showing a frame format of a radio
signal transmitted from the capsule endoscope shown in FIG. 22;
[0046] FIG. 25 is a time chart showing the processing for receiving
field intensity measurement and antenna changeover by the receiving
apparatus shown in FIG. 23;
[0047] FIG. 26 is a time chart showing a variant of the processing
for receiving field intensity measurement and antenna changeover by
the receiving apparatus shown in FIG. 23;
[0048] FIG. 27 is a block diagram showing a structure of a
receiving apparatus according to an eighth embodiment of the
present invention;
[0049] FIG. 28 is a diagram showing a structure of a connecting
unit within a changeover switch;
[0050] FIG. 29 is a time chart showing a receiving field intensity
measurement processing for each frame by the receiving apparatus
shown in FIG. 27;
[0051] FIG. 30 is a flowchart showing an antenna changeover
processing procedure by a selection control unit of the receiving
apparatus shown in FIG. 27;
[0052] FIGS. 31A and 31B are diagrams showing one example of a
connection relationship between receiving antennas and an external
device according to the eighth embodiment of the present invention;
and
[0053] FIGS. 32A and 32B are diagrams showing one example of a
connection relationship between receiving antennas and an external
device according to a ninth embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] A wireless in-subject information acquiring system as the
best mode for carrying out the present invention will be described
below.
[0055] A wireless in-subject information acquiring system
comprising a receiving apparatus according to an embodiment will be
described. The wireless in-subject information acquiring system
uses a capsule endoscope as one example of a in-subject introducing
apparatus.
[0056] FIG. 1 is a schematic diagram showing the entire structure
of the wireless in-subject information acquiring system. As shown
in FIG. 1, the wireless in-subject information acquiring system
comprises a receiving apparatus 2 having a wireless receiving
function, and a capsule endoscope (in-subject introducing
apparatus) 3 introduced inside a subject 1 for imaging a body
cavity image and transmitting data such as video signal to the
receiving apparatus 2. Further, the wireless in-subject information
acquiring system comprises a display device 4 for displaying the
body cavity image based on the video signal received by the
receiving apparatus 2, and a portable recording medium 5 for
exchanging data between the receiving apparatus 2 and the display
device 4. The receiving apparatus 2 comprises a receiving jacket 2a
worn by the subject 1, and an external device 2b for performing a
processing of a radio signal received via the receiving jacket 2a,
or the like.
[0057] The display device 4 is directed for displaying the body
cavity image imaged by the capsule endoscope 3, and has a structure
such as work station for performing image display based on data
obtained by the portable recording medium 5. Specifically, the
display device 4 may be constituted to directly display an image by
a CRT display, a liquid crystal display or the like, alternatively
may be constituted to output an image to other medium such as
printer.
[0058] The portable recording medium 5 has a structure to be
detachable with respect to the external device 2b and the display
device 4 and to be capable of outputting or recording information
on being mounted on the both. Specifically, while the capsule
endoscope 3 is moving inside the body cavity of the subject 1, the
portable recording medium 5 is mounted on the external device 2b to
record data transmitted from the capsule endoscope 3. Then, after
the capsule endoscope 3 is discharged from the subject 1, that is,
after the inside of the subject 1 finishes to be imaged, the
portable recording medium 5 is taken out from the external device
2b to be mounted on the display device 4 so that the recorded data
is read out by the display device 4. The data exchange between the
external device 2b and the display device 4 is performed by the
portable recording medium 5 such as compact flash (registered
trademark) memory so that the subject 1 can more freely act while
his/her body cavity is being imaged than when the external device
2b and the display device 4 are wire-connected, which contributes
to a reduction in time for exchanging data with the display device
4. Here, the data exchange between the external device 2b and the
display device 4 uses the portable recording medium 5, but it is
limited thereto, and it may be constituted to use other recording
apparatus incorporated in the external device 2b to be wired- or
wirelessly connected for data exchange with the display device
4.
[0059] The receiving apparatus 2 will be described with reference
to FIG. 2. The receiving apparatus 2 also has a function of
receiving body cavity image data wirelessly transmitted from the
capsule endoscope 3. FIG. 2 is a block diagram schematically
showing the structure of the receiving apparatus 2. As shown in
FIG. 2, the receiving apparatus 2 has a shape capable of being worn
by the subject 1, and comprises the receiving jacket 2a having
receiving antennas A1 to An, and the external device 2b for
performing a processing for received radio signal, and the like.
The respective receiving antennas A1 to An may be provided in the
receiving jacket 2a to be directly attached to the outer surface of
the subject, or may be detachable with respect to the receiving
jacket 2a.
[0060] The external device 2b has a function of performing a
processing for radio signal transmitted from the capsule endoscope
3. Specifically, the external device 2b, as shown in FIG. 2, has
changeover switches SW for performing connection changeover of the
receiving antennas A1 to An, and a receiving circuit 11 connected
to the rear stage of the changeover switches SW for amplifying and
demodulating a radio signal from the receiving antenna A1 to An
changeover-connected by the changeover switch SW, and further the
rear stage of the receiving circuit 11 is connected with a signal
processing circuit 12 and a sample hold circuit 15. An A/D
converter 16 is further connected to the rear stage of the sample
hold circuit 15. A controller C has a selection controller C1 to
connect a storage unit 13, a display unit 14 and a changeover
controller SC corresponding to the signal processing circuit 12,
the A/D converter 16 and the portable recording medium 5. The
changeover controller SC has intensity-receiving-antenna number
information N1 and video-receiving-antenna number information N2 to
make changeover instruction of the changeover switches SW based on
the number information and to instruct the processing timing of the
sample hold circuit 15, the A/D converter 16 and the selection
controller C1. A power supply unit 17 performs power supply to each
unit described above, and is realized by a battery, for
example.
[0061] The changeover switch SW of the external device 2b
selectively changes over any one of the receiving antennas A1 to An
based on a changeover instruction from the changeover controller
SC, and outputs a radio signal from the changed receiving antenna
A1 to An to the receiving circuit 11. As described above, the
receiving circuit 11 amplifies the radio signal and outputs a
demodulated video signal S1 to the signal processing circuit 12,
and outputs a received intensity signal S2 indicating a receiving
field intensity of the amplified radio signal to the sample hold
circuit 15. Video data processed by the signal processing circuit
12 is stored in the storage unit 13 by the controller C and
displayed by the display unit 14 for output. A signal subjected to
sample hold by the sample hold circuit 15 is converted into a
digital signal by the A/D converter 16 to be fetched by the
controller C, and the selection controller C1 of the controller C
selects a receiving antenna having the largest receiving field
intensity from among the receiving field intensities received in an
intensity receiving period in a synchronization period described
later as a receiving antenna for a video signal period and outputs
it as a signal S4 which assumes a receiving antenna number for
receiving in the intensity receiving period as the
intensity-receiving-antenna number information N1 and a receiving
antenna number for the video signal period as the
video-receiving-antenna number information N2 to the changeover
controller SC. The changeover controller SC holds the
intensity-receiving-antenna number information N1 and the
video-receiving-antenna number information N2 instructed by the
selection controller C1, and outputs a signal S5 which instructs
the changeover switch SW to select and connect the receiving
antenna A1 to An corresponding to the intensity-receiving-antenna
number information N1 during the intensity receiving period and
instructs the changeover switch SW to select and connect the
receiving antenna A1 to An corresponding to the
video-receiving-antenna number information N2 during the video
receiving period, and outputs a signal S3a which instructs a sample
hold timing by the sample hold circuit 15, a signal S3b which
instructs an A/D converting timing by the A/D converter 16, and a
signal S3c which instructs a selection control timing by the
selection controller C1.
