WO2017090107A1 - Capsule endoscope position measurement device - Google Patents

Capsule endoscope position measurement device Download PDF

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Publication number
WO2017090107A1
WO2017090107A1 PCT/JP2015/083015 JP2015083015W WO2017090107A1 WO 2017090107 A1 WO2017090107 A1 WO 2017090107A1 JP 2015083015 W JP2015083015 W JP 2015083015W WO 2017090107 A1 WO2017090107 A1 WO 2017090107A1
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Prior art keywords
circuit
capsule endoscope
phase difference
signal
endoscope position
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PCT/JP2015/083015
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French (fr)
Japanese (ja)
Inventor
吉徳 池田
慎一 中島
明広 窪田
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オリンパス株式会社
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Priority to PCT/JP2015/083015 priority Critical patent/WO2017090107A1/en
Publication of WO2017090107A1 publication Critical patent/WO2017090107A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor

Definitions

  • the present invention relates to a capsule endoscope position measuring device.
  • a capsule endoscope for observing the inside of a living body is used.
  • the position where the capsule endoscope has taken an image is referred to for treatment. For this reason, it is important to measure the position of the capsule endoscope.
  • Patent Document 1 A method for measuring the position of a capsule endoscope is disclosed in Patent Document 1.
  • signals from a radio apparatus inside a living body, that is, a capsule endoscope are received by a plurality of antennas.
  • the position of the capsule endoscope is measured based on the phase difference between the received signals.
  • FIG. 16 shows a configuration of a conventional capsule endoscope position measuring apparatus 9.
  • the capsule endoscope position measuring device 9 includes a plurality of antennas 900, an antenna selection circuit 901, a processing circuit 902, a processing circuit 903, a phase difference measuring circuit 904, and a position calculating circuit 905. And have.
  • the plurality of antennas 900 are arranged outside the living body and receive signals transmitted from the capsule endoscope 2 wirelessly. For example, as shown in FIG. 16, eight antennas 900 are arranged.
  • the antenna selection circuit 901 sequentially selects two antennas 900 from the plurality of antennas 900.
  • Each of the processing circuit 902 and the processing circuit 903 processes each of the signals received by the two antennas 900 selected by the antenna selection circuit 901.
  • the processing circuit 902 and the processing circuit 903 include a filter and an amplifier.
  • the filter removes a signal having a frequency other than a predetermined frequency band from the signal received by the antenna 900.
  • the amplifier amplifies the signal that has passed through the filter.
  • the phase difference measurement circuit 904 measures the phase difference between the signal processed by the processing circuit 902 and the signal processed by the processing circuit 903.
  • the position calculation circuit 905 calculates the position of the capsule endoscope 2 based on the phase difference measured by the phase difference measurement circuit 904.
  • FIG. 17 shows a procedure for measuring the position of the capsule endoscope 2 by a conventional method. A method for measuring the position of the capsule endoscope 2 will be described with reference to FIG.
  • the capsule endoscope 2 transmits a signal wirelessly (step S1001).
  • the plurality of antennas 900 receive the signal from the capsule endoscope 2 (step S1002).
  • the variable N1 is set to 1 and the variable N2 is set to 2 (step S1003).
  • the variables N1 and N2 are managed by a control circuit (not shown).
  • step S1003 when variable N1 and variable N2 are the same (step S1004), variable N2 is incremented by 1 (step S1005).
  • the antenna selection circuit 901 switches between the two antennas 900 (step S1006). Immediately after the position measurement is started, the first two antennas 900 are selected in step S1006.
  • step S1006 When the process in step S1006 is performed again, a combination different from the combination of the two antennas 900 already selected is selected.
  • step S1003 when the variable N1 and the variable N2 are not the same (step S1004), the antenna selection circuit 901 switches between the two antennas 900 (step S1006).
  • each of the processing circuit 902 and the processing circuit 903 processes each of the signals received by the two antennas 900 selected by the antenna selection circuit 901.
  • the phase difference measurement circuit 904 measures the phase difference between the signal processed by the processing circuit 902 and the signal processed by the processing circuit 903 (step S1007).
  • the position calculation circuit 905 holds phase difference information indicating the measured phase difference (step S1008).
  • step S1009 After the phase difference information is held, if the variable N2 is not 8 (step S1009), the variable N2 is incremented by 1 (step S1010). After the variable N2 is incremented by 1, determination in step S1004 is performed. After the phase difference information is held, when the variable N2 is 8 (step S1009), the following processing is performed. If the variable N1 is not 7 (step S1011), the variable N1 is incremented by 1 and the variable N2 is set to a value that is 1 larger than the variable N1 (step S1012). Thereafter, the determination in step S1004 is performed. When the variable N1 is 7 (step S1011), the position calculation circuit 905 calculates the position of the capsule endoscope 2 based on the phase difference information (step S1013).
  • At least three combinations of two antennas 900 are necessary.
  • the number of combinations of the two antennas 900 is large, the calculation accuracy increases.
  • the maximum number of combinations of two antennas 900 is 28. In the method shown in FIG. 17, the phase difference is measured for a maximum of 28 combinations.
  • the position calculation circuit 905 can calculate the distance d nm by the equation (1).
  • the distance d nm is a difference in distance from the capsule endoscope 2 to each of the two antennas 900.
  • ⁇ nm is a phase difference between signals received by each of the two antennas 900.
  • f is the frequency of the signal.
  • V is the transmission speed of the signal in the medium.
  • (x, y, z) is the position coordinate of the capsule endoscope 2.
  • (X m , y m , z m ) and (x n , y n , z n ) are the position coordinates of each of the two antennas 900.
  • Equation (2) is one equation regarding the position coordinates (x, y, z) of the capsule endoscope 2.
  • the unknown is 3.
  • the position calculation circuit 905 can calculate the position of the capsule endoscope 2 by solving simultaneous equations including three or more equations represented by Expression (2).
  • the capsule endoscope position measuring device 9 switches the two antennas 900 sequentially. For this reason, the amount of processing required for selecting the antenna 900 is large.
  • An object of the present invention is to provide a capsule endoscope position measuring device with a reduced processing amount.
  • a capsule endoscope position measurement apparatus includes at least four antennas, an antenna selection circuit, a processing circuit, a reference signal generation circuit, a phase difference measurement circuit, and a position calculation. Circuit.
  • the at least four antennas are disposed outside the living body and receive signals transmitted wirelessly from the capsule endoscope.
  • the antenna selection circuit sequentially selects one antenna from the at least four antennas.
  • a processing circuit processes the signal received by the antenna selected by the antenna selection circuit.
  • the reference signal generation circuit generates a reference signal.
  • the phase difference measurement circuit measures a phase difference between the signal processed by the processing circuit and the reference signal.
  • the position calculation circuit calculates the position of the capsule endoscope based on the phase difference for each of the at least four antennas measured by the phase difference measurement circuit.
  • the capsule endoscope position measurement apparatus further includes a down-conversion circuit that down-converts the frequency of the signal processed by the processing circuit to an intermediate frequency. You may have.
  • the capsule endoscope position measuring device adjusts the intermediate frequency based on the phase difference measured by the phase difference measuring circuit.
  • An adjustment circuit may be further included.
  • the down-conversion circuit may include a voltage controlled oscillator and a mixer.
  • the voltage controlled oscillator generates a signal having a frequency different from the frequency of the signal received by the at least four antennas.
  • the mixer mixes the signal processed by the processing circuit with the signal generated by the voltage controlled oscillator.
  • the capsule endoscope position measuring device uses the frequency band of the signal down-converted by the down-conversion circuit. You may further have the narrow-band filter to restrict
  • the frequency of the reference signal may be set to be the same as the intermediate frequency.
  • the frequency of the reference signal may be set to be the same as the frequency of the signal received by the at least four antennas.
  • the capsule endoscope position measuring device is based on the phase difference measured by the phase difference measuring circuit.
  • a reference frequency adjusting circuit for adjusting the frequency of the reference signal may be further included.
  • the capsule endoscope position measurement device includes a time change measurement circuit and a first phase difference correction circuit. Furthermore, you may have.
  • the time change measuring circuit measures the time change of the phase difference for each of the at least four antennas measured by the phase difference measuring circuit.
  • the first phase difference correction circuit corrects the phase difference for each of the at least four antennas measured by the phase difference measurement circuit based on the time change measured by the time change measurement circuit. To do.
  • the reference signal generation circuit may be a voltage controlled oscillator.
  • the reference signal generation circuit may be a crystal oscillator.
  • the reference signal generation circuit may be any one of the at least four antennas.
  • the reference signal generation circuit may be the antenna having the highest reception intensity among the at least four antennas.
  • the capsule endoscope position measuring device includes: a voltage of the signal processed by the processing circuit; a reference voltage; And a comparator that outputs a binary signal having any one of the two values according to the comparison result.
  • the phase difference measurement circuit may measure the phase difference between the binary signal and the reference signal.
  • the phase difference measurement circuit may be a TDC (Time to Digital Converter).
  • the phase difference measurement circuit may include a phase comparator and a charge pump.
  • the phase comparator compares the phase of the binary signal with the phase of the reference signal.
  • the charge pump outputs a voltage signal corresponding to a difference between the phase of the binary signal compared by the phase comparator and the phase of the reference signal.
  • the phase difference measuring circuit may be a counter.
  • the capsule endoscope position measurement device further includes an intensity measurement circuit and a second phase difference correction circuit.
  • the intensity measurement circuit measures the intensity of the signal processed by the processing circuit.
  • the second phase difference correction circuit corrects the phase difference for each of the at least four antennas measured by the phase difference measurement circuit based on the intensity measured by the intensity measurement circuit.
  • the capsule endoscope position measuring device further includes a variable gain amplifier and a first control circuit.
  • the variable gain amplifier amplifies the signal processed by the processing circuit, and an amplification gain is variable.
  • the first control circuit measures the intensity of the signal processed by the processing circuit, and based on the measured intensity, the intensity of the signal output from the variable gain amplifier is constant.
  • the variable gain amplifier is controlled.
  • the comparator may compare the voltage of the signal output from the variable gain amplifier with the reference voltage, and output the binary signal according to a comparison result.
  • the capsule endoscope position measuring device may further include an attenuator and a second control circuit.
  • the attenuator attenuates the signal processed by the processing circuit, and the attenuation amount is variable.
  • the second control circuit measures the intensity of the signal processed by the processing circuit, and based on the measured intensity, the intensity of the signal output from the attenuator is constant.
  • the comparator may compare the voltage of the signal output from the attenuator with the reference voltage and output the binary signal according to the comparison result.
  • the capsule endoscope position measuring device includes: the signal processed by the processing circuit; and the reference signal. You may further have AD converter which converts each into a digital value.
  • the phase difference measurement circuit may measure the phase difference based on the digital value of the signal processed by the processing circuit and the digital value of the reference signal.
  • the capsule endoscope position measurement apparatus has the antenna selection circuit that sequentially selects one antenna to be detected from at least four antennas. For this reason, the amount of processing is reduced.
  • FIG. 1 shows a configuration of a capsule endoscope position measuring apparatus 1A according to the first embodiment of the present invention.
  • the capsule endoscope position measurement apparatus 1A includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105.
  • the at least four antennas 100 are arranged outside the living body and receive signals transmitted from the capsule endoscope 2 by radio.
  • the antenna selection circuit 101 sequentially selects one antenna 100 from at least four antennas 100.
  • the processing circuit 102 processes a signal received by the antenna 100 selected by the antenna selection circuit 101.
  • the reference signal generation circuit 103 generates a reference signal.
  • the phase difference measurement circuit 104 measures the phase difference between the signal processed by the processing circuit 102 and the reference signal.
  • the position calculation circuit 105 calculates the position of the capsule endoscope 2 based on the phase difference for each of the at least four antennas 100 measured by the phase difference measurement circuit 104.
  • the capsule endoscope 2 is disposed inside the living body.
  • the antenna selection circuit 101 outputs a signal received by the selected antenna 100 to the processing circuit 102.
  • the processing circuit 102 includes a filter and an amplifier.
  • the filter removes a signal having a frequency other than a predetermined frequency band from the signal received by the antenna 100.
  • the amplifier amplifies the signal that has passed through the filter. That is, the processing circuit 102 removes a signal having a frequency other than a predetermined frequency band from the signal received by the antenna 100 with a filter, and amplifies the signal that has passed through the filter with an amplifier.
  • the reference signal is a signal having a predetermined frequency.
  • FIG. 2 shows a procedure for measuring the position of the capsule endoscope 2 in the first embodiment. A method for measuring the position of the capsule endoscope 2 will be described with reference to FIG.
  • the capsule endoscope 2 transmits a signal wirelessly (step S101).
  • the signal transmitted by the capsule endoscope 2 is a signal including an image captured by the capsule endoscope 2 or a signal for position measurement.
  • the reference signal generation circuit 103 After signals are transmitted from the capsule endoscope 2, at least four antennas 100 receive signals from the capsule endoscope 2 (step S102).
  • the reference signal generation circuit 103 After at least four antennas 100 receive the signal, the reference signal generation circuit 103 generates a reference signal (step S103).
  • the variable n is set to 1 (step S104).
  • the variable n is managed by a control circuit (not shown).
  • the antenna selection circuit 101 switches one antenna 100 (step S105). Immediately after the position measurement is started, the first antenna 100 is selected in step S105. When the process in step S105 is performed again, an antenna 100 different from the already selected one antenna 100 is selected.
  • the processing circuit 102 processes the signal received by the single antenna 100 selected by the antenna selection circuit 101.
  • the phase difference measurement circuit 104 measures the phase difference between the signal processed by the processing circuit 102 and the reference signal output from the reference signal generation circuit 103 (step S106).
  • the position calculation circuit 105 holds phase difference information indicating the measured phase difference (step S107).
  • step S108 After the phase difference information is held, if the variable n is not 8 (step S108), the variable n is incremented by 1 (step S109). After the variable n is incremented by 1, the process in step S105 is performed. After the phase difference information is held, when the variable n is 8 (step S108), the position calculation circuit 105 calculates the position of the capsule endoscope 2 based on the phase difference information (step S110).
  • the position of the capsule endoscope 2 In order to calculate the position of the capsule endoscope 2 by the method described later, at least three combinations of the two antennas 100 are necessary. When the number of combinations of the two antennas 100 is large, the calculation accuracy increases. In the method shown in FIG. 2, the phase difference between the signal received by each of the eight antennas 100 and the reference signal is measured. Based on the measurement result, the phase difference between the signals received by each of the two antennas 100 is calculated.
  • the position calculation circuit 105 calculates the phase difference ⁇ nm of the signals received by each of the two antennas 100 using Expression (3).
  • ⁇ m and ⁇ n are phase differences between the signal received by each of the two antennas 100 and the reference signal.
  • ⁇ nm ⁇ n ⁇ m (3)
  • the position calculation circuit 105 receives each of the two antennas 100 by calculating the difference in phase difference between the signal received by each of the two antennas 100 and the reference signal based on Expression (3).
  • the phase difference ⁇ nm of the obtained signal is calculated.
  • Information on the phase of the reference signal is removed by equation (3).
  • the position calculation circuit 105 can calculate the distance d nm by using the phase difference ⁇ nm calculated by the equation (3) in the above-described equation (1).
  • the frequency of the reference signal may be set to be the same as the frequency of signals received by at least four antennas 100.
  • the reference signal generation circuit 103 may be a crystal oscillator.
  • the crystal oscillator may be a temperature compensated crystal oscillator (TCXO).
  • TCXO temperature compensated crystal oscillator
  • the antenna selection circuit 901 selects two antennas 900.
  • the antenna selection circuit 101 selects one antenna 100.
  • the antenna selection circuit 101 can be made smaller than the antenna selection circuit 901.
  • the capsule endoscope position measuring apparatus 1A can measure the phase differences for the 28 combinations of the two antennas 100. For this reason, the processing amount required for selection of the antenna 100 is reduced.
  • the capsule endoscope position measuring device 9 has two processing circuits, that is, a processing circuit 902 and a processing circuit 903. Since two processing circuits are required, the circuit scale is large.
  • the capsule endoscope position measurement apparatus 1 ⁇ / b> A includes a processing circuit 102 that processes a signal received by one antenna 100 selected by the antenna selection circuit 101. Compared with the capsule endoscope position measuring apparatus 9 having two processing circuits, the number of processing circuits is small. For this reason, the circuit scale is reduced.
  • the capsule endoscope position measurement device 9 When position measurement is performed by the capsule endoscope position measurement device 9, the measurement value of the phase difference between the signals received by each of the two antennas 900 is likely to contain an error due to variations in the configuration of the two processing circuits. . The above-mentioned error is reduced by the capsule endoscope position measuring apparatus 1A performing position measurement.
  • FIG. 3 shows a configuration of a capsule endoscope position measuring apparatus 1B according to the second embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1B includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105 and a down-conversion circuit 106 are included. The difference between the configuration shown in FIG. 3 and the configuration shown in FIG. 1 will be described.
  • the down-conversion circuit 106 down-converts the frequency of the signal processed by the processing circuit 102 to an intermediate frequency.
  • the down-conversion circuit 106 includes a local oscillator 1060 and a mixer 1061.
  • the local oscillator 1060 generates a signal having a frequency different from the frequency of signals received by the plurality of antennas 100.
  • the mixer 1061 mixes the signal processed by the processing circuit 102 and the signal generated by the local oscillator 1060. As a result, the mixer 1061 generates a signal having an intermediate frequency and outputs the generated signal.
  • the frequency (intermediate frequency Fi) of the signal output from the mixer 1061 is the difference between the frequency (Fr) of the signal received by at least four antennas 100 and the frequency (Fd) of the signal generated by the local oscillator 1060. It is. When the frequency (Fd) of the signal generated by the local oscillator 1060 is lower than the frequency (Fr) of the signal received by at least four antennas 100, the intermediate frequency Fi is (Fr ⁇ Fd). When the frequency (Fd) of the signal generated by the local oscillator 1060 is higher than the frequency (Fr) of the signal received by at least four antennas 100, the intermediate frequency Fi is (Fd ⁇ Fr).
  • the phase difference measurement circuit 104 measures the phase difference between the signal processed by the down-conversion circuit 106 and the reference signal.
  • the frequency of the reference signal may be set to be the same as the intermediate frequency. That is, the reference signal generation circuit 103 may generate a reference signal having an intermediate frequency.
  • FIG. 3 other than the above, the configuration shown in FIG. 3 is the same as the configuration shown in FIG.
  • the phase difference is measured based on a signal having a frequency lower than the frequency of signals received by at least four antennas 100.
  • the time resolution in the capsule endoscope position measurement apparatus 1A of the first embodiment is the same as the time resolution in the capsule endoscope position measurement apparatus 1B, the resolution of the phase difference in the capsule endoscope position measurement apparatus 1B Is higher than the resolution of the phase difference in the capsule endoscope position measurement apparatus 1A. For this reason, the accuracy of position measurement is improved.
  • FIG. 4 shows a configuration of a capsule endoscope position measuring apparatus 1C according to the third embodiment of the present invention.
  • the capsule endoscope position measurement apparatus 1C includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105, a down-conversion circuit 106A, and an intermediate frequency adjustment circuit 107 are included.
  • the difference between the configuration shown in FIG. 4 and the configuration shown in FIG. 3 will be described.
  • the down-conversion circuit 106A includes a voltage controlled oscillator (VCO) 1060A and a mixer 1061.
  • the local oscillator 1060 is a voltage controlled oscillator 1060A.
  • the voltage controlled oscillator 1060A outputs a signal having a frequency corresponding to the frequency setting value indicated by the input voltage value.
