JP2009066016A - Capsule endoscope capable of detecting extracorporeal discharge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a capsule endoscope that rapidly detects its extracorporeal discharge and outputs no radiowave after extracorporeal discharge. <P>SOLUTION: The capsule endoscope 1 includes an imaging device 112 for imaging the interior of a living body, and a radio transmitter 114 that performs the transmission of the image captured by the imaging device 112 to the outside of the living body, and further includes an extracorporeal discharge detector 117 for detecting the discharge of the capsule endoscope 1 to the outside by acceleration and a transmitting operation controller 120 for controlling the operation of the radio transmitter 114 upon the reception of the signal outputted from the extracorporeal discharge detector 117. The extracorporeal discharge detector 117 includes an acceleration sensor 118 and a free dropping judging device 119. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a capsule endoscope that acquires an image of an imaging target inside a living body.

  In recent years, in the field of endoscopes, diagnostic devices using swallowable capsule endoscopes have been proposed and put into practical use. After being swallowed from the subject's mouth for observation (examination), the capsule endoscope moves inside the living body, for example, the inside of an organ such as the stomach and the small intestine according to its peristaltic movement, It has a function of capturing an in-vivo image as it moves. As such a capsule endoscope, there is Pilcam · SB (registered trademark) of Given Imaging Inc., Israel.

  The capsule endoscope includes an imaging device such as a CCD / CMOS sensor, a wireless transmission device, a transmission antenna, and a power supply device such as a battery that supplies power to each device. Imaging by the imaging device is performed at a speed of 2 frames / second or 15 frames / second. Image data picked up by the image pickup device is modulated by the wireless transmission device, and transmitted from the transmission antenna to the outside of the body wirelessly. Imaging and wireless transmission are generally performed continuously for about 8 to 10 hours while the remaining battery capacity is present.

  Outside the body is an image display device having a receiving antenna, a demodulation circuit, and a display device. In the image display device, the reception antenna receives the radio wave transmitted by the transmission antenna in the capsule endoscope, the received data is demodulated by the demodulation circuit, and the demodulated image data is displayed on the display device.

  The captured image is wirelessly transmitted from the capsule endoscope to an external image display device using radio waves. Since fat, blood, skin, etc. exist in the middle of the transmission path, the attenuation of radio waves is greater than in air. Therefore, it is necessary to increase the radio wave output when the capsule endoscope transmits image data. For this reason, when the capsule endoscope is operated outside the body, it does not meet the regulations for wireless stations that can be operated without a license stipulated by the Radio Law of Japan (the regulations for weak wireless stations). Therefore, when the remaining capacity of the battery is present, that is, when the capsule endoscope is discharged from the body while the capsule endoscope is outputting radio waves, it is necessary to collect the capsule endoscope in the radio wave shielding bag. (Non-Patent Document 1).

  Further, Patent Document 1 discloses an apparatus in which a capsule endoscope that is swallowed by a patient and inspected inside the body is collected in a toilet bowl outside the body. In this device, the magnetic material forming the battery in the capsule is attracted and locked by the magnet provided at the tip of the rod of the collection tool, and is easily stored in the collection bag together with the collection tool. The endoscope can be collected.

  On the other hand, as a method for detecting that the capsule endoscope is discharged from the body, in Patent Document 2, the capsule incorporates an imaging element for performing a medical act of observation, a temperature sensor, and a medical device. After performing the action, the medical action is stopped and the standby mode is entered, and the temperature sensor detects whether the body is excreted outside the body by this standby mode, and activates the notification means by detecting the outside of the body, and notifies with a buzzer. In addition, the capsule can be reliably recovered without being lost.

In Patent Document 3, the capsule endoscope includes a battery, a control information detection circuit to which driving power is supplied from the battery, a system control circuit, a battery, a control information detection circuit, and a system control circuit. A drive control unit disposed in the control unit, and the drive control unit controls the drive of the control information detection circuit, the system control circuit, and the like based on the temperature detected by the temperature sensor unit, and has such a configuration. By providing, an in-subject introduction device such as a capsule endoscope that prevents inadvertent driving outside the subject, and a wireless in-subject information acquisition system using the in-subject introduction device are realized. ing.
JP 2004-267350 A (published September 30, 2004 (2004. 9.30)) JP 2004-261522 A (published September 24, 2004 (2004.24.24)) JP 2005-73888 A (published March 24, 2005 (2005. 3.24)) Given Imaging Diagnosis System Review Report, page 11 http://www.jaame.or.jp/kanren/sin_iryo/H19/70427giv.pdf

  However, since the capsule endoscope is normally discharged to the toilet, the collection is performed in a filthy environment and there is a risk of infection and the like. Usually, the subject is acting outside the hospital during the examination, and it takes time to carry the collection device during the examination. In addition, if a strong radio wave is output outside the body, it may cause malfunction of a medical device such as a pacemaker.