[0062] Detailed structures of the sample hold circuit 15 and the
changeover switch SW will be described with reference to FIG. 3 and
FIG. 4. In FIG. 3, the sample hold circuit 15 has a pulse generator
15a for generating a sample hold pulse, an intensity receiving
sample hold circuit 15b for sample-holding a receiving field
intensity of the intensity receiving period, and a video receiving
sample hold circuit 15c for sample-holding a receiving field
intensity of the video receiving period.
[0063] The pulse generator 15a generates a pulse SH_KYODO and a
pulse SH_EIZO which indicates a timing and a period of the sample
hold by the intensity receiving sample hold circuit 15b based on
the signal S3a input from the changeover controller SC. The pulse
SH_KYODO and the pulse SH_EIZO are output to the switch SW1 of the
intensity receiving sample hold circuit 15b and the switch SW2 of
the video receiving sample hold circuit 15c, respectively.
[0064] The intensity receiving sample hold circuit 15b buffers the
received intensity signal S2 input from the receiving circuit 11 by
an amplifier Amp1. On the other hand, the switch SW1 enters the ON
state during a period indicated from the timing indicated by the
pulse SH_KYODO, charges are accumulated in a capacitor C1 to enter
the OFF state so that the accumulated charges are buffered by an
amplifier Amp2, and consequently the signal buffered by the
amplifier Amp1 is output as a signal KYODO_LVL indicating the
receiving field intensity of the intensity receiving period to the
A/D converter 16.
[0065] On the other hand, the video receiving sample hold circuit
15c is input with the signal buffered by the amplifier Amp1 from
the intensity receiving sample hold circuit 15b. The switch SW2
enters the ON state during a period indicated from a timing
indicated by the pulse SH_EIZO, charges are accumulated in a
capacitor C2 to enter the OFF state so that the accumulated charges
are buffered by an amplifier Amp3, and consequently the signal
buffered by the amplifier Amp1 is output as a signal EIZO_LVL
indicating the receiving field intensity of the video signal period
to the A/D converter 16.
[0066] A detailed structure of the changeover switch SW will now be
described. In FIG. 4, the changeover switch SW has a decoder D1 for
decoding a 3-bit signal S5 input from the changeover controller SC
into an 8-bit signal S51, a switch SW11 connected to the receiving
antennas A1 to A4 for selecting any one of them, a switch SW 12
connected to the receiving antennas A5 to A8 for selecting any one
of them, a switch SW13 connected to the switches SW11 and SW 12 for
selecting and outputting any one of signals Sa and Sb output from
the switches SW11 and SW12, respectively, and an inverting circuit
I1 for securing exclusive logic of the switch SW13 based on the
highest bit input into the decoder.
[0067] The signal S5 is input into the decoder D1 as a 3-bit signal
for selecting any one of the eight receiving antennas A1 to A8.
This 3-bit signal S5 is a signal ANT_SELECT[0], signal
ANT_SELECT[1] and signal ANT_SELECT[2], and the signal indicating
the highest bit is the signal ANT_SELECT[2]. The decoder D1 decodes
the 3-bit signal S5 into the 8-bit signal S51, outputs a lower
4-bit signal S51a to the switch SW11 for switching the
smaller-numbered receiving antennas A1 to A4, and outputs a higher
4-bit signal S51b to the switch SW12 for switching the
larger-numbered receiving antennas A5 to A8. The switches SW11 and
SW12 select any one of the receiving antennas A1 to A8 according to
the signals S51a and S51b, respectively. The switch SW13 selects
any one of the signals Sa and Sb output from the switches SW11 and
SW12 based on the highest bit signal ANT_SELECT[2]. When the switch
11 selects any one of the receiving antennas A1 to A4, the switch
SW12 has not selected any one of the receiving antennas A5 to A8,
but has input an inverting signal of the highest bit signal
ANT_SELECT[2] by the inverting circuit I1 and performed exclusive
logic in order to increase selection accuracy. A signal of the
receiving antenna A1 to A8 finally selected by the switch SW13 is
output to the receiving circuit 11. Here, the receiving antennas A1
to An has been described as the receiving antennas A1 to A8. The
antenna number of each receiving antenna A1 to A8 is identification
information unique to each receiving antennas and the numbers "1"
to "8" are assumed as "0" to "7" for the sake of information
processing.
[0068] The intensity receiving period and video receiving period
described above with reference to FIG. 5 and FIG. 6, that is, a
frame structure of a radio signal will be described, and an outline
of a processing of selecting and changing over the receiving
antennas A1 to An will be described. A radio signal transmitted
from the capsule endoscope 3 is transmitted in unit of frame, and
this frame is constituted of the intensity receiving period and the
video signal period as shown in FIG. 5. The intensity receiving
period is a period corresponding to a preamble signal period for
receiving adjustment. Further, the video signal period can contain
a control signal necessary for receiving a video signal in addition
to the video signal itself.
[0069] Each frame may be transmitted as shown in FIG. 6 and a
no-signal state may be between frames, or each frame may be
continuously transmitted. A frame cycle TT for frame transmission
is short in an imaging area of interest or in an area where the
capsule endoscope 3 fast moves in consideration of effective
utilization of the battery of the capsule endoscope 3, and the
length of the frame cycle TT is flexibly adjusted.
[0070] As shown in FIG. 6, when the n-th frame (n) and the (n+1)-th
frame (n+1) are sequentially transmitted, other receiving antenna
(intensity receiving antenna) different from the receiving antenna
(video receiving antenna) for receiving in the video signal period
of the same frame (n) is changed over in a period ta corresponding
to the intensity receiving period of the frame (n), and the video
receiving antenna is changed over in a period tb including the
video receiving period and a period to the start of the intensity
receiving period of the next frame (n+1). Similarly, in a period
ta' corresponding to the intensity receiving period of the frame
(n+1), the intensity receiving antenna is changed over in the video
signal period of the same frame (n+1) and the video receiving
antenna is changed over in a period tb' including the video
receiving period and a period to the start of the intensity
receiving period of the next frame (n+2).
[0071] At timing t1 in the intensity receiving period of the frame
(n), an intensity detection processing is performed by the sample
hold circuit 15 and the A/D converter 16 and a result thereof is
output to the selection controller C1. Similarly, at timing t2 in
the video signal period of the frame (n), the intensity detection
processing is performed by the sample hold circuit 15 and the A/D
converter 16 and a result thereof is output to the selection
controller C1. Therefore, a margin period to the antenna changeover
processing of the next frame (n+1) is a changeover margin time T
from timing t2 to the start of the intensity receiving period of
the next frame (n+1). Thus, the timing t2 is set at an earlier
point in the video signal period so that the changeover margin time
T can be made long. Due to the long changeover margin time T, the
sample hold circuit 15, the A/D converter 16, the selection
changeover controller C1, the changeover controller SC and the
changeover switch SW do not require high speed performance and can
be realized using a simple circuit apparatus. The receiving field
intensity of the receiving antenna for receiving the video signal
is received and measured in the video signal period and does not
require to be measured in the intensity receiving period so that
the antenna does not require to be changed over at high speed.
