Capsule endoscope and a capsule endoscope system

In a capsule endoscope illuminating units are disposed around an image capturing unit in such a manner that an optical axis of the illuminating units do not intersect with an optical axis of the observation unit, and illumination areas of the illuminating units overlap at substantially a central portion of an image capturing area of the image capturing unit.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The present invention relates to swallowable and capsule-shaped endoscopes and a capsule endoscope system.

2) Description of the Related Art

Swallowable and capsule-shaped endoscopes are known in the art. A patient swallows such a capsule endoscope and as the capsule endoscope passes through an abdominal cavity, it captures images of a stomach, intestines etc. An example of such a capsule endoscope is described below with reference toFIG. 9.

As shown inFIG. 9, the conventional capsule endoscope includes a watertight capsule casing8having a front cover5. The capsule casing8houses an image capturing unit1that captures images of an inside the abdominal cavity, an illuminating unit2that outputs a light to illuminate the inside of the abdominal cavity, a power-supply unit3that supplies power to the image capturing unit1and the illuminating unit2.

The illuminating unit2and the image capturing unit1are disposed near each other and they face toward a front side through the front cover5. The front cover5is partly or fully transparent so that when the illuminating unit2outputs the light, the light illuminates the inside of the abdominal cavity and the image capturing unit1can capture images of inside of the abdominal cavity.

The front cover5is semispherical, because, it is easier for a patient to swallow the capsule endoscope if the front cover5is semispherical, and body fluids can not remain on the front cover5if the front cover5is semispherical (see Japanese Patent Application Laid-open Publication No. 2001-95756).

However, the illuminating unit2disclosed in Japanese Patent Application Laid-open Publication No. 2001-95756 has problems as explained below. As shown inFIG. 10, when many illuminating units2are arranged around the image capturing unit1on a circle, light from all the illuminating units2overlap at a portion that is in front of the image capturing unit1and the portion where the lights overlap is brighter that the portion where there is no overlap.

Because of the unbalance in the brightness, the image quality of the images captured by the image capturing unit degrades and good diagnosis becomes difficult.

SUMMARY OF THE INVENTION

A capsule endoscope according to an aspect of the present invention has an observation unit that has a predetermined observation range and that observes inside of a body of a patient; and a plurality of illuminating units that output light and illuminate the observation range of the observation unit with the light output, wherein each of the illuminating units have a light distribution characteristics that deviates from a center of the observation range of the observation unit, and the lights output by the illuminating units are made to overlap at substantially a central portion of the observation range of the observation unit such that an intensity of the light at the central portion of the observation range is substantially equally to an intensity at a portion other than the central portion of the observation range.

A capsule endoscope according to an aspect of the present invention has an image capturing unit having an optical axis and a vision range and that captures an image of an inside of a body of a patient; and a plurality of illuminating units that output light and illuminate the vision range of the image capturing unit with the light output, wherein each of the illuminating units have a light distribution characteristics that deviates from the optical axis of the image capturing unit, and the lights output by the illuminating units are made to overlap at substantially a central portion of an observation range that is on a line that is an extension of the optical axis of the image capturing unit such that an intensity of the light at the central portion of the observation range is substantially equally to an intensity at a portion other than the central portion of the observation range.

A capsule endoscope according to still another aspect of the present invention includes an image capturing unit that acquires an image of a image capturing portion; and a plurality of illuminating units arranged around the image capturing unit in such a manner that illumination areas of a predetermined number of the illuminating units overlap in such a manner that an intensity of the light in the image capturing portion becomes substantially uniform.

DETAILED DESCRIPTION

Exemplary embodiments of a capsule endoscope and a capsule endoscope system according to the present invention are described below in detail with reference to the accompanying drawings.

FIG. 1is a schematic diagram of an internal structure of a capsule endoscope according to the present invention;FIG. 2is a schematic diagram of a capsule endoscope system;FIG. 3is a front view of a capsule endoscope according to one embodiment;FIG. 4is a schematic diagram for explaining emission of a light from an illuminating unit of the capsule endoscope shown inFIG. 3;FIG. 5is a schematic diagram to explain intensity of the light emitted from the illuminating unit of the capsule endoscope shown inFIG. 3.

FIG. 1is a schematic diagram of an internal structure of a capsule endoscope according to the present invention andFIG. 2is a schematic diagram of a capsule endoscope system

An overall internal structure of the capsule endoscope10is described by referring toFIG. 1. The capsule endoscope10includes a watertight capsule casing14. The capsule casing14includes a capsule trunk22that houses an image capturing unit11that captures images of an inside of an abdominal cavity, an illuminating unit12that outputs a light to illuminate the inside of the abdominal cavity, a power-supply unit13that supplies an electric power to both the image capturing unit11and the illuminating unit12.