  In particular, the detection method of extracorporeal discharge using the temperature sensor disclosed in Patent Document 2 takes time for the heat in the capsule endoscope to diffuse after the extracorporeal discharge. In particular, since the capsule endoscope has a heat source such as an LED inside, there is a problem that discharge cannot be detected immediately.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is to quickly detect that it has been discharged from the body, and after the discharge from the body, the wireless transmission device is stopped and radio waves are not output. Therefore, there is no need to collect the capsule endoscope, and furthermore, since no radio wave is output outside the body, a capsule endoscope capable of detecting extracorporeal discharge without risk of malfunctioning peripheral medical devices and the like is realized. is there.

  In order to solve the above-described problem, the capsule endoscope according to the present invention includes an imaging device that images the inside of a living body, a wireless transmission device that performs processing for transmitting an image captured by the imaging device to the outside of the body, A capsule endoscope having an extracorporeal discharge detecting device that detects that the capsule endoscope is discharged from the body by acceleration, and controls the operation of the wireless transmission device in response to a signal output from the extracorporeal discharge detecting device And a transmission operation control device.

  According to the above configuration, by providing the extracorporeal discharge detection device, it is possible to automatically detect that the capsule endoscope has been discharged out of the body. Further, by providing the transmission operation control device, it is possible to automatically control the start / stop of the operation of the wireless transmission device. As a result, there is an effect that the radio wave output from the capsule endoscope can be automatically stopped.

In the capsule endoscope according to the present invention, it is preferable that the extracorporeal discharge detection device includes an acceleration sensor and a free fall determination device.

By providing the acceleration sensor in the extracorporeal discharge detection device, it is possible to detect that the capsule endoscope is in a free fall state. Since the detection of the free fall state by the acceleration sensor is normally performed within 1 second, the free fall state can be detected quickly. The extracorporeal discharge detection device detects that the capsule endoscope is discharged out of the body only when the capsule endoscope is in a free fall state. When the capsule endoscope is present in the intestine, it is not determined that the capsule endoscope is in a free fall state because it is in contact with the intestinal wall or is subjected to an external force by peristaltic movement. In this case, since the acceleration sensor outputs a signal different from that at the time of free fall, when the capsule endoscope is present in the intestine, it is not erroneously detected that the capsule sensor is discharged from the body.

  In the capsule endoscope according to the present invention, it is preferable that the free fall determination device determines whether or not the capsule endoscope is in a free fall state based on the acceleration measured by the acceleration sensor.

  By providing a free fall determination device for the capsule endoscope, the acceleration sensor can determine whether or not the capsule endoscope is in the free fall state based on the measured acceleration, and control the transmission operation of the signal The wireless transmission device can be controlled by sending it to the device.

  In the capsule endoscope according to the present invention, in the extracorporeal discharge detection device, the output terminal of the free fall determination device is preferably the output terminal of the extracorporeal discharge detection device.

  Since the output terminal of the free fall determination device is the output terminal of the extracorporeal discharge detection device, a signal output from the free fall determination device can be directly input to the transmission operation control device.

  In the capsule endoscope according to the present invention, it is preferable that the transmission operation control device generates a signal for operating the wireless transmission device until a predetermined time has elapsed after the capsule endoscope starts operating. .

  When the capsule endoscope passes through the upper digestive tract such as the esophagus and stomach, the capsule endoscope may be in a free fall state. In this case, when the capsule endoscope is discharged out of the body, it is possible to prevent the external body discharge detection device from erroneously detecting.

  In the capsule endoscope according to the present invention, the transmission operation control device operates the wireless transmission device after a predetermined time has elapsed and the extracorporeal discharge detection device detects a free fall state of the capsule endoscope. It is preferable to continue outputting a signal for stopping.

  Since the transmission operation of the wireless transmission device is stopped when the capsule endoscope is ejected outside the body, it is possible to prevent the capsule endoscope from outputting radio waves outside the body.

  In the capsule endoscope according to the present invention, it is preferable that when the wireless transmission device receives an operation stop signal from the transmission operation control device, the power supply is stopped.

  When the power supply to the wireless transmission device is stopped, the wireless transmission device is in an operation stop state. As a result, the wireless transmission device cannot transmit image data outside the body. It is also possible to prevent the capsule endoscope from outputting radio waves outside the body.

  In the capsule endoscope according to the present invention, it is preferable that the oscillation circuit included in the wireless transmission device stops oscillation after the extracorporeal discharge detecting device detects a free fall state of the capsule endoscope.

  When the oscillation of the oscillation circuit included in the wireless transmission device stops, the wireless transmission device enters an operation stop state. As a result, the wireless transmission device cannot transmit image data outside the body. It is also possible to prevent the capsule endoscope from outputting radio waves outside the body.