Further, this results in a changeover margin because the receiving
field intensity of the self-video signal does not require to be
measured when the receiving field intensities of a plurality of
receiving antennas are measured in the intensity receiving
period.
[0072] An antenna changeover processing procedure will be described
with reference to a flowchart shown in FIG. 7. The antenna
changeover processing is performed by the selection controller C1
and the changeover controller SC. In FIG. 7, the selection
controller C1 first sets, as initial setting, the
video-receiving-antenna number information as the video receiving
antenna number to be No. 1 and the intensity-receiving-antenna
number information as the intensity receiving antenna number to be
No. 2, and registers the same in the video-receiving-antenna number
information N2 and the intensity-receiving-antenna number
information N1 in the changeover controller SC (step S101). Here,
No. 1 to No. n of the video-receiving-antenna number information
and the intensity-receiving-antenna number information are the
numbers corresponding to the receiving antennas A1 to An,
respectively.
[0073] Thereafter, the changeover controller SC determines whether
the intensity receiving period has started (step S102). If the
intensity receiving period has started (step S102, YES), the
changeover controller SC outputs an instruction of changing to the
receiving antenna corresponding to the intensity-receiving-antenna
number information registered in the intensity-receiving-antenna
number information N1 to the changeover switch SW (step S103), and
the changeover switch SW changes to the instructed receiving
antenna. Thereafter, the changeover controller SC causes the sample
hold circuit 15 and the A/D converter 16 to perform a processing of
detecting the receiving field intensity of the intensity receiving
antenna at timing t1 (step S104), and instructs the changeover
switch SW to change to the receiving antenna registered in the
video-receiving-antenna number information N2 at the start of the
video receiving period (step S105) so that the changeover switch SW
changes to the instructed receiving antenna. The changeover time in
step S105 may not be at the start of the video signal period, or
may be within the intensity receiving period if it is at the end of
the field intensity measurement processing for the intensity
receiving antenna.
[0074] Thereafter, the changeover controller SC determines whether
the video signal period has started (step S106). The video signal
period used here may be assumed as a period in which the video
signal is transmitted if the control signal or the like is included
in the video signal period. Thereafter, if the video signal period
has started (Step S106, YES), the sample hold circuit 15 and the
A/D converter 16 are caused to perform the processing of detecting
the receiving field intensity of the intensity receiving antenna at
timing t2 (step S107).
[0075] Thereafter, the selection controller C1 determines whether
the receiving field intensity of the video receiving antenna
received in the video signal period (video receiving antenna
intensity) is smaller than the receiving field intensity of the
intensity receiving antenna received in the intensity receiving
period (intensity receiving antenna intensity) (step S108). If the
video receiving antenna intensity is smaller than the intensity
receiving antenna intensity (step S108, YES), the
video-receiving-antenna number information is registered in the
intensity-receiving-antenna number information N1 as the
intensity-receiving-antenna number information (step S109), and the
processing proceeds to step S110. On the other hand, if the video
receiving antenna intensity is not smaller than the intensity
receiving antenna intensity (step S108, NO), that is, when the
video receiving antenna intensity exceeds the intensity receiving
antenna intensity, the value of the intensity-receiving-antenna
number information N1 is incremented as it is (step S110).
[0076] Thereafter, it is determined whether the value of the
intensity-receiving-antenna number information coincides with the
value of the video-receiving-antenna number information (step
S111), if it coincides therewith (step S111, YES), the processing
proceeds to step S110 to increment the value of the
intensity-receiving-antenna number information, and if it does not
coincides therewith (step S111, NO), it is further determined
whether the intensity-receiving-antenna number information is No. n
(step S112). If the intensity-receiving-antenna number information
is not No. n (step S112, NO), the processing proceeds to step S102
to repeat the above processing, and if the
intensity-receiving-antenna number information is No. n (step S112,
YES), it is further determined whether the video-receiving-antenna
number information is No. 1 (step S113). If the
video-receiving-antenna number information is not No. 1 (step S113,
NO), the intensity-receiving-antenna number information is set and
registered to be No. 1 (step S114), and if the
video-receiving-antenna number information is No. 1 (step S113,
YES), the intensity-receiving-antenna number information is set and
registered to be No. 2 (step S115), and then the processing
proceeds to step S102 to repeat the above processing.
[0077] Since the first embodiment is constituted to measure the
receiving field intensity of the video signal in the video signal
period, to sequentially change to the receiving antenna other than
the receiving antenna for receiving the video signal in the
intensity receiving period to measure the receiving field
intensity, and to change the receiving antenna changed in the
intensity receiving period to the receiving antenna for the video
receiving period when the receiving field intensity measured in the
intensity receiving period exceeds the receiving field intensity
measured in the video receiving period, the intensity receiving
period can be reduced, a margin can be allowed in the time to
change over the receiving antenna in the intensity receiving
period, the intensity detection timing is made earlier in the video
receiving period so that a time margin can be allowed in the
antenna changeover setting between frames, and consequently high
speed performance is not required for the structure on the
receiving field intensity measurement, thereby achieving the simple
structure.
[0078] A second embodiment according to the present invention will
now be described. The second embodiment is constituted so that a
peak hold circuit 18 is further provided between the receiving
circuit 11 and the sample hold circuit 15 according to the first
embodiment.
[0079] FIG. 8 is a block diagram showing a structure of a receiving
apparatus according to the second embodiment of the present
invention. As shown in FIG. 8, the receiving apparatus is provided
with the peak hold circuit 18 and holds a peak value of the
received intensity signal S2 output from the receiving circuit
11.
[0080] Thus, as shown in FIG. 9, the changeover controller SC
outputs a signal Sr to the peak hold circuit 18 at the start of the
intensity receiving period and resets it at timing tr1. Thereafter,
the changeover controller SC acquires a peak value held by the peak
hold circuit 18 at detection timing t3 of the sample hold circuit
15, and again resets the peak hold circuit 18 at timing tr2 at the
start of the video signal period. The sample hold circuit 15
acquires the peak value held by the peak hold circuit 18 at timing
t4 after timing tr2. In other words, the sample hold circuit 15 can
sample the peak value between timing tr1 and timing t3 and can
sample the peak value between timing tr2 and timing tr4, thereby
performing the receiving field intensity measurement with higher
accuracy.
[0081] A third embodiment according to the present invention will
now be described. The third embodiment is constituted so that the
receiving field intensity measurement for all the receiving
antennas is performed in the intensity receiving period to select a
receiving antenna having the largest receiving field intensity as
the video receiving antenna. FIG. 10 is a block diagram showing a
structure of a receiving apparatus according to the third
embodiment of the present invention. As shown in FIG. 10, the
receiving apparatus is provided with a selection controller C3
instead of the selection controller C1. Other configurations are
identical to those in the first embodiment and like numerals are
denoted to like configurations.
[0082] The intensity receiving period and video receiving period
described above with reference to FIG. 11, that is, the frame
structure of a radio signal will be described, and an outline of a
processing of selecting and changing over the receiving antennas A1
to An will be described. A radio signal transmitted from the
capsule endoscope 3 is transmitted in unit of frame and is
constituted of the synchronization period and the video signal
period as shown in FIG. 11. The synchronization period is a period
corresponding to the preamble signal period for receiving
adjustment. Further, the video signal period can contain a control
signal necessary for receiving the video signal in addition to the
video signal itself.
