JP2006305322A - Capsule endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capsule endoscope system capable of obtaining an appropriate exposure value in an imaging device without setting a light detecting device, a light volume recording device, a comparator or the like in a capsule endoscope. <P>SOLUTION: An image signal output from an image sensor 213 of the capsule endoscope 1 is transmitted from a transmitting antenna 23b, and received by a receiving antenna 33a of an external unit 30. A signal processing circuit 303 of the external unit 30 selects a luminance signal from the received image signal. A light volume control signal generating circuit 305 compares the luminance signal to a set value, and generates a light volume control signal with parameters for getting the luminance signal close to the set value. The light volume control signal is transmitted from a transmitting antenna 33b, and received by a receiving antenna 23a of the capsule endoscope 1. A controller of the capsule endoscope 1 indicates a driver 216 to change a current value to be supplied with a LED 211 in response to the light volume control signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capsule endoscope that wirelessly transmits an image signal obtained by a capsule endoscope introduced into a body cavity of a subject to image an inside of the body cavity to an external unit installed outside the subject. Concerning the system.

  As is well known, there is an electronic endoscope system as a system for observing the inside of the digestive tract of a subject. This electronic endoscope system includes an electronic endoscope having a flexible tubular insertion portion in which an imaging device for imaging a subject is incorporated at the tip thereof, and an image signal output from the electronic endoscope. A processor device for performing processing and a monitor for displaying an image based on an image signal processed by the processor device are provided. When actually observing the digestive tract of a subject using such an electronic endoscope system, the insertion portion of the electronic endoscope is orally introduced into the body cavity (digestive tract) of the subject. It must be, but for the subject, the state where the tube constituting the insertion portion was inserted into the throat was very painful and unbearable.

  Therefore, in recent years, in order to eliminate the pain of the subject due to the insertion of the insertion part of the electronic endoscope into the throat, the subject swallows the body cavity (in the digestive tract) of the subject. A capsule endoscope system including a capsule endoscope to be introduced and an extracorporeal unit arranged outside the body of a subject has been developed.

  This capsule endoscope includes an illuminating device (light emitting diode) for illuminating the inside of a body cavity at the time of imaging.

By the way, not only a capsule endoscope but also an endoscope that takes an image of inside a body cavity, a mechanical shutter and a diaphragm are not incorporated in an imaging apparatus due to size restrictions. Therefore, in order to obtain an appropriate exposure value, a method of adjusting the amount of illumination light in the illumination device is taken.
JP-T-2004-535878

  As one of the methods of autonomous exposure adjustment (illumination light adjustment) in the capsule endoscope, the amount and intensity of the light reflected from the body wall in the capsule endoscope is detected as in the previous document. There is a technique in which a light detecting device is incorporated, the amount of light obtained therefrom is recorded, the value is compared with a certain threshold value, and if the value is exceeded, the light amount of the illumination device in the capsule endoscope is controlled.

  However, for capsule endoscopes where small size and light weight are important due to the method of introduction into the body cavity, by incorporating a light detection device, light quantity recording device, comparator, etc. required for these processes There are demerits such as an increase in capsule size and a complicated implementation. In addition, when applied to a disposable capsule endoscope as a countermeasure against infectious diseases, it is necessary to simplify the configuration and processing inside the capsule endoscope as much as possible to reduce the cost. It is hard to say that performing in a mirror is the best method.

  Therefore, the problem of the present invention is that it is not necessary to incorporate a light detection device, a light amount recording device, a comparator, and the like necessary for the above processing in the capsule endoscope. It is an object of the present invention to provide a capsule endoscope system that can obtain an appropriate exposure value in an imaging apparatus only by controlling from the outside of a mirror.

  The capsule endoscope system of the present invention devised to solve the above-described problems is obtained by using an image signal obtained by imaging a body cavity of a capsule endoscope introduced into a body cavity of a subject. A capsule endoscope system that wirelessly transmits to an extracorporeal unit installed outside the body of a subject, the capsule endoscope including a light emitting element and a driving circuit that supplies a driving current to the light emitting element, An objective optical system, an image sensor that outputs an image signal by capturing an image formed by the objective optical system, a transmission device that wirelessly transmits the image signal, a reception device that receives a control signal, and the reception A control circuit that controls the amount of drive current supplied to the light emitting element by the drive circuit in accordance with a control signal for light amount control received by the apparatus, wherein the extracorporeal unit includes the image Of a light quantity control that generates a control signal for light quantity control including a parameter corresponding to a difference between a luminance value indicated by an image signal received by the reception apparatus and a predetermined target value. And a transmission device that wirelessly transmits a control signal for controlling the amount of light.