  In the capsule endoscope according to the present invention, it is possible to quickly detect that the capsule endoscope is discharged from the body. In addition, since the wireless transmission device is stopped and no radio wave is output after being discharged from the body, there is no need to collect the capsule endoscope. In addition, the capsule endoscope according to the present invention does not output radio waves outside the body, so there is no risk of malfunctioning of surrounding medical devices.

  The embodiment of the present invention is described below with reference to FIGS. 1 to 6 and Tables 1 to 4. That is, FIG. 1 is a block diagram showing a configuration of the capsule endoscope according to the present embodiment. FIG. 2 is a block diagram illustrating a configuration of the wireless transmission device. FIG. 3 is a diagram illustrating a configuration of an acceleration measurement portion of the acceleration sensor. FIG. 4 is a block diagram showing the configuration of the free fall determination device. FIG. 5 is a block diagram illustrating a configuration of the transmission operation control apparatus. FIG. 6 is a timing chart showing changes in signals of respective circuits in the transmission operation control apparatus. Table 1 is a truth table of RS-FF403. Table 2 shows the relationship between the voltage at the X input terminal 134, the output signals from the comparators 301 and 302, and the output signal from the AND gate 307. Table 3 shows the relationship between the voltage at the Y input terminal 135, the output signals from the comparators 303 and 304, and the output signal from the AND gate 308. Table 4 shows the relationship between the voltage at the Z input terminal 136, the output signals from the comparators 305 and 306, and the output signal from the AND gate 309.

  First, the configuration of the capsule endoscope 1 will be described with reference to FIG. The capsule endoscope 1 is formed by an outer wall 110. The capsule endoscope 1 includes a lens 111, an imaging device 112, an illumination device 113, a wireless transmission device 114, a transmission antenna 115, a battery 116, an extracorporeal discharge detection device 117, a transmission operation control device 120, and a power line 121. It is.

  The lens 111 plays a role of collecting on the surface of the imaging device 112 the light irradiated from the illumination device 113 and reflected by an organ in the living body. The imaging device 112 performs imaging of an organ in a living body, and a CCD or a CMOS sensor is used. The illumination device 113 irradiates the living body with light, and an LED is used.

  The wireless transmission device 114 is used for performing processing for transmitting image data captured by the imaging device 112 to the outside of the body. FIG. 2 is a diagram illustrating a configuration of the wireless transmission device 114. The wireless transmission device 114 includes an oscillation circuit 501, a modulation circuit 502, and a regulator 503. The oscillation circuit 501 is a circuit that generates a wireless transmission carrier wave and outputs it from an output terminal 511. In addition, the oscillation circuit 501 has a power supply terminal 512. The modulation circuit 502 receives the carrier wave generated by the oscillation circuit 501 from the carrier wave input terminal 517, receives transmission data (captured image data captured by the imaging device 112 in the capsule endoscope 1) from the data input terminal 519, and performs wireless transmission. The transmission data is modulated into an appropriate format (for example, FM modulation) and output from the output terminal 520. In addition, the modulation circuit 502 includes a power supply terminal 518. The regulator 503 is used to supply power with a stable voltage. The regulator 503 has an input terminal 513, an output terminal 514, and an EN terminal 515.

  The transmission antenna 115 is used to transmit the signal processed by the wireless transmission device 114 to the outside of the capsule endoscope 1. The battery 116 supplies power to each device inside the capsule endoscope 1, and a small button battery such as a silver oxide battery is used.

  The extracorporeal discharge detection device 117 is used to detect that the capsule endoscope 1 has been discharged out of the body, and includes an acceleration sensor 118 and a free fall determination device 119 inside. An output terminal 137 of the free fall determination device 119 is an output terminal of the extracorporeal discharge detection device 117.

  The acceleration sensor 118 is used to measure the magnitude of acceleration exerted on the capsule endoscope 1. Hereinafter, the acceleration sensor 118 will be described more specifically.

  When the capsule endoscope 1 is in a free-falling state when discharged from the body, the device inside the capsule endoscope 1 is in a weightless state in which no force is acting in any direction. When it becomes weightless, acceleration is not applied in any direction. Therefore, a free fall state can be detected by measuring acceleration using an acceleration sensor. In order to measure acceleration in an arbitrary direction, a three-axis acceleration sensor that measures acceleration in three directions orthogonal to each other is required (for example, Japanese Patent Laid-Open No. 6-34654 is known as such an acceleration sensor). . The triaxial acceleration sensor measures acceleration for each of three orthogonal axes (hereinafter, the respective axes are referred to as X axis, Y axis, and Z axis), and outputs the acceleration of each axis as an analog signal. Hereinafter, the configuration of the acceleration sensor will be described with reference to FIG.