[0083] Each frame is transmitted as shown in FIG. 11 and a
no-signal state may be between frames or each frame may be
continuously transmitted. A frame cycle TT for frame transmission
is short in an imaging area of interest or in an area where the
capsule endoscope 3 fast moves in consideration of effective
utilization of the battery of the capsule endoscope 3, and the
length of the frame cycle TT is flexibly adjusted.
[0084] As shown in FIG. 11, the synchronization period TS in the
n-th frame (n) has an intensity receiving period TS1 for selecting
a receiving antenna having the largest receiving field intensity
and a synchronization period TS2 for the video signal, and antenna
changeover is performed between the intensity receiving period TS1
and the synchronization period TS2. Here, when the receiving
antennas A1 to An are eight receiving antennas, the antenna
changeover of all the receiving antennas A1 to A8 is performed in
the intensity receiving period TS1 and the receiving field
intensity measurement is performed at timings t1 to t8 within the
period of each changed state. Peak hold pulses at timings t1 to t8
are generated by the pulse generator 15a.
[0085] When the receiving field intensity measurement for all the
receiving antennas A1 to A8 is terminated, the selection controller
C3 selects a receiving antenna having the largest receiving field
intensity at the point and selects the receiving antenna as the
video receiving antenna in the synchronization period TS2 and video
signal period TM. The receiving field intensity measurement by the
video receiving antenna is performed in the video signal period TM
or synchronization period TS2 at timing tt1 or timing tta. The
receiving field intensity measurement by the video receiving
antenna may not be performed if not needed. It is performed for
receiving state confirmation in the third embodiment.
[0086] Since the third embodiment is constituted so that the
receiving field intensity measurement for all the receiving
antennas is performed in the intensity receiving period TS1 to
select a receiving antenna having the largest receiving field
intensity as the video receiving antenna, less video signals are
transmitted in vain and a small number of video signals can be
securely received. Consequently, power saving of the capsule
endoscope 3 can be promoted.
[0087] A fourth embodiment according to the present invention will
now be described. The forth embodiment is constituted so that the
result of the receiving field intensity measurement by the video
receiving antenna is effectively utilized to select and process the
video receiving antenna.
[0088] FIG. 12 is a block diagram showing a structure of a
receiving apparatus according to the fourth embodiment of the
present invention. As shown in FIG. 12, the receiving apparatus is
provided with a selection controller C4 instead of the selection
controller C1. Other configurations are identical to those in the
first embodiment and like numerals are denoted to like
configurations.
[0089] The selection controller C4, as shown in FIG. 13, excludes
the receiving antenna selected as the video signal antenna in the
frame (n-1) from the intensity receiving antennas, and assumes the
remaining seven receiving antennas as the intensity receiving
antennas to cause them to perform the receiving field intensity
measurement for each receiving antenna in the intensity receiving
period TS1. The selection controller C4 determines the receiving
antenna having the largest receiving field intensity in the
intensity receiving period TS1, and compares the receiving field
intensity of the determined receiving antenna with the receiving
field intensity of the video receiving antenna in the frame (n-1)
to select the receiving antenna having the higher receiving field
intensity as the video receiving antenna for the frame (n). The
selected video receiving antenna measures the receiving field
intensity in the synchronization period TS2 or video signal period
TM and a result thereof is used to determine the video receiving
antenna for the frame (n+1).
[0090] Since the fourth embodiment is constituted so that the
receiving field intensity of the video receiving antenna is
measured in the previous video signal period TM having a time
margin and only the receiving antenna is excluded from the
intensity receiving antennas in the intensity receiving period TS1
to select a receiving antenna having the largest receiving field
intensity from among the receiving field intensities as the video
receiving antenna, secure video signals can be received in a short
time.
[0091] Although all the receiving antennas are basically assumed as
the intensity receiving antennas in the aforementioned third and
fourth embodiments, if all the receiving antennas are previously
grouped, for example, only the grouped antennas are basically
subjected to the intensity receiving antennas. Further, not all the
receiving antennas but near receiving antennas predetermined for
the video receiving antenna may be targeted. For example, when all
the receiving antennas are denoted with serial numbers
corresponding to the moving path of the capsule endoscope 3, the
receiving antennas near the video receiving antenna, for example,
having the previous and next two serial numbers may be targeted.
When the receiving antennas are denoted with serial numbers, all
the receiving antennas having larger numbers than that of the
current video receiving antenna are subjected to the intensity
receiving antennas.
[0092] A fifth embodiment according to the present invention will
now be described. The fifth embodiment is constituted so that the
intensity receiving period is provided within the synchronization
period and the synchronization signal is used to perform the
receiving field intensity measurement during the intensity
receiving period. FIG. 14 is a block diagram showing a structure of
a receiving apparatus according to the fifth embodiment of the
present invention. As shown in FIG. 14, this receiving apparatus is
provided with a selection controller C5 instead of the selection
controller C1. Other configurations are identical to those in the
first embodiment and like numerals are denoted to like
configurations.
[0093] Here, the intensity receiving period and video receiving
period described above with reference to FIG. 15 and FIG. 16, that
is, the frame structure of a radio signal will be described and an
outline of a processing of selecting and changing over the
receiving antennas A1 to An will be described. A radio signal
transmitted from the capsule endoscope 3 is transmitted in unit of
frame, and in this frame, the video signal period is conventionally
provided after the intensity receiving period TS1, the
synchronization period TS is provided at the head of the video
signal period, and the video period TM made of m lines is provided
subsequent to the synchronization period TS. In the fifth
embodiment, the intensity receiving period TS1 is shifted to the
synchronization period TS side and the synchronization signal is
used as a signal for the receiving field intensity measurement. The
synchronization signal is a pulse signal having a duty ratio of
50%, for example. When the receiving circuit 11 is constituted to
be separated into an RF module for performing RF signal processing
and a demodulating circuit for performing baseband demodulation,
the synchronization processing for the RF module is performed in
the first half of the synchronization period TS, and then the
synchronization processing for the demodulating circuit is
performed in the second half of the synchronization period TS.
[0094] Each frame is transmitted as shown in FIG. 15 and a
no-signal state may be between frames or each frame may be
continuously transmitted. A frame cycle TT for frame transmission
is short in an imaging area of interest or in an area where the
capsule endoscope 3 fast moves in consideration of effective
utilization of the battery of the capsule endoscope 3, and the
length of the frame cycle TT is flexibly adjusted.
[0095] As shown in FIG. 16, the synchronization period TS in the
n-th frame (n) has the intensity receiving period TS1 for selecting
a receiving antenna having the largest receiving field intensity by
using the synchronization signal and the synchronization period TS2
for the video signal, and antenna changeover is performed between
the intensity receiving period TS1 and the synchronization period
TS2. In FIG. 16, the synchronization signal is used in the
intensity receiving period TS1 to change over two receiving
antennas, and the receiving field intensity of each receiving
antenna is sample-held and received at timings t1, t2 corresponding
to the changed state, respectively. Thereafter, the receiving
antenna for receiving the video signal is changed at timing tc
within the synchronization period TS. The receiving circuit 11
performs the synchronization processing subsequent to the
synchronization period corresponding to the intensity receiving
period TS1 in the changed synchronization period TS2. Thereafter,
the video signal made of m lines is received in the video period
TM. The receiving field intensity of the video receiving antenna is
measured at, for example, timing tt1 in the synchronization period
TS2 and video period TM. The sample hold pulses at timings t1, t2,
tt1 and tta are generated by the pulse generator 15a.
