JP2002345743A - Capsule endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a long-time photography and to reduce size in a capsule endoscope. SOLUTION: This capsule endoscope comprises an LED light source 1 for emitting illuminating light; an image processing unit for taking the reflected image generated from a living body observation part taken by irradiation, converting it to a digital value to generate image data, and further radio transmitting the generated image data; an optical system 3 consisting of a condenser lens and the like for imaging the reflected image on the image processing unit 2; and a battery 5 for supplying power to the LED power source 1 and the image processing unit 2, which are housed in a casing 6. The image processing unit 2 comprises a charge multiplier CCD image pickup device, a driver for driving the CCD, a processing circuit for processing the image data, and a transmitting circuit for radio transmitting the image data, which are arranged on the same board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capsule endoscope which is inserted into a human body to image a living body observation section in the human body.

[0002]

2. Description of the Related Art A capsule endoscope is composed of a light source such as an LED,
A solid-state imaging device such as a CD, a processing system for processing signal charges obtained in the solid-state imaging device to obtain image data, a transmission system for wirelessly transmitting an electric signal to the outside, a light source, a solid-state imaging device, a processing system, and a transmission system Has a power supply for driving the
These are configured by being arranged in a capsule-shaped casing (for example, “A Randomized Trial Comparing W
ireless Capsule Endoscopy With Push Enteroscopy fo
re the Detection of Small-Bowel Lesions, Mark Appl
eyard et al., Rapid Communications, GASTROENTEROLOGY 20
00; 119: 1431-1438 "). Such a capsule endoscope is inserted into a human body, and image data obtained by imaging is wirelessly transmitted by a transmission system, received by a receiving device outside the body, and displayed as a visible image on a monitor.

Since such a capsule endoscope is inserted into a human body without light, if the amount of illumination light is not sufficient, the S / N of an obtained image is deteriorated. For this reason, in the capsule endoscope, a high-output light source is used to irradiate the observation unit with a sufficient amount of illumination light for photographing. Here, since a light source capable of emitting high-power illumination light consumes a large amount of power, it is necessary to use a power supply having a relatively large capacity to drive such a light source.

[0004]

However, when the capacity of the power supply is increased, the size of the power supply also increases. here,
Since the capsule endoscope is inserted into the human body and cannot be increased in size, it is difficult to increase the size of the power supply, that is, the capacity, and it is only possible to use a power supply having a certain capacity. Can not.
As described above, in the capsule endoscope, although the capacity of the power supply is limited, it is necessary to irradiate the observation unit with high-intensity illumination light. There is a problem that it cannot be observed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a capsule endoscope capable of performing photographing for a long time.

[0006]

According to the present invention, there is provided a capsule endoscope comprising: a light source for irradiating an observation unit with illumination light; and a charge multiplier for imaging a reflection image obtained in the observation unit by irradiation of the illumination light. Solid-state imaging device, a driving unit that drives the solid-state imaging device, a processing unit that processes output signals obtained in the solid-state imaging device to obtain image data, and a transmission unit that wirelessly transmits the image data, A power supply that supplies power to the solid-state imaging device, the driving unit, the processing unit, the transmission unit, and the light source;
And a capsule-type housing that houses the driving unit, the processing unit, the transmitting unit, the light source, and the power supply.

The charge multiplying type solid-state image pickup device multiplies the imaged signal charge by a multiplication factor based on a multiplication factor control signal as described in, for example, Japanese Patent Application Laid-Open No. 7-176721. In addition, by mounting this solid-state imaging device on various imaging devices, it is possible to improve the imaging sensitivity of the imaging device and control the imaging sensitivity. That is,
Even if the light amount of the optical image is insufficient for imaging using a conventional imaging device, if imaging is performed using this solid-state imaging device, it can be displayed as a visible image, and It is also possible to appropriately control the imaging sensitivity according to the imaging conditions. A charge multiplying type solid-state imaging device having such a charge multiplying means is a CMD (Charge Multiplying).
Detector) -CCD, which collides electrons and atoms in a strong electric field region, multiplies signal charges by a charge multiplication effect generated by this ionization, and improves the imaging sensitivity of the imaging device.