  The acceleration sensor 118 has a pair of electrodes composed of a movable electrode 201 and a fixed electrode 202, and the fixed electrode 202 is fixed to the acceleration sensor 118. The movable electrode 201 is supported by the acceleration sensor 118 via an elastic body such as a spring 203. In this way, the capacitor 205 is formed by the movable electrode 201 and the fixed electrode 202. The capacity measurement circuit 204 measures the capacity of the capacitor 205 and outputs the measurement result as an analog signal.

  The free fall determination device 119 is used to determine whether or not the capsule endoscope 1 is in a free fall state based on the magnitude of acceleration output from the acceleration sensor 118. Hereinafter, the configuration of the free fall determination device 119 will be described more specifically.

  FIG. 4 is a block diagram showing the configuration of the free fall determination device 119. The free fall determination device 119 is a device that determines whether or not the capsule endoscope 1 is in a free fall state based on the triaxial acceleration measured by the acceleration sensor 118. The free fall determination device 119 inputs three analog signals representing the acceleration of each of the three axes and outputs one digital signal. If it is determined that the state is a free fall state, the H level is output. If it is determined that the state is not a free fall state, the L level is output. In the present specification, the digital signal hereinafter means a digital signal composed of binary values of H level and L level. In addition, although the structure of the free fall determination apparatus 119 is as above-mentioned, detailed operation | movement is mentioned later.

  The transmission operation control device 120 is used to stop the operation of the wireless transmission device 114 when the extracorporeal discharge detection device 117 detects the extracorporeal discharge of the capsule endoscope 1. The configuration of the transmission operation control device 120 will be described based on FIG. FIG. 5 is a block diagram illustrating a configuration of the transmission operation control device 120.

  The transmission operation control device 120 includes a timer 401, a two-input AND gate 402, and an RS flip-flop 403 (hereinafter referred to as RS-FF 403). The timer 401 is a circuit that outputs an L level until a certain time elapses from the start of operation and outputs an H level after a certain time elapses. The RS-FF 403 is a digital signal circuit for both input and output. The R terminal 412 and the S terminal 411 are input terminals, and the Q terminal 413 is an output terminal. In this apparatus, the R terminal 412 is grounded. Table 1 shows the truth table of RS-FF403.

  As shown in Table 1, when the L level is input to both the R terminal 412 and the S terminal 411 of the RS-FF 403 when the Q terminal 413 is outputting the L level, the Q terminal 413 is set to the L level. Output. When the L level is input to both the R terminal 412 and the S terminal 411 of the RS-FF 403 while the Q terminal is outputting the H level, the Q terminal 413 outputs the H level. That is, when the L level is input to both the R terminal and the S terminal, the state of the output terminal of the Q terminal does not change. When the L level is input to the R terminal 412 and the H level is input to the S terminal 411, the Q terminal 413 outputs the H level. When the H level is input to the R terminal 412 and the L level is input to the S terminal 411, the Q terminal 413 outputs the L level. When the H level is input to the R terminal 412 and the H level is input to the S terminal 411, the level output from the Q terminal 413 is not specified.

  The power line 121 is used to supply power from the battery 116 to each device.

  In the above configuration, the operation of the capsule endoscope 1 according to the present embodiment will be described as follows.

  First, referring to FIG. 1, image data captured by the imaging device 112 is output from the output terminal 130 and input from the input terminal 140 to the wireless transmission device 114. When the wireless transmission device 114 is in an operating state, the image data is modulated. The modulated image data is sent from the output terminal 142 to the transmission antenna 115, and then sent to the outside of the capsule endoscope 1 by radio.

  The acceleration sensor 118 has three output terminals, an X output terminal 131, a Y output terminal 132, and a Z output terminal 133, and is connected to the X input terminal 134, the Y input terminal 135, and the Z input terminal 136 of the free fall determination device 119, respectively. ing. The acceleration sensor 118 measures the acceleration applied to the capsule endoscope 1, and the output terminals 131 to 133 output signals representing the acceleration. The output signal is input to the free fall determination device 119.

  The free fall determination device 119 determines whether or not the capsule endoscope 1 is in a free fall state based on the acceleration input from the input terminal. The free fall determination device 119 outputs a signal indicating the determination result, that is, a signal indicating whether or not the capsule endoscope 1 is in a free fall state from the output terminal 137. A signal output from the output terminal 137 is input to the transmission operation control device 120 through the input terminal 138.