  • the mixer 1061 is the same as the mixer 1061 in the down-conversion circuit 106.
  • the intermediate frequency adjustment circuit 107 controls the down-conversion circuit 106A based on the phase difference measured by the phase difference measurement circuit 104. Specifically, the intermediate frequency adjustment circuit 107 controls the frequency setting value of the signal generated by the voltage controlled oscillator 1060A based on the phase difference measured by the phase difference measurement circuit 104. As a result, the intermediate frequency adjustment circuit 107 adjusts the intermediate frequency based on the phase difference measured by the phase difference measurement circuit 104. The intermediate frequency adjustment circuit 107 controls the frequency setting value so that the phase difference measured by the phase difference measurement circuit 104 is constant.
  • the capsule endoscope position measurement apparatus 1B of the second embodiment it is difficult to make the frequency of the signal output from the down-conversion circuit 106 and the reference signal completely the same due to the influence of individual differences in the circuit. For this reason, the phase difference between the signal output from the down-conversion circuit 106 and the reference signal may change over time. Since the phase difference includes a time-dependent error, the accuracy of position measurement may be reduced. The error included in the phase difference measured by the position measurement using the antenna 100 last selected by the antenna selection circuit 101 was measured by the position measurement using the antenna 100 first selected by the antenna selection circuit 101. It tends to be larger than the error included in the phase difference.
  • the capsule endoscope position measurement apparatus 1C according to the third embodiment can reduce the error of the phase difference depending on time by adjusting the intermediate frequency.
  • FIG. 5 shows a configuration of a capsule endoscope position measuring apparatus 1D according to the fourth embodiment of the present invention.
  • the capsule endoscope position measurement apparatus 1D includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a voltage controlled oscillator (VCO) 103A, and a phase difference measurement circuit 104.
  • a position calculation circuit 105, a down-conversion circuit 106, and a reference frequency adjustment circuit 108 The configuration shown in FIG. 5 will be described while referring to differences from the configuration shown in FIG.
  • the reference signal generation circuit 103 is a voltage controlled oscillator (VCO) 103A.
  • the voltage controlled oscillator 103A outputs a signal having a frequency corresponding to the frequency setting value indicated by the input voltage value.
  • the reference frequency adjusting circuit 108 controls the voltage controlled oscillator 103A based on the phase difference measured by the phase difference measuring circuit 104. Specifically, the reference frequency adjusting circuit 108 controls the frequency setting value of the signal generated by the voltage controlled oscillator 103A based on the phase difference measured by the phase difference measuring circuit 104. Thus, the reference frequency adjustment circuit 108 adjusts the reference frequency based on the phase difference measured by the phase difference measurement circuit 104.
  • the reference frequency adjustment circuit 108 controls the frequency setting value so that the phase difference measured by the phase difference measurement circuit 104 is constant.
  • the reference signal generation circuit 103 may be a voltage controlled oscillator 103A.
  • the at least one capsule endoscope position measurement device according to the first to third embodiments may include a reference frequency adjustment circuit 108.
  • the capsule endoscope position measuring apparatus 1D can reduce the time-dependent phase difference error by adjusting the frequency of the reference signal.
  • FIG. 6 shows a configuration of a capsule endoscope position measuring apparatus 1E according to the fifth embodiment of the present invention.
  • the capsule endoscope position measurement apparatus 1E includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, The position calculation circuit 105, the down-conversion circuit 106A, the intermediate frequency adjustment circuit 107, the time change measurement circuit 109, and the first phase difference correction circuit 110 are included.
  • the configuration shown in FIG. 6 will be described while referring to differences from the configuration shown in FIG.
  • the time change measuring circuit 109 measures the time change of the phase difference for each of at least four antennas 100 measured by the phase difference measuring circuit 104.
  • the first phase difference correction circuit 110 corrects the phase difference for each of the at least four antennas 100 measured by the phase difference measurement circuit 104 based on the time change measured by the time change measurement circuit 109.
  • the phase difference between the signal output from the down-conversion circuit 106A and the reference signal may change over time.
  • the time change measurement circuit 109 and the first phase difference correction circuit 110 are circuits for further reducing a time-dependent phase difference error. An example of processing by the time change measurement circuit 109 and the first phase difference correction circuit 110 will be described.
  • the phase difference measurement circuit 104 measures the first phase difference.
  • the phase difference measurement circuit 104 measures the second phase difference.
  • the antenna selection circuit 101 selects the first antenna from at least four antennas 100.
  • the time change measuring circuit 109 calculates the time change of the phase difference by dividing the difference between the first phase difference and the second phase difference by the time from the first time to the second time.
  • the time change of the calculated phase difference is a change amount of the phase difference per unit time.
  • the time change measurement circuit 109 outputs the calculated time change of the phase difference to the first phase difference correction circuit 110.
  • the phase difference corresponding to the first antenna is the first phase difference.
  • the antenna selection circuit 101 selects a second antenna different from the first antenna among at least four antennas 100.
  • the phase difference measurement circuit 104 measures a third phase difference based on the signal received by the second antenna.
  • the first phase difference correction circuit 110 corrects the third phase difference based on the time change of the phase difference and the time from the first time to the third time. Specifically, the first phase difference correction circuit 110 multiplies the time change of the phase difference by the time from the first time to the third time, thereby reducing the error included in the third phase difference. calculate.
  • the first phase difference correction circuit 110 corrects the third phase difference by subtracting the calculated error from the third phase difference.
  • the first phase difference correction circuit 110 corrects the phase difference by the above processing.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1E may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the at least one capsule endoscope position measurement device may include a time change measurement circuit 109 and a first phase difference correction circuit 110.
  • the capsule endoscope position measuring apparatus 1E can reduce the time-dependent phase difference error by correcting the phase difference based on the time change of the phase difference.
  • FIG. 7 shows a configuration of a capsule endoscope position measuring apparatus 1F according to the sixth embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1F includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a phase difference measurement circuit 104, a position calculation circuit 105, a maximum An intensity selection circuit 111 and a processing circuit 112 are included. The difference between the configuration shown in FIG. 7 and the configuration shown in FIG. 1 will be described.
  • the reference signal generation circuit 103 is any one of at least four antennas 100. Specifically, the reference signal generation circuit 103 is the antenna 100 having the highest reception strength among at least four antennas 100.
  • the maximum intensity selection circuit 111 selects the antenna 100 having the highest reception intensity, and outputs a signal received by the selected antenna 100 to the processing circuit 112.
  • the configuration of the processing circuit 112 is the same as the configuration of the processing circuit 102.
  • the processing circuit 112 processes the signal output from the maximum intensity selection circuit 111.
  • the phase difference measurement circuit 104 measures the phase difference between signals processed by the processing circuit 102 and the processing circuit 112.
  • FIG. 7 is similar to the configuration shown in FIG.
  • the reference signal generation circuit 103 may be an antenna 100 other than the antenna 100 having the highest reception intensity. That is, the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measurement apparatus 1F may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring device 1F measures the phase difference between two signals received from the same capsule endoscope 2. Since the frequency of the two signals is the same, the time change of the measured phase difference is unlikely to occur. For this reason, the capsule endoscope position measurement apparatus 1F can perform position measurement with higher accuracy.
  • the capsule endoscope position measurement apparatus 1F can use a signal having a high signal-to-noise ratio (S / N ratio). For this reason, the capsule endoscope position measurement apparatus 1F can perform position measurement with higher accuracy.
  • FIG. 8 shows a configuration of a capsule endoscope position measuring apparatus 1G according to the seventh embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1G includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and a narrow band filter 113 are included.
  • the difference between the configuration shown in FIG. 8 and the configuration shown in FIG. 4 will be described.
  • the narrow band filter 113 limits the frequency band of the signal down-converted by the down-conversion circuit 106A.
  • the narrowband filter 113 passes only a signal having a frequency in a predetermined band including an intermediate frequency among signals output from the down-conversion circuit 106A.
  • the width of the pass band of the narrow band filter 113 is 0.1% or less of the intermediate frequency.
  • the phase difference measurement circuit 104 measures the phase difference between the signal output from the narrowband filter 113 and the reference signal.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measuring apparatus 1D.
  • the capsule endoscope position measurement device 1G may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement device 1D.
  • the capsule endoscope position measurement apparatus 1G may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the at least one capsule endoscope position measurement device may include the narrowband filter 113.
  • the capsule endoscope position measuring apparatus 1G includes the narrow band filter 113, so that noise of signals received by at least four antennas 100 can be removed. For this reason, the capsule endoscope position measurement apparatus 1G can perform position measurement with higher accuracy.
  • the intermediate frequency adjustment circuit 107 adjusts the intermediate frequency so that the intermediate frequency becomes constant, the pass band of the narrow band filter 113 can be made narrower. That is, the effect of noise removal by the narrow band filter 113 is further improved. For this reason, the capsule endoscope position measurement apparatus 1G can perform position measurement with higher accuracy.
  • FIG. 9 shows a configuration of a capsule endoscope position measuring apparatus 1H according to the eighth embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1H includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, and a TDC (Time to Digital Converter).
  • 104A a position calculation circuit 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and a comparator 114.
  • the difference between the configuration illustrated in FIG. 9 and the configuration illustrated in FIG. 4 will be described.
  • the comparator 114 compares the voltage of the signal processed by the processing circuit 102 with the reference voltage, and outputs a binary signal having any one of the two values according to the comparison result.
  • the phase difference measurement circuit 104 measures the phase difference between the binary signal and the reference signal.
  • the phase difference measuring circuit 104 is a TDC 104A.
  • the capsule endoscope position measuring apparatus 1H includes a reference voltage generation circuit that generates a reference voltage.
  • the reference voltage generated by the reference voltage generation circuit is input to the comparator 114.
  • the comparator 114 may include a reference voltage generation circuit. For example, when the voltage of the signal processed by the processing circuit 102 is equal to or higher than the reference voltage, the comparator 114 outputs a high level signal. When the voltage of the signal processed by the processing circuit 102 is less than the reference voltage, the comparator 114 outputs a low level signal. High in the first condition may be changed to Low, and Low in the second condition may be changed to High.
  • the reference signal is a binary signal.
  • the TDC 104A measures the time difference between the first time at which the binary signal pulse output from the comparator 114 is detected and the second time at which the reference signal pulse is detected. Measure. The time measured by the TDC 104A corresponds to the phase difference. The TDC 104A outputs the measured time as a digital value.
  • the position calculation circuit 105 calculates the position of the capsule endoscope 2 based on the phase difference measured by the TDC 104A, that is, time.
  • the time measured by the TDC 104A is t nm and the transmission speed of the signal in the medium is V
  • the distance d nm in the above-described formula (1) and formula (2) is the time t nm and the transmission speed.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1H may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1H may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring apparatus 1H may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
  • the capsule endoscope position measurement apparatus 1A may include a TDC 104A and a comparator 114.
  • the capsule endoscope position measuring device 1H includes the TDC 104A and the comparator 114, the configuration is simplified and the power consumption is reduced.
  • the capsule endoscope position measurement apparatus 1H can perform position measurement with higher accuracy.
  • FIG. 10 shows a configuration of a capsule endoscope position measuring apparatus 1I according to the ninth embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1I includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104B, A position calculation circuit 105, a down-conversion circuit 106A, a comparator 114, and an AD converter 115 are included.
  • the configuration shown in FIG. 10 will be described while referring to differences from the configuration shown in FIG.
  • the comparator 114 is the same as the comparator 114 in the capsule endoscope position measuring apparatus 1H.
  • the phase difference measurement circuit 104B includes a phase comparator 1040, a charge pump 1041, and a loop filter 1042.
  • the phase comparator 1040 compares the phase of the binary signal output from the comparator 114 with the phase of the reference signal.
  • the charge pump 1041 outputs a voltage signal corresponding to the difference between the phase of the binary signal compared by the phase comparator 1040 and the phase of the reference signal.
  • the loop filter 1042 removes unnecessary frequency components from the voltage signal output from the charge pump 1041.
  • the loop filter 1042 outputs a signal from which unnecessary frequency components are removed.
  • the loop filter 1042 is a low-pass filter.
  • the analog signal output from the loop filter 1042 has a voltage corresponding to the phase difference between the binary signal output from the comparator 114 and the reference signal.
  • the phase comparator 1040, the charge pump 1041, and the loop filter 1042 constitute a general PLL (Phase Locked Loop).
  • the phase difference measurement circuit 104B may not include the loop filter 1042.
  • the AD converter 115 converts the signal output from the loop filter 1042 into a digital value.
  • the frequency of the signal generated by the voltage controlled oscillator 1060A is controlled based on the signal output from the loop filter 1042. For this reason, the capsule endoscope position measuring apparatus 1H does not have the intermediate frequency adjusting circuit 107 in the capsule endoscope position measuring apparatus 1C.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1I may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1I may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring apparatus 1I may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
  • the capsule endoscope position measuring device 1I includes the phase difference measuring circuit 104B configured by a PLL, the circuit scale is reduced and the cost is reduced.
  • FIG. 11 shows the configuration of a capsule endoscope position measuring apparatus 1J according to the tenth embodiment of the present invention.
  • the capsule endoscope position measurement apparatus 1J includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a counter 104C, and a position calculation circuit. 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and a comparator 114. The difference between the configuration shown in FIG. 11 and the configuration shown in FIG. 4 will be described.
  • the comparator 114 is the same as the comparator 114 in the capsule endoscope position measuring apparatus 1H.
  • the phase difference measurement circuit 104 is a counter 104C.
  • the counter 104C counts the time between the first time when the pulse of the binary signal output from the comparator 114 is detected and the second time when the pulse of the reference signal is detected. Measure the phase difference.
  • the counter 104C starts counting when a pulse of the binary signal output from the comparator 114 is detected, and ends counting when a pulse of the reference signal is detected.
  • the counter 104C may start counting when a pulse of the reference signal is detected, and may end counting when a pulse of the binary signal output from the comparator 114 is detected. Accordingly, the counter 104C measures the phase difference between the binary signal output from the comparator 114 and the reference signal.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measuring device 1J may include the reference frequency adjusting circuit 108 in the capsule endoscope position measuring device 1D.
  • the capsule endoscope position measurement device 1J may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement device 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring device 1J may include the narrow band filter 113 in the capsule endoscope position measuring device 1G.
  • the circuit scale is reduced.
  • FIG. 12 shows a configuration of a capsule endoscope position measuring apparatus 1K according to the eleventh embodiment of the present invention.
  • the capsule endoscope position measurement apparatus 1K includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a TDC 104A, and a position calculation circuit 105.
  • the configuration shown in FIG. 12 will be described while referring to differences from the configuration shown in FIG.
  • the intensity measurement circuit 116 measures the intensity of the signal processed by the processing circuit 102.
  • the second phase difference correction circuit 117 corrects the phase difference for each of the at least four antennas 100 measured by the phase difference measurement circuit 104, that is, the TDC 104A, based on the intensity measured by the intensity measurement circuit 116.
  • the intensity measurement circuit 116 measures the intensity of the signal down-converted by the down-conversion circuit 106A. That is, the intensity measurement circuit 116 measures the intensity of the signal output from the down-conversion circuit 106A. The intensity measurement circuit 116 may measure the intensity of the signal input to the down-conversion circuit 106A.
  • the binary signal output from the comparator 114 has characteristics according to the intensity of the signal input to the comparator 114. Specifically, each time of the rise and fall of the binary signal changes according to the strength of the signal input to the comparator 114. When the intensity of the signal input to the comparator 114 is larger, each time of rising and falling of the binary signal is shorter. If each time of the rise and fall of the binary signal is not constant, an error is included in the phase difference, that is, the time measured by the TDC 104A. Therefore, the second phase difference correction circuit 117 corrects the time measured by the TDC 104A based on the intensity measured by the intensity measurement circuit 116.
  • the second phase difference correction circuit 117 calculates a time correction value based on the difference between the intensity measured by the intensity measurement circuit 116 and the reference intensity.
  • the time correction value is based on the difference between the rise or fall time of the binary signal corresponding to the reference intensity and the rise or fall time of the binary signal corresponding to the intensity measured by the intensity measurement circuit 116.
  • the second phase difference correction circuit 117 corrects the time measured by the TDC 104A based on the time correction value.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1K may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1K may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring apparatus 1K may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
  • the capsule endoscope position measuring apparatus 1K may include a counter 104C in the capsule endoscope position measuring apparatus 1J instead of the TDC 104A.
  • the capsule endoscope position measurement apparatus 1K includes the intensity measurement circuit 116 and the second phase difference correction circuit 117, so that the position measurement can be performed with higher accuracy.
  • FIG. 13 shows the configuration of a capsule endoscope position measuring apparatus 1L according to the twelfth embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1L includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a TDC 104A, and a position calculation circuit 105.
  • the configuration shown in FIG. 13 is different from the configuration shown in FIG.
  • the variable gain amplifier 118 amplifies the signal processed by the processing circuit 102 and the amplification gain is variable.
  • the first control circuit 119 measures the intensity of the signal processed by the processing circuit 102, and based on the measured intensity, the variable gain is set so that the intensity of the signal output from the variable gain amplifier 118 is constant.
  • the amplifier 118 is controlled.
  • the comparator 114 compares the voltage of the signal output from the variable gain amplifier 118 with a reference voltage, and outputs a binary signal according to the comparison result.
  • the variable gain amplifier 118 amplifies the signal down-converted by the down-conversion circuit 106A. That is, the variable gain amplifier 118 amplifies the signal output from the down-conversion circuit 106A.
  • the variable gain amplifier 118 may amplify the signal input to the down-conversion circuit 106A.
  • the first control circuit 119 measures the intensity of the signal down-converted by the down-conversion circuit 106A. That is, the first control circuit 119 measures the intensity of the signal output from the down-conversion circuit 106A. The first control circuit 119 may measure the strength of the signal input to the down-conversion circuit 106A.
  • the rise time and fall time of the binary signal change according to the intensity of the signal input to the comparator 114. Since the intensity of the signal output from the variable gain amplifier 118 becomes constant, the rise and fall times of the binary signal become constant.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1L may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1L may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring device 1L may include the narrow band filter 113 in the capsule endoscope position measuring device 1G.
  • the capsule endoscope position measuring apparatus 1L may include a counter 104C in the capsule endoscope position measuring apparatus 1J instead of the TDC 104A.
  • the capsule endoscope position measuring apparatus 1L includes the variable gain amplifier 118 and the first control circuit 119, so that position measurement can be performed with higher accuracy.
  • FIG. 14 shows a configuration of a capsule endoscope position measuring apparatus 1M according to the thirteenth embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1M includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a TDC 104A, and a position calculation circuit 105.
  • the configuration shown in FIG. 14 will be described while referring to differences from the configuration shown in FIG.
  • the attenuator 120 attenuates the signal processed by the processing circuit 102, and the attenuation amount is variable.
  • the second control circuit 121 measures the intensity of the signal processed by the processing circuit 102, and controls the attenuator 120 so that the intensity of the signal output from the attenuator 120 is constant based on the measured intensity. To do.
  • the comparator 114 compares the voltage of the signal output from the attenuator 120 with a reference voltage, and outputs a binary signal according to the comparison result.
  • the attenuator 120 attenuates the signal down-converted by the down-conversion circuit 106A. That is, the attenuator 120 attenuates the signal output from the down-conversion circuit 106A.
  • the attenuator 120 may attenuate the signal input to the down-conversion circuit 106A.