[0096] The selection controller C5 is constituted to select a
receiving antenna having the largest receiving field intensity from
among the receiving field intensities received in the intensity
receiving period TS1 as the receiving antenna for the video signal
period, but is not limited thereto and may be constituted to select
a receiving antenna having the largest receiving field intensity,
including the receiving field intensity of the video receiving
antenna in addition to the receiving field intensities of the
receiving antennas received in the synchronization period TS1, as
the video receiving antenna.
[0097] The fifth embodiment is constituted so that the intensity
receiving period TS1 is contained in the synchronization period TS,
but is not limited thereto and may be constituted so that part of
the intensity receiving period TS1 is overlapped on the
synchronization period TS.
[0098] Since the fifth embodiment is constituted so that the
intensity receiving period TS1 is provided in the synchronization
period TS and the synchronization signal is used to perform the
receiving field intensity measurement in the intensity receiving
period TS1, the intensity receiving period does not require to be
newly provided, thereby reducing the transmission power of the
capsule endoscope 3 to be consumed per frame.
[0099] A sixth embodiment according to the present invention will
now be described. A wireless in-subject information acquiring
system shown in the sixth embodiment corresponds to the
transmitting/receiving system and uses a capsule endoscope as one
example of the transmitting apparatus (in-subject introducing
apparatus).
[0100] FIG. 17 is a block diagram schematically showing a structure
of the capsule endoscope 3 according to the sixth embodiment of the
present invention. As shown in FIG. 17, the capsule endoscope 3
comprises a LED 19 for radiating an imaging area when imaging the
inside of the subject 1, a LED drive circuit 20 for controlling a
drive state of the LED 19, a CCD 21 as imaging means for imaging an
area radiated by the LED 19, and a signal processing circuit 22 for
processing an image signal output from the CCD 21 into imaging
information in a desired form. The capsule endoscope 3 further
comprises a CCD drive circuit 25 for controlling a drive state of
the CCD 21, an RF transmitting unit 23 for modulating image data
imaged by the CCD 21 and processed by the signal processing circuit
22 to generate an RF signal, a transmitting antenna unit 24 for
transmitting an RF signal output from the RF transmitting unit 23,
and a system control circuit 26 for controlling operations of the
LED drive circuit 20, the CCD drive circuit 25 and the RF
transmitting unit 23. The CCD 21, the signal processing circuit 22
and the CCD drive circuit 25 are collectively called an imaging
circuit 27.
[0101] The capsule endoscope 3 comprises the above mechanism to
acquire image information of an inspected site radiated by the LED
19 through the CCD 21 while it is being introduced into the subject
1. The acquired image information is signal-processed into a video
signal by the signal processing circuit 22 and converted into an RF
signal in the RF transmitting unit 23, and then is transmitted to
the outside via the transmitting antenna unit 24.
[0102] The signal processing circuit 22 comprises a dummy signal
adder 22a, and the dummy signal adder 22a adds a dummy pulse for
receiving intensity measurement used when synchronizing with the
horizontal synchronization signal and the vertical synchronization
signal of the video signal and detecting the receiving field
intensity of each receiving antenna from a radio signal received by
each receiving antenna described later within the vertical blanking
period. For example, a counter is provided which is synchronized
with the horizontal synchronization signal and the vertical
synchronization signal, and a dummy pulse is generated by using a
count value of the counter as a reference to be embedded in the
vertical blanking period. The position or frequency of the dummy
pulse is arbitrary if it is in the vertical blanking period.
[0103] The capsule endoscope 3 comprises a sensor unit 35 for
detecting a signal of predetermined magnetism, light, radio wave or
the like, and a drive control unit 34 for controlling the drive of
the system control circuit 26 for entirely controlling the
processings of the LED drive circuit, the CCD drive circuit 25, the
RF transmitting unit 23 and the respective units. The sensor unit
35 is realized by, for example, a pH sensor, and detects whether
the capsule endoscope 3 has reached a predetermined position in the
subject so that the drive control unit 34 controls the driving of
each unit based on the result. Thus, the power consumption can be
restricted.
[0104] The drive control unit 34 is supplied with power for a
battery 40 as an energy supply source via a power supply switch 33
in a power supply switch circuit 30. The battery 40 is realized by
a button battery made of silver oxide, for example. The power
supply switch 33 is a so-called main power supply switch of the
capsule endoscope 3. The power supply switch circuit 30 further has
a signal detecting circuit 31 and a switch control circuit 32. The
signal detecting circuit 31 as external signal detecting means for
detecting a signal from the outside of the capsule endoscope 3 is
realized by a reed switch and is turned ON/OFF through
proximity/separation of a magnet 50 with respect to the reed
switch. In other words, the switch control circuit 32 which ON/OFF
operates depending on whether a magnetic force acts on the reed
switch controls to cause ON/OFF of the power supply switch 33 to
perform toggle operation based on a control signal, that is, an
ON/OFF signal from the signal detecting circuit 31. The ON/OFF of
the power supply switch 33 by the magnet 50 is performed before
being introduced into the subject to perform operation check of the
capsule endoscope 3.
[0105] FIG. 18 is a block diagram showing a structure of a
receiving apparatus according to the sixth embodiment of the
present invention. As shown in FIG. 18, the receiving apparatus is
provided with a selection controller C6 instead of the selection
controller C1. Other configurations are identical to those in the
first embodiment and like numerals are denoted to like
configurations.
[0106] Here, the synchronization period and video receiving period
described above with reference to FIG. 19 and FIG. 20, that is, the
frame structure of a radio signal will be described, and a
processing of selecting and changing over the receiving antennas A1
to An will be described. A radio signal transmitted from the
capsule endoscope 3 is transmitted in unit of frame, and the frame
is constituted, as shown in FIG. 19, of the synchronization period
TS as the additional part including information for synchronization
and the video signal period TM as the information body part
including information body. The synchronization period TS is a
period corresponding to the preamble signal period for receiving
adjustment. Further, the video signal period TM is a period for
receiving a video signal, and the video signal has a field period
TF1 in which odd-numbered field signals are transmitted, a vertical
blanking period TV and a field TF2 in which even-numbered field
signals are transmitted. A dummy pulse P added by the dummy signal
adder 22a is inserted into the vertical blanking period TV as
described above. A control signal necessary for receiving the video
signal may be included in the video signal period TM in addition to
the horizontal video signal itself. The synchronization period and
the video receiving period may be provided as independent periods
or may be provided as overlapped periods.
[0107] Each frame is transmitted as shown in FIG. 20 and a
no-signal state may be between frames or each frame may be
continuously transmitted. A frame cycle TT for frame transmission
is short in an imaging area of interest or in an area where the
capsule endoscope 3 fast moves in consideration of effective
utilization of the battery of the capsule endoscope 3, and the
length of the frame cycle TT is flexibly adjusted.
[0108] As shown in FIG. 20, the receiving antenna is changed over
between the field periods TF1, TF2 and the vertical blanking period
TV in the n-th frame (n). The video receiving antenna stands for a
receiving antenna for receiving in the synchronization period TS
and each field period TF1, TF2. The intensity receiving antenna
stands for a receiving antenna for receiving in the vertical
blanking period TV. The selection controller C1 measures the
receiving field intensity in the period for changing to the
intensity receiving antenna, selects and changes a receiving
antenna having the largest receiving field intensity including the
receiving field intensity of the current video receiving antenna as
the receiving antenna in the period for changing to the next video
receiving antenna, and selects the intensity receiving antenna
except for at least the immediately previous video receiving
antenna in the period for changing to the next intensity receiving
antenna. A receiving antenna having the largest receiving field
intensity at the point is selected as the video receiving antenna
through the above repetition.