The capsule casing14has a front cover20with a window20athat allows the light L output from the illuminating unit12to pass through but does not allow a reflected light of the light L to reach to the image capturing unit11. A rear cover23, if required, may be provided to the capsule trunk22. It is assumed that, the rear cover23is provided integrally with the capsule trunk and is flat, however, the rear cover may be dome-shaped.

The front cover20may be divided clearly into a window20afor illumination that allows light L from the illuminating unit12to pass through and a window20bfor image capturing through which the image capturing unit captures the images. Further, in the present embodiment, the whole of the front cover20is transparent and areas of the window20aand the window20bare partly overlapping.

The image capturing unit11is installed on an image capturing substrate24. The image capturing unit11includes a solid-state image sensor25and an image forming lens26. The solid-state image sensor25is, for example, a charged couple device (CCD), and captures images in the range that is illuminated by the light L. The image forming lens26includes a fixed lens26awhich forms an image of an object on the solid-state image sensor25and a movable lens26b. The image forming lens26forms a sharp image by being controlled by a focusing unit28. The focusing unit28includes a fixing frame28ato firmly hold the fix lens26aand a movable frame28bto movably hold the movable lens26b.

The image capturing unit11is not limited to the CCD, but may be a complementary metal-oxide semiconductor (CMOS).

The illuminating unit12is provided on an illuminating substrate30is, for example, a light emitting diode (LED). A plurality of the illuminating units12(four in the present embodiment) are disposed around the image forming lens26.

The power-supply unit13is installed on a power-supply substrate32that has an internal switch31. A button battery cell (hereinafter, “button cell”)33, for example, is used as a source of the power supply. It is assumed here that the button cell is a silver-oxide cell; however, the button cell may be a rechargeable cell, a dynamo cell, and the like.

It is assumed here that the internal switch31is a magnetic switch that can be made ON/OFF using a magnet.

A wireless unit42, which includes an antenna etc., for performing wireless communication with outside is installed on a wireless substrate41and performs communication with the outside according to the requirement.

A signal-processing and control unit43that processes and controls the various units mentioned above is installed on the image capturing substrate24and executes various processes in the capsule endoscope.

The signal-processing and control unit43includes an image-signal processing function of image-data generation etc. which includes correlated double sampling (CDS), for example, a transmission-signal generating function to perform mixing of an image signal and a synchronization signal (in a case of analog transmission) and addition of a mistake-correction sign (in a case of digital transmission), a modulation function to convert in cooperation with a modulator, to a phase-shift keying (PSK) modulation, a minimum-shift keying (MSK) modulation, a Gaussian minimum-shift keying (GMSK) modulation, a quadrature minimum-shift keying (QMSK) modulation, and an amplitude-shift keying (ASK) modulation format, for example, a power-supply control function to control the power supply according to ON-OFF operation of a switch, a timing-generator (TG) function to control a driver circuit like an LED driver circuit, a storage function to store various data like parameters of line and frame etc. and performs various signal processing and controls.

The signal processing may include image-data correction (white balance (WB) correction, γ correction, color processing, automatic gain control (AGC) etc.), analog-digital conversion (ADC), automatic exposure control function (AE), and the like.

FIG. 2is a schematic diagram of the capsule endoscope system50according to the present embodiment. The capsule endoscope system50uses the capsule endoscope10to check a patient.

The capsule endoscope system50includes, for example, the capsule endoscope10and its package51, a jacket53that is to be worn by a patient52, a detachable receiver54that can be detachably attached to the jacket53, and a work station55that processes information which is received in the receiver54.

Antennas56a,56b,56c, and56dwhich catch electric waves of image signals transmitted from the wireless unit42of the capsule endoscope10are installed in the jacket53and are provided to enable wireless communication or wired communication by a cable with the receiver54. Further, number of antennas installed in the jacket53is not limited to four and would be more so that the electric waves from the capsule endoscope10can be received properly.

The receiver54includes a display57that displays information necessary for observation (examination) and an input section58to input information necessary for observation (examination). Moreover, a CF (compact flash (registered trademark)) memory59that stores image data, is detachably mounted on the receiver54. Further, the receiver54is provided with a power-supply unit60that can supply power even while carrying and a signal processing and control section61that performs processing required for observation (examination). A dry battery cell, a lithium-ion secondary battery cell, nickel-hydrogen battery cell etc. are examples of the power-supply unit60and it may be a rechargeable battery cell as well.