  • the second control circuit 121 measures the intensity of the signal down-converted by the down-conversion circuit 106A. That is, the second control circuit 121 measures the intensity of the signal output from the down-conversion circuit 106A. The second control circuit 121 may measure the strength of the signal input to the down-conversion circuit 106A.
  • the rise time and fall time of the binary signal change according to the intensity of the signal input to the comparator 114. Since the intensity of the signal output from the attenuator 120 becomes constant, each time of the rise and fall of the binary signal becomes constant.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1M may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1M may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring device 1M may include the narrow band filter 113 in the capsule endoscope position measuring device 1G.
  • the capsule endoscope position measuring apparatus 1M may include a counter 104C in the capsule endoscope position measuring apparatus 1J instead of the TDC 104A.
  • the capsule endoscope position measurement apparatus 1M includes the attenuator 120 and the second control circuit 121, so that the position measurement can be performed with higher accuracy.
  • the attenuator 120 has a smaller delay given to the signal than the variable gain amplifier 118 in the capsule endoscope position measuring apparatus 1L.
  • FIG. 15 shows a configuration of a capsule endoscope position measuring apparatus 1N according to the fourteenth embodiment of the present invention.
  • the capsule endoscope position measuring apparatus 1N includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and an AD converter 122 are included.
  • the configuration shown in FIG. 15 will be described while referring to differences from the configuration shown in FIG.
  • the AD converter 122 converts each of the signal processed by the processing circuit 102 and the reference signal into a digital value.
  • the phase difference measurement circuit 104 measures the phase difference based on the digital value of the signal processed by the processing circuit 102 and the digital value of the reference signal.
  • the AD converter 122 periodically performs AD conversion.
  • a first digital value sequence of the signal processed by the processing circuit 102 and a second digital value sequence of the reference signal are output from the AD converter 122.
  • the first digital value sequence and the second digital value sequence include a plurality of digital values generated at different times.
  • the AD converter 122 may include a first AD converter that converts the signal processed by the processing circuit 102 into a digital value, and a second AD converter that converts the reference signal into a digital value.
  • the phase difference measurement circuit 104 calculates the correlation between the first digital value sequence and the second digital value sequence using the cross-correlation function. In the first digital value sequence and the second digital value sequence, a shift in the time direction at a position having a high correlation is a phase difference.
  • the phase difference measurement circuit 104 calculates a phase difference by calculating a time direction deviation between the first digital value sequence and the second digital value sequence.
  • the AD converter 122 converts the signal down-converted by the down-conversion circuit 106A into a digital value. That is, the AD converter 122 converts the signal output from the down-conversion circuit 106A into a digital value.
  • the AD converter 122 may convert the signal input to the down-conversion circuit 106A into a digital value.
  • the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement apparatus 1N may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
  • the capsule endoscope position measurement device 1N may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement device 1E.
  • the reference signal generation circuit 103 may be any one of at least four antennas 100.
  • the capsule endoscope position measuring apparatus 1N may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
  • the at least one capsule endoscope position measurement device may include the AD converter 122.
  • the capsule endoscope position measurement device 1N can measure the position with higher accuracy by measuring the phase difference based on the digital value.
  • the amount of processing is reduced.

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Abstract

Disclosed is a capsule endoscope position measurement device wherein at least four antennas are disposed outside of a living body, and receive signals transmitted from a capsule endoscope in a wireless manner. An antenna selection circuit sequentially selects one antenna from among at least the four antennas. A processing circuit processes the signal received by the antenna selected by the antenna selection circuit. A reference signal generation circuit generates a reference signal. A phase difference measurement circuit measures a phase difference between the signal processed by the processing circuit, and the reference signal. A position calculation circuit calculates the position of the capsule endoscope on the basis of the phase differences measured with respect to at least the four antennas, said phase differences having been measured by the phase difference measurement circuit.

Description

カプセル内視鏡位置測定装置Capsule endoscope position measuring device
　本発明は、カプセル内視鏡位置測定装置に関する。 The present invention relates to a capsule endoscope position measuring device.
　生体の内部を観察するためのカプセル内視鏡が利用されている。カプセル内視鏡が撮影を行った位置は、治療のために参照される。このため、カプセル内視鏡の位置の測定が重要である。 A capsule endoscope for observing the inside of a living body is used. The position where the capsule endoscope has taken an image is referred to for treatment. For this reason, it is important to measure the position of the capsule endoscope.
　カプセル内視鏡の位置を測定する方法が特許文献１に開示されている。特許文献１の段落００３５から００４３に開示された方法において、生体の内部の無線装置すなわちカプセル内視鏡からの信号が複数のアンテナによって受信される。受信された各信号の位相差に基づいてカプセル内視鏡の位置が測定される。 A method for measuring the position of a capsule endoscope is disclosed in Patent Document 1. In the method disclosed in paragraphs 0035 to 0043 of Patent Document 1, signals from a radio apparatus inside a living body, that is, a capsule endoscope, are received by a plurality of antennas. The position of the capsule endoscope is measured based on the phase difference between the received signals.
　特許文献１に開示された方法によりカプセル内視鏡の位置を測定するカプセル内視鏡位置測定装置の例を説明する。図１６は、従来技術のカプセル内視鏡位置測定装置９の構成を示している。図１６に示すように、カプセル内視鏡位置測定装置９は、複数のアンテナ９００と、アンテナ選択回路９０１と、処理回路９０２と、処理回路９０３と、位相差測定回路９０４と、位置算出回路９０５とを有する。 An example of a capsule endoscope position measuring apparatus that measures the position of a capsule endoscope by the method disclosed in Patent Document 1 will be described. FIG. 16 shows a configuration of a conventional capsule endoscope position measuring apparatus 9. As shown in FIG. 16, the capsule endoscope position measuring device 9 includes a plurality of antennas 900, an antenna selection circuit 901, a processing circuit 902, a processing circuit 903, a phase difference measuring circuit 904, and a position calculating circuit 905. And have.
　複数のアンテナ９００は、生体の外部に配置され、かつカプセル内視鏡２から無線で送信された信号を受信する。例えば、図１６に示すように８本のアンテナ９００が配置される。アンテナ選択回路９０１は、複数のアンテナ９００から２本のアンテナ９００を順次選択する。処理回路９０２と処理回路９０３との各々は、アンテナ選択回路９０１によって選択された２本のアンテナ９００によって受信された信号の各々を処理する。例えば、処理回路９０２と処理回路９０３とは、フィルタとアンプとを有する。フィルタは、アンテナ９００によって受信された信号のうち所定の周波数帯域以外の周波数を有する信号を除去する。アンプは、フィルタを通過した信号を増幅する。位相差測定回路９０４は、処理回路９０２によって処理された信号と、処理回路９０３によって処理された信号との位相差を測定する。位置算出回路９０５は、位相差測定回路９０４によって測定された位相差に基づいて、カプセル内視鏡２の位置を算出する。 The plurality of antennas 900 are arranged outside the living body and receive signals transmitted from the capsule endoscope 2 wirelessly. For example, as shown in FIG. 16, eight antennas 900 are arranged. The antenna selection circuit 901 sequentially selects two antennas 900 from the plurality of antennas 900. Each of the processing circuit 902 and the processing circuit 903 processes each of the signals received by the two antennas 900 selected by the antenna selection circuit 901. For example, the processing circuit 902 and the processing circuit 903 include a filter and an amplifier. The filter removes a signal having a frequency other than a predetermined frequency band from the signal received by the antenna 900. The amplifier amplifies the signal that has passed through the filter. The phase difference measurement circuit 904 measures the phase difference between the signal processed by the processing circuit 902 and the signal processed by the processing circuit 903. The position calculation circuit 905 calculates the position of the capsule endoscope 2 based on the phase difference measured by the phase difference measurement circuit 904.
　図１７は、従来技術の方法によりカプセル内視鏡２の位置を測定する手順を示す。図１７を参照し、カプセル内視鏡２の位置を測定する方法を説明する。 FIG. 17 shows a procedure for measuring the position of the capsule endoscope 2 by a conventional method. A method for measuring the position of the capsule endoscope 2 will be described with reference to FIG.
　カプセル内視鏡２が無線で信号を送信する（ステップＳ１００１）。カプセル内視鏡２から信号が送信された後、複数のアンテナ９００は、カプセル内視鏡２からの信号を受信する（ステップＳ１００２）。複数のアンテナ９００が信号を受信した後、変数Ｎ１が１に設定され、かつ変数Ｎ２が２に設定される（ステップＳ１００３）。変数Ｎ１と変数Ｎ２とは、図示していない制御回路によって管理される。ステップＳ１００３の後、変数Ｎ１と変数Ｎ２とが同一である場合（ステップＳ１００４）、変数Ｎ２が１増加する（ステップＳ１００５）。その後、アンテナ選択回路９０１は、２本のアンテナ９００を切り替える（ステップＳ１００６）。位置測定が開始された直後は、ステップＳ１００６において、最初の２本のアンテナ９００が選択される。ステップＳ１００６における処理が再度行われる場合、既に選択された２本のアンテナ９００の組合せと異なる組合せが選択される。ステップＳ１００３の後、変数Ｎ１と変数Ｎ２とが同一でない場合（ステップＳ１００４）、アンテナ選択回路９０１は、２本のアンテナ９００を切り替える（ステップＳ１００６）。 The capsule endoscope 2 transmits a signal wirelessly (step S1001). After the signal is transmitted from the capsule endoscope 2, the plurality of antennas 900 receive the signal from the capsule endoscope 2 (step S1002). After the plurality of antennas 900 receive the signal, the variable N1 is set to 1 and the variable N2 is set to 2 (step S1003). The variables N1 and N2 are managed by a control circuit (not shown). After step S1003, when variable N1 and variable N2 are the same (step S1004), variable N2 is incremented by 1 (step S1005). Thereafter, the antenna selection circuit 901 switches between the two antennas 900 (step S1006). Immediately after the position measurement is started, the first two antennas 900 are selected in step S1006. When the process in step S1006 is performed again, a combination different from the combination of the two antennas 900 already selected is selected. After step S1003, when the variable N1 and the variable N2 are not the same (step S1004), the antenna selection circuit 901 switches between the two antennas 900 (step S1006).
　２本のアンテナ９００が切り替えられた後、処理回路９０２と処理回路９０３との各々は、アンテナ選択回路９０１によって選択された２本のアンテナ９００によって受信された信号の各々を処理する。位相差測定回路９０４は、処理回路９０２によって処理された信号と、処理回路９０３によって処理された信号との位相差を測定する（ステップＳ１００７）。位置算出回路９０５は、測定された位相差を示す位相差情報を保持する（ステップＳ１００８）。 After the two antennas 900 are switched, each of the processing circuit 902 and the processing circuit 903 processes each of the signals received by the two antennas 900 selected by the antenna selection circuit 901. The phase difference measurement circuit 904 measures the phase difference between the signal processed by the processing circuit 902 and the signal processed by the processing circuit 903 (step S1007). The position calculation circuit 905 holds phase difference information indicating the measured phase difference (step S1008).
　位相差情報が保持された後、変数Ｎ２が８でない場合（ステップＳ１００９）、変数Ｎ２が１増加する（ステップＳ１０１０）。変数Ｎ２が１増加した後、ステップＳ１００４における判断が行われる。位相差情報が保持された後、変数Ｎ２が８である場合（ステップＳ１００９）、以下の処理が行われる。変数Ｎ１が７でない場合（ステップＳ１０１１）、変数Ｎ１が１増加し、かつ変数Ｎ２が、変数Ｎ１よりも１大きい値に設定される（ステップＳ１０１２）。その後、ステップＳ１００４における判断が行われる。変数Ｎ１が７である場合（ステップＳ１０１１）、位置算出回路９０５は、位相差情報に基づいて、カプセル内視鏡２の位置を算出する（ステップＳ１０１３）。 After the phase difference information is held, if the variable N2 is not 8 (step S1009), the variable N2 is incremented by 1 (step S1010). After the variable N2 is incremented by 1, determination in step S1004 is performed. After the phase difference information is held, when the variable N2 is 8 (step S1009), the following processing is performed. If the variable N1 is not 7 (step S1011), the variable N1 is incremented by 1 and the variable N2 is set to a value that is 1 larger than the variable N1 (step S1012). Thereafter, the determination in step S1004 is performed. When the variable N1 is 7 (step S1011), the position calculation circuit 905 calculates the position of the capsule endoscope 2 based on the phase difference information (step S1013).
　２本のアンテナ９００の組合せが少なくとも３組必要である。２本のアンテナ９００の組合せの数が多い場合、算出精度が上がる。例えば、８本のアンテナ９００が配置されている場合、２本のアンテナ９００の組合せの最大数は２８である。図１７に示す方法では、最大で２８通りの組合せに対して、位相差が測定される。 少 な く と も At least three combinations of two antennas 900 are necessary. When the number of combinations of the two antennas 900 is large, the calculation accuracy increases. For example, when eight antennas 900 are arranged, the maximum number of combinations of two antennas 900 is 28. In the method shown in FIG. 17, the phase difference is measured for a maximum of 28 combinations.
　位置算出回路９０５がカプセル内視鏡２の位置を算出する方法を説明する。位置算出回路９０５は、式（１）により距離ｄｎｍを算出することができる。式（１）において、距離ｄｎｍは、カプセル内視鏡２から２本のアンテナ９００の各々までの距離の差である。φｎｍは、２本のアンテナ９００の各々によって受信された信号の位相差である。ｆは、信号の周波数である。Ｖは、媒質内の信号の伝達速度である。 A method by which the position calculation circuit 905 calculates the position of the capsule endoscope 2 will be described. The position calculation circuit 905 can calculate the distance d nm by the equation (1). In equation (1), the distance d nm is a difference in distance from the capsule endoscope 2 to each of the two antennas 900. φ nm is a phase difference between signals received by each of the two antennas 900. f is the frequency of the signal. V is the transmission speed of the signal in the medium.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　距離ｄｎｍは、式（２）を満たす。式（２）において、（ｘ，ｙ，ｚ）は、カプセル内視鏡２の位置座標である。（ｘｍ，ｙｍ，ｚｍ）と（ｘｎ，ｙｎ，ｚｎ）とは、２本のアンテナ９００の各々の位置座標である。 The distance d nm satisfies the formula (2). In equation (2), (x, y, z) is the position coordinate of the capsule endoscope 2. (X m , y m , z m ) and (x n , y n , z n ) are the position coordinates of each of the two antennas 900.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　式（２）は、カプセル内視鏡２の位置座標（ｘ，ｙ，ｚ）に関する１つの方程式である。式（２）において未知数は３である。式（２）が示す方程式を３つ以上含む連立方程式を解くことにより、位置算出回路９０５は、カプセル内視鏡２の位置を算出することができる。 Equation (2) is one equation regarding the position coordinates (x, y, z) of the capsule endoscope 2. In Equation (2), the unknown is 3. The position calculation circuit 905 can calculate the position of the capsule endoscope 2 by solving simultaneous equations including three or more equations represented by Expression (2).
日本国特開２００４－２１９３２９号公報Japanese Unexamined Patent Publication No. 2004-219329
　カプセル内視鏡位置測定装置９は、２本のアンテナ９００を順次切り替える。このため、アンテナ９００の選択に要する処理量が多い。 The capsule endoscope position measuring device 9 switches the two antennas 900 sequentially. For this reason, the amount of processing required for selecting the antenna 900 is large.
　本発明は、処理量が削減されたカプセル内視鏡位置測定装置を提供することを目的とする。 An object of the present invention is to provide a capsule endoscope position measuring device with a reduced processing amount.
　本発明の第１の態様によれば、カプセル内視鏡位置測定装置は、少なくとも４本のアンテナと、アンテナ選択回路と、処理回路と、基準信号生成回路と、位相差測定回路と、位置算出回路とを有する。前記少なくとも４本のアンテナは、生体の外部に配置され、かつカプセル内視鏡から無線で送信された信号を受信する。アンテナ選択回路は、前記少なくとも４本のアンテナから１本の前記アンテナを順次選択する。処理回路は、前記アンテナ選択回路によって選択された前記アンテナによって受信された前記信号を処理する。基準信号生成回路は、基準信号を生成する。位相差測定回路は、前記処理回路によって処理された前記信号と前記基準信号との位相差を測定する。位置算出回路は、前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差に基づいて、前記カプセル内視鏡の位置を算出する。 According to the first aspect of the present invention, a capsule endoscope position measurement apparatus includes at least four antennas, an antenna selection circuit, a processing circuit, a reference signal generation circuit, a phase difference measurement circuit, and a position calculation. Circuit. The at least four antennas are disposed outside the living body and receive signals transmitted wirelessly from the capsule endoscope. The antenna selection circuit sequentially selects one antenna from the at least four antennas. A processing circuit processes the signal received by the antenna selected by the antenna selection circuit. The reference signal generation circuit generates a reference signal. The phase difference measurement circuit measures a phase difference between the signal processed by the processing circuit and the reference signal. The position calculation circuit calculates the position of the capsule endoscope based on the phase difference for each of the at least four antennas measured by the phase difference measurement circuit.
　本発明の第２の態様によれば、第１の態様において、前記カプセル内視鏡位置測定装置は、前記処理回路によって処理された前記信号の周波数を中間周波数にダウンコンバートするダウンコンバート回路をさらに有してもよい。 According to a second aspect of the present invention, in the first aspect, the capsule endoscope position measurement apparatus further includes a down-conversion circuit that down-converts the frequency of the signal processed by the processing circuit to an intermediate frequency. You may have.
　本発明の第３の態様によれば、第２の態様において、前記カプセル内視鏡位置測定装置は、前記位相差測定回路によって測定された位相差に基づいて、前記中間周波数を調整する中間周波数調整回路をさらに有してもよい。 According to a third aspect of the present invention, in the second aspect, the capsule endoscope position measuring device adjusts the intermediate frequency based on the phase difference measured by the phase difference measuring circuit. An adjustment circuit may be further included.
　本発明の第４の態様によれば、第２または第３の態様において、前記ダウンコンバート回路は、電圧制御発振器と、ミキサとを有してもよい。前記電圧制御発振器は、前記少なくとも４本のアンテナによって受信される前記信号の周波数と異なる周波数を有する信号を生成する。前記ミキサは、前記処理回路によって処理された前記信号と、前記電圧制御発振器によって生成された前記信号とを混合する。 According to the fourth aspect of the present invention, in the second or third aspect, the down-conversion circuit may include a voltage controlled oscillator and a mixer. The voltage controlled oscillator generates a signal having a frequency different from the frequency of the signal received by the at least four antennas. The mixer mixes the signal processed by the processing circuit with the signal generated by the voltage controlled oscillator.
　本発明の第５の態様によれば、第２から第４の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、前記ダウンコンバート回路によってダウンコンバートされた前記信号の周波数帯域を制限する狭帯域フィルタをさらに有してもよい。 According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the capsule endoscope position measuring device uses the frequency band of the signal down-converted by the down-conversion circuit. You may further have the narrow-band filter to restrict | limit.
　本発明の第６の態様によれば、第２から第５の態様のいずれか１つにおいて、前記基準信号の周波数は、前記中間周波数と同一になるように設定されてもよい。 According to the sixth aspect of the present invention, in any one of the second to fifth aspects, the frequency of the reference signal may be set to be the same as the intermediate frequency.
　本発明の第７の態様によれば、第１の態様において、前記基準信号の周波数は、前記少なくとも４本のアンテナによって受信される前記信号の周波数と同一になるように設定されてもよい。 According to a seventh aspect of the present invention, in the first aspect, the frequency of the reference signal may be set to be the same as the frequency of the signal received by the at least four antennas.