  If comprised in this way, the image signal obtained when the image pick-up element imaged the image formed with the objective optical system of a capsule endoscope will be wirelessly transmitted by the transmitter. In the extracorporeal unit that has received this image signal by the receiving device, the control signal generation circuit for light amount control extracts the luminance value indicated by this image signal, and based on the difference between this luminance value and a predetermined target value, A control signal for light amount control including parameters for bringing the former closer to the latter is generated, and the transmission device wirelessly transmits the control signal for light amount control. In the capsule endoscope that has received the control signal for the light amount control by the receiving device, the control circuit controls the amount of drive current supplied to the light emitting element by the drive circuit according to the control signal for the light amount control. . Therefore, since the capsule endoscope does not require a light detection device, a light quantity recording device, a comparator, etc., the overall size and weight of the capsule endoscope can be reduced, and the configuration and processing inside the capsule can be reduced. Can be simple.

  In general, image (pixel) signals obtained from image sensors such as CCD and CMOS in video cameras, etc. are extracted from luminance and color difference signals through multiple stages of image processing circuits such as a matrix circuit, and then NTSC etc. Video signal. Therefore, in the present invention, the luminance value may be acquired based on the luminance signal extracted in the process of constructing the video signal in the extracorporeal unit.

  According to the capsule endoscope system of the present invention, it is not necessary to incorporate a light detection device, a light amount recording device, a comparator, and the like in the capsule endoscope. Nevertheless, an appropriate exposure value in the imaging apparatus can be obtained by controlling the driving circuit of the illumination apparatus from an extracorporeal unit arranged outside the capsule endoscope.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1

  The capsule endoscope system according to the first embodiment of the present invention is orally introduced into a body cavity of a subject and images the body cavity, and wirelessly transmits an image signal obtained by imaging the body cavity. The capsule endoscope 1 (see FIG. 1) to be transmitted and the image signal transmitted from the capsule endoscope 1 are received, and various control signals are sent to the capsule endoscope 1 to be examined. It is comprised from the extracorporeal unit 2 (refer FIG. 2) installed outside the person's body.

  FIG. 1 is a sectional view showing a longitudinal section along the central axis in order to represent the internal configuration of the capsule endoscope 1. In order to simplify the following description, the left side of FIG. 1 is defined as “front side” and the right side of FIG. 1 is defined as “rear side”.

  As shown in FIG. 1, the capsule endoscope 1 includes a cylindrical frame 20 that houses circuit components, an imaging unit 21 that is housed in the frame 20, a battery case 22, and these components. And a capsule 10 for protecting it in a liquid-tight manner.

  The capsule 10 includes a cylindrical barrel portion 101 whose rear end portion is semispherical and a hemispherical transparent cover 102 that is liquid-tightly fitted to the front end of the barrel portion 101. Therefore, the capsule 10 has a so-called capsule shape as a whole. The transparent cover 102 serves as a dome port that keeps the distance from the objective optical system 212 of the imaging unit 21 to the subject moderate.

  The battery case 22 is an insulator having a bottomed cylindrical shape whose diameter is slightly smaller than that of the frame 20. The battery case 22 houses the battery 220 in a space inside thereof, and is inserted into the frame 20 with its open end facing the imaging substrate 210. In this state, the outer peripheral surface of the battery case 22 is in contact with the inner peripheral surface of the frame 20. A receiving antenna 23 a (receiving device), a transmitting antenna 23 b (transmitting device), and a power switch circuit 24 are mounted on the rear end surface of the battery case 22.

  Further, a cathode contact portion 222 that is a spring-like electrode that contacts the cathode of the battery 220 is mounted on the bottom surface inside the battery case 22. The cathode contact portion 222 is electrically connected to the ground electrode of each circuit component described later via the power switch circuit 24. The power supply electrode of each circuit component is connected to the anode of the battery 220 through each circuit pattern, through the circuit pattern on the imaging substrate 210 (and the circuit pattern on the frame 20 and the circuit pattern on the battery case 22). Is conducting.