In the charge multiplying type solid-state image pickup device, the charge multiplying means multiplies the signal charge in a stage preceding the charge detection circuit which sequentially converts the signal charge into a signal voltage and takes it out as an output signal. The S / N of the output signal can be improved without multiplying the read noise generated in the circuit. Therefore, by using the charge multiplying solid-state imaging device, it is possible to improve the S / N of an output signal in an imaging device that may perform imaging in an environment where the amount of optical image is insufficient. Further, since the multiplication factor of the signal charge can be changed by the multiplication factor control signal, the imaging sensitivity equipped with the charge multiplication type solid-state imaging device can be controlled.

An endoscope apparatus using such a charge multiplying solid-state imaging device is disclosed in Japanese Patent Application Laid-Open No. 2001-29313.

Here, in the capsule endoscope according to the present invention, at least the solid-state imaging device, the driving means,
It is preferable that the processing unit and the transmitting unit are provided on the same substrate.

In the capsule endoscope according to the present invention, the solid-state imaging device may be a CCD imaging device or a MOS imaging device.

[0012]

According to the present invention, since the reflected image is picked up by using the charge multiplying solid-state image pickup device, even if the amount of illumination light is weak, the signal charge obtained by the picking up can be reduced. You can multiply and improve the shooting sensitivity,
Even if the power consumption of the light source is reduced, the S / N of the image data can be improved. Therefore, since a light source having a small output can be used, a longer-time shooting can be performed using a power supply having a limited capacity. In addition, since the capacity of the power supply can be reduced, the size of the power supply can be reduced, whereby the size of the capsule endoscope can be reduced. Further, the electric power can be used for other purposes such as position detection, posture detection, and posture control of the capsule endoscope, and thereby, the convenience of the capsule endoscope according to the present invention can be improved.

Further, by arranging at least the solid-state imaging device, the driving means, the processing means and the transmitting means on the same substrate, these can be made compact. Therefore, the size of the capsule endoscope can be further reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an internal configuration of a capsule endoscope according to an embodiment of the present invention. As shown in FIG. 1, a capsule endoscope according to an embodiment of the present invention includes an LED light source 1 that emits illumination light, captures a reflection image generated from a living body observation unit by irradiating the illumination light, and converts the reflected image into a digital value. An image processing unit 2 for generating image data and transmitting the generated image data wirelessly, an optical system 3 including a condensing lens for forming a reflected image on the image processing unit 2, and an LED light source 1. The image processing unit 2 and a battery 4 for supplying power to the image processing unit 2.
D light source 1, image processing unit 2, optical system 3, and battery 4
Are housed in a capsule-shaped casing 5. The front end 5A of the housing 5 is made of a transparent member so as to transmit the illumination light and the reflected image.

FIG. 2 is a schematic diagram showing the configuration of the image processing unit 2. As shown in FIG. 2, the image processing unit 2
Are obtained in the CCD image sensor 11 of the charge multiplication type, which captures a reflected image obtained in the living body observation section by irradiation of illumination light to obtain an output signal, the CCD driver 12 for driving the CCD image sensor 11, and the CCD image sensor 11. A CCD imaging device comprising: a processing circuit 13 for performing processing such as A / D conversion on the output signal obtained to obtain digital image data; and a transmission circuit 14 for wirelessly transmitting the image data obtained by the processing circuit 13. 11, a CCD driver 12, a processing circuit 13, and a transmission circuit 14 are provided on the same substrate 15.