  The transmission operation control device 120 generates a signal for operating or stopping the wireless transmission device 114 based on the signal input from the input terminal 138. The generated signal is output from the output terminal 139 and input from the control terminal 141 to the wireless transmission device 114. When a signal indicating an operation is input to the control terminal 141, the wireless transmission device 114 performs processing for transmitting captured image data. Conversely, when a signal indicating operation stop is input to the control terminal 141, the wireless transmission device 114 does not perform transmission processing. When transmission processing is not performed, radio waves are not output from the transmission antenna 115. That is, whether or not the capsule endoscope 1 performs radio wave output is determined by a signal input to the control terminal 141, that is, an output signal of the transmission operation control device 120.

  Here, the operation of the acceleration sensor 118 serving as a basis for determining whether or not the transmission processing of the wireless transmission device 114 is necessary will be described with reference to FIG. When acceleration is applied to the acceleration sensor 118, a force acts on the spring 203, and the length of the spring 203 becomes longer or shorter than the natural length. Therefore, the distance between the movable electrode 201 and the fixed electrode 202 changes, and the capacitance of the capacitor 205 changes. Therefore, the analog signal output from the capacitance measuring circuit 204 changes.

On the other hand, when the acceleration sensor 118 is in a weightless state, that is, when the capsule endoscope 1 is in a free fall state, no force is applied to the spring 203, so the length of the spring 203 is a natural length. The movable electrode 201 and the fixed electrode 202 maintain a certain distance. Therefore, the capacitor 205 also has a constant capacity, and the capacity measurement circuit 204 outputs a signal that maintains a constant voltage. Hereinafter, the voltage of the signal output from the acceleration sensor 118 at the time of free fall is referred to as zero G voltage, and hereinafter referred to as V _0G .

  The uniaxial acceleration can be measured by the mechanism shown in FIG. If three mechanisms shown in FIG. 3 are arranged so as to be orthogonal to each other, the triaxial acceleration can be measured. The X output terminal 131 of the acceleration sensor 118 outputs an X-axis acceleration, the Y output terminal 132 outputs a Y-axis acceleration, and the Z output terminal 133 outputs a signal indicating the Z-axis acceleration.

Next, the operation of the free fall determination device 119 will be described. As shown in FIG. 1, since the X input terminal 134 of the free fall determination device 119 is connected to the X output terminal 131 of the acceleration sensor 118, an analog signal representing the X-axis acceleration is input to the X input terminal 134. Similarly, an analog signal representing the Y-axis acceleration is inputted to the Y input terminal 135, and an analog signal representing the Z-axis acceleration is inputted to the Z input terminal 136. Hereinafter, the voltage of the signal at the X input terminal 134 is denoted as V _X , the voltage of the signal at the Y input terminal 135 is denoted as V _Y, and the voltage of the signal at the Z input terminal 136 is denoted as V _Z.

Here, consider a case where the capsule endoscope 1 is in a free fall state. At this time, the voltage of the signal representing the acceleration of each axis is _V0G . Therefore, when V _X = V _Y = V _Z = V _0G , the free fall determination device 119 outputs the H level, and at other times outputs the L level, the predetermined purpose can be achieved.

  As shown in FIG. 4, the free fall determination device 119 includes six comparators 301 to 306, three two-input AND gates 307 to 309, one three-input AND gate 310, and two constants. And voltage sources 311 and 312.

  The comparator is a circuit that inputs two analog signals and outputs one digital signal. The input terminals of the comparator are called + input terminal and −input terminal, respectively. If (+ input terminal voltage) ≧ (−input terminal voltage), an H level is output, and if (+ input terminal voltage) <(− input terminal voltage), an L level is output.

  The AND gate is a circuit having an arbitrary number of inputs and one output, and both input and output are digital signals. When all inputs are at the H level, the H level is output, and otherwise, the L level is output.

The constant voltage source is a circuit that outputs a signal maintaining a constant voltage. The constant voltage source 311 outputs a signal that maintains a constant voltage that is equal to or higher than _V0G . Hereinafter, the voltage is described as V _{0G +} . The constant voltage source 312 outputs a signal that maintains a constant voltage that is equal to or lower than _V0G . Hereinafter, the voltage is referred to as V _0G− . That is, V _0G− , V _0G , and V _{0G +} satisfy V _0G− ≦ V _0G ≦ V _{0G +} .

  Next, the block diagram which shows the structure of the free fall determination apparatus 119 is demonstrated based on FIG.

When the voltage V _X of the X input terminal 134 becomes V _X ≦ V _{0G +} , the comparator 301 becomes (+ input terminal voltage V _{0G +} ) ≧ ( _−input terminal voltage V _X ). Therefore, the comparator 301 outputs the H level. On the contrary, when V _X > V _{0G +} , the comparator 301 becomes (+ input terminal voltage V _{0G +} ) <(− input terminal voltage V _X ). Therefore, the comparator 301 outputs the L level. Similarly, when V _X ≧ V _0G− , the comparator 302 _outputs an H level, and when V _X <V _0G− , the comparator 302 outputs an L level. When the outputs of the comparators 301 and 302 are both at the H level, the AND gate 307 outputs the H level. As described above, the AND gate 307 outputs an H level when V _0G− ≦ V _X ≦ V _{0G +} , and outputs an L level when it is not (V _X <V _0G− or V _X > V _{0G +} ). Here, Table 2 shows a relationship between signals output from the comparators 301 and 302 and the AND gate 307.