  The frame 20 is a cylindrical circuit board, and holds the imaging unit 21 and the battery case 22 inside thereof. A circuit pattern for relaying the wiring formed on the battery case 22 and the wiring on the imaging substrate 210 described later is printed on the inner peripheral surface of the frame 20.

  The imaging unit 21 is a unit that captures an image in a body cavity, and includes an objective optical system 212, a lens barrel 202, an imaging substrate 210, and a light emitting diode 211, an image sensor 213, and an LED mounted on the imaging substrate 210. It consists of circuit components such as a driver 214, a modem circuit 216, a controller 215, and the like.

  The lens barrel 202 is a frame for holding the objective optical system 212 and the light emitting diode 211 in the frame 20, and has a cylindrical shape whose radius is slightly smaller than that of the frame 20. The lens barrel 202 is fixed in the frame 20 so that the front end surface thereof is slightly recessed from the front edge of the frame 20. The lens barrel 202 has an objective lens holding hole 202a extending therethrough along the central axis thereof, and light emitting diode fixing holes 202b are formed in two point-symmetric positions with the objective lens holding hole 202a interposed therebetween. I'm leaning. A plurality of lenses constituting the objective optical system 212 are fitted into the objective lens holding hole 202a on the lens barrel 202, and a light emitting diode 211 is fitted into each light emitting diode fixing hole 202b.

  As each light emitting diode 211 as a light emitting element, a high luminance type light emitting diode that emits white light is used. Each light emitting diode 211 is connected to the imaging substrate 210 through a lead wire 2111 drawn through the light emitting diode fixing hole 202 b of the lens barrel 202, and is supplied from the imaging substrate 210 through the lead wire 2111. Light is emitted by the drive current.

  The objective optical system 212 is an optical system for connecting an image in the body cavity, and is fixed in the objective lens holding hole 202a of the lens barrel 202 so that its optical axis is coaxial with the central axis of the transparent cover 102. Has been.

  The image sensor 213 serving as an image sensor is an image sensor such as a CCD that photoelectrically converts an image formed on the image plane by the objective optical system 212 for each of the primary colors of RGB. A body cavity formed by the objective optical system 212 The image inside is converted into an image signal.

  The imaging substrate 210 has a flat cylindrical shape slightly smaller in diameter than the frame 20 and is coaxially bonded to the rear end surface of the lens barrel 202. Therefore, in a state where the imaging unit 21 is held inside the frame 20, the outer peripheral surface of the imaging substrate 210 is in contact with the inner peripheral surface of the frame 20. An image sensor 213 is mounted at the center of the surface of the imaging substrate 210 that is bonded to the lens barrel 202, and is connected to the light emitting diode 211 at each position overlapping the light emitting diode fixing holes 202 b of the lens barrel 202. A lead wire 2111 is connected. Various circuit components such as the light emitting diode 211, the image sensor 213, the LED driver 214, the modulation / demodulation circuit 216, and the controller 215 are mounted on the imaging substrate 210.

  Each LED driver 214 (hereinafter referred to as “driver 214” in the present specification) is a circuit that supplies a driving current to each light emitting diode 211 based on a power source from the battery 220, and a current value of the driving current. Alternatively, the amount of power supplied to each light emitting diode 211 during the unit time is increased or decreased by changing the voltage value or the drive current supply time during the unit time in the pulse-wise modulation.

  The controller 215 is a circuit that controls the capsule endoscope 1 as a whole, and in particular, power supplied to each driver 214 during a unit time based on a control signal for controlling the amount of light received from the extracorporeal unit 2. Control to change the amount. Note that the power of the capsule endoscope 1 may be supplied from the outside through electromagnetic waves instead of the battery 220.

  FIG. 3 is a block diagram showing an internal circuit of the capsule endoscope 1. As shown in FIG. 3, the modulation / demodulation circuit 216 includes a reception block 216a connected to the reception antenna 23a and a transmission block 216b connected to the transmission antenna 23b. The reception block 216a is provided with a reception amplifier 216a1 and a demodulation circuit 216a2. The transmission block 216b is provided with a modulation circuit 216b1 and a transmission amplifier 216b2.