[0109] A timing at which the receiving antenna having the largest
receiving field intensity is selected may be selected after a
predetermined number of times of the receiving field intensity
measurement, and the video receiving antenna selected at the
previous time may be selected during the measurement. Since the
moving path of the capsule endoscope 3 is previously known, the
odd-numbered field in the frame to be first transmitted previously
selects the video receiving antenna and the video receiving antenna
of the odd-numbered field in the second and subsequent frames may
set the receiving antenna selected in the vertical blanking period
TV in the first frame.
[0110] In FIG. 20, the receiving field intensity measurement is
performed twice at timings t1 and t2 in the vertical blanking
period TV, but is not limited thereto and may be performed only one
time or more than three times. When performing the receiving field
intensity measurement several times, it is preferable to perform
the receiving field intensity measurement for different receiving
antennas. The field intensity of the video receiving antenna is
measured at timing tt1 in the field period TF1, but the receiving
field intensity may be measured at timing tta in the
synchronization period TS. The timings t1, t2, tt1 and tt2 are
pulses generated by the pulse generator 15a. Here, the receiving
field intensity measurement is performed in the horizontal blanking
period TV added with a dummy pulse P, but even when the dummy pulse
is added to the entire vertical blanking period TV, the receiving
field intensity measurement may not be performed for the entire
horizontal blanking period TV.
[0111] The antenna changeover between the field period TF1, TF2 and
the vertical blanking period TV is possible with high accuracy
because it can use the synchronization of the vertical blanking
period.
[0112] The synchronization period TS is about 3 ms, and a period as
long as the synchronization period TS may be added before the
synchronization period as a period for the receiving field
measurement to measure the receiving field intensity. But, since
the vertical blanking period TV is a period of 100 ms or more, the
receiving field intensity for many receiving antennas can be
measured in the period. Naturally, the synchronization period for
the receiving field measurement may be a format to be added before
the synchronization period TS.
[0113] Since the sixth embodiment is constituted so that the dummy
pulse P for the receiving field intensity measurement is added to
the vertical blanking period TV to perform the receiving field
intensity measurement for selecting the video receiving antenna in
the long vertical blanking period TV, the optimum video receiving
antenna having the largest receiving field intensity can be
selected with high accuracy. Further, the synchronization period
can be reduced and consequently the transmission time in the frame
is reduced, thereby achieving power saving of the capsule endoscope
3.
[0114] In the sixth embodiment, description is made as each frame
being transmitted without synchronization between frames, but in
the case of 2-frame transmission, it is preferable that the
vertical blanking period is provided between frames and the
receiving field intensity measurement for selecting the optimum
video receiving antenna is performed even in the vertical blanking
period similarly as in the vertical blanking period between the
fields TF1 and TF2 (refer to FIG. 21). Further, although the
imaging in an interlace manner has been described in the
aforementioned sixth embodiment, in the case of the interlace
manner, if the frames are continuously transmitted, the vertical
blanking period TV occurs, thereby applying the present
embodiment.
[0115] A seventh embodiment according to the present invention will
now be described. The seventh embodiment is constituted so that a
dummy pulse for the receiving field intensity measurement is added
in the horizontal blanking period in the video signal period to
perform the receiving field intensity measurement for selecting the
video receiving antenna in the long horizontal blanking period.
[0116] FIG. 22 is a block diagram schematically showing a structure
of a capsule endoscope according to the seventh embodiment of the
present invention. As shown in FIG. 22, the capsule endoscope 3 is
provided with a dummy signal adder 22b instead of the dummy signal
adder 22a shown in FIG. 17a. Further, FIG. 23 is a block diagram
showing a structure of a receiving apparatus according to the
seventh embodiment of the present invention. As shown in FIG. 23,
the receiving apparatus is provided with a selection controller C7
instead of the selection controller C1. Other configurations are
identical to those in the sixth embodiment and like numerals are
denoted to like configurations.
[0117] As shown in FIG. 22, the signal processing circuit 22
comprises the dummy signal adder 22b, and the dummy signal adder
22b adds a dummy pulse for the receiving intensity measurement used
when synchronizing with the horizontal synchronization signal and
vertical synchronization signal of the video signal and detecting
the receiving field intensity of each antenna from the radio signal
received by each receiving antenna described later during the
horizontal blanking period. For example, a counter is provided
which synchronizes with the horizontal synchronization signal and
the vertical synchronization signal, and a dummy pulse is generated
by using a count value of the counter as a reference to be embedded
in the horizontal blanking period. The position or frequency of the
dummy pulse is arbitrary if it is in the horizontal blanking
period. It is not necessary to add the dummy pulse to all the
horizontal blanking periods, and the dummy pulse may be added to
only the required horizontal blanking periods.
[0118] The synchronization period and video receiving period
described above with reference to FIG. 24 and FIG. 25, that is, the
frame structure of a radio signal will be described and a
processing of selecting and changing over the receiving antennas A1
to An will be described. A radio signal transmitted from the
capsule endoscope 3 is transmitted in unit of frame, and, as shown
in FIG. 24, the frame is constituted of the synchronization period
TS as the additional part including information for synchronization
and the video signal period TM as the information body part
including information body. The synchronization period TS is a
period corresponding to the preamble signal period for receiving
adjustment. The video signal period TM is a period for receiving a
video signal, and the video signal has a video line period TH in
which a video line signal for each line is transmitted and a
horizontal blanking period Th inserted between the video line
periods TH. A dummy pulse P added by the dummy signal adder 22a is
inserted into the horizontal blanking period Th as described above.
The video signal period TM can contain a control signal necessary
for receiving the video signal in addition to the horizontal video
signal itself. The synchronization period and the video receiving
period may be provided as independent periods or may be provided as
overlapped periods.
[0119] Each frame is transmitted as shown in FIG. 25 and a
no-signal state may be between frames or each frame may be
continuously transmitted. A frame cycle TT for frame transmission
is short in an imaging area of interest or in an area where the
capsule endoscope 3 fast moves in consideration of effective
utilization of the battery of the capsule endoscope 3, and the
length of the frame cycle TT is flexibly adjusted.
[0120] As shown in FIG. 25, the receiving antenna is changed over
at timing tc in the synchronization period TS in the n-th frame (n)
and the receiving antenna is changed over between the video line
period TH and the horizontal blanking period Th. The video
receiving antenna stands for a receiving antenna for receiving in a
period TSH after timing tc in the synchronization period TS and the
video line period TH at the first line as well as each video line
period TH after the second line. The intensity receiving antenna
stands for a receiving antenna for receiving in a period TSS before
timing tc in the synchronization period TS and each horizontal
blanking period Th. The selection controller C1 measures the
receiving field intensity in a period for changing to the intensity
receiving antenna, selects and changes a receiving antenna having
the largest receiving field intensity including the receiving field
intensity of the current video receiving antenna as the receiving
antenna in a period for changing to the next video receiving
antenna, and selects the intensity receiving antenna except for at
least the immediately previous video receiving antenna in a period
for changing to the next intensity receiving antenna. A receiving
antenna having the largest receiving field intensity at the point
is selected as the video receiving antenna through the above
repetition.