Similarly, as shown in Table 3, the AND gate 308 is at the H level when V _0G− ≦ V _Y ≦ V _{0G +} , and at other _times (V _Y <V _0G− or V _Y > V _{0G +} ). Output level. Further, as shown in Table 4, the AND gate 309 is at the H level when V _0G− ≦ V _Z ≦ V _{0G +} , and at the L level when V _Z <V _0G− or V _Z > V _{0G +.} Is output. The AND gate 310 outputs an H level only when all the AND gates 307 to 309 output an H level, and outputs an L level otherwise. That is, the AND gate 310 outputs an H level only when V _X , V _Y , and V _Z are all _{equal to} or higher than V _{0G− and lower} than V _{0G +} .

Here, when the constant voltage sources 311 and 312 are set so that V _0G− and V _{0G +} are equal to V _0G , the AND gate 310 is at the H level when V _X = V _Y = V _Z = V _0G. Is output, and L level is output at other times. That is, the AND gate 310 outputs an H level only when the capsule endoscope 1 is in a free fall state, and outputs an L level at other times. The output of the AND gate 310 is connected to the output terminal 137 of the free fall determination device 119. Therefore, the free fall determination device 119 outputs an H level only when in a free fall state, and outputs an L level at other times.

In this way, the free fall determination device 119 can determine that the capsule endoscope 1 is in the free fall state. Note that the values of V _0G− and V _{0G +} may be set to values close to V _0G in consideration of the measurement error of the acceleration sensor 118, and the voltage value regarded as a free fall state may have a width.

  The extracorporeal discharge detection device 117 includes the acceleration sensor 118 and the free fall determination device 119, and the output terminal of the free fall determination device 119 is an output terminal of the extracorporeal discharge detection device 117. As described above, the extracorporeal discharge detection device 117 has a structure capable of detecting that the capsule endoscope 1 is in a free fall state.

  Next, the operation of the transmission operation control device 120 will be described with reference to FIG.

  When the extracorporeal discharge detection device 117 detects that the capsule endoscope 1 is in a free fall state, the transmission operation control device 120 controls to stop the operation of the wireless transmission device 114. However, when the capsule endoscope 1 passes through the upper digestive tract of the stomach / esophagus, it may be in a free fall state. When a free fall state that occurs while passing through the upper gastrointestinal tract is detected and the operation of the wireless transmission device 114 is stopped, the captured image of the lower gastrointestinal tract cannot be transmitted to the outside of the capsule endoscope 1. In order to prevent this, it is necessary to keep the wireless transmission device 114 in an operating state until a certain time (about 1 to 2 hours) after the operation starts, even if the extracorporeal discharge detection device 117 detects a free fall state. There is. On the other hand, when the capsule endoscope 1 is in a free fall state after a certain time has elapsed, it means that the capsule endoscope 1 has been discharged out of the body. Since a captured image while the capsule endoscope 1 exists in the body is necessary for diagnosis, it is necessary to transmit the captured image to an image display device outside the body. That is, the wireless transmission device 114 needs to be in an operating state until a certain time has elapsed and the capsule endoscope 1 is in a free fall state. After being discharged out of the body and in a free fall state, the capsule endoscope 1 is landed and is not in the free fall state. At this time, since the capsule endoscope 1 is outside the body, it is necessary to stop the output of radio waves. In summary, a signal for setting the wireless transmission device 114 to the operating state is generated until a certain time has elapsed from the start of the operation and until the extracorporeal discharge detection device 117 detects the free fall state. The transmission operation control device 120 is required to generate a signal for setting the operation stop state.

  The extracorporeal discharge detection device 117 outputs an H level when the capsule endoscope 1 is in a free fall state, and outputs an L level when it is not. In addition, when the H level is input to the control terminal 141 of the wireless transmission device 114, the wireless transmission device 114 enters an operation stop state, and when the L level is input, the wireless transmission device 114 enters an operation state. That is, the transmission operation control device 120 may be any device that outputs an L level until a certain time has elapsed from the start of the operation and the extracorporeal discharge detection device 117 outputs an H level, and thereafter outputs an H level.

  FIG. 6 is a timing chart showing the relationship between the signals output by the circuits in the transmission operation control apparatus 120. The timer 401 outputs an L level until a certain time has elapsed after the operation starts. Since the AND gate 402 receives the signals of the input terminal 138 and the timer 401, the AND gate 402 outputs the L level regardless of the state of the input terminal 138, that is, the state of the signal output from the extracorporeal discharge detection device 117. Since the Q terminal 413 of the RS-FF 403 maintains the previous state while the L level is input to the S terminal 411, it continues to output the L level.