  In FIG. 3, a signal received by the receiving antenna 23a (a signal obtained by modulating various control signals such as a control signal for controlling the amount of light to be described later on a carrier wave) is input to the receiving amplifier 216a1 in the receiving block 216a. The reception amplifier 216a1 amplifies the input signal and inputs the amplified signal to the demodulation circuit 216a2 in the reception block 216a. The demodulation circuit 216a2 demodulates various control signals modulated on the carrier wave, and inputs the demodulated various control signals to a controller 215 as a control circuit.

  The controller 215 executes various controls according to the input control signal. One of the controls is illumination light quantity control based on a control signal for light quantity control described later. That is, the content of the control signal for controlling the light amount includes a parameter that increases or decreases the light emission amount of each light emitting diode 211 by a unit amount, or a parameter that directly specifies the light emission amount of each light emitting diode 211. It is. When the content of the control signal for light quantity control is the former parameter, the controller 215 determines the amount of power supplied to each light emitting diode 211 during the unit time to the driver 214. An instruction to increase or decrease by a unit amount is given according to the content of the control signal for. Further, when the control signal for controlling the light amount is the latter parameter, the controller 215 determines the amount of power supplied to the light emitting diode 211 during the unit time to the driver 214 for the light amount control. An instruction to change to a value corresponding to the content of the control signal is given.

  A driver 214 as a drive circuit supplies a drive current having a current value corresponding to an instruction from the controller 215 to the light emitting diode 211. At this time, if the instruction from the controller 215 increases or decreases the drive current by the unit amount, the driver 214 increases or decreases the drive current that has been supplied to the light emitting diode 211 by the unit amount. Let If the instruction from the controller 215 is to change the current value of the drive current to a specific value, the driver 214 changes the current value of the drive current supplied to the light emitting diode 211 to the instructed value. .

  An image of the test object formed by the objective optical system 212 by the reflected light from the test object illuminated by the illumination light emitted from the light emitting diode 211 by the drive current supplied in this manner is captured by the image sensor 213. And converted into an image signal. This image signal is input to the modulation circuit 216b1 of the transmission block 216b. The modulation circuit 216b1 modulates the received video signal with a predetermined carrier wave. The signal modulated in this way is amplified by the transmission amplifier 216b2, and then transmitted through the transmission antenna 23b.

  2A and 2B are a front view and a rear view of the extracorporeal unit 2, respectively. As shown in these drawings, the extracorporeal unit 2 has a vest that the subject wears on the upper body. A large number of small receiving antennas 33a are distributed and attached at positions overlapping the abdomen and its periphery on the surface. In addition, a receiving module 30, a memory 31, and a battery 32 are attached to a position overlapping the chest on the surface. On the other hand, one transmission antenna 33b is attached to the rear surface. As the transmission antenna 33b, a transmission antenna having a wide directivity is used so that a signal can be received wherever the capsule endoscope 1 is located in the digestive tract. On the other hand, the receiving antenna 33a is distributed in a large number in a range where the signal can be received according to the reception status of the signal from the capsule endoscope 1 but the range in which the signal can be received is overlapped with the entire abdomen. Has been.

  FIG. 4 is a block diagram showing an internal configuration of the receiving module 30. As shown in FIG. 4, the receiving module 30 includes a receiving amplifier 301 connected to each receiving antenna 33a, a demodulating circuit 302 connected to the receiving amplifier 301, and a signal processing circuit connected to the demodulating circuit 302. 303, an information compression circuit 304 and a light amount control signal generation circuit 305 connected to the signal processing circuit 303, a modulation circuit 306 connected to the light amount control signal generation circuit 305, and a transmission connected to the modulation circuit 306, respectively. The amplifier 307 is configured.

  A signal (a signal obtained by modulating an image signal onto a carrier wave) received by any one of the reception antennas 33 a is amplified by the reception amplifier 301 and input to the demodulation circuit 302. The demodulation circuit 302 demodulates the image signal modulated on the carrier wave, and inputs the demodulated image signal (that is, a signal indicating the luminance distribution for each primary color of RGB) to the signal processing circuit 303.