[0121] The timing at which the receiving antenna having the largest
receiving field intensity is selected may be selected after a
predetermined number of times of the receiving field intensity
measurement, and the video receiving antenna selected at the
previous time may be selected. For example, the video receiving
antenna may be selected and determined in unit of frame. In this
case, the video receiving antenna selected and determined in the
frame (n) is used as the video receiving antenna in the next frame
(n+1).
[0122] In FIG. 25, the receiving field intensity measurement is
performed once in the period TSS before timing tc in the
synchronization period TS and each horizontal blanking period Th,
respectively, but is not limited thereto and the receiving field
intensity measurement may be performed several times, and in this
case, the receiving field intensity measurement for a plurality of
different receiving antennas may be performed. The timings t0 to t2
and tt1 to tt3 are pulses generated by the pulse generator 15a.
Here, although the receiving field intensity measurement is
performed in the horizontal blanking period Th added with the dummy
pulses P, even when the dummy pulses are added to all the
horizontal blanking periods Th, the receiving field intensity
measurement may not be performed for all the horizontal blanking
periods Th.
[0123] The antenna changeover between the video line period TH and
the horizontal blanking period Th is possible with high accuracy
because it can use the synchronization of the horizontal
blanking.
[0124] Since the seventh embodiment is constituted so that the
dummy pulse P for the receiving field intensity measurement is
added in the horizontal blanking period Th in the video signal
period TM to perform the receiving field intensity measurement for
selecting the video receiving antenna in the long horizontal
blanking period Th, the optimum video receiving antenna having the
largest receiving field intensity can be selected with high
accuracy and fineness.
[0125] In the aforementioned seventh embodiment, although the
antenna changeover is performed at timing tc in the synchronization
period TS, since the receiving field intensity measurement
sufficient for selecting the optimum video receiving antenna can be
performed only in the horizontal blanking period Th, it is
preferable that the synchronization period TSS is deleted to assume
the synchronization period TSH having only the period TSH necessary
for the synchronization of the video signal receiving as shown in
FIG. 26. In this case, the synchronization period can be reduced
and consequently the transmission time in the frame is reduced,
thereby achieving the power saving of the capsule endoscope 3.
[0126] An eighth embodiment according to the present invention will
now be described. The eighth embodiment is constituted so that only
the receiving antennas A1 to An connected to the changeover
switches are set as the intensity receiving antennas.
[0127] FIG. 27 is a block diagram showing a structure of a
receiving apparatus according to the eighth embodiment of the
present invention. As shown in FIG. 27, the receiving apparatus is
provided with a changeover switch SW2 having a connecting unit COM
with connectors CON1 to CONn instead of the changeover switch SW
and a selection controller C8 instead of the selection controller
C1. Other configurations are identical to those in the first
embodiment and like numerals are denoted to like
configurations.
[0128] The changeover switch SW2 of the external device 2b
selectively changes any one of the receiving antennas A1 to An
based on the changeover instruction from the changeover controller
SC, and outputs a radio signal from the changed receiving antenna
A1 to An to the receiving circuit 11. Here, the changeover switch
SW2 has the connecting unit CON as antenna changeover means for
connecting each receiving antenna A1 to An in correspondence to the
arrangement position of the receiving antenna A1 to An. On the
other hand, each receiving antenna A1 to An has a connector CON1 to
CONn connected to the connecting unit CON.
[0129] The connecting unit CON has a detecting function of
detecting a connection state of each connector CON1 to CONn. For
example, the connecting unit CON has a detecting circuit as shown
in FIG. 28 for the connector CON1 and has a similar detecting
circuit also for other connector CON2 to CONn. In FIG. 28, the
connector CON1 connects a signal line LS and an earth line LG from
the receiving antenna A1 to the connecting unit CON and branches
the earth line LG for output. The connecting unit CON outputs the
signal line LS to the changeover unit SW1 as it is, which is
changed over based on the signal S5 instructing the changeover and
is output to the receiving circuit 11. On the other hand, one end
of the earth line LG is grounded as it is and the other end of the
earth line LG is connected to a constant voltage source VDD. When
the connector CON1 is connected to the connecting unit CON, a
voltage signal from the constant voltage source VDD flows to one
end of the earth line LG so that a signal S6 is not output to the
selection controller C1 of the external controller C, and when the
connector CON1 is not connected to the connecting unit CON, the
voltage signal from the constant voltage source VDD is output to
the selection controller C1 as the signal S6 as it is. Therefore,
the selection controller C1 detects the presence of the signal S6
as the voltage signal to determine whether the connector CON1, that
is, the receiving antenna A1 is connected. A similar detecting
circuit is provided in correspondence to each connector CON2 to
CONn so that the selection controller C1 can senses the connection
state of each receiving antenna A1 to An.
[0130] In FIG. 27, the receiving circuit 11 amplifies a radio
signal and outputs the demodulated video signal S1 to the signal
processing circuit 12, and outputs the received intensity signal S2
indicating the receiving field intensity of the amplified radio
signal to the sample hold circuit 15. The video data processed by
the signal processing circuit 12 is stored in the storage unit 13
by the controller C, and is displayed and output by the display
unit 14. The signal subjected to sample-hold by the sample hold
circuit 15 is converted into a digital signal by the A/D converter
16 to be fetched in the controller C, and the selection controller
C1 of the controller C selects a receiving antenna having the
largest receiving field intensity from among the receiving field
intensities received in the intensity receiving period described
later as the receiving antenna for the video signal period, and
sequentially selects the receiving antenna other than the selected
receiving antenna as the receiving antenna for the intensity
receiving period, and outputs it as the signal S4 which assumes the
respective receiving antenna numbers as the video-receiving-antenna
number information N2 and the intensity-receiving-antenna number
information N1 to the changeover controller SC. Here, the selection
controller C1 sets only the currently connected receiving antenna
A1 to An based on the signal S6 as the receiving antenna to be
changed over. Further, the controller C stores the receiving field
intensity in the intensity receiving period and the receiving field
intensity in the video receiving period in the storage unit 13
together with the video data in correspondence to the selected
receiving antenna. The stored receiving field intensity of each
receiving antenna is information for calculating the position of
the capsule endoscope 3 in the body when the video data is
received.
[0131] Here, the intensity receiving period and video receiving
period described above with reference to FIG. 5 and FIG. 29, that
is, the frame structure of a radio signal will be described and an
outline of a processing of selecting and changing over the
receiving antenna A1 to An will be described. A radio signal
transmitted from the capsule endoscope 3 is transmitted in unit of
frame, and as shown in FIG. 5, the frame is constituted of the
intensity receiving period as the additional part including
information for the receiving field intensity measurement and the
video signal period as the information body part including
information body. The intensity receiving period is a period
corresponding to the preamble signal period for receiving
adjustment. Further, the video signal period can contain a control
signal necessary for receiving the video signal in addition to the
video signal itself. The intensity receiving period and the video
receiving period may be provided as independent periods or may be
provided as overlapped periods.
[0132] Each frame is transmitted as shown in FIG. 29 and a
no-signal state may be between frames or each frame may be
continuously transmitted. A frame cycle TT for frame transmission
is short in an imaging area of interest or in an area where the
capsule endoscope 3 fast moves in consideration of effective
utilization of the battery of the capsule endoscope 3, and the
length of the frame cycle TT is flexibly adjusted.