  After a predetermined time has elapsed, the timer 401 outputs an H level. Until the capsule endoscope 1 is in a free-fall state, the extracorporeal discharge detection device 117 outputs an L level, so the input terminal 138 is at an L level. As a result, the output of the AND gate 402 becomes L level. Therefore, the state of the Q terminal 413 of the RS-FF 403 remains at the L level. Here, the operation when the capsule endoscope 1 is discharged out of the body and the out-of-body discharge detecting device 117 detects the free fall state will be described with reference to Table 1. At this time, since the output of the extracorporeal discharge detection device 117 is at the H level, the state of the input terminal 138 is at the H level. Since the output of the timer 401 is also at the H level, the output of the AND gate 402 that receives them is also at the H level. That is, the state of the S terminal 411 of the RS-FF 403 changes from the L level to the H level and the R terminal 412 changes to the L level, so that the state of the Q terminal 413 changes from the L level to the H level. Thereafter, since the Q terminal 413 outputs an H level and the R terminal 412 is at an L level, the Q terminal 413 has an H level state regardless of the state of the S terminal 411 from the truth table of Table 1. continue.

  The Q terminal 413 of the RS-FF 403 is connected to the output terminal 139 of the transmission operation control device 120. That is, from the timing chart of FIG. 6, the transmission operation control device 120 outputs an L level until a certain time has elapsed from the start of operation and the extracorporeal discharge detection device 117 detects a free fall state, and the extracorporeal discharge detection device 117. Continues to output H level after detecting a free fall state.

  As described above, the transmission operation control device 120 sends a signal for setting the wireless transmission device 114 to the operation state until a certain time has elapsed from the start of the operation and the extracorporeal discharge detection device 117 detects the free fall state, and thereafter the wireless transmission device 114 A signal for stopping the operation is generated.

  Next, the operation of the wireless transmission device 114 will be described with reference to FIG.

  As described above, the wireless transmission device 114 includes the oscillation circuit 501, the modulation circuit 502, and the regulator 503. The oscillation circuit 501 is a circuit that generates a wireless transmission carrier wave and outputs it from an output terminal 511. The modulation circuit 502 receives the carrier wave generated by the oscillation circuit 501 from the carrier wave input terminal 517, receives transmission data (captured image data captured by the imaging device 112 in the capsule endoscope 1) from the data input terminal 519, and performs wireless transmission. Modulate transmission data into a suitable format (for example, FM modulation). The regulator 503 is used to supply power with a stable voltage. The regulator 503 has an input terminal 513, an output terminal 514, and an EN terminal 515. Power is supplied to the input terminal 513 of the regulator 503. The power supplied from the input terminal 513 is stepped up / down to a specific voltage and output from the output terminal 514. A digital signal for controlling the operation of the regulator 503 is input to the EN terminal 515. When the L level is input to the EN terminal 515, the regulator 503 enters an operating state and supplies power from the output terminal 514. When the H level is input, the regulator 503 stops operating and does not supply power from the output terminal 514.

  The output terminal 139 of the transmission operation control device 120 is connected to the control terminal 141 of the wireless transmission device 114 and the EN terminal 515 of the regulator 503. An input terminal 513 of the regulator 503 is connected to the battery 116 through the power supply line 121, and an output terminal 514 is connected to the power supply terminals 512 and 518 of the oscillation circuit 501 and the modulation circuit 502.

  When the L level is input to the control terminal 141, the EN terminal 515 of the regulator 503 becomes the L level, so that the regulator 503 operates and power is supplied to the oscillation circuit 501 and the modulation circuit 502. Captured image data output from the output terminal 130 of the imaging device 112 is input to the modulation circuit 502 through the input terminal 140 and the data input terminal 519. The captured image data is modulated, sent to the transmission antenna 115 through the output terminal 520 and the output terminal 142 of the wireless transmission device 114, and sent to the outside of the capsule endoscope 1 as a radio wave. That is, the capsule endoscope 1 outputs radio waves. On the other hand, when the H level is input to the control terminal 141, the EN terminal 515 of the regulator 503 becomes the H level, so that the regulator 503 stops its operation. Therefore, power is not supplied to the oscillation circuit 501 and the modulation circuit 502, and the oscillation circuit 501 and the modulation circuit 502 do not operate. The oscillation circuit 501 stops oscillation, and the modulation circuit 502 does not perform modulation. For this reason, radio waves are not output from the transmission antenna 115.

  As described above, whether or not the capsule endoscope 1 outputs radio waves is determined by the input of the control terminal 141, that is, the output signal of the transmission operation control device 120.