  The signal processing circuit 303 separates the image signal into a luminance signal and a color difference signal by performing an RGB-YCC matrix operation on the image signals for each of RGB colors constituting the input image signal. Then, a video signal is generated based on the separated luminance signal and color difference signal and input to the information compression circuit 304, and only the luminance signal is input to the light amount control signal generation circuit 305.

  The information compression circuit 304 compresses the input video signal by performing a compression process such as MPEG on the input video signal, and stores it in the memory 31.

  On the other hand, the light quantity control signal generation circuit 305 sets the average value of the luminance of each entire frame of the video signal or a certain part in the frame as a specific range based on the luminance signal input from the signal processing circuit 303, The average value of luminance in the specific range portion of each frame is calculated. Then, the light amount control signal generation circuit 305 compares the average brightness value calculated in this way with a target value set in advance so that proper exposure can be obtained, and the former difference (difference = image) with respect to the latter. (Luminance indicated by the signal−predetermined target value) is calculated. Then, the light amount control signal generation circuit 305 calculates a light emission amount necessary for increasing or decreasing the average luminance value by this difference, and indicates a parameter corresponding to the light emission amount (a parameter corresponding to the difference, an image signal indicates). A parameter corresponding to the light emission amount necessary for canceling the difference between the luminance value and the predetermined target value) is input to the modulation circuit 306 as a light amount control signal. Alternatively, the light amount control signal generation circuit 305 may use a parameter (a parameter corresponding to the difference, a luminance value indicated by the image signal corresponding to the predetermined target value) to decrease the emitted light amount by a unit amount if the calculated difference is a positive value. A parameter indicating that the difference is positive), and a parameter indicating that the amount of emitted light is increased by a unit amount if the calculated difference is a negative value (a parameter corresponding to the difference, the luminance indicated by the image signal for a predetermined target value) A parameter indicating that the difference between the values is negative is input to the modulation circuit 306 as a control signal for light amount control.

  The modulation circuit 306 modulates the control signal for light amount control input by the light amount control signal generation circuit 305 with a predetermined carrier wave. The signal modulated in this way is amplified by the transmission amplifier 307 and then transmitted through the transmission antenna 33b.

  The operation of each part when photographing the subject's digestive tract using the capsule endoscope system of the present embodiment configured as described above is as follows. First, a subject wearing the extracorporeal unit 2 swallows the capsule endoscope 1 whose power is turned on by activating the power switch circuit 24 and introduces it into the stomach. At this time, the controller 215 instructs the driver 214 to supply the drive current to the light emitting diode 211 at a predetermined initial value when the power is turned on. In response to this instruction, the driver 214 supplies an initial value of drive current to the light emitting diode 211, so that the light emitting diode 211 emits light. In this way, the image sensor 213 images the body cavity illuminated by the illumination light emitted from the light emitting diode 211, and inputs an image signal obtained by the imaging to the transmission block 216b. Then, the image signal is modulated by the modulation circuit 216b1, amplified by the transmission amplifier 216b2, and transmitted from the transmission antenna 23b.

  When the capsule endoscope 1 enters the reception area of one of the reception antennas 33a of the extracorporeal unit 2 (that is, inside the stomach), this image signal is received by the reception antenna 33a and amplified by the reception amplifier 301. Then, it is demodulated by the demodulation circuit 302, converted into a video signal by the signal processing circuit 303, compressed by the information compression circuit 304, and stored in the memory 31. At the same time, only the luminance signal is extracted from the image signal by the signal processing circuit 303 and input to the light quantity control signal generation circuit 305. The light amount control signal generation circuit 305 sets the luminance average value of the entire frame or a certain part of the frame as a specific range for each frame constituting the image signal, and calculates the luminance average value of the specific range portion of each frame. The control signal for the light quantity control having the above-described content is generated. The control signal for controlling the amount of light is modulated by the modulation circuit 306, amplified by the transmission amplifier 307, and transmitted from the transmission antenna 33b. Since the area that can receive the signal from the transmission antenna 33b includes the reception area of each reception antenna 33a, the amount of light is received by the reception antenna 23a of the capsule endoscope 1 that exists in the reception area of any of the reception antennas 33a. A control signal for control is received.