FIG. 3 is a diagram showing the configuration of the CCD image sensor 11. As shown in FIG. 3, the CCD image sensor 11 is a frame transfer type CMD-CCD image sensor, and a light receiving unit 21 for converting a captured optical image into a signal charge.
A storage unit 22 for temporarily storing and transferring signal charges; a horizontal transfer unit 23 for performing horizontal transfer of signal charges; a charge multiplying unit 24 for multiplying signal charges based on an input multiplication control signal; An output unit 2 that changes the charge into a signal voltage, amplifies the signal voltage, and outputs the amplified signal to an image processing unit 2 from an output terminal 27.
5 is provided.

The light receiving section 21 is composed of n vertical transfer CCDs 31 and n ′ horizontal transfer CCDs for performing vertical conversion of photoelectric conversion and signal charges. For ease of explanation, FIG.
Describes a light receiving unit 21 composed of three vertical and four vertical transfer CCDs 31, but the actual CCD image pickup device 11 has hundreds of vertical transfer CCDs 31 both vertically and horizontally.
Is provided.

The storage section 22 is composed of a vertical transfer CCD 33 which is light-shielded by a thin metal film or the like and temporarily stores signal charges and performs vertical transfer. Horizontal transfer unit 23
Comprises a horizontal transfer CCD 35.

The charge multiplying unit 24 includes m charge multiplying cells 3
6. The signal charges input to the charge multiplying unit 24 are sequentially transferred while being multiplied based on a multiplication control signal which is a continuous pulse signal. The charge multiplication cell 36 collides electrons and atoms in a strong charge region, and uses a charge multiplication effect generated by ionization to
The input charge is multiplied and output, and the multiplication factor changes according to the signal characteristics of the multiplication control signal. In FIG. 3, the storage unit 22, the horizontal transfer unit 2
3 and the charge multiplying unit 24 are also simplified and described like the light receiving unit 21.

The output section 25 includes a charge detection section 37 for converting a signal charge into a signal voltage (output signal) and an output amplifier 38 for amplifying the output signal.

The CCD driver 12 is a CCD image pickup device 1
1 to output an operation control signal for controlling the operation timing and a multiplication factor control signal for controlling the multiplication factor in the charge multiplication section 24. By outputting a gain control signal having a desired peak value set by the user,
The charge multiplication factor in the charge multiplication unit 24 can be controlled.

The processing circuit 13 performs processing and A processing on the output signal obtained by the CCD image pickup device 11.
/ D conversion into digital image data.

Next, the operation of this embodiment will be described. The endoscope according to the present embodiment is inserted into a human body in a state where the LED light source 1 is driven, and an LED is provided on a living body observation unit in the human body.
Illumination light emitted from the light source 1 is applied. The reflected image obtained in the living body observation unit by the irradiation of the illumination light is formed on the CCD image sensor 11 of the image processing unit 2 via the optical system 3.

In the CCD image sensor 11, the light receiving section 2
The reflected image is received by one vertical transfer CCD 31 and photoelectrically converted to an electric signal corresponding to the intensity of the light.
The signal charges stored in the vertical transfer CCD 31 are stored in the storage section 2
2 is transferred to the vertical transfer CCD 33. The signal charges transferred to the vertical transfer CCD 33 of the storage unit 22 are vertically transferred in parallel and sequentially sent to the horizontal transfer CCD 35 of the horizontal transfer unit 23.

In the horizontal transfer section 23, when the signal charges of the pixels in one horizontal line are input, the signal charges are transferred in the horizontal direction and sequentially transferred to the charge multiplying cells 36 of the charge multiplying section 24. In the charge multiplication cell 36, the signal charges are sequentially transferred while being multiplied based on the multiplication factor control signal. The signal charge output from the last charge multiplying cell 36 to the output unit 25 provided at the right end is converted into a signal voltage by the charge detection unit 37, amplified by the output amplifier 38, and output from the output terminal 27 as an output signal. Is output.