　本発明の第８の態様によれば、第１から第７の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、前記位相差測定回路によって測定された位相差に基づいて、前記基準信号の周波数を調整する基準周波数調整回路をさらに有してもよい。 According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the capsule endoscope position measuring device is based on the phase difference measured by the phase difference measuring circuit. A reference frequency adjusting circuit for adjusting the frequency of the reference signal may be further included.
　本発明の第９の態様によれば、第１から第８の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、時間変化測定回路と、第１の位相差補正回路とをさらに有してもよい。前記時間変化測定回路は、前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差の時間変化を測定する。前記第１の位相差補正回路は、前記時間変化測定回路によって測定された前記時間変化に基づいて、前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差を補正する。 According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the capsule endoscope position measurement device includes a time change measurement circuit and a first phase difference correction circuit. Furthermore, you may have. The time change measuring circuit measures the time change of the phase difference for each of the at least four antennas measured by the phase difference measuring circuit. The first phase difference correction circuit corrects the phase difference for each of the at least four antennas measured by the phase difference measurement circuit based on the time change measured by the time change measurement circuit. To do.
　本発明の第１０の態様によれば、第１から第９の態様のいずれか１つにおいて、前記基準信号生成回路は、電圧制御発振器であってもよい。 According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the reference signal generation circuit may be a voltage controlled oscillator.
　本発明の第１１の態様によれば、第１から第９の態様のいずれか１つにおいて、前記基準信号生成回路は、水晶発振器であってもよい。 According to an eleventh aspect of the present invention, in any one of the first to ninth aspects, the reference signal generation circuit may be a crystal oscillator.
　本発明の第１２の態様によれば、第１から第７の態様のいずれか１つにおいて、前記基準信号生成回路は、前記少なくとも４本のアンテナのいずれか１つであってもよい。 According to a twelfth aspect of the present invention, in any one of the first to seventh aspects, the reference signal generation circuit may be any one of the at least four antennas.
　本発明の第１３の態様によれば、第１２の態様において、前記基準信号生成回路は、前記少なくとも４本のアンテナのうち受信強度が最も高い前記アンテナであってもよい。 According to a thirteenth aspect of the present invention, in the twelfth aspect, the reference signal generation circuit may be the antenna having the highest reception intensity among the at least four antennas.
　本発明の第１４の態様によれば、第１から第１３の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、前記処理回路によって処理された前記信号の電圧と基準電圧とを比較し、かつ比較結果に応じて２値のいずれか１つを有する２値信号を出力する比較器をさらに有してもよい。前記位相差測定回路は、前記２値信号と前記基準信号との前記位相差を測定してもよい。 According to a fourteenth aspect of the present invention, in any one of the first to thirteenth aspects, the capsule endoscope position measuring device includes: a voltage of the signal processed by the processing circuit; a reference voltage; And a comparator that outputs a binary signal having any one of the two values according to the comparison result. The phase difference measurement circuit may measure the phase difference between the binary signal and the reference signal.
　本発明の第１５の態様によれば、第１４の態様において、前記位相差測定回路は、ＴＤＣ（Ｔｉｍｅ　ｔｏ　Ｄｉｇｉｔａｌ　Ｃｏｎｖｅｒｔｅｒ）であってもよい。 According to a fifteenth aspect of the present invention, in the fourteenth aspect, the phase difference measurement circuit may be a TDC (Time to Digital Converter).
　本発明の第１６の態様によれば、第１４の態様において、前記位相差測定回路は、位相比較器と、チャージポンプとを有してもよい。前記位相比較器は、前記２値信号の位相と前記基準信号の位相とを比較する。前記チャージポンプは、前記位相比較器によって比較された前記２値信号の位相と前記基準信号の位相との差に応じた電圧信号を出力する。 According to a sixteenth aspect of the present invention, in the fourteenth aspect, the phase difference measurement circuit may include a phase comparator and a charge pump. The phase comparator compares the phase of the binary signal with the phase of the reference signal. The charge pump outputs a voltage signal corresponding to a difference between the phase of the binary signal compared by the phase comparator and the phase of the reference signal.
　本発明の第１７の態様によれば、第１４の態様において、前記位相差測定回路は、カウンタであってもよい。 According to a seventeenth aspect of the present invention, in the fourteenth aspect, the phase difference measuring circuit may be a counter.
　本発明の第１８の態様によれば、第１４から第１７の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、強度測定回路と、第２の位相差補正回路とをさらに有してもよい。前記強度測定回路は、前記処理回路によって処理された前記信号の強度を測定する。前記第２の位相差補正回路は、前記強度測定回路によって測定された前記強度に基づいて、前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差を補正する。 According to an eighteenth aspect of the present invention, in any one of the fourteenth to seventeenth aspects, the capsule endoscope position measurement device further includes an intensity measurement circuit and a second phase difference correction circuit. You may have. The intensity measurement circuit measures the intensity of the signal processed by the processing circuit. The second phase difference correction circuit corrects the phase difference for each of the at least four antennas measured by the phase difference measurement circuit based on the intensity measured by the intensity measurement circuit.
　本発明の第１９の態様によれば、第１４から第１７の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、可変ゲインアンプと、第１の制御回路とをさらに有してもよい。前記可変ゲインアンプは、前記処理回路によって処理された前記信号を増幅し、かつ増幅のゲインが可変である。前記第１の制御回路は、前記処理回路によって処理された前記信号の強度を測定し、かつ測定された前記強度に基づいて、前記可変ゲインアンプから出力される信号の強度が一定になるように前記可変ゲインアンプを制御する。前記比較器は、前記可変ゲインアンプから出力された前記信号の電圧と前記基準電圧とを比較し、かつ比較結果に応じて前記２値信号を出力してもよい。 According to a nineteenth aspect of the present invention, in any one of the fourteenth to seventeenth aspects, the capsule endoscope position measuring device further includes a variable gain amplifier and a first control circuit. May be. The variable gain amplifier amplifies the signal processed by the processing circuit, and an amplification gain is variable. The first control circuit measures the intensity of the signal processed by the processing circuit, and based on the measured intensity, the intensity of the signal output from the variable gain amplifier is constant. The variable gain amplifier is controlled. The comparator may compare the voltage of the signal output from the variable gain amplifier with the reference voltage, and output the binary signal according to a comparison result.
　本発明の第２０の態様によれば、第１４から第１７の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、アッテネータと、第２の制御回路とをさらに有してもよい。前記アッテネータは、前記処理回路によって処理された前記信号を減衰させ、かつ減衰量が可変である。前記第２の制御回路は、前記処理回路によって処理された前記信号の強度を測定し、かつ測定された前記強度に基づいて、前記アッテネータから出力される信号の強度が一定になるように前記アッテネータを制御する。前記比較器は、前記アッテネータから出力された前記信号の電圧と前記基準電圧とを比較し、かつ比較結果に応じて前記２値信号を出力してもよい。 According to a twentieth aspect of the present invention, in any one of the fourteenth to seventeenth aspects, the capsule endoscope position measuring device may further include an attenuator and a second control circuit. Good. The attenuator attenuates the signal processed by the processing circuit, and the attenuation amount is variable. The second control circuit measures the intensity of the signal processed by the processing circuit, and based on the measured intensity, the intensity of the signal output from the attenuator is constant. To control. The comparator may compare the voltage of the signal output from the attenuator with the reference voltage and output the binary signal according to the comparison result.
　本発明の第２１の態様によれば、第１から第１３の態様のいずれか１つにおいて、前記カプセル内視鏡位置測定装置は、前記処理回路によって処理された前記信号と前記基準信号との各々をデジタル値に変換するＡＤ変換器をさらに有してもよい。前記位相差測定回路は、前記処理回路によって処理された前記信号の前記デジタル値と前記基準信号の前記デジタル値とに基づいて、前記位相差を測定してもよい。 According to a twenty-first aspect of the present invention, in any one of the first to thirteenth aspects, the capsule endoscope position measuring device includes: the signal processed by the processing circuit; and the reference signal. You may further have AD converter which converts each into a digital value. The phase difference measurement circuit may measure the phase difference based on the digital value of the signal processed by the processing circuit and the digital value of the reference signal.
　上記の各態様によれば、カプセル内視鏡位置測定装置は、少なくとも４本のアンテナから検出対象の１本のアンテナを順次選択するアンテナ選択回路を有する。このため、処理量が削減される。 According to each of the above aspects, the capsule endoscope position measurement apparatus has the antenna selection circuit that sequentially selects one antenna to be detected from at least four antennas. For this reason, the amount of processing is reduced.
本発明の第１の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 1st Embodiment of this invention. 本発明の第１の実施形態においてカプセル内視鏡の位置を測定する手順を示すフローチャートである。It is a flowchart which shows the procedure which measures the position of a capsule endoscope in the 1st Embodiment of this invention. 本発明の第２の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 2nd Embodiment of this invention. 本発明の第３の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 3rd Embodiment of this invention. 本発明の第４の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 4th Embodiment of this invention. 本発明の第５の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 5th Embodiment of this invention. 本発明の第６の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 6th Embodiment of this invention. 本発明の第７の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 7th Embodiment of this invention. 本発明の第８の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 8th Embodiment of this invention. 本発明の第９の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 9th Embodiment of this invention. 本発明の第１０の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 10th Embodiment of this invention. 本発明の第１１の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 11th Embodiment of this invention. 本発明の第１２の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 12th Embodiment of this invention. 本発明の第１３の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 13th Embodiment of this invention. 本発明の第１４の実施形態のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of the 14th Embodiment of this invention. 従来技術のカプセル内視鏡位置測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the capsule endoscope position measuring apparatus of a prior art. 従来技術の方法によりカプセル内視鏡の位置を測定する手順を示すフローチャートである。It is a flowchart which shows the procedure which measures the position of a capsule endoscope by the method of a prior art.
　図面を参照し、本発明の実施形態を説明する。 Embodiments of the present invention will be described with reference to the drawings.
　（第１の実施形態）
　図１は、本発明の第１の実施形態のカプセル内視鏡位置測定装置１Ａの構成を示している。図１に示すように、カプセル内視鏡位置測定装置１Ａは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４と、位置算出回路１０５とを有する。 (First embodiment)
FIG. 1 shows a configuration of a capsule endoscope position measuring apparatus 1A according to the first embodiment of the present invention. As shown in FIG. 1, the capsule endoscope position measurement apparatus 1A includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105.
　少なくとも４本のアンテナ１００は、生体の外部に配置され、かつカプセル内視鏡２から無線で送信された信号を受信する。アンテナ選択回路１０１は、少なくとも４本のアンテナ１００から１本のアンテナ１００を順次選択する。処理回路１０２は、アンテナ選択回路１０１によって選択されたアンテナ１００によって受信された信号を処理する。基準信号生成回路１０３は、基準信号を生成する。位相差測定回路１０４は、処理回路１０２によって処理された信号と基準信号との位相差を測定する。位置算出回路１０５は、位相差測定回路１０４によって測定された、少なくとも４本のアンテナ１００の各々に対する位相差に基づいて、カプセル内視鏡２の位置を算出する。 The at least four antennas 100 are arranged outside the living body and receive signals transmitted from the capsule endoscope 2 by radio. The antenna selection circuit 101 sequentially selects one antenna 100 from at least four antennas 100. The processing circuit 102 processes a signal received by the antenna 100 selected by the antenna selection circuit 101. The reference signal generation circuit 103 generates a reference signal. The phase difference measurement circuit 104 measures the phase difference between the signal processed by the processing circuit 102 and the reference signal. The position calculation circuit 105 calculates the position of the capsule endoscope 2 based on the phase difference for each of the at least four antennas 100 measured by the phase difference measurement circuit 104.
　カプセル内視鏡２は、生体の内部に配置される。アンテナ選択回路１０１は、選択されたアンテナ１００によって受信された信号を処理回路１０２に出力する。例えば、処理回路１０２は、フィルタとアンプとを有する。フィルタは、アンテナ１００によって受信された信号のうち所定の周波数帯域以外の周波数を有する信号を除去する。アンプは、フィルタを通過した信号を増幅する。つまり、処理回路１０２は、アンテナ１００によって受信された信号のうち所定の周波数帯域以外の周波数を有する信号をフィルタによって除去し、かつフィルタを通過した信号をアンプによって増幅する。基準信号は、所定の周波数を有する信号である。 The capsule endoscope 2 is disposed inside the living body. The antenna selection circuit 101 outputs a signal received by the selected antenna 100 to the processing circuit 102. For example, the processing circuit 102 includes a filter and an amplifier. The filter removes a signal having a frequency other than a predetermined frequency band from the signal received by the antenna 100. The amplifier amplifies the signal that has passed through the filter. That is, the processing circuit 102 removes a signal having a frequency other than a predetermined frequency band from the signal received by the antenna 100 with a filter, and amplifies the signal that has passed through the filter with an amplifier. The reference signal is a signal having a predetermined frequency.
　図２は、第１の実施形態においてカプセル内視鏡２の位置を測定する手順を示す。図２を参照し、カプセル内視鏡２の位置を測定する方法を説明する。 FIG. 2 shows a procedure for measuring the position of the capsule endoscope 2 in the first embodiment. A method for measuring the position of the capsule endoscope 2 will be described with reference to FIG.
　カプセル内視鏡２が無線で信号を送信する（ステップＳ１０１）。例えば、カプセル内視鏡２が送信する信号は、カプセル内視鏡２が撮影した画像を含む信号、または位置測定のための信号である。カプセル内視鏡２から信号が送信された後、少なくとも４本のアンテナ１００は、カプセル内視鏡２からの信号を受信する（ステップＳ１０２）。少なくとも４本のアンテナ１００が信号を受信した後、基準信号生成回路１０３は、基準信号を生成する（ステップＳ１０３）。基準信号が生成された後、変数ｎが１に設定される（ステップＳ１０４）。変数ｎは、図示していない制御回路によって管理される。ステップＳ１０４の後、アンテナ選択回路１０１は、１本のアンテナ１００を切り替える（ステップＳ１０５）。位置測定が開始された直後は、ステップＳ１０５において、最初の１本のアンテナ１００が選択される。ステップＳ１０５における処理が再度行われる場合、既に選択された１本のアンテナ１００と異なるアンテナ１００が選択される。 The capsule endoscope 2 transmits a signal wirelessly (step S101). For example, the signal transmitted by the capsule endoscope 2 is a signal including an image captured by the capsule endoscope 2 or a signal for position measurement. After signals are transmitted from the capsule endoscope 2, at least four antennas 100 receive signals from the capsule endoscope 2 (step S102). After at least four antennas 100 receive the signal, the reference signal generation circuit 103 generates a reference signal (step S103). After the reference signal is generated, the variable n is set to 1 (step S104). The variable n is managed by a control circuit (not shown). After step S104, the antenna selection circuit 101 switches one antenna 100 (step S105). Immediately after the position measurement is started, the first antenna 100 is selected in step S105. When the process in step S105 is performed again, an antenna 100 different from the already selected one antenna 100 is selected.
　１本のアンテナ１００が切り替えられた後、処理回路１０２は、アンテナ選択回路１０１によって選択された１本のアンテナ１００によって受信された信号を処理する。位相差測定回路１０４は、処理回路１０２によって処理された信号と、基準信号生成回路１０３から出力された基準信号との位相差を測定する（ステップＳ１０６）。位置算出回路１０５は、測定された位相差を示す位相差情報を保持する（ステップＳ１０７）。 After the single antenna 100 is switched, the processing circuit 102 processes the signal received by the single antenna 100 selected by the antenna selection circuit 101. The phase difference measurement circuit 104 measures the phase difference between the signal processed by the processing circuit 102 and the reference signal output from the reference signal generation circuit 103 (step S106). The position calculation circuit 105 holds phase difference information indicating the measured phase difference (step S107).
　位相差情報が保持された後、変数ｎが８でない場合（ステップＳ１０８）、変数ｎが１増加する（ステップＳ１０９）。変数ｎが１増加した後、ステップＳ１０５における処理が行われる。位相差情報が保持された後、変数ｎが８である場合（ステップＳ１０８）、位置算出回路１０５は、位相差情報に基づいて、カプセル内視鏡２の位置を算出する（ステップＳ１１０）。 After the phase difference information is held, if the variable n is not 8 (step S108), the variable n is incremented by 1 (step S109). After the variable n is incremented by 1, the process in step S105 is performed. After the phase difference information is held, when the variable n is 8 (step S108), the position calculation circuit 105 calculates the position of the capsule endoscope 2 based on the phase difference information (step S110).
　後述する方法によりカプセル内視鏡２の位置を算出するためには、２本のアンテナ１００の組合せが少なくとも３組必要である。２本のアンテナ１００の組合せの数が多い場合、算出精度が上がる。図２に示す方法では、８本のアンテナ１００の各々によって受信された信号と基準信号との位相差が測定される。その測定結果に基づいて、２本のアンテナ１００の各々によって受信された信号の位相差が算出される。 In order to calculate the position of the capsule endoscope 2 by the method described later, at least three combinations of the two antennas 100 are necessary. When the number of combinations of the two antennas 100 is large, the calculation accuracy increases. In the method shown in FIG. 2, the phase difference between the signal received by each of the eight antennas 100 and the reference signal is measured. Based on the measurement result, the phase difference between the signals received by each of the two antennas 100 is calculated.
　位置算出回路１０５がカプセル内視鏡２の位置を算出する方法を説明する。位置算出回路１０５は、式（３）により、２本のアンテナ１００の各々によって受信された信号の位相差φｎｍを算出する。式（３）において、φｍとφｎとは、２本のアンテナ１００の各々によって受信された信号と基準信号との位相差である。
　φｎｍ＝φｎ－φｍ　・・・（３） A method by which the position calculation circuit 105 calculates the position of the capsule endoscope 2 will be described. The position calculation circuit 105 calculates the phase difference φ nm of the signals received by each of the two antennas 100 using Expression (3). In Expression (3), φ m and φ n are phase differences between the signal received by each of the two antennas 100 and the reference signal.
φ nm = φ n −φ m (3)
　位置算出回路１０５は、式（３）に基づいて、２本のアンテナ１００の各々によって受信された信号と基準信号との位相差の差を算出することにより、２本のアンテナ１００の各々によって受信された信号の位相差φｎｍを算出する。式（３）により、基準信号の位相に関する情報は除去される。位置算出回路１０５は、前述した式（１）において、式（３）により算出された位相差φｎｍを使用することにより、距離ｄｎｍを算出することができる。 The position calculation circuit 105 receives each of the two antennas 100 by calculating the difference in phase difference between the signal received by each of the two antennas 100 and the reference signal based on Expression (3). The phase difference φ nm of the obtained signal is calculated. Information on the phase of the reference signal is removed by equation (3). The position calculation circuit 105 can calculate the distance d nm by using the phase difference φ nm calculated by the equation (3) in the above-described equation (1).
　基準信号の周波数は、少なくとも４本のアンテナ１００によって受信される信号の周波数と同一になるように設定されてもよい。 The frequency of the reference signal may be set to be the same as the frequency of signals received by at least four antennas 100.
　基準信号生成回路１０３は、水晶発振器であってもよい。水晶発振器は、温度補償水晶発振器（ＴＣＸＯ）であってもよい。水晶発振器を使用することにより、基準信号の周波数の精度が高まり、かつ基準信号が安定する。このため、位置測定の精度が向上する。 The reference signal generation circuit 103 may be a crystal oscillator. The crystal oscillator may be a temperature compensated crystal oscillator (TCXO). By using a crystal oscillator, the accuracy of the frequency of the reference signal is increased and the reference signal is stabilized. For this reason, the accuracy of position measurement is improved.