  The control signal for controlling the amount of light is amplified by the reception amplifier 216a1, demodulated by the demodulation circuit 216a2, and input to the controller 215. Based on the control signal for controlling the light amount, the controller 215 instructs the driver 214 to increase or decrease the drive current supplied to the light emitting diode 211 (or to the light emitting diode 211 as described above). (Instruction to increase or decrease the length of the period during which the drive current is supplied during unit time).

  By repeating the feedback control via wireless communication between the capsule endoscope 1 and the extracorporeal unit 2 as described above, the average luminance value calculated in the light amount control signal generation circuit 305 substantially matches the target value. It becomes like this. In other words, the amount of illumination light emitted from the light emitting diode 211 is automatically adjusted so that the image sensor 213 can obtain appropriate exposure.

  Thereafter, even if the object to be imaged by the capsule endoscope 1 is a part having a low reflectance or a part having a high reflectance, the image sensor 213 can always obtain appropriate exposure by the feedback control described above. .

  By continuing the imaging as described above, the video signal obtained by the imaging is accumulated in the memory 31. Then, after the capsule endoscope 1 passes through the target site, or after the capsule endoscope 1 stops operating, the video signal is read from the memory 31 and a moving image based on the video signal is displayed on the monitor. By displaying, the doctor can make a diagnosis.

  According to the present embodiment described above, the light emission amount of the light-emitting diode for obtaining proper exposure is autonomously calculated inside the capsule endoscope 1 introduced into the body cavity (in the digestive tract) of the subject. Therefore, the size and weight of the entire capsule endoscope 1 can be reduced.

Embodiment 2

  In the capsule endoscope system according to the second embodiment of the present invention, the light amount control signal generation circuit 305 of the reception module 30 generates a control signal for light amount control as compared with the first embodiment described above. The process is different. That is, in the first embodiment described above, the reference value that the light intensity control signal generation circuit 305 compares with the average luminance value received from the signal processing circuit 303 is a single value having no width, but the lower limit value and the upper limit value. In the second embodiment, a value having a predetermined width may be used.

  Hereinafter, the flow of control in the receiving module 30 according to the second embodiment will be described with reference to the flowchart of FIG.

  As shown in FIG. 4, when a frame of a new image signal is received through the reception antenna 33a, the reception amplifier 301, and the demodulation circuit 302 (S1), the signal processing circuit 303 is the same as in the case of the first embodiment described above. A luminance signal is extracted from the frame and input to the light quantity control signal generation circuit 305 (S2).

  Based on the luminance signal input from the signal processing circuit 303, the light amount control signal generation circuit 305 sets an average value of luminance in the entire frame of the video signal or a part of the frame in advance as a specific range, The average value of the luminance in the specific range portion is calculated. The light quantity control signal generation circuit 305 first compares the brightness average value calculated in this way with the lower limit value of the target value (S3). When the average brightness value is below the lower limit value, a parameter indicating that the amount of emitted light is increased by a unit amount (or a parameter corresponding to the difference, or a difference between the brightness values indicated by the image signal with respect to a predetermined target value). (Parameter indicating negative) is generated (S4), and the generated parameter is input to the modulation circuit 306 as a control signal for light quantity control (S7).

  On the other hand, when the average luminance value is equal to or greater than the lower limit value, the light quantity control signal generation circuit 305 next compares the average luminance value with the upper limit value of the target value (S5). When the average brightness value exceeds the upper limit value, a parameter indicating that the amount of emitted light is decreased by a unit amount (or a parameter corresponding to the difference, or a difference between the brightness values indicated by the image signal with respect to a predetermined target value). (Parameter indicating positive) is generated (S6), and the generated parameter is input to the modulation circuit 306 as a control signal for light quantity control (S7).

  On the other hand, when the luminance average value is equal to or lower than the upper limit value, the amount of illumination light is appropriate, and the light amount control signal generation circuit 305 does not generate any control signal for light amount control.

  Since other configurations and operations in the second embodiment are the same as those in the first embodiment described above, description thereof will be omitted.