The work station55has processing functions to perform diagnosis based on images of internal organs in a body of a patient which a doctor or a nurse has captured by the capsule endoscope10. This work station55is provided with a CF memory reader/writer61. It is not shown in the diagram but the receiver54and the CF memory reader/writer61have interfaces that can be connected to enable communication, and read and write the CF memory59.

Moreover, the work station55has a communication function for connecting to a network and via this network a medical examination result of the patient is stored in a database. Further, the work station55has a display62and inputs the captured image data of inside of the patient's body from the receiver54and displays images of internal organs etc. on the display62.

When carrying out the examination, the capsule endoscope10is taken out from the package51and the patient52swallows the capsule endoscope10. The capsule endoscope10passes through esophagus of the patient, advances to an abdominal cavity due to peristalsis of an alimentary canal cavity and captures images inside the abdominal cavity one after another.

The capsule endoscope10transmits, continuously or intermittently, the electric signals corresponding to the captured images via the wireless unit42. The antennas56ato56dreceive those electric signals and transmit them to the receiver54.

The receiver54stores the electric signals in the CF memory59in the form of captured image data. The operation of the receiver54is not synchronized with the start of image capturing of the capsule endoscope10, but, the start and the end of receiving are controlled by an operation of the input section58. Moreover, the captured image data may be still-image data that is captured at a plurality of frames per second for displaying them as moving images or may be normal video-image data.

When the observation (examination) of the patient52by the capsule endoscope10is completed, the CF memory59is taken out of the receiver54and inserted into the CF memory reader/writer61. The data in the CF memory59is transferred to the work station55. In the work station55, the data for each patient is stored and managed separately.

Thus, the captured image data of the inside of the abdominal cavity that is captured by the capsule endoscope10and stored by the receiver54is displayed as image data by the display62in the work station55. This enables to acquire data useful for physiological research and to make a diagnosis of a physical change caused by a disease of the entire alimentary canal in the human body including internal organs which are not accessible (like a small intestine) by an ultrasonic probe, endoscope etc.

The illuminating unit according to the present embodiment is shown inFIGS. 3 and 4.

Each illuminating unit12includes a light emitting body12a. Each light emitting body12ais tilted outward from a central axis C of the capsule endoscope20and tilted from a front side towards a back side so that a center of axis of the light L from each the light emitting bodies12ais inclined away from the central axis C. The central axis C passes through a center of an observation region, and it is also a center of the capsule trunk22of the capsule endoscope10shown inFIG. 1. It is assumed here that the optical axis of the image forming lens26of the image capturing unit11and the center axis C coincide; however, they need not coincide. If they do not coincide, the light emitting body12ais tilted outward from the optical axis of the image forming lens26from a front side towards a back side so that the optical axis of the image forming lens26functions as the center of the observation region.

Because the light emitting bodies12ain the illuminating units12are tilted in this manner, although there is an overlap of light in the central portion, the brightness at the central portion of the observation region and the portion other than the central portion of the observation region is substantially the same.

In other words, as shown inFIG. 5, when the illuminating units are disposed around the image capturing unit11, when brightness of the light L from the illuminating unit12is indicated by constant-light lines (amount of light is maximum where distance between the lines is small), the intensity of the light is adjusted such that central light towards an outer side of the capsule endoscope rather than central side of the illuminating unit12is high and the light that illuminates the central portion of the illuminating range of the light that is emitted from the light emitting body12ain the illuminating unit12is allowed to be incident in a different direction (hereinafter, “anisotropy factor of light”) such that the brightness of the light that illuminates the observation central portion of the illuminating range of the light from the light that is emitted from the light emitting body12ain the illuminating unit12is less than incident light that illuminates a portion excluding the illuminating range of the observation central portion of the illuminating range.

As a result, a brightness of the observation central portion of the illuminating range that is illuminated by the plurality of light emitting bodies12aand the brightness of the portion excluding the observation central portion of the illuminating range that is illuminated by a single light emitting body becomes same or substantially same.

According to the present embodiment, since the observation central portion of the illuminating range has a predetermined brightness because of an overlap of lights from the plurality (four in the present embodiment) of the light emitting bodies12a,12a,12a, and12aand in the portion other than the observation central portion of the illuminating range has substantially the same brightness as the brightness of the central portion, with merely the light emitting body12a, the overall illuminating range can be made to have a uniform brightness, thereby having balanced brightness. As a result, it is possible to provide the capsule endoscope that enables to capture a good diagnosis image with the image capturing unit.