　カプセル内視鏡位置測定装置９において、アンテナ選択回路９０１は２本のアンテナ９００を選択する。一方、カプセル内視鏡位置測定装置１Ａにおいて、アンテナ選択回路１０１は１本のアンテナ１００を選択する。このため、アンテナ選択回路１０１をアンテナ選択回路９０１よりも小さくすることができる。アンテナ選択回路１０１が８本のアンテナ１００を順次選択することにより、カプセル内視鏡位置測定装置１Ａは、２本のアンテナ１００に関する２８通りの組合せに対する位相差を測定することができる。このため、アンテナ１００の選択に要する処理量が削減される。 In the capsule endoscope position measuring apparatus 9, the antenna selection circuit 901 selects two antennas 900. On the other hand, in the capsule endoscope position measuring apparatus 1A, the antenna selection circuit 101 selects one antenna 100. For this reason, the antenna selection circuit 101 can be made smaller than the antenna selection circuit 901. When the antenna selection circuit 101 sequentially selects the eight antennas 100, the capsule endoscope position measuring apparatus 1A can measure the phase differences for the 28 combinations of the two antennas 100. For this reason, the processing amount required for selection of the antenna 100 is reduced.
　カプセル内視鏡位置測定装置９は、２つの処理回路すなわち処理回路９０２と処理回路９０３とを有する。２つの処理回路が必要であるため、回路規模が大きい。一方、カプセル内視鏡位置測定装置１Ａは、アンテナ選択回路１０１によって選択された１本のアンテナ１００によって受信された信号を処理する処理回路１０２を有する。２つの処理回路を有するカプセル内視鏡位置測定装置９と比較して、処理回路の数が少ない。このため、回路規模が削減される。 The capsule endoscope position measuring device 9 has two processing circuits, that is, a processing circuit 902 and a processing circuit 903. Since two processing circuits are required, the circuit scale is large. On the other hand, the capsule endoscope position measurement apparatus 1 </ b> A includes a processing circuit 102 that processes a signal received by one antenna 100 selected by the antenna selection circuit 101. Compared with the capsule endoscope position measuring apparatus 9 having two processing circuits, the number of processing circuits is small. For this reason, the circuit scale is reduced.
　カプセル内視鏡位置測定装置９により位置測定が行われる場合、２つの処理回路の構成のばらつきにより、２本のアンテナ９００の各々によって受信された信号の位相差の測定値に誤差が含まれやすい。カプセル内視鏡位置測定装置１Ａが位置測定を行うことにより、上記の誤差が低減される。 When position measurement is performed by the capsule endoscope position measurement device 9, the measurement value of the phase difference between the signals received by each of the two antennas 900 is likely to contain an error due to variations in the configuration of the two processing circuits. . The above-mentioned error is reduced by the capsule endoscope position measuring apparatus 1A performing position measurement.
　（第２の実施形態）
　図３は、本発明の第２の実施形態のカプセル内視鏡位置測定装置１Ｂの構成を示している。図３に示すように、カプセル内視鏡位置測定装置１Ｂは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４と、位置算出回路１０５と、ダウンコンバート回路１０６とを有する。図３に示す構成について、図１に示す構成と異なる点を説明する。 (Second Embodiment)
FIG. 3 shows a configuration of a capsule endoscope position measuring apparatus 1B according to the second embodiment of the present invention. As shown in FIG. 3, the capsule endoscope position measuring apparatus 1B includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105 and a down-conversion circuit 106 are included. The difference between the configuration shown in FIG. 3 and the configuration shown in FIG. 1 will be described.
　ダウンコンバート回路１０６は、処理回路１０２によって処理された信号の周波数を中間周波数にダウンコンバートする。ダウンコンバート回路１０６は、局部発振器１０６０と、ミキサ１０６１とを有する。局部発振器１０６０は、複数のアンテナ１００によって受信される信号の周波数と異なる周波数を有する信号を生成する。ミキサ１０６１は、処理回路１０２によって処理された信号と、局部発振器１０６０によって生成された信号とを混合する。これによって、ミキサ１０６１は、中間周波数を有する信号を生成し、かつ生成された信号を出力する。ミキサ１０６１から出力される信号の周波数（中間周波数Ｆｉ）は、少なくとも４本のアンテナ１００によって受信される信号の周波数（Ｆｒ）と、局部発振器１０６０によって生成される信号の周波数（Ｆｄ）との差である。局部発振器１０６０が生成する信号の周波数（Ｆｄ）が、少なくとも４本のアンテナ１００によって受信される信号の周波数（Ｆｒ）よりも低い場合、中間周波数Ｆｉは、（Ｆｒ－Ｆｄ）である。局部発振器１０６０が生成する信号の周波数（Ｆｄ）が、少なくとも４本のアンテナ１００によって受信される信号の周波数（Ｆｒ）よりも高い場合、中間周波数Ｆｉは、（Ｆｄ－Ｆｒ）である。 The down-conversion circuit 106 down-converts the frequency of the signal processed by the processing circuit 102 to an intermediate frequency. The down-conversion circuit 106 includes a local oscillator 1060 and a mixer 1061. The local oscillator 1060 generates a signal having a frequency different from the frequency of signals received by the plurality of antennas 100. The mixer 1061 mixes the signal processed by the processing circuit 102 and the signal generated by the local oscillator 1060. As a result, the mixer 1061 generates a signal having an intermediate frequency and outputs the generated signal. The frequency (intermediate frequency Fi) of the signal output from the mixer 1061 is the difference between the frequency (Fr) of the signal received by at least four antennas 100 and the frequency (Fd) of the signal generated by the local oscillator 1060. It is. When the frequency (Fd) of the signal generated by the local oscillator 1060 is lower than the frequency (Fr) of the signal received by at least four antennas 100, the intermediate frequency Fi is (Fr−Fd). When the frequency (Fd) of the signal generated by the local oscillator 1060 is higher than the frequency (Fr) of the signal received by at least four antennas 100, the intermediate frequency Fi is (Fd−Fr).
　位相差測定回路１０４は、ダウンコンバート回路１０６によって処理された信号と基準信号との位相差を測定する。基準信号の周波数は、中間周波数と同一になるように設定されてもよい。つまり、基準信号生成回路１０３は、中間周波数を有する基準信号を生成してもよい。 The phase difference measurement circuit 104 measures the phase difference between the signal processed by the down-conversion circuit 106 and the reference signal. The frequency of the reference signal may be set to be the same as the intermediate frequency. That is, the reference signal generation circuit 103 may generate a reference signal having an intermediate frequency.
　上記以外の点については、図３に示す構成は、図１に示す構成と同様である。 3 other than the above, the configuration shown in FIG. 3 is the same as the configuration shown in FIG.
　第２の実施形態のカプセル内視鏡位置測定装置１Ｂにおいて、少なくとも４本のアンテナ１００によって受信される信号の周波数よりも低い周波数を有する信号に基づいて位相差が測定される。第１の実施形態のカプセル内視鏡位置測定装置１Ａにおける時間分解能と、カプセル内視鏡位置測定装置１Ｂにおける時間分解能とが同一である場合、カプセル内視鏡位置測定装置１Ｂにおける位相差の分解能は、カプセル内視鏡位置測定装置１Ａにおける位相差の分解能よりも高い。このため、位置測定の精度が向上する。 In the capsule endoscope position measurement apparatus 1B of the second embodiment, the phase difference is measured based on a signal having a frequency lower than the frequency of signals received by at least four antennas 100. When the time resolution in the capsule endoscope position measurement apparatus 1A of the first embodiment is the same as the time resolution in the capsule endoscope position measurement apparatus 1B, the resolution of the phase difference in the capsule endoscope position measurement apparatus 1B Is higher than the resolution of the phase difference in the capsule endoscope position measurement apparatus 1A. For this reason, the accuracy of position measurement is improved.
　（第３の実施形態）
　図４は、本発明の第３の実施形態のカプセル内視鏡位置測定装置１Ｃの構成を示している。図４に示すように、カプセル内視鏡位置測定装置１Ｃは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４と、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７とを有する。図４に示す構成について、図３に示す構成と異なる点を説明する。 (Third embodiment)
FIG. 4 shows a configuration of a capsule endoscope position measuring apparatus 1C according to the third embodiment of the present invention. As shown in FIG. 4, the capsule endoscope position measurement apparatus 1C includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105, a down-conversion circuit 106A, and an intermediate frequency adjustment circuit 107 are included. The difference between the configuration shown in FIG. 4 and the configuration shown in FIG. 3 will be described.
　ダウンコンバート回路１０６Ａは、電圧制御発振器（ＶＣＯ）１０６０Ａと、ミキサ１０６１とを有する。ダウンコンバート回路１０６Ａにおいて、局部発振器１０６０は電圧制御発振器１０６０Ａである。電圧制御発振器１０６０Ａは、入力された電圧値が示す周波数設定値に対応する周波数を有する信号を出力する。ミキサ１０６１は、ダウンコンバート回路１０６におけるミキサ１０６１と同一である。 The down-conversion circuit 106A includes a voltage controlled oscillator (VCO) 1060A and a mixer 1061. In the down conversion circuit 106A, the local oscillator 1060 is a voltage controlled oscillator 1060A. The voltage controlled oscillator 1060A outputs a signal having a frequency corresponding to the frequency setting value indicated by the input voltage value. The mixer 1061 is the same as the mixer 1061 in the down-conversion circuit 106.
　中間周波数調整回路１０７は、位相差測定回路１０４によって測定された位相差に基づいて、ダウンコンバート回路１０６Ａを制御する。具体的には、中間周波数調整回路１０７は、位相差測定回路１０４によって測定された位相差に基づいて、電圧制御発振器１０６０Ａによって生成される信号の周波数設定値を制御する。これによって、中間周波数調整回路１０７は、位相差測定回路１０４によって測定された位相差に基づいて、中間周波数を調整する。中間周波数調整回路１０７は、位相差測定回路１０４によって測定された位相差が一定となるように周波数設定値を制御する。 The intermediate frequency adjustment circuit 107 controls the down-conversion circuit 106A based on the phase difference measured by the phase difference measurement circuit 104. Specifically, the intermediate frequency adjustment circuit 107 controls the frequency setting value of the signal generated by the voltage controlled oscillator 1060A based on the phase difference measured by the phase difference measurement circuit 104. As a result, the intermediate frequency adjustment circuit 107 adjusts the intermediate frequency based on the phase difference measured by the phase difference measurement circuit 104. The intermediate frequency adjustment circuit 107 controls the frequency setting value so that the phase difference measured by the phase difference measurement circuit 104 is constant.
　上記以外の点については、図４に示す構成は、図３に示す構成と同様である。 4 is the same as the configuration shown in FIG. 3 with respect to points other than those described above.
　第２の実施形態のカプセル内視鏡位置測定装置１Ｂにおいて、回路の個体差の影響により、ダウンコンバート回路１０６から出力される信号と基準信号との周波数を完全に同一にすることが難しい。このため、ダウンコンバート回路１０６から出力される信号と基準信号との位相差が時間の経過により変化する場合がある。位相差が、時間に依存する誤差を含むため、位置測定の精度が低下する場合がある。アンテナ選択回路１０１によって最後に選択されたアンテナ１００を使用する位置測定により測定された位相差に含まれる誤差は、アンテナ選択回路１０１によって最初に選択されたアンテナ１００を使用する位置測定により測定された位相差に含まれる誤差よりも大きくなりやすい。第３の実施形態のカプセル内視鏡位置測定装置１Ｃは、中間周波数を調整することにより、時間に依存する位相差の誤差を低減することができる。 In the capsule endoscope position measurement apparatus 1B of the second embodiment, it is difficult to make the frequency of the signal output from the down-conversion circuit 106 and the reference signal completely the same due to the influence of individual differences in the circuit. For this reason, the phase difference between the signal output from the down-conversion circuit 106 and the reference signal may change over time. Since the phase difference includes a time-dependent error, the accuracy of position measurement may be reduced. The error included in the phase difference measured by the position measurement using the antenna 100 last selected by the antenna selection circuit 101 was measured by the position measurement using the antenna 100 first selected by the antenna selection circuit 101. It tends to be larger than the error included in the phase difference. The capsule endoscope position measurement apparatus 1C according to the third embodiment can reduce the error of the phase difference depending on time by adjusting the intermediate frequency.
　（第４の実施形態）
　図５は、本発明の第４の実施形態のカプセル内視鏡位置測定装置１Ｄの構成を示している。図５に示すように、カプセル内視鏡位置測定装置１Ｄは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、電圧制御発振器（ＶＣＯ）１０３Ａと、位相差測定回路１０４と、位置算出回路１０５と、ダウンコンバート回路１０６と、基準周波数調整回路１０８とを有する。図５に示す構成について、図３に示す構成と異なる点を説明する。 (Fourth embodiment)
FIG. 5 shows a configuration of a capsule endoscope position measuring apparatus 1D according to the fourth embodiment of the present invention. As shown in FIG. 5, the capsule endoscope position measurement apparatus 1D includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a voltage controlled oscillator (VCO) 103A, and a phase difference measurement circuit 104. A position calculation circuit 105, a down-conversion circuit 106, and a reference frequency adjustment circuit 108. The configuration shown in FIG. 5 will be described while referring to differences from the configuration shown in FIG.
　基準信号生成回路１０３は、電圧制御発振器（ＶＣＯ）１０３Ａである。電圧制御発振器１０３Ａは、入力された電圧値が示す周波数設定値に対応する周波数を有する信号を出力する。基準周波数調整回路１０８は、位相差測定回路１０４によって測定された位相差に基づいて、電圧制御発振器１０３Ａを制御する。具体的には、基準周波数調整回路１０８は、位相差測定回路１０４によって測定された位相差に基づいて、電圧制御発振器１０３Ａによって生成される信号の周波数設定値を制御する。これによって、基準周波数調整回路１０８は、位相差測定回路１０４によって測定された位相差に基づいて、基準周波数を調整する。基準周波数調整回路１０８は、位相差測定回路１０４によって測定された位相差が一定となるように周波数設定値を制御する。 The reference signal generation circuit 103 is a voltage controlled oscillator (VCO) 103A. The voltage controlled oscillator 103A outputs a signal having a frequency corresponding to the frequency setting value indicated by the input voltage value. The reference frequency adjusting circuit 108 controls the voltage controlled oscillator 103A based on the phase difference measured by the phase difference measuring circuit 104. Specifically, the reference frequency adjusting circuit 108 controls the frequency setting value of the signal generated by the voltage controlled oscillator 103A based on the phase difference measured by the phase difference measuring circuit 104. Thus, the reference frequency adjustment circuit 108 adjusts the reference frequency based on the phase difference measured by the phase difference measurement circuit 104. The reference frequency adjustment circuit 108 controls the frequency setting value so that the phase difference measured by the phase difference measurement circuit 104 is constant.
　上記以外の点については、図５に示す構成は、図３に示す構成と同様である。 5 is the same as the configuration shown in FIG. 3 with respect to points other than those described above.
　第１および第３の実施形態の少なくとも１つのカプセル内視鏡位置測定装置において、基準信号生成回路１０３は電圧制御発振器１０３Ａであってもよい。第１から第３の実施形態の少なくとも１つのカプセル内視鏡位置測定装置は、基準周波数調整回路１０８を有してもよい。 In the at least one capsule endoscope position measuring device of the first and third embodiments, the reference signal generation circuit 103 may be a voltage controlled oscillator 103A. The at least one capsule endoscope position measurement device according to the first to third embodiments may include a reference frequency adjustment circuit 108.
　カプセル内視鏡位置測定装置１Ｄは、基準信号の周波数を調整することにより、時間に依存する位相差の誤差を低減することができる。 The capsule endoscope position measuring apparatus 1D can reduce the time-dependent phase difference error by adjusting the frequency of the reference signal.
　（第５の実施形態）
　図６は、本発明の第５の実施形態のカプセル内視鏡位置測定装置１Ｅの構成を示している。図６に示すように、カプセル内視鏡位置測定装置１Ｅは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４と、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、時間変化測定回路１０９と、第１の位相差補正回路１１０とを有する。図６に示す構成について、図４に示す構成と異なる点を説明する。 (Fifth embodiment)
FIG. 6 shows a configuration of a capsule endoscope position measuring apparatus 1E according to the fifth embodiment of the present invention. As shown in FIG. 6, the capsule endoscope position measurement apparatus 1E includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, The position calculation circuit 105, the down-conversion circuit 106A, the intermediate frequency adjustment circuit 107, the time change measurement circuit 109, and the first phase difference correction circuit 110 are included. The configuration shown in FIG. 6 will be described while referring to differences from the configuration shown in FIG.
　時間変化測定回路１０９は、位相差測定回路１０４によって測定された、少なくとも４本のアンテナ１００の各々に対する位相差の時間変化を測定する。第１の位相差補正回路１１０は、時間変化測定回路１０９によって測定された時間変化に基づいて、位相差測定回路１０４によって測定された、少なくとも４本のアンテナ１００の各々に対する位相差を補正する。 The time change measuring circuit 109 measures the time change of the phase difference for each of at least four antennas 100 measured by the phase difference measuring circuit 104. The first phase difference correction circuit 110 corrects the phase difference for each of the at least four antennas 100 measured by the phase difference measurement circuit 104 based on the time change measured by the time change measurement circuit 109.
　上記以外の点については、図６に示す構成は、図４に示す構成と同様である。 Regarding the points other than the above, the configuration shown in FIG. 6 is the same as the configuration shown in FIG.
　前述したように、ダウンコンバート回路１０６Ａから出力される信号と基準信号との位相差が時間の経過により変化する場合がある。時間変化測定回路１０９と第１の位相差補正回路１１０とは、時間に依存する位相差の誤差をより低減するための回路である。時間変化測定回路１０９と第１の位相差補正回路１１０とによる処理の例を説明する。 As described above, the phase difference between the signal output from the down-conversion circuit 106A and the reference signal may change over time. The time change measurement circuit 109 and the first phase difference correction circuit 110 are circuits for further reducing a time-dependent phase difference error. An example of processing by the time change measurement circuit 109 and the first phase difference correction circuit 110 will be described.
　第１の時刻において、位相差測定回路１０４は第１の位相差を測定する。第１の時刻よりも後の第２の時刻において、位相差測定回路１０４は第２の位相差を測定する。第１の時刻と第２の時刻とにおいて、アンテナ選択回路１０１は、少なくとも４本のアンテナ１００のうち第１のアンテナを選択する。時間変化測定回路１０９は、第１の位相差と第２の位相差との差を第１の時刻から第２の時刻までの時間で除算することにより、位相差の時間変化を算出する。算出された位相差の時間変化は、単位時間当たりの位相差の変化量である。時間変化測定回路１０９は、算出された位相差の時間変化を第１の位相差補正回路１１０に出力する。第１のアンテナに対応する位相差は、第１の位相差である。 At the first time, the phase difference measurement circuit 104 measures the first phase difference. At a second time after the first time, the phase difference measurement circuit 104 measures the second phase difference. At the first time and the second time, the antenna selection circuit 101 selects the first antenna from at least four antennas 100. The time change measuring circuit 109 calculates the time change of the phase difference by dividing the difference between the first phase difference and the second phase difference by the time from the first time to the second time. The time change of the calculated phase difference is a change amount of the phase difference per unit time. The time change measurement circuit 109 outputs the calculated time change of the phase difference to the first phase difference correction circuit 110. The phase difference corresponding to the first antenna is the first phase difference.
　アンテナ選択回路１０１は、少なくとも４本のアンテナ１００のうち第１のアンテナと異なる第２のアンテナを選択する。第２の時刻よりも後の第３の時刻において、位相差測定回路１０４は、第２のアンテナによって受信された信号に基づく第３の位相差を測定する。第１の位相差補正回路１１０は、位相差の時間変化と第１の時刻から第３の時刻までの時間とに基づいて、第３の位相差を補正する。具体的には、第１の位相差補正回路１１０は、位相差の時間変化と第１の時刻から第３の時刻までの時間とを乗算することにより、第３の位相差に含まれる誤差を算出する。第１の位相差補正回路１１０は、第３の位相差から、算出された誤差を減算することにより、第３の位相差を補正する。アンテナ選択回路１０１によって第２のアンテナが切り替えられる毎に、第１の位相差補正回路１１０は、上記の処理により位相差を補正する。 The antenna selection circuit 101 selects a second antenna different from the first antenna among at least four antennas 100. At a third time after the second time, the phase difference measurement circuit 104 measures a third phase difference based on the signal received by the second antenna. The first phase difference correction circuit 110 corrects the third phase difference based on the time change of the phase difference and the time from the first time to the third time. Specifically, the first phase difference correction circuit 110 multiplies the time change of the phase difference by the time from the first time to the third time, thereby reducing the error included in the third phase difference. calculate. The first phase difference correction circuit 110 corrects the third phase difference by subtracting the calculated error from the third phase difference. Each time the second antenna is switched by the antenna selection circuit 101, the first phase difference correction circuit 110 corrects the phase difference by the above processing.
　カプセル内視鏡位置測定装置１Ｅにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｅは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。 In the capsule endoscope position measurement apparatus 1E, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1E may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D.
　第１から第４の実施形態の少なくとも１つのカプセル内視鏡位置測定装置は、時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。 The at least one capsule endoscope position measurement device according to the first to fourth embodiments may include a time change measurement circuit 109 and a first phase difference correction circuit 110.
　カプセル内視鏡位置測定装置１Ｅは、位相差の時間変化に基づいて位相差を補正することにより、時間に依存する位相差の誤差を低減することができる。 The capsule endoscope position measuring apparatus 1E can reduce the time-dependent phase difference error by correcting the phase difference based on the time change of the phase difference.
　（第６の実施形態）
　図７は、本発明の第６の実施形態のカプセル内視鏡位置測定装置１Ｆの構成を示している。図７に示すように、カプセル内視鏡位置測定装置１Ｆは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、位相差測定回路１０４と、位置算出回路１０５と、最大強度選択回路１１１と、処理回路１１２とを有する。図７に示す構成について、図１に示す構成と異なる点を説明する。 (Sixth embodiment)
FIG. 7 shows a configuration of a capsule endoscope position measuring apparatus 1F according to the sixth embodiment of the present invention. As shown in FIG. 7, the capsule endoscope position measuring apparatus 1F includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a phase difference measurement circuit 104, a position calculation circuit 105, a maximum An intensity selection circuit 111 and a processing circuit 112 are included. The difference between the configuration shown in FIG. 7 and the configuration shown in FIG. 1 will be described.
　基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つである。具体的には、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のうち受信強度が最も高いアンテナ１００である。最大強度選択回路１１１は、受信強度が最も高いアンテナ１００を選択し、かつ選択されたアンテナ１００によって受信された信号を処理回路１１２に出力する。処理回路１１２の構成は、処理回路１０２の構成と同一である。処理回路１１２は、最大強度選択回路１１１から出力された信号を処理する。位相差測定回路１０４は、処理回路１０２と処理回路１１２との各々によって処理された信号の位相差を測定する。 The reference signal generation circuit 103 is any one of at least four antennas 100. Specifically, the reference signal generation circuit 103 is the antenna 100 having the highest reception strength among at least four antennas 100. The maximum intensity selection circuit 111 selects the antenna 100 having the highest reception intensity, and outputs a signal received by the selected antenna 100 to the processing circuit 112. The configuration of the processing circuit 112 is the same as the configuration of the processing circuit 102. The processing circuit 112 processes the signal output from the maximum intensity selection circuit 111. The phase difference measurement circuit 104 measures the phase difference between signals processed by the processing circuit 102 and the processing circuit 112.
　上記以外の点については、図７に示す構成は、図１に示す構成と同様である。 Regarding the points other than the above, the configuration shown in FIG. 7 is similar to the configuration shown in FIG.
　基準信号生成回路１０３は、受信強度が最も高いアンテナ１００以外のアンテナ１００であってもよい。つまり、基準信号生成回路１０３は、少なくとも４本のアンテナ１００の任意の１つであってもよい。 The reference signal generation circuit 103 may be an antenna 100 other than the antenna 100 having the highest reception intensity. That is, the reference signal generation circuit 103 may be any one of at least four antennas 100.
　カプセル内視鏡位置測定装置１Ｆは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。 The capsule endoscope position measurement apparatus 1F may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E.
　第１から第３の実施形態の少なくとも１つのカプセル内視鏡位置測定装置において、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。 In the at least one capsule endoscope position measurement device according to the first to third embodiments, the reference signal generation circuit 103 may be any one of at least four antennas 100.
　カプセル内視鏡位置測定装置１Ｆは、同一のカプセル内視鏡２から受信された２つの信号の位相差を測定する。２つの信号の周波数は同一であるため、測定される位相差の時間変化は発生しにくい。このため、カプセル内視鏡位置測定装置１Ｆは、位置測定をより高精度に行うことができる。 The capsule endoscope position measuring device 1F measures the phase difference between two signals received from the same capsule endoscope 2. Since the frequency of the two signals is the same, the time change of the measured phase difference is unlikely to occur. For this reason, the capsule endoscope position measurement apparatus 1F can perform position measurement with higher accuracy.
　受信強度が最も高いアンテナ１００が選択されることにより、カプセル内視鏡位置測定装置１Ｆは、信号対雑音比（Ｓ／Ｎ比）が高い信号を使用することができる。このため、カプセル内視鏡位置測定装置１Ｆは、位置測定をより高精度に行うことができる。 By selecting the antenna 100 having the highest reception intensity, the capsule endoscope position measurement apparatus 1F can use a signal having a high signal-to-noise ratio (S / N ratio). For this reason, the capsule endoscope position measurement apparatus 1F can perform position measurement with higher accuracy.
　（第７の実施形態）
　図８は、本発明の第７の実施形態のカプセル内視鏡位置測定装置１Ｇの構成を示している。図８に示すように、カプセル内視鏡位置測定装置１Ｇは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４と、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、狭帯域フィルタ１１３とを有する。図８に示す構成について、図４に示す構成と異なる点を説明する。 (Seventh embodiment)
FIG. 8 shows a configuration of a capsule endoscope position measuring apparatus 1G according to the seventh embodiment of the present invention. As shown in FIG. 8, the capsule endoscope position measuring apparatus 1G includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and a narrow band filter 113 are included. The difference between the configuration shown in FIG. 8 and the configuration shown in FIG. 4 will be described.
　狭帯域フィルタ１１３は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号の周波数帯域を制限する。狭帯域フィルタ１１３は、ダウンコンバート回路１０６Ａから出力される信号のうち中間周波数を含む所定の帯域の周波数を有する信号のみを通過させる。例えば、狭帯域フィルタ１１３の通過帯域の幅は、中間周波数の０．１％以下である。位相差測定回路１０４は、狭帯域フィルタ１１３から出力された信号と基準信号との位相差を測定する。 The narrow band filter 113 limits the frequency band of the signal down-converted by the down-conversion circuit 106A. The narrowband filter 113 passes only a signal having a frequency in a predetermined band including an intermediate frequency among signals output from the down-conversion circuit 106A. For example, the width of the pass band of the narrow band filter 113 is 0.1% or less of the intermediate frequency. The phase difference measurement circuit 104 measures the phase difference between the signal output from the narrowband filter 113 and the reference signal.
　上記以外の点については、図８に示す構成は、図４に示す構成と同様である。 Other than the above, the configuration shown in FIG. 8 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｇにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｇは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｇは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｇにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。 In the capsule endoscope position measuring apparatus 1G, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measuring apparatus 1D. The capsule endoscope position measurement device 1G may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement device 1D. The capsule endoscope position measurement apparatus 1G may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E. In the capsule endoscope position measurement apparatus 1G, the reference signal generation circuit 103 may be any one of at least four antennas 100.
　第２から第６の実施形態の少なくとも１つのカプセル内視鏡位置測定装置は、狭帯域フィルタ１１３を有してもよい。 The at least one capsule endoscope position measurement device according to the second to sixth embodiments may include the narrowband filter 113.
　カプセル内視鏡位置測定装置１Ｇは、狭帯域フィルタ１１３を有することにより、少なくとも４本のアンテナ１００によって受信された信号の雑音を除去することができる。このため、カプセル内視鏡位置測定装置１Ｇは、位置測定をより高精度に行うことができる。 The capsule endoscope position measuring apparatus 1G includes the narrow band filter 113, so that noise of signals received by at least four antennas 100 can be removed. For this reason, the capsule endoscope position measurement apparatus 1G can perform position measurement with higher accuracy.
　中間周波数が一定となるように中間周波数調整回路１０７が中間周波数を調整することにより、狭帯域フィルタ１１３の通過帯域をより狭くすることができる。つまり、狭帯域フィルタ１１３による雑音除去の効果がより向上する。このため、カプセル内視鏡位置測定装置１Ｇは、位置測定をより高精度に行うことができる。 When the intermediate frequency adjustment circuit 107 adjusts the intermediate frequency so that the intermediate frequency becomes constant, the pass band of the narrow band filter 113 can be made narrower. That is, the effect of noise removal by the narrow band filter 113 is further improved. For this reason, the capsule endoscope position measurement apparatus 1G can perform position measurement with higher accuracy.
　（第８の実施形態）
　図９は、本発明の第８の実施形態のカプセル内視鏡位置測定装置１Ｈの構成を示している。図９に示すように、カプセル内視鏡位置測定装置１Ｈは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、ＴＤＣ（Ｔｉｍｅ　ｔｏ　Ｄｉｇｉｔａｌ　Ｃｏｎｖｅｒｔｅｒ）１０４Ａと、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、比較器１１４とを有する。図９に示す構成について、図４に示す構成と異なる点を説明する。 (Eighth embodiment)
FIG. 9 shows a configuration of a capsule endoscope position measuring apparatus 1H according to the eighth embodiment of the present invention. As shown in FIG. 9, the capsule endoscope position measuring apparatus 1H includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, and a TDC (Time to Digital Converter). 104A, a position calculation circuit 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and a comparator 114. The difference between the configuration illustrated in FIG. 9 and the configuration illustrated in FIG. 4 will be described.
　比較器１１４は、処理回路１０２によって処理された信号の電圧と基準電圧とを比較し、かつ比較結果に応じて２値のいずれか１つを有する２値信号を出力する。位相差測定回路１０４は、２値信号と基準信号との位相差を測定する。位相差測定回路１０４は、ＴＤＣ１０４Ａである。 The comparator 114 compares the voltage of the signal processed by the processing circuit 102 with the reference voltage, and outputs a binary signal having any one of the two values according to the comparison result. The phase difference measurement circuit 104 measures the phase difference between the binary signal and the reference signal. The phase difference measuring circuit 104 is a TDC 104A.
　例えば、カプセル内視鏡位置測定装置１Ｈは、基準電圧を生成する基準電圧生成回路を有する。基準電圧生成回路によって生成された基準電圧が比較器１１４に入力される。比較器１１４は、基準電圧生成回路を含んでもよい。例えば、処理回路１０２によって処理された信号の電圧が基準電圧以上である場合、比較器１１４は、Ｈｉｇｈレベルの信号を出力する。処理回路１０２によって処理された信号の電圧が基準電圧未満である場合、比較器１１４は、Ｌｏｗレベルの信号を出力する。上記の最初の条件におけるＨｉｇｈがＬｏｗに変更され、かつ上記の２番目の条件におけるＬｏｗがＨｉｇｈに変更されてもよい。 For example, the capsule endoscope position measuring apparatus 1H includes a reference voltage generation circuit that generates a reference voltage. The reference voltage generated by the reference voltage generation circuit is input to the comparator 114. The comparator 114 may include a reference voltage generation circuit. For example, when the voltage of the signal processed by the processing circuit 102 is equal to or higher than the reference voltage, the comparator 114 outputs a high level signal. When the voltage of the signal processed by the processing circuit 102 is less than the reference voltage, the comparator 114 outputs a low level signal. High in the first condition may be changed to Low, and Low in the second condition may be changed to High.
　例えば、基準信号は、２値信号である。ＴＤＣ１０４Ａは、比較器１１４から出力された２値信号のパルスが検出される第１の時刻と、基準信号のパルスが検出される第２の時刻との間の時間を測定することにより、位相差を測定する。ＴＤＣ１０４Ａによって測定された時間は、位相差に対応する。ＴＤＣ１０４Ａは、測定された時間をデジタル値として出力する。 For example, the reference signal is a binary signal. The TDC 104A measures the time difference between the first time at which the binary signal pulse output from the comparator 114 is detected and the second time at which the reference signal pulse is detected. Measure. The time measured by the TDC 104A corresponds to the phase difference. The TDC 104A outputs the measured time as a digital value.
　位置算出回路１０５は、ＴＤＣ１０４Ａによって測定された位相差すなわち時間に基づいて、カプセル内視鏡２の位置を算出する。ＴＤＣ１０４Ａによって測定された時間がｔｎｍであり、かつ媒質内の信号の伝達速度がＶである場合、前述した式（１）と式（２）とにおける距離ｄｎｍは、時間ｔｎｍと伝達速度Ｖとの積である。 The position calculation circuit 105 calculates the position of the capsule endoscope 2 based on the phase difference measured by the TDC 104A, that is, time. When the time measured by the TDC 104A is t nm and the transmission speed of the signal in the medium is V, the distance d nm in the above-described formula (1) and formula (2) is the time t nm and the transmission speed. The product of V.
　上記以外の点については、図９に示す構成は、図４に示す構成と同様である。 For the points other than the above, the configuration shown in FIG. 9 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｈにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｈは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｈは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｈにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｈは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。 In the capsule endoscope position measurement apparatus 1H, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1H may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1H may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E. In the capsule endoscope position measurement apparatus 1H, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring apparatus 1H may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
　第１の実施形態のカプセル内視鏡位置測定装置１Ａは、ＴＤＣ１０４Ａと比較器１１４とを有してもよい。 The capsule endoscope position measurement apparatus 1A according to the first embodiment may include a TDC 104A and a comparator 114.
　カプセル内視鏡位置測定装置１ＨがＴＤＣ１０４Ａと比較器１１４とを有することにより、構成が簡単となり、かつ消費電力が低減される。ＴＤＣ１０４Ａが位相差を測定することにより、カプセル内視鏡位置測定装置１Ｈは、位置測定をより高精度に行うことができる。 Since the capsule endoscope position measuring device 1H includes the TDC 104A and the comparator 114, the configuration is simplified and the power consumption is reduced. When the TDC 104A measures the phase difference, the capsule endoscope position measurement apparatus 1H can perform position measurement with higher accuracy.
　（第９の実施形態）
　図１０は、本発明の第９の実施形態のカプセル内視鏡位置測定装置１Ｉの構成を示している。図１０に示すように、カプセル内視鏡位置測定装置１Ｉは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４Ｂと、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、比較器１１４と、ＡＤ変換器１１５とを有する。図１０に示す構成について、図４に示す構成と異なる点を説明する。 (Ninth embodiment)
FIG. 10 shows a configuration of a capsule endoscope position measuring apparatus 1I according to the ninth embodiment of the present invention. As shown in FIG. 10, the capsule endoscope position measuring apparatus 1I includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104B, A position calculation circuit 105, a down-conversion circuit 106A, a comparator 114, and an AD converter 115 are included. The configuration shown in FIG. 10 will be described while referring to differences from the configuration shown in FIG.
　比較器１１４は、カプセル内視鏡位置測定装置１Ｈにおける比較器１１４と同一である。位相差測定回路１０４Ｂは、位相比較器１０４０と、チャージポンプ１０４１と、ループフィルタ１０４２とを有する。位相比較器１０４０は、比較器１１４から出力された２値信号の位相と基準信号の位相とを比較する。チャージポンプ１０４１は、位相比較器１０４０によって比較された２値信号の位相と基準信号の位相との差に応じた電圧信号を出力する。ループフィルタ１０４２は、チャージポンプ１０４１から出力された電圧信号から、不要な周波数成分を除去する。ループフィルタ１０４２は、不要な周波数成分が除去された信号を出力する。例えば、ループフィルタ１０４２は、ローパスフィルタである。ループフィルタ１０４２から出力されるアナログ信号は、比較器１１４から出力された２値信号と、基準信号との位相差に応じた電圧を有する。位相比較器１０４０とチャージポンプ１０４１とループフィルタ１０４２とは、一般的なＰＬＬ（Ｐｈａｓｅ　Ｌｏｃｋｅｄ　Ｌｏｏｐ）を構成する。位相差測定回路１０４Ｂは、ループフィルタ１０４２を有していなくてもよい。 The comparator 114 is the same as the comparator 114 in the capsule endoscope position measuring apparatus 1H. The phase difference measurement circuit 104B includes a phase comparator 1040, a charge pump 1041, and a loop filter 1042. The phase comparator 1040 compares the phase of the binary signal output from the comparator 114 with the phase of the reference signal. The charge pump 1041 outputs a voltage signal corresponding to the difference between the phase of the binary signal compared by the phase comparator 1040 and the phase of the reference signal. The loop filter 1042 removes unnecessary frequency components from the voltage signal output from the charge pump 1041. The loop filter 1042 outputs a signal from which unnecessary frequency components are removed. For example, the loop filter 1042 is a low-pass filter. The analog signal output from the loop filter 1042 has a voltage corresponding to the phase difference between the binary signal output from the comparator 114 and the reference signal. The phase comparator 1040, the charge pump 1041, and the loop filter 1042 constitute a general PLL (Phase Locked Loop). The phase difference measurement circuit 104B may not include the loop filter 1042.
　ＡＤ変換器１１５は、ループフィルタ１０４２から出力された信号をデジタル値に変換する。電圧制御発振器１０６０Ａによって生成される信号の周波数は、ループフィルタ１０４２から出力された信号に基づいて制御される。このため、カプセル内視鏡位置測定装置１Ｈは、カプセル内視鏡位置測定装置１Ｃにおける中間周波数調整回路１０７を有していない。 The AD converter 115 converts the signal output from the loop filter 1042 into a digital value. The frequency of the signal generated by the voltage controlled oscillator 1060A is controlled based on the signal output from the loop filter 1042. For this reason, the capsule endoscope position measuring apparatus 1H does not have the intermediate frequency adjusting circuit 107 in the capsule endoscope position measuring apparatus 1C.
　上記以外の点については、図１０に示す構成は、図４に示す構成と同様である。 Other than the above, the configuration shown in FIG. 10 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｉにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｉは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｉは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｉにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｉは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。 In the capsule endoscope position measurement apparatus 1I, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1I may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1I may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E. In the capsule endoscope position measuring apparatus 1I, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring apparatus 1I may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
　カプセル内視鏡位置測定装置１Ｉが、ＰＬＬで構成された位相差測定回路１０４Ｂを有することにより、回路規模が削減され、かつコストが低下する。 Since the capsule endoscope position measuring device 1I includes the phase difference measuring circuit 104B configured by a PLL, the circuit scale is reduced and the cost is reduced.
　（第１０の実施形態）
　図１１は、本発明の第１０の実施形態のカプセル内視鏡位置測定装置１Ｊの構成を示している。図１１に示すように、カプセル内視鏡位置測定装置１Ｊは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、カウンタ１０４Ｃと、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、比較器１１４とを有する。図１１に示す構成について、図４に示す構成と異なる点を説明する。 (Tenth embodiment)
FIG. 11 shows the configuration of a capsule endoscope position measuring apparatus 1J according to the tenth embodiment of the present invention. As shown in FIG. 11, the capsule endoscope position measurement apparatus 1J includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a counter 104C, and a position calculation circuit. 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and a comparator 114. The difference between the configuration shown in FIG. 11 and the configuration shown in FIG. 4 will be described.
　比較器１１４は、カプセル内視鏡位置測定装置１Ｈにおける比較器１１４と同一である。位相差測定回路１０４は、カウンタ１０４Ｃである。カウンタ１０４Ｃは、比較器１１４から出力された２値信号のパルスが検出される第１の時刻と、基準信号のパルスが検出される第２の時刻との間の時間をカウントすることにより、位相差を測定する。例えば、カウンタ１０４Ｃは、比較器１１４から出力された２値信号のパルスが検出されたときにカウントを開始し、かつ基準信号のパルスが検出されたときにカウントを終了する。カウンタ１０４Ｃは、基準信号のパルスが検出されたときにカウントを開始し、かつ比較器１１４から出力された２値信号のパルスが検出されたときにカウントを終了してもよい。これによって、カウンタ１０４Ｃは、比較器１１４から出力された２値信号と基準信号との位相差を測定する。 The comparator 114 is the same as the comparator 114 in the capsule endoscope position measuring apparatus 1H. The phase difference measurement circuit 104 is a counter 104C. The counter 104C counts the time between the first time when the pulse of the binary signal output from the comparator 114 is detected and the second time when the pulse of the reference signal is detected. Measure the phase difference. For example, the counter 104C starts counting when a pulse of the binary signal output from the comparator 114 is detected, and ends counting when a pulse of the reference signal is detected. The counter 104C may start counting when a pulse of the reference signal is detected, and may end counting when a pulse of the binary signal output from the comparator 114 is detected. Accordingly, the counter 104C measures the phase difference between the binary signal output from the comparator 114 and the reference signal.
　上記以外の点については、図１１に示す構成は、図４に示す構成と同様である。 Other than the above, the configuration shown in FIG. 11 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｊにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｊは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｊは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｊにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｊは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。 In the capsule endoscope position measurement apparatus 1J, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measuring device 1J may include the reference frequency adjusting circuit 108 in the capsule endoscope position measuring device 1D. The capsule endoscope position measurement device 1J may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement device 1E. In the capsule endoscope position measurement apparatus 1J, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring device 1J may include the narrow band filter 113 in the capsule endoscope position measuring device 1G.
　カプセル内視鏡位置測定装置１Ｊがカウンタ１０４Ｃを有することにより、回路規模が削減される。 Since the capsule endoscope position measuring device 1J has the counter 104C, the circuit scale is reduced.
　（第１１の実施形態）
　図１２は、本発明の第１１の実施形態のカプセル内視鏡位置測定装置１Ｋの構成を示している。図１２に示すように、カプセル内視鏡位置測定装置１Ｋは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、ＴＤＣ１０４Ａと、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、比較器１１４と、強度測定回路１１６と、第２の位相差補正回路１１７とを有する。図１２に示す構成について、図９に示す構成と異なる点を説明する。 (Eleventh embodiment)
FIG. 12 shows a configuration of a capsule endoscope position measuring apparatus 1K according to the eleventh embodiment of the present invention. As shown in FIG. 12, the capsule endoscope position measurement apparatus 1K includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a TDC 104A, and a position calculation circuit 105. A down conversion circuit 106A, an intermediate frequency adjustment circuit 107, a comparator 114, an intensity measurement circuit 116, and a second phase difference correction circuit 117. The configuration shown in FIG. 12 will be described while referring to differences from the configuration shown in FIG.
　強度測定回路１１６は、処理回路１０２によって処理された信号の強度を測定する。第２の位相差補正回路１１７は、強度測定回路１１６によって測定された強度に基づいて、位相差測定回路１０４すなわちＴＤＣ１０４Ａによって測定された、少なくとも４本のアンテナ１００の各々に対する位相差を補正する。 The intensity measurement circuit 116 measures the intensity of the signal processed by the processing circuit 102. The second phase difference correction circuit 117 corrects the phase difference for each of the at least four antennas 100 measured by the phase difference measurement circuit 104, that is, the TDC 104A, based on the intensity measured by the intensity measurement circuit 116.
　カプセル内視鏡位置測定装置１Ｋにおいて、強度測定回路１１６は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号の強度を測定する。つまり、強度測定回路１１６は、ダウンコンバート回路１０６Ａから出力された信号の強度を測定する。強度測定回路１１６は、ダウンコンバート回路１０６Ａに入力される信号の強度を測定してもよい。 In the capsule endoscope position measuring apparatus 1K, the intensity measurement circuit 116 measures the intensity of the signal down-converted by the down-conversion circuit 106A. That is, the intensity measurement circuit 116 measures the intensity of the signal output from the down-conversion circuit 106A. The intensity measurement circuit 116 may measure the intensity of the signal input to the down-conversion circuit 106A.
　比較器１１４から出力される２値信号は、比較器１１４に入力される信号の強度に応じた特性を有する。具体的には、比較器１１４に入力される信号の強度に応じて、２値信号の立ち上がりと立ち下がりとの各々の時間が変化する。比較器１１４に入力される信号の強度がより大きい場合、２値信号の立ち上がりと立ち下がりとの各々の時間がより短い。２値信号の立ち上がりと立ち下がりとの各々の時間が一定でない場合、ＴＤＣ１０４Ａによって測定された位相差すなわち時間に誤差が含まれる。このため、第２の位相差補正回路１１７は、強度測定回路１１６によって測定された強度に基づいて、ＴＤＣ１０４Ａによって測定された時間を補正する。例えば、第２の位相差補正回路１１７は、強度測定回路１１６によって測定された強度と基準強度との差に基づいて、時間補正値を算出する。時間補正値は、基準強度に対応する２値信号の立ち上がりまたは立ち下がりの時間と、強度測定回路１１６によって測定された強度に対応する２値信号の立ち上がりまたは立ち下がりの時間との差に基づく。第２の位相差補正回路１１７は、ＴＤＣ１０４Ａによって測定された時間を時間補正値に基づいて補正する。 The binary signal output from the comparator 114 has characteristics according to the intensity of the signal input to the comparator 114. Specifically, each time of the rise and fall of the binary signal changes according to the strength of the signal input to the comparator 114. When the intensity of the signal input to the comparator 114 is larger, each time of rising and falling of the binary signal is shorter. If each time of the rise and fall of the binary signal is not constant, an error is included in the phase difference, that is, the time measured by the TDC 104A. Therefore, the second phase difference correction circuit 117 corrects the time measured by the TDC 104A based on the intensity measured by the intensity measurement circuit 116. For example, the second phase difference correction circuit 117 calculates a time correction value based on the difference between the intensity measured by the intensity measurement circuit 116 and the reference intensity. The time correction value is based on the difference between the rise or fall time of the binary signal corresponding to the reference intensity and the rise or fall time of the binary signal corresponding to the intensity measured by the intensity measurement circuit 116. The second phase difference correction circuit 117 corrects the time measured by the TDC 104A based on the time correction value.
　上記以外の点については、図１２に示す構成は、図９に示す構成と同様である。 Other than the above, the configuration shown in FIG. 12 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｋにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｋは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｋは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｋにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｋは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。カプセル内視鏡位置測定装置１Ｋは、ＴＤＣ１０４Ａの代わりにカプセル内視鏡位置測定装置１Ｊにおけるカウンタ１０４Ｃを有してもよい。 In the capsule endoscope position measurement apparatus 1K, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1K may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1K may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E. In the capsule endoscope position measurement apparatus 1K, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring apparatus 1K may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G. The capsule endoscope position measuring apparatus 1K may include a counter 104C in the capsule endoscope position measuring apparatus 1J instead of the TDC 104A.
　カプセル内視鏡位置測定装置１Ｋは、強度測定回路１１６と第２の位相差補正回路１１７とを有することにより、位置測定をより高精度に行うことができる。 The capsule endoscope position measurement apparatus 1K includes the intensity measurement circuit 116 and the second phase difference correction circuit 117, so that the position measurement can be performed with higher accuracy.
　（第１２の実施形態）
　図１３は、本発明の第１２の実施形態のカプセル内視鏡位置測定装置１Ｌの構成を示している。図１３に示すように、カプセル内視鏡位置測定装置１Ｌは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、ＴＤＣ１０４Ａと、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、比較器１１４と、可変ゲインアンプ（ＶＧＡ）１１８と、第１の制御回路１１９とを有する。図１３に示す構成について、図９に示す構成と異なる点を説明する。 (Twelfth embodiment)
FIG. 13 shows the configuration of a capsule endoscope position measuring apparatus 1L according to the twelfth embodiment of the present invention. As shown in FIG. 13, the capsule endoscope position measuring apparatus 1L includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a TDC 104A, and a position calculation circuit 105. A down conversion circuit 106A, an intermediate frequency adjustment circuit 107, a comparator 114, a variable gain amplifier (VGA) 118, and a first control circuit 119. The configuration shown in FIG. 13 is different from the configuration shown in FIG.
　可変ゲインアンプ１１８は、処理回路１０２によって処理された信号を増幅し、かつ増幅のゲインが可変である。第１の制御回路１１９は、処理回路１０２によって処理された信号の強度を測定し、かつ測定された強度に基づいて、可変ゲインアンプ１１８から出力される信号の強度が一定になるように可変ゲインアンプ１１８を制御する。比較器１１４は、可変ゲインアンプ１１８から出力された信号の電圧と基準電圧とを比較し、かつ比較結果に応じて２値信号を出力する。 The variable gain amplifier 118 amplifies the signal processed by the processing circuit 102 and the amplification gain is variable. The first control circuit 119 measures the intensity of the signal processed by the processing circuit 102, and based on the measured intensity, the variable gain is set so that the intensity of the signal output from the variable gain amplifier 118 is constant. The amplifier 118 is controlled. The comparator 114 compares the voltage of the signal output from the variable gain amplifier 118 with a reference voltage, and outputs a binary signal according to the comparison result.
　カプセル内視鏡位置測定装置１Ｌにおいて、可変ゲインアンプ１１８は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号を増幅する。つまり、可変ゲインアンプ１１８は、ダウンコンバート回路１０６Ａから出力された信号を増幅する。可変ゲインアンプ１１８は、ダウンコンバート回路１０６Ａに入力される信号を増幅してもよい。 In the capsule endoscope position measuring apparatus 1L, the variable gain amplifier 118 amplifies the signal down-converted by the down-conversion circuit 106A. That is, the variable gain amplifier 118 amplifies the signal output from the down-conversion circuit 106A. The variable gain amplifier 118 may amplify the signal input to the down-conversion circuit 106A.
　カプセル内視鏡位置測定装置１Ｌにおいて、第１の制御回路１１９は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号の強度を測定する。つまり、第１の制御回路１１９は、ダウンコンバート回路１０６Ａから出力された信号の強度を測定する。第１の制御回路１１９は、ダウンコンバート回路１０６Ａに入力される信号の強度を測定してもよい。 In the capsule endoscope position measurement apparatus 1L, the first control circuit 119 measures the intensity of the signal down-converted by the down-conversion circuit 106A. That is, the first control circuit 119 measures the intensity of the signal output from the down-conversion circuit 106A. The first control circuit 119 may measure the strength of the signal input to the down-conversion circuit 106A.
　前述したように、比較器１１４に入力される信号の強度に応じて、２値信号の立ち上がりと立ち下がりとの各々の時間が変化する。可変ゲインアンプ１１８から出力される信号の強度が一定になることにより、２値信号の立ち上がりと立ち下がりとの各々の時間が一定になる。 As described above, the rise time and fall time of the binary signal change according to the intensity of the signal input to the comparator 114. Since the intensity of the signal output from the variable gain amplifier 118 becomes constant, the rise and fall times of the binary signal become constant.
　上記以外の点については、図１３に示す構成は、図９に示す構成と同様である。 Other than the above, the configuration shown in FIG. 13 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｌにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｌは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｌは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｌにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｌは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。カプセル内視鏡位置測定装置１Ｌは、ＴＤＣ１０４Ａの代わりにカプセル内視鏡位置測定装置１Ｊにおけるカウンタ１０４Ｃを有してもよい。 In the capsule endoscope position measurement apparatus 1L, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1L may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1L may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E. In the capsule endoscope position measuring apparatus 1L, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring device 1L may include the narrow band filter 113 in the capsule endoscope position measuring device 1G. The capsule endoscope position measuring apparatus 1L may include a counter 104C in the capsule endoscope position measuring apparatus 1J instead of the TDC 104A.
　カプセル内視鏡位置測定装置１Ｌは、可変ゲインアンプ１１８と第１の制御回路１１９とを有することにより、位置測定をより高精度に行うことができる。 The capsule endoscope position measuring apparatus 1L includes the variable gain amplifier 118 and the first control circuit 119, so that position measurement can be performed with higher accuracy.
　（第１３の実施形態）
　図１４は、本発明の第１３の実施形態のカプセル内視鏡位置測定装置１Ｍの構成を示している。図１４に示すように、カプセル内視鏡位置測定装置１Ｍは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、ＴＤＣ１０４Ａと、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、比較器１１４と、アッテネータ（ＡＴＴ）１２０と、第２の制御回路１２１とを有する。図１４に示す構成について、図９に示す構成と異なる点を説明する。 (13th Embodiment)
FIG. 14 shows a configuration of a capsule endoscope position measuring apparatus 1M according to the thirteenth embodiment of the present invention. As shown in FIG. 14, the capsule endoscope position measuring apparatus 1M includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a TDC 104A, and a position calculation circuit 105. A down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, a comparator 114, an attenuator (ATT) 120, and a second control circuit 121. The configuration shown in FIG. 14 will be described while referring to differences from the configuration shown in FIG.
　アッテネータ１２０は、処理回路１０２によって処理された信号を減衰させ、かつ減衰量が可変である。第２の制御回路１２１は、処理回路１０２によって処理された信号の強度を測定し、かつ測定された強度に基づいて、アッテネータ１２０から出力される信号の強度が一定になるようにアッテネータ１２０を制御する。比較器１１４は、アッテネータ１２０から出力された信号の電圧と基準電圧とを比較し、かつ比較結果に応じて２値信号を出力する。 The attenuator 120 attenuates the signal processed by the processing circuit 102, and the attenuation amount is variable. The second control circuit 121 measures the intensity of the signal processed by the processing circuit 102, and controls the attenuator 120 so that the intensity of the signal output from the attenuator 120 is constant based on the measured intensity. To do. The comparator 114 compares the voltage of the signal output from the attenuator 120 with a reference voltage, and outputs a binary signal according to the comparison result.
　カプセル内視鏡位置測定装置１Ｍにおいて、アッテネータ１２０は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号を減衰させる。つまり、アッテネータ１２０は、ダウンコンバート回路１０６Ａから出力された信号を減衰させる。アッテネータ１２０は、ダウンコンバート回路１０６Ａに入力される信号を減衰させてもよい。 In the capsule endoscope position measurement apparatus 1M, the attenuator 120 attenuates the signal down-converted by the down-conversion circuit 106A. That is, the attenuator 120 attenuates the signal output from the down-conversion circuit 106A. The attenuator 120 may attenuate the signal input to the down-conversion circuit 106A.
　カプセル内視鏡位置測定装置１Ｍにおいて、第２の制御回路１２１は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号の強度を測定する。つまり、第２の制御回路１２１は、ダウンコンバート回路１０６Ａから出力された信号の強度を測定する。第２の制御回路１２１は、ダウンコンバート回路１０６Ａに入力される信号の強度を測定してもよい。 In the capsule endoscope position measuring apparatus 1M, the second control circuit 121 measures the intensity of the signal down-converted by the down-conversion circuit 106A. That is, the second control circuit 121 measures the intensity of the signal output from the down-conversion circuit 106A. The second control circuit 121 may measure the strength of the signal input to the down-conversion circuit 106A.
　前述したように、比較器１１４に入力される信号の強度に応じて、２値信号の立ち上がりと立ち下がりとの各々の時間が変化する。アッテネータ１２０から出力される信号の強度が一定になることにより、２値信号の立ち上がりと立ち下がりとの各々の時間が一定になる。 As described above, the rise time and fall time of the binary signal change according to the intensity of the signal input to the comparator 114. Since the intensity of the signal output from the attenuator 120 becomes constant, each time of the rise and fall of the binary signal becomes constant.
　上記以外の点については、図１４に示す構成は、図９に示す構成と同様である。 Other than the above, the configuration shown in FIG. 14 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｍにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｍは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｍは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｍにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｍは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。カプセル内視鏡位置測定装置１Ｍは、ＴＤＣ１０４Ａの代わりにカプセル内視鏡位置測定装置１Ｊにおけるカウンタ１０４Ｃを有してもよい。 In the capsule endoscope position measurement apparatus 1M, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1M may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1M may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement apparatus 1E. In the capsule endoscope position measurement apparatus 1M, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring device 1M may include the narrow band filter 113 in the capsule endoscope position measuring device 1G. The capsule endoscope position measuring apparatus 1M may include a counter 104C in the capsule endoscope position measuring apparatus 1J instead of the TDC 104A.
　カプセル内視鏡位置測定装置１Ｍは、アッテネータ１２０と第２の制御回路１２１とを有することにより、位置測定をより高精度に行うことができる。アッテネータ１２０は、カプセル内視鏡位置測定装置１Ｌにおける可変ゲインアンプ１１８と比較して、信号に与える遅延が小さい。 The capsule endoscope position measurement apparatus 1M includes the attenuator 120 and the second control circuit 121, so that the position measurement can be performed with higher accuracy. The attenuator 120 has a smaller delay given to the signal than the variable gain amplifier 118 in the capsule endoscope position measuring apparatus 1L.
　（第１４の実施形態）
　図１５は、本発明の第１４の実施形態のカプセル内視鏡位置測定装置１Ｎの構成を示している。図１５に示すように、カプセル内視鏡位置測定装置１Ｎは、少なくとも４本のアンテナ１００と、アンテナ選択回路１０１と、処理回路１０２と、基準信号生成回路１０３と、位相差測定回路１０４と、位置算出回路１０５と、ダウンコンバート回路１０６Ａと、中間周波数調整回路１０７と、ＡＤ変換器１２２とを有する。図１５に示す構成について、図４に示す構成と異なる点を説明する。 (Fourteenth embodiment)
FIG. 15 shows a configuration of a capsule endoscope position measuring apparatus 1N according to the fourteenth embodiment of the present invention. As shown in FIG. 15, the capsule endoscope position measuring apparatus 1N includes at least four antennas 100, an antenna selection circuit 101, a processing circuit 102, a reference signal generation circuit 103, a phase difference measurement circuit 104, A position calculation circuit 105, a down-conversion circuit 106A, an intermediate frequency adjustment circuit 107, and an AD converter 122 are included. The configuration shown in FIG. 15 will be described while referring to differences from the configuration shown in FIG.
　ＡＤ変換器１２２は、処理回路１０２によって処理された信号と基準信号との各々をデジタル値に変換する。位相差測定回路１０４は、処理回路１０２によって処理された信号のデジタル値と基準信号のデジタル値とに基づいて、位相差を測定する。 The AD converter 122 converts each of the signal processed by the processing circuit 102 and the reference signal into a digital value. The phase difference measurement circuit 104 measures the phase difference based on the digital value of the signal processed by the processing circuit 102 and the digital value of the reference signal.
　ＡＤ変換器１２２は、周期的にＡＤ変換を行う。処理回路１０２によって処理された信号の第１のデジタル値列と基準信号の第２のデジタル値列とがＡＤ変換器１２２から出力される。第１のデジタル値列と第２のデジタル値列とは、互いに異なる時刻に生成された複数のデジタル値を含む。ＡＤ変換器１２２は、処理回路１０２によって処理された信号をデジタル値に変換する第１のＡＤ変換器と、基準信号をデジタル値に変換する第２のＡＤ変換器とを含んでもよい。例えば、位相差測定回路１０４は、相互相関関数を使用して第１のデジタル値列と第２のデジタル値列との相関を算出する。第１のデジタル値列と第２のデジタル値列とにおいて、相関が高い位置の時間方向のずれが位相差である。位相差測定回路１０４は、第１のデジタル値列と第２のデジタル値列との時間方向のずれを算出することにより、位相差を算出する。 The AD converter 122 periodically performs AD conversion. A first digital value sequence of the signal processed by the processing circuit 102 and a second digital value sequence of the reference signal are output from the AD converter 122. The first digital value sequence and the second digital value sequence include a plurality of digital values generated at different times. The AD converter 122 may include a first AD converter that converts the signal processed by the processing circuit 102 into a digital value, and a second AD converter that converts the reference signal into a digital value. For example, the phase difference measurement circuit 104 calculates the correlation between the first digital value sequence and the second digital value sequence using the cross-correlation function. In the first digital value sequence and the second digital value sequence, a shift in the time direction at a position having a high correlation is a phase difference. The phase difference measurement circuit 104 calculates a phase difference by calculating a time direction deviation between the first digital value sequence and the second digital value sequence.
　カプセル内視鏡位置測定装置１Ｎにおいて、ＡＤ変換器１２２は、ダウンコンバート回路１０６Ａによってダウンコンバートされた信号をデジタル値に変換する。つまり、ＡＤ変換器１２２は、ダウンコンバート回路１０６Ａから出力された信号をデジタル値に変換する。ＡＤ変換器１２２は、ダウンコンバート回路１０６Ａに入力される信号をデジタル値に変換してもよい。 In the capsule endoscope position measuring apparatus 1N, the AD converter 122 converts the signal down-converted by the down-conversion circuit 106A into a digital value. That is, the AD converter 122 converts the signal output from the down-conversion circuit 106A into a digital value. The AD converter 122 may convert the signal input to the down-conversion circuit 106A into a digital value.
　上記以外の点については、図１５に示す構成は、図４に示す構成と同様である。 Other than the above, the configuration shown in FIG. 15 is the same as the configuration shown in FIG.
　カプセル内視鏡位置測定装置１Ｎにおいて、基準信号生成回路１０３は、カプセル内視鏡位置測定装置１Ｄにおける電圧制御発振器１０３Ａであってもよい。カプセル内視鏡位置測定装置１Ｎは、カプセル内視鏡位置測定装置１Ｄにおける基準周波数調整回路１０８を有してもよい。カプセル内視鏡位置測定装置１Ｎは、カプセル内視鏡位置測定装置１Ｅにおける時間変化測定回路１０９と第１の位相差補正回路１１０とを有してもよい。カプセル内視鏡位置測定装置１Ｎにおいて、基準信号生成回路１０３は、少なくとも４本のアンテナ１００のいずれか１つであってもよい。カプセル内視鏡位置測定装置１Ｎは、カプセル内視鏡位置測定装置１Ｇにおける狭帯域フィルタ１１３を有してもよい。 In the capsule endoscope position measurement apparatus 1N, the reference signal generation circuit 103 may be the voltage controlled oscillator 103A in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement apparatus 1N may include the reference frequency adjustment circuit 108 in the capsule endoscope position measurement apparatus 1D. The capsule endoscope position measurement device 1N may include the time change measurement circuit 109 and the first phase difference correction circuit 110 in the capsule endoscope position measurement device 1E. In the capsule endoscope position measurement apparatus 1N, the reference signal generation circuit 103 may be any one of at least four antennas 100. The capsule endoscope position measuring apparatus 1N may include the narrow band filter 113 in the capsule endoscope position measuring apparatus 1G.
　第１および第２の実施形態の少なくとも１つのカプセル内視鏡位置測定装置は、ＡＤ変換器１２２を有してもよい。 The at least one capsule endoscope position measurement device according to the first and second embodiments may include the AD converter 122.
　カプセル内視鏡位置測定装置１Ｎは、デジタル値に基づいて位相差を測定することにより、位置測定をより高精度に行うことができる。 The capsule endoscope position measurement device 1N can measure the position with higher accuracy by measuring the phase difference based on the digital value.
　以上、本発明の好ましい実施形態を説明したが、本発明はこれら実施形態およびその変形例に限定されることはない。本発明の趣旨を逸脱しない範囲で、構成の付加、省略、置換、およびその他の変更が可能である。また、本発明は前述した説明によって限定されることはなく、添付のクレームの範囲によってのみ限定される。 As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment and its modification. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. Further, the present invention is not limited by the above description, and is limited only by the scope of the appended claims.
　本発明の各実施形態によれば、処理量が削減される。 According to each embodiment of the present invention, the amount of processing is reduced.
　１Ａ，１Ｂ，１Ｃ，１Ｄ，１Ｅ，１Ｆ，１Ｇ，１Ｈ，１Ｉ，１Ｊ，１Ｋ，１Ｌ，１Ｍ，１Ｎ，９　カプセル内視鏡位置測定装置
　１００，９００　アンテナ
　１０１，９０１　アンテナ選択回路
　１０２，１１２，９０２，９０３　処理回路
　１０３　基準信号生成回路
　１０３Ａ，１０６０Ａ　ＶＣＯ
　１０４，１０４Ｂ，９０４　位相差測定回路
　１０４Ａ　ＴＤＣ
　１０４Ｃ　カウンタ
　１０５，９０５　位置算出回路
　１０６，１０６Ａ　ダウンコンバート回路
　１０７　中間周波数調整回路
　１０８　基準周波数調整回路
　１０９　時間変化測定回路
　１１０　第１の位相差補正回路
　１１１　最大強度選択回路
　１１３　狭帯域フィルタ
　１１４　比較器
　１１５，１２２　ＡＤ変換器
　１１６　強度測定回路
　１１７　第２の位相差補正回路
　１１８　可変ゲインアンプ
　１１９　第１の制御回路
　１２０　アッテネータ
　１２１　第２の制御回路
　１０４０　位相比較器
　１０４１　チャージポンプ
　１０４２　ループフィルタ
　１０６０　局部発振器
　１０６１　ミキサ 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J, 1K, 1L, 1M, 1N, 9 Capsule endoscope position measuring device 100, 900 Antenna 101, 901 Antenna selection circuit 102, 112, 902, 903 Processing circuit 103 Reference signal generation circuit 103A, 1060A VCO
104, 104B, 904 Phase difference measuring circuit 104A TDC
104C Counter 105, 905 Position calculation circuit 106, 106A Down-conversion circuit 107 Intermediate frequency adjustment circuit 108 Reference frequency adjustment circuit 109 Time variation measurement circuit 110 First phase difference correction circuit 111 Maximum intensity selection circuit 113 Narrow band filter 114 Comparator 115 , 122 AD converter 116 Intensity measuring circuit 117 Second phase difference correction circuit 118 Variable gain amplifier 119 First control circuit 120 Attenuator 121 Second control circuit 1040 Phase comparator 1041 Charge pump 1042 Loop filter 1060 Local oscillator 1061 Mixer

Claims (21)

  1. 　生体の外部に配置され、かつカプセル内視鏡から無線で送信された信号を受信する少なくとも４本のアンテナと、
    　前記少なくとも４本のアンテナから１本の前記アンテナを順次選択するアンテナ選択回路と、
    　前記アンテナ選択回路によって選択された前記アンテナによって受信された前記信号を処理する処理回路と、
    　基準信号を生成する基準信号生成回路と、
    　前記処理回路によって処理された前記信号と前記基準信号との位相差を測定する位相差測定回路と、
    　前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差に基づいて、前記カプセル内視鏡の位置を算出する位置算出回路と、
    　を有するカプセル内視鏡位置測定装置。     At least four antennas arranged outside the living body and receiving signals transmitted wirelessly from the capsule endoscope;
    An antenna selection circuit that sequentially selects one of the at least four antennas;
    A processing circuit for processing the signal received by the antenna selected by the antenna selection circuit;
    A reference signal generation circuit for generating a reference signal;
    A phase difference measuring circuit for measuring a phase difference between the signal processed by the processing circuit and the reference signal;
    A position calculating circuit that calculates the position of the capsule endoscope based on the phase difference for each of the at least four antennas measured by the phase difference measuring circuit;
    A capsule endoscope position measuring device having
  2. 　前記処理回路によって処理された前記信号の周波数を中間周波数にダウンコンバートするダウンコンバート回路をさらに有する
    　請求項１に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to claim 1, further comprising a down-conversion circuit that down-converts the frequency of the signal processed by the processing circuit to an intermediate frequency.
  3. 　前記位相差測定回路によって測定された位相差に基づいて、前記中間周波数を調整する中間周波数調整回路をさらに有する
    　請求項２に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measuring device according to claim 2, further comprising an intermediate frequency adjusting circuit that adjusts the intermediate frequency based on the phase difference measured by the phase difference measuring circuit.
  4. 　前記ダウンコンバート回路は、
    　前記少なくとも４本のアンテナによって受信される前記信号の周波数と異なる周波数を有する信号を生成する電圧制御発振器と、
    　前記処理回路によって処理された前記信号と、前記電圧制御発振器によって生成された前記信号とを混合するミキサと、
    　を有する
    　請求項２または請求項３に記載のカプセル内視鏡位置測定装置。     The down-conversion circuit is
    A voltage controlled oscillator that generates a signal having a frequency different from the frequency of the signal received by the at least four antennas;
    A mixer that mixes the signal processed by the processing circuit with the signal generated by the voltage controlled oscillator;
    The capsule endoscope position measuring device according to claim 2 or 3.
  5. 　前記ダウンコンバート回路によってダウンコンバートされた前記信号の周波数帯域を制限する狭帯域フィルタをさらに有する
    　請求項２から請求項４のいずれか一項に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to any one of claims 2 to 4, further comprising a narrowband filter that limits a frequency band of the signal downconverted by the downconversion circuit.
  6. 　前記基準信号の周波数は、前記中間周波数と同一になるように設定される
    　請求項２から請求項５のいずれか一項に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to any one of claims 2 to 5, wherein a frequency of the reference signal is set to be the same as the intermediate frequency.
  7. 　前記基準信号の周波数は、前記少なくとも４本のアンテナによって受信される前記信号の周波数と同一になるように設定される
    　請求項１に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to claim 1, wherein a frequency of the reference signal is set to be the same as a frequency of the signal received by the at least four antennas.
  8. 　前記位相差測定回路によって測定された位相差に基づいて、前記基準信号の周波数を調整する基準周波数調整回路をさらに有する請求項１から請求項７のいずれか一項に記載のカプセル内視鏡位置測定装置。 The capsule endoscope position according to any one of claims 1 to 7, further comprising a reference frequency adjustment circuit that adjusts a frequency of the reference signal based on a phase difference measured by the phase difference measurement circuit. measuring device.
  9. 　前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差の時間変化を測定する時間変化測定回路と、
    　前記時間変化測定回路によって測定された前記時間変化に基づいて、前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差を補正する第１の位相差補正回路と、
    　をさらに有する請求項１から請求項８のいずれか一項に記載のカプセル内視鏡位置測定装置。     A time change measuring circuit for measuring a time change of the phase difference for each of the at least four antennas measured by the phase difference measuring circuit;
    A first phase difference correction circuit that corrects the phase difference for each of the at least four antennas measured by the phase difference measurement circuit based on the time change measured by the time change measurement circuit;
    The capsule endoscope position measuring device according to any one of claims 1 to 8, further comprising:
  10. 　前記基準信号生成回路は、電圧制御発振器である
    　請求項１から請求項９のいずれか一項に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to any one of claims 1 to 9, wherein the reference signal generation circuit is a voltage controlled oscillator.
  11. 　前記基準信号生成回路は、水晶発振器である
    　請求項１から請求項９のいずれか一項に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to any one of claims 1 to 9, wherein the reference signal generation circuit is a crystal oscillator.
  12. 　前記基準信号生成回路は、前記少なくとも４本のアンテナのいずれか１つである
    　請求項１から請求項７のいずれか一項に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to any one of claims 1 to 7, wherein the reference signal generation circuit is any one of the at least four antennas.
  13. 　前記基準信号生成回路は、前記少なくとも４本のアンテナのうち受信強度が最も高い前記アンテナである
    　請求項１２に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measurement apparatus according to claim 12, wherein the reference signal generation circuit is the antenna having the highest reception intensity among the at least four antennas.
  14. 　前記処理回路によって処理された前記信号の電圧と基準電圧とを比較し、かつ比較結果に応じて２値のいずれか１つを有する２値信号を出力する比較器をさらに有し、
    　前記位相差測定回路は、前記２値信号と前記基準信号との前記位相差を測定する
    　請求項１から請求項１３のいずれか一項に記載のカプセル内視鏡位置測定装置。     A comparator that compares the voltage of the signal processed by the processing circuit with a reference voltage and outputs a binary signal having any one of the two values according to the comparison result;
    The capsule endoscope position measurement device according to any one of claims 1 to 13, wherein the phase difference measurement circuit measures the phase difference between the binary signal and the reference signal.
  15. 　前記位相差測定回路は、ＴＤＣ（Ｔｉｍｅ　ｔｏ　Ｄｉｇｉｔａｌ　Ｃｏｎｖｅｒｔｅｒ）である
    　請求項１４に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measuring device according to claim 14, wherein the phase difference measuring circuit is a TDC (Time to Digital Converter).
  16. 　前記位相差測定回路は、
    　前記２値信号の位相と前記基準信号の位相とを比較する位相比較器と、
    　前記位相比較器によって比較された前記２値信号の位相と前記基準信号の位相との差に応じた電圧信号を出力するチャージポンプと、
    　を有する
    　請求項１４に記載のカプセル内視鏡位置測定装置。     The phase difference measuring circuit is
    A phase comparator that compares the phase of the binary signal with the phase of the reference signal;
    A charge pump that outputs a voltage signal according to a difference between the phase of the binary signal compared with the phase of the reference signal and the phase of the reference signal;
    The capsule endoscope position measuring device according to claim 14.
  17. 　前記位相差測定回路は、カウンタである
    　請求項１４に記載のカプセル内視鏡位置測定装置。     The capsule endoscope position measuring device according to claim 14, wherein the phase difference measuring circuit is a counter.
  18. 　前記処理回路によって処理された前記信号の強度を測定する強度測定回路と、
    　前記強度測定回路によって測定された前記強度に基づいて、前記位相差測定回路によって測定された、前記少なくとも４本のアンテナの各々に対する前記位相差を補正する第２の位相差補正回路と、
    　をさらに有する
    　請求項１４から請求項１７のいずれか一項に記載のカプセル内視鏡位置測定装置。     An intensity measurement circuit for measuring the intensity of the signal processed by the processing circuit;
    A second phase difference correction circuit that corrects the phase difference for each of the at least four antennas measured by the phase difference measurement circuit based on the intensity measured by the intensity measurement circuit;
    The capsule endoscope position measuring device according to any one of claims 14 to 17, further comprising:
  19. 　前記処理回路によって処理された前記信号を増幅し、かつ増幅のゲインが可変である可変ゲインアンプと、
    　前記処理回路によって処理された前記信号の強度を測定し、かつ測定された前記強度に基づいて、前記可変ゲインアンプから出力される信号の強度が一定になるように前記可変ゲインアンプを制御する第１の制御回路と、
    　をさらに有し、
    　前記比較器は、前記可変ゲインアンプから出力された前記信号の電圧と前記基準電圧とを比較し、かつ比較結果に応じて前記２値信号を出力する
    　請求項１４から請求項１７のいずれか一項に記載のカプセル内視鏡位置測定装置。     A variable gain amplifier that amplifies the signal processed by the processing circuit and has a variable gain;
    Measuring the intensity of the signal processed by the processing circuit, and controlling the variable gain amplifier so that the intensity of the signal output from the variable gain amplifier is constant based on the measured intensity. 1 control circuit;
    Further comprising
    The comparator compares the voltage of the signal output from the variable gain amplifier with the reference voltage, and outputs the binary signal according to a comparison result. The capsule endoscope position measuring device according to Item.
  20. 　前記処理回路によって処理された前記信号を減衰させ、かつ減衰量が可変であるアッテネータと、
    　前記処理回路によって処理された前記信号の強度を測定し、かつ測定された前記強度に基づいて、前記アッテネータから出力される信号の強度が一定になるように前記アッテネータを制御する第２の制御回路と、
    　をさらに有し、
    　前記比較器は、前記アッテネータから出力された前記信号の電圧と前記基準電圧とを比較し、かつ比較結果に応じて前記２値信号を出力する
    　請求項１４から請求項１７のいずれか一項に記載のカプセル内視鏡位置測定装置。     An attenuator that attenuates the signal processed by the processing circuit and has a variable attenuation;
    A second control circuit that measures the intensity of the signal processed by the processing circuit and controls the attenuator so that the intensity of the signal output from the attenuator is constant based on the measured intensity When,
    Further comprising
    18. The comparator according to claim 14, wherein the comparator compares the voltage of the signal output from the attenuator with the reference voltage, and outputs the binary signal according to a comparison result. The capsule endoscope position measuring device as described.
  21. 　前記処理回路によって処理された前記信号と前記基準信号との各々をデジタル値に変換するＡＤ変換器をさらに有し、
    　前記位相差測定回路は、前記処理回路によって処理された前記信号の前記デジタル値と前記基準信号の前記デジタル値とに基づいて、前記位相差を測定する
    　請求項１から請求項１３のいずれか一項に記載のカプセル内視鏡位置測定装置。     An AD converter that converts each of the signal processed by the processing circuit and the reference signal into a digital value;
    The phase difference measurement circuit measures the phase difference based on the digital value of the signal processed by the processing circuit and the digital value of the reference signal. The capsule endoscope position measuring device according to Item.
PCT/JP2015/083015 2015-11-25 2015-11-25 Capsule endoscope position measurement device WO2017090107A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004219329A (en) * 2003-01-16 2004-08-05 Ntt Docomo Inc Method, system and instrument for measuring position, and in-vivo wireless device
JP2007010639A (en) * 2004-08-16 2007-01-18 Rcs:Kk Active tag apparatus
JP2013540261A (en) * 2010-08-23 2013-10-31 アメド スマート トラッキング ソリューションズ ゲゼルシャフト ミット ベシュレンクテル ハフツング Position determination by RFID tag

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004219329A (en) * 2003-01-16 2004-08-05 Ntt Docomo Inc Method, system and instrument for measuring position, and in-vivo wireless device
JP2007010639A (en) * 2004-08-16 2007-01-18 Rcs:Kk Active tag apparatus
JP2013540261A (en) * 2010-08-23 2013-10-31 アメド スマート トラッキング ソリューションズ ゲゼルシャフト ミット ベシュレンクテル ハフツング Position determination by RFID tag

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