  The capsule endoscope 1 according to the present invention has the above configuration.

  The effects of the capsule endoscope 1 according to the present embodiment in the above configuration will be described as follows.

  As described above, according to the present embodiment, the signal generated by the transmission operation control device 120 determines whether or not the capsule endoscope 1 outputs radio waves. The transmission operation control device 120 generates a signal for performing radio wave output until a certain period of time has elapsed from the start of the operation and the extracorporeal discharge detection device 117 detects that the capsule endoscope 1 is in a free fall state. Then, after the extracorporeal discharge detection device 117 detects that the capsule endoscope 1 is in a free fall state, a signal for stopping radio wave output is generated.

  As a result, data transmission to the outside of the body is not stopped while the capsule endoscope 1 is passing through the esophagus, the upper digestive tract of the stomach, and the intestine. Data transmission to the outside by the wireless transmission device is stopped when a free fall state occurs during discharge from the body. After the extracorporeal discharge, the capsule endoscope 1 is landed, and the data transmission to the outside by the wireless transmission device continues to stop even after the capsule endoscope 1 is not in the free fall state.

  As a result, since the capsule endoscope 1 does not perform radio wave output outside the body, it can satisfy the radio wave regulations of Japan. Therefore, it is not necessary to collect the capsule endoscope 1 in the radio wave shielding bag. In addition, since the free fall state is normally detected within 1 second, wireless transmission can be quickly stopped after the body is discharged.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be applied to a capsule endoscope that acquires an image of an imaging target inside a living body.

It is a block diagram which shows the structure of the capsule endoscope which concerns on embodiment. It is a block diagram which shows the structure of a radio | wireless transmitter. It is a figure which shows the structure of the acceleration measurement part of an acceleration sensor. It is a block diagram which shows the structure of a free fall determination apparatus. It is a block diagram which shows the structure of a transmission operation control apparatus. It is a timing diagram which shows the change of the signal of each circuit in a transmission operation control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capsule endoscope 110 Outer wall 111 Lens 112 Imaging device 113 Illumination device 114 Wireless transmission device 115 Transmission antenna 116 Battery 117 Extracorporeal discharge detection device 118 Acceleration sensor 119 Free fall determination device 120 Transmission operation control device 121 Power supply line 130, 137, 139 , 142, 511, 514, 520 output terminal 131 X output terminal 132 Y output terminal 133 Z output terminal 134 X input terminal 135 Y input terminal 136 Z input terminal 138, 140, 513 input terminal 141 control terminal 201 movable electrode 202 fixed electrode 203 Spring 204 Capacitance measurement circuit 205 Capacitor 301, 302, 303, 304, 305, 306 Comparator 307, 308, 309, 402 2-input AND gate 310 3-input AND gate 311, 312 Constant voltage Source 401 Timer 403 RS flip-flop 411 S terminal 412 R terminal 413 Q terminal 501 Oscillation circuit 502 Modulation circuit 503 Regulator 512, 518 Power supply terminal 515 EN terminal 517 Carrier input terminal 519 Data input terminal

Claims (8)

In a capsule endoscope having an imaging device that images the inside of a living body, and a wireless transmission device that performs processing for transmitting an image captured by the imaging device to the outside of the body,
An extracorporeal discharge detection device that detects by acceleration that the capsule endoscope has been discharged from the body, and a transmission operation control device that controls the operation of the wireless transmission device in response to a signal output from the extracorporeal discharge detection device. A capsule endoscope further comprising the capsule endoscope.   The capsule endoscope according to claim 1, wherein the extracorporeal discharge detection device includes an acceleration sensor and a free fall determination device.   The capsule endoscope according to claim 2, wherein the free fall determination device determines whether or not the capsule endoscope is in a free fall state based on the acceleration measured by the acceleration sensor.   The capsule endoscope according to claim 2, wherein in the extracorporeal discharge detection device, an output terminal of the free fall determination device is an output terminal of the extracorporeal discharge detection device.   2. The transmission operation control device according to claim 1, wherein the transmission operation control device generates a signal for setting the wireless transmission device in an operation state until a predetermined time elapses after the capsule endoscope starts operation. Capsule endoscope.   The transmission operation control device continues to output a signal for stopping the operation of the wireless transmission device after a certain time has elapsed and the extracorporeal discharge detection device detects a free fall state of the capsule endoscope. The capsule endoscope according to claim 1.   The capsule endoscope according to claim 1, wherein when the wireless transmission device receives an operation stop signal from the transmission operation control device, power supply is stopped.   The capsule endoscope according to claim 1, wherein the oscillation circuit included in the wireless transmission device stops oscillation after the extracorporeal discharge detection device detects a free fall state of the capsule endoscope.

Images