The longitudinal cross-sectional view of the capsule endoscope which is embodiment of this invention Front view (A) and rear view (B) of extracorporeal unit Block diagram showing the internal circuit of the capsule endoscope Block diagram showing the internal circuit of the extracorporeal unit The flowchart which shows operation | movement of the external unit in 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capsule endoscope 2 External unit 23a Reception antenna 23b Transmission antenna 30 Reception module 33a Reception antenna 33b Transmission antenna 211 Light emitting diode 213 Image sensor 214 LED driver 215 Controller 216 Modulation / demodulation circuit 216a Reception block 216b Transmission block 302 Demodulation circuit 303 Signal processing circuit 305 Light quantity control signal generation circuit 306 Modulation circuit

Claims (7)

A capsule endoscope system that wirelessly transmits an image signal obtained by imaging a capsule cavity introduced into a body cavity of a subject to an external unit installed outside the body of the subject. And
The capsule endoscope is:
A light emitting element;
A drive circuit for supplying power to the light emitting element;
An objective optical system;
An image sensor that outputs an image signal by capturing an image formed by the objective optical system;
A transmission device for wirelessly transmitting the image signal;
A receiving device for receiving the control signal;
A control circuit for controlling the amount of power per unit time supplied to the light emitting element by the drive circuit in response to a control signal for light amount control received by the receiving device;
The extracorporeal unit is
A receiving device for receiving the image signal;
A control signal generation circuit for light amount control for generating a control signal for light amount control including a parameter corresponding to a difference between a luminance value indicated by the image signal received by the receiving device and a predetermined target value;
A capsule endoscope system comprising: a transmission device that wirelessly transmits a control signal for controlling the amount of light. The control signal for the light amount control includes a parameter corresponding to a light emission amount necessary for canceling a difference between a luminance value indicated by the image signal and the predetermined target value,
The control circuit controls the power amount per unit time supplied to the light emitting element by the drive circuit to be a power amount per unit time corresponding to the light emission amount. Capsule endoscope system. The control signal for the light amount control includes a parameter indicating whether a difference in luminance value indicated by the image signal with respect to the predetermined target value is positive or negative,
The control circuit reduces the amount of power per unit time that the drive circuit supplies to the light emitting element if the difference is positive, while the unit that the drive circuit supplies to the light emitting element if the difference is negative The capsule endoscope system according to claim 1, wherein the drive circuit is controlled to increase an amount of electric power per hour. The predetermined target value is a value having a certain width between a predetermined lower limit value and an upper limit value, and the control signal for the light amount control is such that the luminance value indicated by the image signal is lower than the lower limit value. If it is low, it indicates that the difference between the two is negative, and if the luminance value indicated by the image signal is higher than the upper limit value, it indicates that the difference between the two is positive.
The control circuit increases the power supplied to the light emitting element by the drive circuit when the control signal for the light amount control indicates that the difference is negative, while the control signal for the light amount control 2. The capsule according to claim 1, wherein when the control signal indicates that the difference is positive, the drive circuit is controlled to reduce power supplied to the light emitting element by the drive circuit. Endoscope system. The control signal for the light amount control includes a parameter corresponding to a light emission amount necessary for canceling a difference between a luminance value indicated by the image signal and the predetermined target value,
The control circuit controls the supply period in which the drive circuit supplies power to the light emitting element during a unit time so as to be a supply period corresponding to the light emission amount. Capsule endoscope system. The control signal for the light amount control includes a parameter indicating whether a difference in luminance value indicated by the image signal with respect to the predetermined target value is positive or negative,
If the difference is positive, the control circuit reduces a supply period in which the drive circuit supplies power to the light emitting element during unit time, while if the difference is negative, the drive circuit causes the light emitting element to The capsule endoscope system according to claim 1, wherein the drive circuit is controlled so as to increase a supply period during which power is supplied during unit time. The predetermined target value is a value having a certain width between a predetermined lower limit value and an upper limit value, and the control signal for the light amount control is such that the luminance value indicated by the image signal is lower than the lower limit value. A low value indicates that the difference between the two is negative, and a luminance value indicated by the image signal is higher than the upper limit value indicates that the difference between the two is positive.
The control circuit increases a supply period for supplying power during a unit time that the drive circuit supplies to the light emitting element when the control signal for controlling the light amount indicates that the difference is negative. On the other hand, when the difference from the upper limit value is positive, the drive circuit is configured to reduce the supply period for supplying power during the unit time that the drive circuit supplies the light emitting element. The capsule endoscope system according to claim 1, wherein the capsule endoscope system is controlled.