Thereafter, the signal charges of the next horizontal line are transferred from the storage unit 22 to the horizontal transfer unit 23. By repeating such an operation, signal charges are sequentially read out from the lower left pixel of the light receiving section 21 in the right direction. When the signal charges of one horizontal line are read out, the signal charges of one horizontal line thereon are next read. Are read out and sequentially moved, and all signal charges forming an image are read out to obtain an output signal.

The output signal output from the CCD image pickup device 11 is subjected to process processing in a processing circuit 13 and
It is converted into a digital signal by / D conversion and output as image data.

The image data output from the processing circuit 13 is wirelessly transmitted by the transmission circuit 14, received by an externally provided receiving device (not shown), and displayed as a visible image on a monitor.

As described above, according to the present embodiment, since the reflected image of the living body observation section is imaged using the charge multiplying type CCD image sensor 11, the illumination light emitted from the LED light source 1 Even if the amount of light is weak, the signal charge obtained by imaging can be multiplied to improve the photographing sensitivity, thereby improving the S / N of the image data even if the power consumption of the LED light source 1 is reduced. Can be done. Therefore,
Since the LED light source 1 having a small output can be used, longer-time shooting can be performed using the battery 4 having a limited capacity. In addition, since the capacity of the battery 4 can be reduced, a smaller battery 4 can be used, whereby the size of the capsule endoscope according to the present embodiment can be reduced. Further, the electric power can be used for other purposes such as position detection, posture detection, and posture control of the capsule endoscope, and thereby, the convenience of the capsule endoscope can be improved.

Further, the CCD image pickup device 11, the CCD driver 12, the processing circuit 13, and the transmission circuit 14 are mounted on the same substrate 1.
By arranging them on the device 5, they can be made compact. Therefore, the size of the capsule endoscope can be further reduced.

In the above embodiment, the image pickup is performed by using the charge multiplying type CCD image pickup device 11.
Imaging may be performed using a charge multiplication type MOS imaging device. In this case, a CCD can be used as the charge multiplying unit.

In the above embodiment, the CCD image pickup device 11, the CCD driver 12, the processing circuit 13, and the transmission circuit 14 are provided on the same substrate 15, but they may be provided on separate substrates. Good.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an internal configuration of a capsule endoscope according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of an image processing unit.

FIG. 3 is a diagram showing a configuration of a CCD image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED light source 2 Image processing unit 3 Optical system 4 Battery 5 Housing 11 CCD image sensor 12 CCD driver 13 Processing circuit 14 Transmission circuit 15 Substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H04N 5/225 H04N 5/225 C 5C055 5/335 5/335 Z 7/18 7/18 MF term ( Reference) 2H040 BA00 CA12 CA23 DA12 DA51 GA02 GA11 4C038 CC00 4C061 JJ20 LL01 5C022 AA09 AB67 AC42 AC61 AC73 AC77 5C024 BX02 CX41 CY42 CY48 EX22 GY01 GY44 HX46 5C054 AA01 CC02 CC07 CD12 CH02 DA07 EA01 FC02 EA01

Claims (4)

[Claims] A light source for irradiating an observation unit with illumination light; a charge multiplying solid-state imaging device for imaging a reflection image obtained in the observation unit by irradiation of the illumination light; A driving unit that processes an output signal obtained in the solid-state imaging device to obtain image data; a transmission unit that wirelessly transmits the image data; a solid-state imaging device; the driving unit; and the processing unit; A power supply that supplies power to the transmitting unit and the light source; and a capsule-type housing that houses the solid-state imaging device, the driving unit, the processing unit, the transmitting unit, the light source, and the power source. Characteristic capsule endoscope. 2. The capsule endoscope according to claim 1, wherein at least the solid-state imaging device, the driving unit, the processing unit, and the transmitting unit are provided on a same substrate. 3. The capsule endoscope according to claim 1, wherein the solid-state imaging device is a CCD imaging device. 4. The capsule endoscope according to claim 1, wherein the solid-state imaging device is a MOS imaging device.