Due to this, the amount of light of the light in a plane that is identical to a plane perpendicular to the central axis of the capsule endoscope is allowed to be roughly the same.

There is example drawback in the conventional capsule endoscope is that although the desired brightness can be acquired in the central portion, the desired brightness cannot be acquired in a portion other than the central portion.

If the power supply from the power-supply unit13is increased to obtain the desired brightness in a portion other than the central portion, then the central portion becomes brighter than desired, moreover, this also leads to increased power consumption.

For this, since by making an arrangement as in the present embodiment, the observation central portion of the illuminating range is allowed to acquire the desired brightness by using the plurality of light emitting sections and the portion excluding the central portion is allowed to acquire roughly the same or the same brightness as that of the central portion by using a single light emitting body, the central portion can acquire the desired brightness and an occurrence of a situation in which the portion other than the central portion cannot acquire the desired brightness can be avoided.

In other words, according to the present embodiment, in a case where the portion other than the central portion does not have the desired brightness, the central portion does not have the desired, brightness similarly. In such a case, when the power supply from the power-supply unit13is increased, the overall portion becomes bright. Therefore, the power supply can be used effectively and it is possible to prevent unnecessary power consumption as in the conventional case.

FIG. 6is a schematic diagram for explaining emission of a light from an illuminating unit of a capsule endoscope according to a second embodiment.

In the first embodiment shown inFIG. 4the light emitting bodies12ain the illuminating unit12are tilted. In the second embodiment, as shown inFIG. 6, the illuminating units12themselves are tilted by using a tilting member71such that the illuminating units12are inclined from front side towards back side in an outward direction from the central axis of the capsule endoscope.

A light emitting surface of the light emitting body12aand a light emitting surface of the illuminating unit12are parallel. Therefore, there is no change incorporated in a structure of the illuminating unit12. The existing illuminating units may be used and tilting is provided by the tilting member71. By tilting, the observation central portion of the illuminating range is allowed to acquire a predetermined brightness due to the light gathered from the plurality of light emitting sections and the illuminating range other than the central portion is allowed to acquire roughly the same or the same brightness as the predetermined brightness of the central portion by using a single light emitting section12a. Therefore, the overall illuminating range has a uniform brightness, thereby imparting balance of the brightness. As a result, it is possible to provide the capsule endoscope that enables to capture a good diagnosis image with the image capturing unit.

FIG. 7is a schematic diagram for explaining emission of a light from an illuminating unit of a capsule endoscope according to a third embodiment.FIG. 8is an enlarged view for explaining emission of a light from an illuminating unit of a capsule endoscope according to the third embodiment.

As shown inFIGS. 7 and 8, in the present embodiment, instead of tilting the illuminating unit12with an inbuilt light emitting body12aby using the tilting member71as in the second embodiment, a reflecting member72is provided on a back side of the illuminating unit12. A part of emitting light that is emitted from the illuminating unit12is caused to reflect from the reflecting member72, thereby changing orientation characteristics. Thus, a total of the light including reflected light and emerged light is allowed to have an anisotropy factor of light.

According to the present embodiment, not only the emerged light but also a part of the emerged light is caused to be reflected by using the reflecting member72on the back surface of the illuminating unit12. Therefore, there is not change incorporated in a structure of the illuminating unit12. The existing illuminating unit is used and the light is a total of the emerged light and the reflected light. An observation central portion of the illuminating range is allowed to acquire a predetermined brightness by the light gathered from the plurality of light emitting sections and the illuminating range other than the central portion is allowed to acquire roughly the same or the same brightness as the predetermined brightness of the central portion by using a single light emitting body12a. Therefore, the overall illuminating range has a uniform brightness, thereby imparting balance of the brightness. As a result, it is possible to provide the capsule endoscope that enables to capture a good diagnosis image with the image capturing unit.

Moreover, in the present embodiment, the image capturing unit11is disposed in the central portion and the illuminating units12are disposed around, and the number of the illuminating units12is not limited in particular.

Furthermore, in the present invention, the illuminating unit12is not to be disposed around the image capturing unit11restrictedly and any structure in which the plurality of illuminating units12is used to illuminate uniformly an image capturing range in the capsule endoscope can be used for the illuminating unit.

Thus, according to the present invention, it is possible to provide a capsule endoscope that enables to capture a good diagnosis image by allowing a uniform illumination of overall illuminating plane by light.

Moreover, since an illuminating range becomes uniform by using this capsule endoscope, a good image can be captured, and it is possible to provide a capsule endoscope system that enables to contribute to an improved diagnostic analysis.