[0133] As shown in FIG. 29, when the n-th frame (n) and the
(n+1)-th frame (n+1) are sequentially transmitted, other receiving
antenna (intensity receiving antenna) different from the receiving
antenna (video receiving antenna) for receiving in the video signal
period of the same frame (n) is changed over in the period ta
corresponding to the intensity receiving period of the frame (n)
and the video receiving antenna is changed over in the period tb
including the video receiving period and the period to the start of
the intensity receiving period of the next frame (n+1). Similarly,
the intensity receiving antenna is changed over in the video signal
period of the same frame (n+1) in a period ta' corresponding to the
intensity receiving period of the frame (n+1), and the video
receiving antenna is changed over in a period tb' including the
video receiving period and the period to the start of the intensity
receiving period of the next frame (n+2).
[0134] The intensity detection processing is performed by the
sample hold circuit 15 and the A/D converter 16 at timing t1, t1'
during the intensity receiving period of the frame (n) and the
frame (n+1), and the result thereof is output to the selection
controller C1. When fast changeover of the receiving antenna or
fast receiving field intensity measurement processing is possible,
a plurality of intensity receiving antennas may be changed over in
the intensity receiving period to measure a plurality of receiving
field intensities. For example, as shown in FIG. 29, the receiving
field intensity may be sequentially measured at timings t2 and t3
after timing t1, and the receiving field intensity may be
sequentially measured at timings t2' and t3' after timing t1'.
[0135] Here, the antenna changeover processing procedure will be
described with reference to a flowchart shown in FIG. 30. In FIG.
30, the selection controller C8 first detects the connection state
of the connector CON1 to CONn based on the signal S6 (step S201).
Thereafter, the receiving antenna A1 to An corresponding to the
connected connector CON1 to CONn is set as the intensity receiving
antenna (step S202). Thereafter, the receiving field intensity of
each set intensity receiving antenna is measured (step S203), and
an intensity receiving antenna having the largest receiving field
intensity is set as the video receiving antenna (step S204).
Thereafter, the video signal for one frame is received by the video
receiving antenna (step S205).
[0136] Thereafter, it is determined whether the connection state of
the connector CON1 to CONn has changed (step S206). If the
connections state has changed (step S206, YES), the processing
proceeds to step S202, where the receiving antenna connected after
the change is reset as the intensity receiving antenna and the
above processing is repeated. On the other hand, if the connection
state has not changed (step S206, NO), the processing proceeds to
step S203, where the above processing is repeated to perform the
changeover processing to the optimum video receiving antenna.
[0137] For example, there will be considered a case where as shown
in FIG. 31A, there are the receiving antennas A1 to A6
corresponding to six arrangement positions "1" to "6", each
receiving antenna A1 to A6 comprises the connector CON1 to CON6,
respectively, the connectors CON1 to CON4 are connected to the
corresponding connecting portions of the connecting unit CON,
respectively, and the connectors CON5 and CON6 are not connected
thereto. In this case, since it is detected that only the receiving
antennas A1 to A4 are connected, the receiving antennas A1 to A4
are set as the intensity receiving antennas, and the video
receiving antenna having the largest receiving field intensity is
selected from among the receiving antennas A1 to A4.
[0138] Thereafter, when the connectors CON1 and CON2 are
disconnected and the connectors CON5 and CON6 are newly connected
as shown in FIG. 31B, the selection controller C1 sets only the
receiving antennas A3 to A6 as the intensity receiving antennas,
and an intensity receiving antenna having the largest receiving
field intensity is selected as the video receiving antenna from
among the intensity receiving antennas.
[0139] Since the eighth embodiment is constituted so that only the
connected receiving antennas A1 to An out of the connector CON1 to
CONn are set as the intensity receiving antennas, the time to
measure the receiving field intensity for all the intensity
receiving antennas is reduced, thereby reducing the time for the
antenna changeover processing. Particularly, when only the antenna
corresponding to the site to be observed in the body is connected
or the number of antennas to be used in a patient having small
stature is reduced, it is possible to securely acquire necessary
receiving images with simple changeover processing.
[0140] A ninth embodiment according to the present invention will
now be described. Although the aforementioned eighth embodiment is
constituted to comprise all the receiving antennas A1 to An
corresponding to the arrangement positions "1" to "6" and to select
the intensity receiving antenna based on the presence of the
connection with the corresponding connector CON1 to CONn, the ninth
embodiment is constituted so that only the receiving antennas
necessary for acquiring the antenna receiving field intensity, on
which the image receiving and the position calculation of the
capsule endoscope 3 are based, are connected to reduce the number
of receiving antennas A1 to An so that a reduced number of
receiving antennas are reused to efficiently acquire the receiving
image and the antenna receiving field intensity. For example, there
is constituted so that the antenna at the position unnecessary for
the receiving is replaced and reused at a position necessary for
the receiving along with the movement of the capsule endoscope 3 in
the body.
[0141] In other words, the structures of the connectors CON1 to
CONn of the receiving antennas A1 to An are made identical and the
connector CON1 to CONn is made possible to be connected to the
connecting portion of any arrangement position so that a minimum
number of receiving antennas are used.
[0142] As shown in FIG. 32A, the receiving antennas A1 to A4 are
arranged at the positions corresponding to the arrangement
positions "1" to "4" where the receiving image would be acquired
and the connectors CON1 to CON4 are connected to the corresponding
connecting portions. Consequently, the receiving antennas A1 to A4
are set as the intensity receiving antennas so that a desired
receiving image and the receiving field intensity of each antenna
can be obtained by a minimum number of receiving antennas and with
simple changeover processing.
[0143] From the arrangement state shown in FIG. 32A, when the
receiving images corresponding to other arrangement positions "3"
to "6" are to be obtained, aerial portions of the receiving
antennas arranged at the arrangement positions "1" and "2" are
moved to the portions corresponding to the arrangement positions
"5" and "6" and the connectors CON1 and CON2 are instead connected
to the connecting portions of the connectors CON5 and CON6,
respectively (FIG. 32B). In this manner, the four receiving
antennas can be reused to function as the six receiving antennas.
Also in this case, the number of intensity receiving antennas is
not increased and the changeover processing can be performed by a
minimum number of receiving antennas. Further, the time for the
intensity receiving antenna changeover processing is reduced,
thereby rapidly and securely selecting the optimum video receiving
antenna. Furthermore, the number of antennas to be mounted on a
patient at one time can be reduced, thereby reducing a load on the
patient.
[0144] Since the connectors CON1 to CONn correspond to the
arrangement positions of the receiving antennas A1 to An in the
aforementioned eighth end ninth embodiments, if the connection
changes, the changeover information is recorded in correspondence
to the receiving image to be used as index information indicating
the position of the receiving image.
[0145] Since the antenna can be replaced, the antenna at the
position unnecessary for the receiving is replaced and reused at a
position necessary for the receiving along with the movement of the
capsule endoscope in the body, thereby obtaining the necessary
receiving image and the antenna receiving field intensity on which
the position calculation of the capsule endoscope is based by a
small number of antennas.
[0146] The structures described in the aforementioned eighth and
ninth embodiments are applicable to the aforementioned first to
seventh embodiments. In this case, the selection controller C1, C3
to C7 may control as the selection controller C8.
[0147] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *