KR102448927B1 - Capsule endoscope image receiver and capsule endoscope device having the same - Google Patents

Abstract

A capsule endoscope image receiver according to an embodiment of the present invention receives first and second differential signals from a receiving electrode unit configured to receive first and second differential signals from a capsule endoscope image transmitter through a human body communication channel, and a receiving electrode unit receive, an analog amplifier configured to output first and second amplified differential signals based on the received first and second differential signals, and receive the first and second amplified differential signals from the analog amplifier; a first amplifier configured to reconstruct image information based on the received first and second amplified differential signals, wherein the analog amplifier is configured to output a first amplified differential signal based on the first differential signal; a second amplifier configured to output a second amplified differential signal based on the second differential signal, and connected between the first inverting input terminal of the first amplifier and the second inverting input terminal of the second amplifier, the first and second amplifiers 2 The high frequency component of the amplified differential signals includes an input impedance configured to obtain a higher differential signal amplification gain than the low frequency component.

Description

Capsule endoscope image receiver and capsule endoscope device including same

The present invention relates to image signal processing, and more particularly, to a capsule endoscope image receiver and a capsule endoscope apparatus including the same.

The endoscope is generally inserted into the human body through the oral cavity or anus, and is a device that takes images of abnormal lesions occurring on the digestive tract along the digestive tract in the body and reads them. In general, a mammary gland endoscope is used, and the mammary gland endoscope has a limit in that the reach is limited by the length of the mammary gland. Accordingly, a capsule endoscope for transmitting an image or an image photographed from a digestive system in the body to a receiving device attached outside the body using wireless communication technology has been developed. The receiving device of the capsule endoscope records the transmitted image or image, and reconfirms the image after the recording is finished, so that the presence or absence of an abnormal lesion in the body may be confirmed.

Since the capsule endoscope transmits and receives signals wirelessly, there is no limitation on the reach of the internal digestive system of the examination device. Accordingly, it is possible to photograph and record all the paths that food moves. In particular, in the case of a small intestine that cannot be reached by a conventional mammary endoscope, lesions can be photographed, and diseases occurring in the small intestine can be confirmed in advance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a capsule endoscope image receiver that compensates for attenuation occurring in a signal transmission/reception process of the capsule endoscope apparatus, and a capsule endoscope apparatus including the same.

A capsule endoscope image receiver according to an embodiment of the present invention includes: a receiving electrode unit configured to receive first and second differential signals from a capsule endoscope image transmitter through a human body communication channel; an analog amplifier configured to receive the first and second differential signals from the receiving electrode and output first and second amplified differential signals based on the received first and second differential signals; and a signal restoration unit configured to receive the first and second amplified differential signals from the analog amplification unit and to restore image information based on the received first and second amplified differential signals, wherein the analog amplification unit comprises: a first amplifier configured to output the first amplified differential signal based on the first differential signal; a second amplifier configured to output the second amplified differential signal based on the second differential signal; and a first inverting input terminal of the first amplifier and a second inverting input terminal of the second amplifier, wherein a high-frequency component of the first and second amplified differential signals has a higher differential signal amplification gain than a low-frequency component and an input impedance configured to obtain.

In an exemplary embodiment, the input impedance includes an input resistor and an input capacitor connected in parallel between the first inverting input terminal and the second inverting input terminal.

In an exemplary embodiment, the analog amplifier further includes first and second feedback resistors, the first feedback resistor being connected between the first output terminal of the first amplifier and the first inverting input terminal, A second feedback resistor is connected between the second output terminal of the second amplifier and the second inverting input terminal.

In an exemplary embodiment, the difference between the first and second amplified differential signals has a magnitude amplified by the differential signal amplification gain than the difference between the first and second differential signals, and the differential signal amplification gain is It is determined based on the first feedback resistor, the second feedback resistor, and the input impedance.

In an exemplary embodiment, the receiving electrode unit includes a first receiving electrode configured to receive the first differential signal and a second receiving electrode configured to receive the second differential signal, wherein the first amplifier includes the first receiving electrode receiving the first differential signal from an electrode through a first amplifier coupling capacitor, and the second amplifier receiving the second differential signal from the second receiving electrode through a second amplifier coupling capacitor.

In an exemplary embodiment, the signal restoration unit includes a band-pass filter configured to block noise of the first and second amplified differential signals received from the analog amplification unit.

In an exemplary embodiment, the band-pass filter receives the first amplified differential signal from a first output terminal of the first amplifier through a first filter coupling capacitor, and the band-pass filter receives the first amplified differential signal of the second amplifier. Receives the second amplified differential signal from a second output terminal through a second filter coupling capacitor.

In an exemplary embodiment, the signal restoration unit includes a digital restoration circuit that restores a data signal and a clock signal based on the first and second amplified differential signals, the data signal includes the image information, and the The clock signal includes clock signal information from the capsule endoscope image transmitter.

In an exemplary embodiment, the capsule endoscope image receiver receives the data signal and the clock signal from the digital restoration circuit, and the capsule endoscope image transmitter captures the image based on the received data signal and the received clock signal. It further includes a digital receiver for restoring the image.

In an exemplary embodiment, the signal restoration unit blocks the noise of the first and second amplified differential signals received from the analog amplifier and outputs the first and second filtered differential signals from which the noise is blocked. configured bandpass filter; and receiving the first and second filtered differential signals, and a comparison signal restored to a size that the digital receiver can process based on the received first and second filtered differential signals to the digital recovery circuit and a comparator configured to output.

In an exemplary embodiment, the comparator receives the first filtered differential signal from the band pass filter through a first comparator coupling capacitor, and receives the first filtered differential signal from the band pass filter through a second comparator coupling capacitor received differential signals.

The capsule endoscope apparatus according to an embodiment of the present invention captures an image inside the body, obtains image information based on the captured image, and generates first and second differential signals including the obtained image information, respectively. Capsule endoscope image transmitter to output; and a capsule endoscope image receiver, wherein the capsule endoscope image receiver includes: a receiving electrode unit configured to receive the first and second differential signals from the capsule endoscope image transmitter through a human body communication channel; an analog amplifier configured to receive the first and second differential signals from the receiving electrode and output first and second amplified differential signals based on the received first and second differential signals; and a signal restoration unit configured to receive the first and second amplified differential signals from the analog amplification unit, and restore the image information based on the received first and second amplified differential signals, wherein the analog The amplifier comprises: a first amplifier configured to output the first amplified differential signal based on the first differential signal; a second amplifier configured to output the second amplified differential signal based on the second differential signal; and a first inverting input terminal of the first amplifier and a second inverting input terminal of the second amplifier, wherein a high-frequency component of the first and second amplified differential signals has a higher differential signal amplification gain than a low-frequency component and an input impedance configured to obtain.

In an exemplary embodiment, the receiving electrode unit includes a first receiving electrode configured to receive the first differential signal and a second receiving electrode configured to receive the second differential signal, wherein the capsule endoscope image transmitter is located inside the body an image sensor for capturing the image of and outputting an image signal including the obtained image information; a signal driver receiving the image signal from the image sensor and outputting the first and second differential signals based on the image signal; a first transmitting electrode configured to receive the first differential signal from the signal driver and output the first differential signal to the first receiving electrode through the human body communication channel; and a second transmitting electrode configured to receive the second differential signal from the signal driver and output the second differential signal to the second receiving electrode through the human body communication channel.

In an exemplary embodiment, the first transmit electrode receives the first differential signal from the signal driver through a first current limiting resistor, and the second transmit electrode receives the first differential signal from the signal driver through a second current limiting resistor Receive a second differential signal.

According to an embodiment of the present invention, there is provided a capsule endoscope image receiver and a capsule endoscope apparatus including the same for compensating for attenuation generated in the signal transmission/reception process of the capsule endoscope.

In addition, there are provided a capsule endoscope image receiver and a capsule endoscope apparatus including the same, in which an endoscope image signal in which an error and a bit width variation are suppressed is restored by compensating for a gain of an attenuated high frequency band signal.

1 is a view showing a capsule endoscope apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing the capsule endoscope image transmitter of FIG. 1 by way of example;
FIG. 3 is a view showing the capsule endoscope image receiver of FIG. 1 by way of example;
4 is a graph exemplarily showing signals of the capsule endoscope apparatus including the capsule endoscope image receiver of FIG. 3 in the frequency domain.
5 is a graph exemplarily showing signals of the capsule endoscope apparatus including the capsule endoscope image receiver of FIG. 3 in the time domain.
6 is a diagram exemplarily showing an analog amplifier according to an embodiment of the present invention.
7 is a graph exemplarily showing voltage characteristics of the analog amplifier of FIG. 6 in the frequency domain.
8 is a graph exemplarily showing a data signal restored according to an embodiment of the present invention in the time domain.
FIG. 9 is a view showing the capsule endoscope image receiver of FIG. 1 by way of example;
10A is a graph exemplarily measuring an amplified differential signal according to an embodiment of the present invention.
10B is a graph exemplarily measuring an amplified differential signal according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described clearly and in detail to the extent that those skilled in the art can easily practice the present invention.

1 is a view showing a capsule endoscope apparatus according to an embodiment of the present invention. Referring to FIG. 1 , the capsule endoscope apparatus 1000 may include a capsule endoscope image transmitter 1100 and a capsule endoscope image receiver 1200 . An image of the inside of the body may be acquired by the capsule endoscope apparatus 1000 .

The capsule endoscope image transmitter 1100 may include a first transmission electrode 1131 and a second transmission electrode 1132 . The capsule endoscope image transmitter 1100 may capture an image inside the body. Image information of the capsule endoscope may be acquired based on the captured image inside the body.

The capsule endoscope image transmitter 1100 may output the first differential signal DF1 through the first transmission electrode 1131 . The capsule endoscope image transmitter 1100 may output the second differential signal DF2 through the second transmission electrode 1132 .

In this case, each of the first differential signal DF1 and the second differential signal DF2 may include image information of the capsule endoscope. According to an embodiment of the present invention, image information of the capsule endoscope may be transmitted based on a difference between the first differential signal DF1 and the second differential signal DF2.

That is, the capsule endoscope image transmitter 1100 transmits image information in the form of a differential signal, so that the capsule endoscope image transmitter 1100 and the capsule endoscope image receiver 1200 are resistant to noise and interference. Wireless communication may be provided.

In an exemplary embodiment, the capsule endoscopy image transmitter 1100 may be an ingestible sensor ingested by mouth. For example, the capsule endoscopy image transmitter 1100 may be in the form of a pill and may be a module having a size that can be taken orally.

In an exemplary embodiment, the capsule endoscope image transmitter 1100 may photograph the path of food movement and the digestive system in the body. Unlike the case of photographing with a mammary gland endoscope, the subject can carry on a daily life while photographing the capsule endoscope.

The capsule endoscope image receiver 1200 may include at least one pair of receiving electrodes. Each of the at least one pair of receiving electrodes may include at least one first receiving electrode receiving the first differential signal DF1 and at least one second receiving electrode receiving the second differential signal DF2 . For brevity of the drawing, a pair of receiving electrodes 1211 and 1212 is illustrated in FIG. 1 , but the scope of the present invention is not limited thereto.

The capsule endoscope image receiver 1200 may receive the first differential signal DF1 through the first receiving electrode 1211 . The capsule endoscope image receiver 1200 may receive the second differential signal DF2 through the second receiving electrode 1212 . The capsule endoscope image receiver 1200 may reconstruct an image inside the body based on the received differential signals DF1 and DF2.

According to an embodiment of the present invention, the first differential signal DF1 and the second differential signal DF2 output from the capsule endoscope image transmitter 1100 may be received by the capsule endoscope image receiver 1200 through a human body communication channel. have. The human body communication channel may be a communication channel using a part of the body as a signal transmission medium. The human body communication channel may have a characteristic of a low-pass filter (LPF) that passes a signal of a low frequency band and blocks a signal of a high frequency band.

Accordingly, each of the first differential signal DF1 and the second differential signal DF2 received by the capsule endoscope image receiver 1200 is a signal in which a degree of attenuation of a component of a high frequency band is greater than a degree of attenuation of a component of a low frequency band. can That is, the capsule endoscope image receiver 1200 may receive the first differential signal DF1 and the second differential signal DF2 in which the components of the high frequency band are attenuated.

FIG. 2 is a view showing the capsule endoscope image transmitter of FIG. 1 by way of example; Referring to FIG. 2 , the capsule endoscope image transmitter 1100 may include an image sensor 1110 , a signal driver 1120 , and a transmission electrode unit 1130 . The capsule endoscope image transmitter 1100 may output a first differential signal DF1 and a second differential signal DF2 including image information.

The image sensor 1110 may capture an image inside the body. The image sensor 1110 may acquire image information based on the captured image of the inside of the body. The image sensor 1110 may output an image signal IMG including image information.

The signal driver 1120 may receive the image signal IMG from the image sensor 1110 . The signal driver 1120 may output a first differential signal DF1 and a second differential signal DF2 based on the received image signal IMG. Each of the differential signals DF1 and DF2 may include image information. Each of the differential signals DF1 and DF2 may be a digital signal having a first voltage level or a second voltage level. The second voltage level may be higher than the first voltage level.

In an exemplary embodiment, the differential signals DF1 and DF2 output from the signal driver 1120 may be digital signals having short rising times and short falling times. In this case, the rise time may mean a time required to rise from the first voltage level to the second voltage level. The fall time may mean a time required to fall from the second voltage level to the first voltage level.

A digital signal having a short rise time and a short fall time may refer to a signal having a small degree of attenuation of a component of a high frequency band. That is, the differential signals DF1 and DF2 output from the signal driver 1120 may be signals in which the magnitudes of the components of the high frequency band and the magnitudes of the components of the low frequency band are similar.

The transmission electrode unit 1130 may include a first transmission electrode 1131 and a second transmission electrode 1132 . The first transmission electrode 1131 may output the first differential signal DF1 received from the signal driver 1120 . The second transmission electrode 1132 may output the second differential signal DF2 received from the signal driver 1120 .

In an exemplary embodiment, when the image signal IMG received by the signal driver 1120 has a second voltage level higher than the first voltage level, the signal driver 1120 applies a current to the first transmission electrode 1131 . can be printed out. The current radiated from the first transmitting electrode 1131 may flow into the second transmitting electrode 1132 and the first receiving electrode 1211 through the human body communication channel. Accordingly, information on the image signal IMG having the second voltage level may be transmitted to the capsule endoscope image receiver.

In an exemplary embodiment, when the image signal IMG received by the signal driver 1120 has a first voltage level lower than the second voltage level, the signal driver 1120 applies a current to the second transmission electrode 1132 . can be printed out. The current radiated from the second transmitting electrode 1132 may flow into the first transmitting electrode 1131 and the second receiving electrode 1212 through the human body communication channel. Accordingly, information on the image signal IMG of the first voltage level may be transmitted to the capsule endoscope image receiver.

In an exemplary embodiment, a current limiting resistor may be connected between the signal driver 1120 and the transmission electrode unit 1130 . The current limiting resistor may be a resistor connected to prevent excessive current from flowing through the body. For example, a first current limiting resistor R _ir1 may be connected between the signal driver 1120 and the first transmission electrode 1131 . A second current limiting resistor R _ir2 may be connected between the signal driver 1120 and the second transmission electrode 1132 .

That is, the first transmission electrode 1131 may receive the first differential signal DF1 from the signal driver 1120 through the first current limiting resistor R _ir1 . The second transmission electrode 1132 may receive the second differential signal DF2 from the signal driver 1120 through the second current limiting resistor R _ir2 .

In an exemplary embodiment, the rise time and fall time of the differential signals DF1 and DF2 output from the transmission electrode unit 1130 are increased in the process of receiving the differential signals DF1 and DF2 from the signal driver 1120 . may be a signal. The signal with increased rise time and fall time may be a signal in which a degree of attenuation of a component of a high frequency band is greater than a degree of attenuation of a component of a low frequency band. That is, the differential signals DF1 and DF2 output from the transmission electrode unit 1130 may be signals in which the magnitude of the component of the high frequency band is smaller than the magnitude of the component of the low frequency band.

FIG. 3 is a view showing the capsule endoscope image receiver of FIG. 1 by way of example; Referring to FIG. 3 , the capsule endoscope image receiver 1200 may include a receiving electrode unit 1210 , an analog amplifying unit 1220 , a signal restoring unit 1230 , and a digital receiving unit 1240 . The capsule endoscope image receiver 1200 may reconstruct an image inside the body based on the received differential signals DF1 and DF2.

The receiving electrode unit 1210 may include at least one pair of receiving electrodes. In more detail, the reception electrode unit 1210 may include at least one first reception electrode that transmits the first differential signal DF1 received from the first transmission electrode to the analog amplifier 1220 . The reception electrode unit 1210 may include at least one second reception electrode that transmits the second differential signal DF2 received from the second transmission electrode to the analog amplifier 1220 . For better understanding of the present invention, the receiving electrode unit 1210 is illustrated in FIG. 3 as including a pair of receiving electrodes, but the scope of the present invention is not limited thereto.

In an exemplary embodiment, the receiving electrode unit 1210 may include a first receiving electrode 1211 and a second receiving electrode 1212 . The first receiving electrode 1211 may receive the first differential signal DF1 output from the first transmitting electrode through a human body communication channel. The second receiving electrode 1212 may receive the second differential signal DF2 output from the second transmitting electrode through a human body communication channel. The received differential signals DF1 and DF2 may be signals in which a component of a high frequency band is attenuated.

The analog amplifier 1220 may receive the first differential signal DF1 through the first receiving electrode 1211 . The analog amplifier 1220 may receive the second differential signal DF2 through the second receiving electrode 1212 . The analog amplifier 1220 may amplify the received first differential signal DF1 to output the first amplified differential signal ADF1 . The analog amplifier 1220 may amplify the received second differential signal DF2 to output the second amplified differential signal ADF2 .

The analog amplifier 1220 may be a module that amplifies the differential signals DF1 and DF2 received from the reception electrode 1210 with a differential signal amplification gain. The differential signal amplification gain may mean a value obtained by dividing the difference between the amplified differential signals ADF1 and ADF2 by the difference between the differential signals DF1 and DF2.

In an exemplary embodiment, the analog amplifier 1220 may include an input resistance and a feedback resistance. The differential signal amplification gain may be determined based on a ratio between the input resistance and the feedback resistance.

In an exemplary embodiment, the analog amplifier 1220 may be a module having a differential signal amplification gain in a high frequency band and a differential signal amplification gain in a low frequency band similar to each other. In this case, the differential signal amplification gain may be expressed by an equation that does not have a zero point in the frequency domain. That is, each of the differential signals ADF1 and ADF2 amplified by the analog amplifier 1220 may be a signal in which the magnitude of the component of the high frequency band is smaller than the magnitude of the component of the low frequency band.

The signal restoration unit 1230 may include a band pass filter 1231 , a comparator 1232 , and a digital restoration circuit 1233 . The signal recovery unit 1230 may receive the amplified differential signals ADF1 and ADF2 from the analog amplifier 1220 . The signal restoration unit 1230 may be a module that restores the data signal DT and the clock signal CLK based on the amplified differential signals ADF1 and ADF2 .

In this case, the data signal DT may be a digital signal obtained by reconstructing the image signal generated by the capsule endoscope image transmitter. The clock signal CLK may be a signal obtained by recovering a clock signal used in the capsule endoscope image transmitter. That is, the data signal DT may be a signal including image information inside the body. The signal restoration unit 1230 may restore image information inside the body. The clock signal CLK may include information on a clock signal from the capsule endoscope image transmitter.

The band pass filter 1231 may receive the amplified differential signals ADF1 and ADF2 from the analog amplifier 1220 . The band pass filter 1231 may output the first filtered differential signal FDF1 and the second filtered differential signal FDF2 .

In this case, the first filtered differential signal FDF1 may be a signal in which noise is blocked from the first amplified differential signal ADF1 . The second filtered differential signal FDF2 may be a signal in which noise is blocked from the second amplified differential signal ADF2 . That is, the band pass filter 1231 may be a band pass filter (BPF) that blocks noise of the amplified differential signals ADF1 and ADF2 .

The comparator 1232 may receive the filtered differential signals FDF1 and FDF2 from the band pass filter 1231 . The comparator 1232 may output a comparison signal CP. The comparison signal CP may be a signal in which the differential signals FDF1 and FDF2 are restored to the size of a digital signal that can be processed by the digital receiver 1240 . That is, the comparator 1232 may be a module that restores the size of the filtered differential signals FDF1 and FDF2 to the size of the digital signal that can be processed by the digital receiver 1240 and transmits it to the digital recovery circuit 1233. .

The digital recovery circuit 1233 may receive the comparison signal CP from the comparator 1232 . The digital recovery circuit 1233 may output the data signal DT and the clock signal CLK to the digital receiver 1240 . The data signal DT and the clock signal CLK may be signals restored from the comparison signal CP. That is, the digital restoration circuit 1233 may be a circuit that restores the data signal DT and the clock signal CLK from the comparison signal CP.

The digital receiver 1240 may receive the data signal DT and the clock signal CLK from the digital recovery circuit 1233 . The digital receiver 1240 may reconstruct an image inside the body based on the received data signal DT and the clock signal CLK. The image inside the body restored by the digital receiver 1240 may be a distorted image due to attenuation generated in the process of being modulated into a digital signal and attenuation through a human body communication channel.

As described above, according to an embodiment of the present invention, a capsule endoscope image receiver 1200 including an analog amplifier 1220 having a differential signal amplification gain in a high frequency band and a differential signal amplification gain in a low frequency band is provided. can be At this time, each of the amplified differential signals FDF1 and FDF2 output from the analog amplifier 1220 may be a signal having a high-frequency component smaller than a low-frequency component.

4 is a graph exemplarily showing signals of the capsule endoscope apparatus including the capsule endoscope image receiver of FIG. 3 in the frequency domain. Referring to FIG. 4 , an image signal frequency waveform F _-IMG , a transmission differential signal frequency waveform F _DFS , and a reception differential signal frequency waveform F _DFR are exemplarily shown in the frequency domain.

The image signal frequency waveform F _-IMG is a waveform showing the magnitude of the voltage of the image signal IMG output from the image sensor 1110 of the capsule endoscope imaging transmitter 1100 of FIG. 2 in the frequency domain. The image signal frequency waveform F _-IMG is shown by a dashed line.

Referring to the image signal frequency waveform (F _-IMG ), the magnitude of the first image voltage (V _I1 ) is the magnitude of a frequency (0.5f _B ) component that is half of the base band frequency in the image signal (IMG). can The magnitude V _I2 of the second image voltage may be the magnitude of the baseband frequency f _B component of the image signal IMG.

In an exemplary embodiment, the magnitude of the high frequency band component and the magnitude of the low frequency band component in the image signal IMG may be similar to each other. For example, the magnitude (V _I1 ) of the first image voltage and the magnitude (V _I2 ) of the second image voltage may be similar to each other.

The transmission differential signal frequency waveform F _DFS is a waveform showing the magnitude of the difference between the differential signals DF1 and DF2 output from the transmission electrode unit 1130 of the capsule endoscope image transmitter 1100 of FIG. 2 in the frequency domain. . The transmit differential signal frequency waveform F _DFS is shown as a dash-single dotted line.

As described above, the gain may be attenuated while the differential signal is transmitted through the human body communication channel. In order to facilitate understanding of the present invention, a differential signal output from the transmission electrode unit and a differential signal received from the reception electrode unit are described separately. That is, the differential signal output from the transmit electrode unit is described in the transmit differential signal frequency waveform (F _DFS ), and the differential signal received at the receive electrode unit is described in the receive differential signal frequency waveform (F _DFR ).

Referring to the transmission differential signal frequency waveform F _DFS , the magnitude of the first transmission voltage (V _S1 ) is the differential signal (DF1, DF2) of the frequency (0.5f _B ) component that is half the baseband frequency in the transmission electrode part. It may be the size of the difference between them. The magnitude of the second transmission voltage V _S2 may be the magnitude of the difference between the differential signals DF1 and DF2 of the baseband frequency f _B component in the transmission electrode unit.

In an exemplary embodiment, in the process of receiving the differential signals DF1 and DF2 from the signal driver 1120 of the differential signals DF1 and DF2 output from the transmission electrode unit 1130 , the rise time and the fall time are increased. Accordingly, the high-frequency component may be attenuated signals.

In this case, the difference between the differential signals of the high frequency component in the transmission electrode unit may be more attenuated than the difference between the differential signals of the low frequency component. For example, the difference between the magnitude of the second image voltage V _I2 and the magnitude of the second transmission voltage V _S2 is the difference between the magnitude of the first image voltage V _I1 and the magnitude of the first transmission voltage V _S1 . may be greater than the difference.

The received differential signal frequency waveform (F _DFR ) is a waveform showing the magnitude of the difference between the differential signals DF1 and DF2 received by the reception electrode unit 1210 of the capsule endoscope image receiver 1200 of FIG. 3 in the frequency domain. . The received differential signal frequency waveform F _DFR is shown as a solid line.

Referring to the received differential signal frequency waveform (F _DFR ), the magnitude of the first received voltage (V _R1 ) is the differential signal (DF1, DF2) of the frequency (0.5f _B ) component that is half the baseband frequency in the reception electrode part It may be the size of the difference between them. The magnitude of the second reception voltage V _S2 may be the magnitude of the difference between the differential signals DF1 and DF2 of the baseband frequency f _B component in the reception electrode unit.

In an exemplary embodiment, as each of the differential signals DF1 and DF2 is attenuated while being transmitted through a human body communication channel having a low pass characteristic, the difference between the differential signals of the high frequency component in the receiving electrode unit is a differential signal of the low frequency component It can be attenuated more than the difference between them. For example, the difference between the magnitude of the second transmission voltage (V _S2 ) and the magnitude of the second reception voltage (V _R2 ) is the difference between the magnitude of the first transmission voltage (V _S1 ) and the magnitude of the first reception voltage (V _R1 ) may be greater than the difference.

5 is a graph exemplarily showing signals of the capsule endoscope apparatus including the capsule endoscope image receiver of FIG. 3 in the time domain. Referring to FIG. 5 , an image signal graph G _IMG , a transmission differential signal graph G _DFS , a reception differential signal graph G _DFR , and a data signal graph G _DT are illustrated.

The image signal graph G _IMG exemplarily illustrates the voltage of the image signal IMG output from the image sensor 1110 of the capsule endoscope image transmitter 1100 of FIG. 2 in the time domain.

The image signal IMG may be a periodically toggled signal. Toggling may mean that the voltage level of a specific signal changes. For example, when the image signal IMG is toggled, the value of the image signal IMG changes from the first voltage level V ₁ to the second voltage level V ₂ or the second voltage level V ₂ . may mean changing to the first voltage level (V ₁ ).

In an exemplary embodiment, the image signal IMG may be a signal toggling for each bit, which is a minimum unit having information. In this case, the image signal IMG may include a baseband frequency f _B component. The image signal IMG may include a frequency (0.5f _B ) component that is half the baseband frequency toggling after consecutive '2' bits.

Since the period is the reciprocal of the frequency, the image signal IMG may have a waveform of the baseband period _TB corresponding to the baseband frequency f _B component. Also, the image signal IMG may have a waveform having a period ( _2TB ) twice the baseband period corresponding to a frequency (0.5f _B ) component that is half of the baseband frequency. That is, the image signal IMG may include a component of the baseband period T _B and a component of the period 2T _B that is '2' times the baseband period.

The transmission differential signal graph G _DFS exemplarily illustrates voltages of the differential signals DF1 and DF2 output from the transmission electrode unit 1130 of the capsule endoscope image transmitter 1100 of FIG. 2 in the time domain. The differential signals DF1 and DF2 output from the transmission electrode unit 1130 may be signals attenuated due to an increase in rise time and fall time.

In the transmission differential signal graph G _DFS , the first differential transmission signal DFS1 may be the first differential signal DF1 output from the transmission electrode unit 1130 . The first transmission differential signal DFS1 is shown by a solid line. The second transmission differential signal DFS2 may be the second differential signal DF2 output from the transmission electrode unit 1130 . The second transmission differential signal DFS2 is shown by a dotted line.

In an exemplary embodiment, each of the transmission differential signals DFS1 and DFS2 may include a component of the baseband period T _B . The first transmission voltage difference D _S1 may be a voltage difference having a maximum magnitude among voltage differences between the transmission differential signals DFS1 and DFS2 in a component of the baseband period T _B .

In an exemplary embodiment, each of the transmission differential signals _DFS1 and DFS2 may include a component of the period 2TB of '2' times the baseband period. The second transmission voltage difference D _S2 may be a voltage difference having the largest magnitude among the voltage differences between the transmission differential signals _DFS1 and DFS2 in a component of the period 2TB that is '2' times the baseband period.

In an exemplary embodiment, the voltage difference between the transmission differential signals DFS1 and DFS2 may be greater in a degree of attenuation in a high frequency component than in a degree of attenuation in a low frequency component. That is, the magnitude of the voltage difference of the high frequency component may be smaller than the magnitude of the voltage difference of the low frequency component. For example, the first transmission voltage difference D _S1 may be smaller than the second transmission voltage difference D _S2 .

The received differential signal graph G _DFR exemplarily illustrates voltages of the differential signals DF1 and DF2 received at the receiving electrode unit 1210 of the capsule endoscope image receiver 1200 of FIG. 3 in the time domain. The differential signals DF1 and DF2 received by the receiving electrode unit 1210 may be signals attenuated as they are transmitted through a human body communication channel.

In the reception differential signal graph G _DFR , the first differential reception signal DFR1 may be the first differential signal DF1 received by the reception electrode unit 1210 . The first received differential signal DFR1 is shown by a solid line. The second reception differential signal DFR2 may be the second differential signal DF2 received from the reception electrode unit 1210 . The second receive differential signal DFR2 is shown by a dotted line.

In an exemplary embodiment, each of the received differential signals DFR1 and DFR2 may include a component of the baseband period T _B . The first reception voltage difference D _R1 may be a voltage difference having a maximum magnitude among voltage differences between the reception differential signals DFR1 and DFR2 in a component of the baseband period T _B .

In an exemplary embodiment, each of the received differential signals DFR1 and _DFR2 may include a component of the period 2TB of '2' times the baseband period. The second reception voltage difference D _R2 may be a voltage difference having the largest magnitude among the voltage differences between the reception differential signals DFR1 and _DFR2 in a component of the period 2TB that is '2' times the baseband period.

In an exemplary embodiment, the voltage difference between the received differential signals DFR1 and DFR2 may be greater in the degree of attenuation in the high frequency component than in the low frequency component. For example, the first transmission voltage difference D _S1 may be smaller than the second transmission voltage difference D _S2 . A value obtained by subtracting the first reception voltage difference D _R1 from the first transmission voltage difference D _S1 may be greater than a value obtained by subtracting the second reception voltage difference D _R2 from the second transmission voltage difference D _S2 . Accordingly, the first received voltage difference D _R1 may be smaller than the second received voltage difference D _R2 .

The data signal graph (G _DT ) exemplarily shows the data signal (DT _ma ) and the ideal data signal (DT _id ) output from the digital restoration circuit 1233 of the capsule endoscope image receiver 1200 of FIG. 3 in the time domain did it In this case, the ideal data signal DT _id may be similar to the image signal IMG shown in the image signal graph G _IMG .

In an exemplary embodiment, the data signal DT _ma according to the embodiment of FIG. 3 may be a signal in which a bit error occurs as a high frequency component is attenuated. For example, the data signal DT _ma according to the embodiment of FIG. 3 may have a bit width different from that of the ideal data signal DT _id .

In an exemplary embodiment, the image inside the body restored based on the data signal (eg, DT _ma ) having a bit width different from the ideal data signal (DT _id ) may be an image with reduced quality .

As described above, according to an embodiment of the present invention, a high frequency component of a differential signal may be attenuated due to an increase in rise time and fall time. As the differential signal is transmitted through a human body communication channel, a high-frequency component may be attenuated. The data signal (eg, DT _ma ) restored based on the differential signal in which the high frequency component is attenuated may be a signal in which a bit width shift is generated.

6 is a diagram exemplarily showing an analog amplifier according to an embodiment of the present invention. Referring to FIG. 6 , the analog amplifier 1220 may include a first amplifier 1221 , a second amplifier 1222 , and an input impedance 1223 . The analog amplifier 1220 may have a first input terminal N _i1 , a second input terminal N _i2 , a first output terminal N _o1 , and a second output terminal N _o2 . A connection relationship between the terminals N _i1 , N _o1 , N _i2 , and N _o2 in the analog amplifier 1220 will be described with reference to FIGS. 3 and 6 .

The first input terminal N _i1 may be connected to the first receiving electrode 1211 . The first differential signal DF1 may be received through the first input terminal N _i1 . The second input terminal N _i2 may be connected to the second receiving electrode 1212 . The second differential signal DF2 may be received through the second input terminal N _i2 .

The first output terminal N _o1 may be connected to the signal restoration unit 1230 . The first amplified differential signal ADF1 may be output through the first output terminal N _o1 . The second output terminal N _o2 may be connected to the signal restoration unit 1230 . The second amplified differential signal ADF2 may be output through the second output terminal N _o2 .

The first amplifier 1221 may have a first non-inverting input terminal N _aip1 , a first inverting input terminal N _ain1 , and a first amplifying output terminal N _ao1 . The first amplifier 1221 may be an operational amplifier (OPAMP) that operates by receiving a positive driving voltage V _ddp and a negative driving voltage V _ddn .

The first amplifier 1221 may receive an input voltage through the first non-inverting input terminal N _aip1 . In an exemplary embodiment, the first non-inverting input terminal N _aip1 may be connected to the first bias resistor R _b1 . The first bias resistor R _b1 may be a device that provides a bias voltage to the first amplifier 1221 .

In an exemplary embodiment, the first non-inverting input terminal N _aip1 may be connected to the first input terminal N _i1 through the first amplifier coupling capacitor C _ac1 . The first amplifier coupling capacitor C _ac1 may be a device that passes the AC component and blocks the DC component in the first differential signal.

The first inverting input terminal N _ain1 may be connected to the second amplifier 1222 through the input impedance 1223 . The first inverting input terminal N _ain1 may be connected to the first amplification output terminal N _ao1 through the first feedback resistor R _f1 .

The first amplified differential signal may be output from the first amplified output terminal N _ao1 . The first amplified differential signal may be a signal obtained by amplifying the first differential signal based on the input impedance 1223 and the first feedback resistor R _f1 . The first amplified differential signal output from the first amplified output terminal N _ao1 may be output to the signal restoration unit through the first output terminal N _o1 .

The second amplifier 1222 may have a second non-inverting input terminal N _aip2 , a second inverting input terminal N _ain2 , and a second amplifying output terminal N _ao2 . The second amplifier 1222 may be an operational amplifier (OPAMP) that operates by receiving a positive driving voltage V _ddp and a negative driving voltage V _ddn .

The second amplifier 1222 may receive an input voltage through the second non-inverting input terminal N _aip2 . In an exemplary embodiment, the second non-inverting input terminal N _aip2 may be connected to the second bias resistor R _b2 . The second bias resistor R _b2 may be a device that provides a bias voltage to the second amplifier 1222 .

In an exemplary embodiment, the second non-inverting input terminal N _aip2 may be connected to the second input terminal N _i2 through the second amplifier coupling capacitor C _ac2 . The second amplifier coupling capacitor C _ac2 may be a device that passes the AC component and blocks the DC component in the second differential signal.

The second inverting input terminal N _ain2 may be connected to the first amplifier 1221 through the input impedance 1223 . The second inverting input terminal N _ain2 may be connected to the second amplification output terminal N _ao2 through the second feedback resistor R _f2 . The second differential signal may be amplified based on the input impedance 1223 and the second feedback resistor R _f2 .

A second amplified differential signal may be output from the second amplified output terminal N _ao2 . The second amplified differential signal may be a signal obtained by amplifying the second differential signal based on the input impedance 1223 and the second feedback resistor R _f2 . The second amplified differential signal output from the second amplified output terminal N _ao2 may be output to the signal restoration unit through the second output terminal N _o2 .

The input impedance 1223 may be connected between the first inverting input terminal N _ain1 and the second inverting input terminal N _ain2 . The input impedance 1223 may be a circuit that suppresses a component of a low frequency band and allows a component of a high frequency band to pass therethrough. In an exemplary embodiment, the input impedance 1223 may be a circuit including an input resistor (R _i ) and an input capacitor (C _i ) connected in parallel.

In an exemplary embodiment, the analog amplifier 1220 may have a differential signal amplification gain in a high frequency band greater than a differential signal amplification gain in a low frequency band. The differential signal amplification gain may mean a value obtained by dividing the difference between the amplified differential signals by the difference between the differential signals.

For example, the input impedance 1223 is a circuit including an input resistor (R _i ) and an input capacitor (C _i ) connected in parallel, and a first feedback resistor (R _f1 ) and a second feedback resistor (R _f2 ) are In the case of the feedback resistor R _f having the same resistance value in ohms, the differential signal amplification gain in the analog amplifier 1220 may be expressed by the following equation.

Referring to Equation 1, GA _v may represent a differential signal amplification gain in the analog amplifier 1220 according to an embodiment of the present invention. R _f is the magnitude value of the feedback resistor. Z is the magnitude value of the equivalent impedance in ohms with respect to the input impedance including the input resistance (R _i ) and the input capacitor (C _i ) connected in parallel. Z may be a value that varies according to frequency. If Z in Equation 1 is expressed as a function of frequency, GA _v may be expressed as an equation having a zero point.

When Equation 1 is applied, the differential signal amplification gain GA _v in the low frequency band may be different from the differential signal amplification gain GA _v in the high frequency band. The differential signal amplification gain (GA _v ) in the low frequency band may be approximated by the following equation.

Referring to Equation 2, GA _vl may represent a value obtained by approximating the gain of the differential signal amplification in the analog amplifier 1220 in the low frequency band according to the embodiment of the present invention. R _f is the magnitude value of the feedback resistor. R _i is the magnitude value of the input resistance.

In an exemplary embodiment, the input capacitor C _i may operate as an open circuit with respect to a signal of a low frequency band. An input impedance including an input resistance (R _i ) and an input capacitor (C _i ) connected in parallel may be approximated by an input resistance (R _i ). At this time, the input capacitor (C _i ) may be ignored.

Accordingly, Z in Equation 1 can be approximated as R _i . Equation 2 can be derived based on the approximated Z. That is, by applying Equation 2, a differential signal amplification gain GA _vl approximated in a low frequency band may be provided. Meanwhile, the differential signal amplification gain (GA _v ) in the high frequency band may be approximated by the following equation.

Referring to Equation 3, GA _vh may represent a value obtained by approximating the gain of the differential signal amplification in the analog amplifier 1220 in the high frequency band according to the embodiment of the present invention. R _f is the magnitude value of the feedback resistor. f is the magnitude value of the frequency expressed in hertz. C _i is a value representing the capacitance of the input capacitor.

In an exemplary embodiment, the input capacitor C _i may operate as a short circuit with respect to a signal of a high frequency band. An input impedance including an input resistor (R _i ) and an input capacitor (C _i ) connected in parallel may be approximated by an input capacitor (C _i ). At this time, the input resistance (R _i ) may be neglected.

Accordingly, Z in Equation 1 may be approximated as an impedance value of the input capacitor C _i for a signal having a frequency f. Equation 3 can be derived based on the approximated Z. That is, by applying Equation 3, a differential signal amplification gain GA _vh approximated in a high frequency band may be provided.

In an exemplary embodiment, the differential signal amplification gain GA _vh approximated in the high frequency band may be greater than the differential signal amplification gain GA _vl approximated in the low frequency band. Referring to Equations 2 and 3, unlike the differential signal amplification gain approximated in the low frequency band (GA _vl ), the differential signal amplification gain approximated in the high frequency band (GA _vh ) is linearly proportional to the frequency (f). can increase by

As described above, according to an embodiment of the present invention, the analog amplifier 1220 may be provided in which the differential signal amplification gain in the high frequency band is greater than the differential signal amplification gain in the low frequency band. Accordingly, amplified differential signals having similar magnitudes of components in the high frequency band and those in the low frequency band may be obtained.

7 is a graph exemplarily showing voltage characteristics of the analog amplifier of FIG. 6 in the frequency domain. Referring to FIG. 7 , a differential amplifier input waveform (F _-DI ), a differential amplifier output waveform (F _-DO ), and an amplification gain waveform (F _-AG ) are exemplarily shown in the frequency domain.

The differential amplifier input waveform (F _-DI ) is a first differential signal received to the analog amplifier 1220 through the first input terminal (N _i1 ) in FIG. 6 and the analog amplifier through the second input terminal (N _i2 ) It is a waveform showing the magnitude of the difference between the second differential signal received by 1220 in the frequency domain. The differential amplifier input waveform F _-DI is shown as a solid line.

Referring to the differential amplifier input waveform (F _-DI ) and FIG. 6 , the magnitude of the first differential input voltage (V _DI1 ) is a frequency (0.5f _B ) that is half of the baseband frequency received through the first input terminal (N _i1 ) ) may be the magnitude of a difference between the first differential signal of a component and the second differential signal of a frequency (0.5f _B ) component that is half the baseband frequency received through the second input terminal N _i2 . The magnitude (V _DI2 ) of the second differential input voltage is the first differential signal of the baseband frequency (f _B ) component received through the first input terminal (N _i1 ) and the baseband received through the second input terminal (N _i2 ) It may be the magnitude of the difference between the second differential signals of the frequency (f _B ) component.

In an exemplary embodiment, in the differential signals received from the analog amplifier, the high-frequency component is attenuated as the rise time and the fall time are increased, and as the high-frequency component is attenuated as the high-frequency component is transmitted through the human body communication channel, the magnitude of the high-frequency component is increased The signals may be smaller than the magnitude of the low frequency component. For example, the magnitude (V _DI2 ) of the second differential input voltage may be smaller than the magnitude (V _DI1 ) of the first differential input voltage.

The amplification gain waveform F _-AG is a waveform showing the differential signal amplification gain GA _v in the analog amplifier 1220 of FIG. 6 in the frequency domain. The amplification gain waveform F _-AG is shown as a dashed line.

Referring to the amplification gain waveform (F _-AG ) and FIG. 6 , the first amplification gain (G _-1 ) is a differential signal of a frequency (0.5f _B ) component that is half of the baseband frequency in the analog amplifier 1220 is amplified It may be a ratio The second amplification gain (G ₋₂ ) may be a ratio at which the differential signal of the baseband frequency (f _B ) component is amplified by the analog amplifier 1220 .

In an exemplary embodiment, the analog amplifier may be provided in which the differential signal amplification gain GA _v in the high frequency band is greater than the differential signal amplification gain GA _v in the low frequency band. For example, the second amplification gain G _-2 may be greater than the first amplification gain G _-1 .

In an exemplary embodiment, due to the limitation of the amplifier element, the differential signal amplification gain (GA _v ) of the analog amplifier may be saturated in a high frequency region above the threshold frequency. Accordingly, although not shown in FIG. 7 , the amplification gain waveform F _-AG may represent a differential signal amplification gain GA _v that does not linearly increase in a region above the threshold frequency.

The differential amplifier output waveform (F _-DO ) is a first amplified differential signal output through the first output terminal (N _o1 ) in FIG. 6 and a second amplified differential signal output through the second output terminal (N _o2 ) It is a waveform showing the magnitude of the difference in the frequency domain. The differential amplifier output waveform F _-DO is shown as a dash-single dotted line.

Referring to the differential amplifier output waveform (F _-DO ) and FIG. 6 , the magnitude of the first differential output voltage (V _DO1 ) is a frequency (0.5f _B ) that is half the baseband frequency output from the first output terminal (N _o1 ) ) may be the magnitude of the difference between the first amplified differential signal of the component and the second amplified differential signal of the frequency (0.5f _B ) component that is half the baseband frequency output from the second output terminal (N _o2 ).

The magnitude (V _DO2 ) of the second differential output voltage is the first amplified differential signal of the baseband frequency (f _B ) component output from the first output terminal (N _o1 ) and the second output terminal (N _o2 ). It may be a magnitude of a difference between the second amplified differential signal of the baseband frequency (f _B ) component.

In an exemplary embodiment, the amplified differential signals output from the analog amplifier may be signals in which a gain of an attenuated high-frequency component is compensated. In the analog amplifier, the differential signal amplification gain (GA _v ) may compensate for the gain of the attenuated high-frequency component.

For example, the difference between the magnitude of the first differential output voltage (V _DO1 ) and the magnitude of the first differential input voltage (V _DI1 ) is the first amplification gain (G ₋₁ ) and the magnitude of the first differential output voltage (V _DO1 ) ) can be equal to the difference between In addition, the difference between the magnitude of the second differential output voltage (V _DO2 ) and the magnitude of the second differential input voltage (V _DI2 ) is the second amplification gain (G _-2 ) and the magnitude of the second differential output voltage (V _DO2 ) can be equal to the difference.

In an exemplary embodiment, in the amplified differential signals output from the analog amplifier, the magnitude of the high frequency component and the magnitude of the low frequency component may be similar. For example, the magnitude of the first differential output voltage V _DO1 and the magnitude of the second differential output voltage V _DO2 may be similar.

As described above, according to an embodiment of the present invention, by compensating for a gain of a high-frequency component attenuated as the rise time and fall time increases and the high-frequency component attenuated as it is transmitted through a human body communication channel, the magnitude of the high-frequency component and An analog amplifier for outputting amplified differential signals having similar magnitudes of low-frequency components may be provided.

8 is a graph exemplarily showing a data signal restored according to an embodiment of the present invention in the time domain. Referring to FIG. 8 , the ideal data signal DT _id , the data signal DT _ma according to the embodiment of FIG. 3 , and the data signal DT _mb according to the embodiment of FIG. 6 are exemplarily shown in the time domain. do. Since the characteristics of the ideal data signal DT _id and the data signal DT _ma according to the embodiment of FIG. 3 are similar to those described in the data signal graph G _DT of FIG. 5 , a detailed description thereof will be omitted.

The data signal DT _mb according to the embodiment of FIG. 6 may be a data signal restored based on the amplified differential signals output from the analog amplifier 1220 of FIG. 6 . In this case, the amplified differential signals may be signals in which the magnitude of the high frequency component and the magnitude of the low frequency component are similar as the gain of the attenuated high frequency component is compensated.

In an exemplary embodiment, the data signal DT _mb according to the embodiment of FIG. 6 may be a signal having a reduced bit error than the data signal DT _ma according to the embodiment of FIG. 3 . The data signal DT _mb according to the embodiment of FIG. 6 may have a bit width similar to that of the ideal data signal DT _id .

In an exemplary embodiment, the image inside the body restored based on the data signal (eg, DT _mb ) having a bit width similar to the ideal data signal (DT _id ) may be an image having excellent image quality. For example, the image inside the body reconstructed based on the data signal DT _mb according to the embodiment of FIG. 6 is higher than the image inside the body restored based on the data signal DT _ma according to the embodiment of FIG. 3 . The image may be of excellent quality.

As described above, according to an embodiment of the present invention, an analog amplifier for compensating for the gain of the attenuated high-frequency component may be provided. A data signal (eg, DT _mb ) reconstructed based on the differential signals in which the gain of the attenuated high frequency component is compensated may be a signal in which a bit width shift is suppressed.

FIG. 9 is a view showing the capsule endoscope image receiver of FIG. 1 by way of example; Referring to FIG. 9 , the capsule endoscope image receiver 2200 may include a receiving electrode unit 2210 , an analog amplifying unit 2220 , a signal restoring unit 2230 , and a digital receiving unit 2240 . Since the characteristics of the receiving electrode unit 2210 , the analog amplifier unit 2220 , and the digital receiving unit 2240 are similar to those described in FIG. 3 , a detailed description thereof will be omitted.

The signal restoration unit 2230 may include a bandpass filter 2231 , a comparator 2232 , and a digital restoration circuit 2233 . The band pass filter 2231 may receive the first amplified differential signal ADF1 from the analog amplifier 2220 through the first filter coupling capacitor C _fc1 . The band pass filter 2231 may receive the second amplified differential signal ADF2 from the analog amplifier 2220 through the second filter coupling capacitor C _fc2 .

The first filter coupling capacitor C _fc1 may be a device that passes the AC component of the first amplified differential signal ADF1 and blocks the DC component. The second filter coupling capacitor C _fc2 may be a device that passes the AC component of the second amplified differential signal ADF2 and blocks the DC component.

The comparator 2232 may receive the first filtered differential signal FDF1 from the band pass filter 2231 through the first comparator coupling capacitor C _cc1 . The comparator 2232 may receive the second filtered differential signal _FDF2 from the band pass filter 2231 through the second comparator coupling capacitor C cc2 .

The first comparator coupling capacitor C _cc1 may be a device that passes the AC component of the first filtered differential signal FDF1 and blocks the DC component. The second comparator coupling capacitor C _cc2 may be a device that passes the AC component of the second filtered differential signal FDF2 and blocks the DC component.

As described above, according to an embodiment of the present invention, the band pass filter 2231 receives the differential signals ADF1 and ADF2 amplified through the filter coupling capacitors C _{fc1 and} C _fc2 that block the DC component. ) can be provided. In addition, a comparator 2232 for receiving the filtered differential signals FDF1 and _FDF2 through the comparator coupling capacitors C _{cc1 and} C cc2 for blocking the DC component may be provided.

10A is a graph exemplarily measuring an amplified differential signal according to an embodiment of the present invention. Referring to FIG. 10A , the first amplified differential signal output from the analog amplifier (eg, the analog amplifier of FIG. 3 ) having a differential signal amplification gain in the high frequency band and the differential signal amplification gain in the low frequency band is similar; and Waveforms obtained by measuring the second amplified differential signal are exemplarily shown.

The first measurement waveform ADFa1 according to the embodiment of FIG. 3 may be the measured waveform of the first amplified differential signal ADF1 of FIG. 3 . The first measurement waveform ADFa1 according to the embodiment of FIG. 3 is illustrated by a solid line. The second measurement waveform ADFa2 according to the embodiment of FIG. 3 may be the measured waveform of the second amplified differential signal ADF2 of FIG. 3 . The second measurement waveform ADFa2 according to the embodiment of FIG. 3 is illustrated by a broken line.

The measurement waveforms ADFa1 and ADFa2 according to the embodiment of FIG. 3 have waveforms of the high frequency period T _Aa1 according to the embodiment of FIG. 3 and waveforms of the low frequency period T _Aa2 according to the embodiment of FIG. 3 . can In an exemplary embodiment, the voltage difference between the measurement waveforms ADFa1 and ADFa2 according to the embodiment of FIG. 3 having the high frequency period T Aa1 according to the embodiment of FIG. 3 is the low frequency period (T _Aa1 ) according to the embodiment of FIG. T _Aa2 ) may be smaller than the voltage difference between the measurement waveforms ADFa1 and ADFa2 according to the embodiment of FIG. 3 .

As described above, according to an embodiment of the present invention, the amplitude of the high frequency component of the amplified differential signals measured by the analog amplifier having the same differential signal amplification gain in the high frequency band and the differential signal amplification gain in the low frequency band is the same as the low frequency component. may be smaller than the size of

10B is a graph exemplarily measuring an amplified differential signal according to an embodiment of the present invention. Referring to FIG. 10B , the first amplified differential signal output from the analog amplifier (eg, the analog amplifier of FIG. 6 ) in which the differential signal amplification gain in the high frequency band is greater than the differential signal amplification gain in the low frequency band; and Waveforms obtained by measuring the second amplified differential signal are exemplarily shown.

The first measurement waveform ADFb1 according to the embodiment of FIG. 6 may be a waveform obtained by measuring the first amplified differential signal output from the analog amplifier of FIG. 6 . The first measurement waveform ADFb1 according to the embodiment of FIG. 6 is illustrated by a solid line. The second measurement waveform ADFb2 according to the embodiment of FIG. 6 may be a waveform obtained by measuring the second amplified differential signal output from the analog amplifier of FIG. 6 . The second measurement waveform ADFb2 according to the embodiment of FIG. 6 is illustrated by a broken line.

The measurement waveforms ADFb1 and ADFb2 according to the embodiment of FIG. 6 have waveforms of the high frequency period T _Aa1 according to the embodiment of FIG. 6 and waveforms of the low frequency period T _Aa2 according to the embodiment of FIG. 6 . can In an exemplary embodiment, the voltage difference between the measurement waveforms ADFb1 and ADFb2 according to the embodiment of FIG. 6 having the high frequency period T Aa1 according to the embodiment of FIG. 6 is the low frequency period (T _Aa1 ) according to the embodiment of FIG. T _Aa2 ) may be similar to the voltage difference between the measurement waveforms ADFb1 and ADFb2 according to the embodiment of FIG. 6 .

As described above, according to an embodiment of the present invention, the amplified differential signals measured by the analog amplifier in which the differential signal amplification gain in the high frequency band is greater than the differential signal amplification gain in the low frequency band are the magnitude of the high frequency component and the low frequency component. may be similar in size.

The above are specific embodiments for carrying out the present invention. The present invention will include not only the above-described embodiments, but also simple design changes or easily changeable embodiments. In addition, the present invention will include techniques that can be easily modified and implemented using the embodiments. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be defined by the claims described below as well as the claims and equivalents of the present invention.

1000: capsule endoscope device
1100: capsule endoscope image transmitter
1200: capsule endoscope image receiver
1210: receiving electrode unit
1220: analog amplification unit
1230: signal restoration unit
1240: digital receiver

Claims (14)

a receiving electrode unit configured to receive first and second differential signals from the capsule endoscope image transmitter through a human body communication channel;
an analog amplifier configured to receive the first and second differential signals from the receiving electrode and output first and second amplified differential signals based on the received first and second differential signals; and
and a signal restoration unit configured to receive the first and second amplified differential signals from the analog amplification unit, and to restore image information based on the received first and second amplified differential signals,
The analog amplifier includes:
a first amplifier configured to output the first amplified differential signal based on the first differential signal;
a second amplifier configured to output the second amplified differential signal based on the second differential signal; and
connected between the first inverting input terminal of the first amplifier and the second inverting input terminal of the second amplifier, and obtain a differential signal amplification gain in which a high frequency component of the first and second amplified differential signals is higher than a low frequency component A capsule endoscopic imaging receiver comprising an input impedance configured to The method of claim 1,
wherein the input impedance includes an input resistor and an input capacitor connected in parallel between the first inverting input terminal and the second inverting input terminal. 3. The method of claim 2,
The analog amplifier further includes first and second feedback resistors, the first feedback resistor is connected between the first output terminal of the first amplifier and the first inverting input terminal, the second feedback resistor is the A capsule endoscope image receiver connected between the second output terminal of the second amplifier and the second inverting input terminal. 4. The method of claim 3,
The difference between the first and second amplified differential signals has a magnitude amplified by the differential signal amplification gain than the difference between the first and second differential signals,
The differential signal amplification gain is determined based on the first feedback resistor, the second feedback resistor, and the input impedance. The method of claim 1,
The receiving electrode unit includes a first receiving electrode configured to receive the first differential signal and a second receiving electrode configured to receive the second differential signal,
the first amplifier receives the first differential signal from the first receiving electrode through a first amplifier coupling capacitor;
The second amplifier is a capsule endoscope image receiver for receiving the second differential signal from the second receiving electrode through a second amplifier coupling capacitor. The method of claim 1,
The signal restoration unit includes a band-pass filter configured to block noise of the first and second amplified differential signals received from the analog amplification unit. 7. The method of claim 6,
The band-pass filter receives the first amplified differential signal from a first output terminal of the first amplifier through a first filter coupling capacitor,
The band-pass filter is a capsule endoscope image receiver for receiving the second amplified differential signal from the second output terminal of the second amplifier through a second filter coupling capacitor. The method of claim 1,
The signal restoration unit includes a digital restoration circuit that restores a data signal and a clock signal based on the first and second amplified differential signals,
The data signal includes the image information, and the clock signal includes clock signal information from the capsule endoscope image transmitter. 9. The method of claim 8,
The capsule endoscopy image receiver comprises:
Capsule endoscope further comprising a digital receiver receiving the data signal and the clock signal from the digital restoration circuit, and reconstructing the image captured by the capsule endoscope image transmitter based on the received data signal and the received clock signal video receiver. 10. The method of claim 9,
The signal restoration unit:
a band pass filter configured to block noise of the first and second amplified differential signals received from the analog amplifier and output the first and second filtered differential signals from which the noise is cut off; and
Receives the first and second filtered differential signals, and outputs a comparison signal restored to a size that the digital receiver can process based on the received first and second filtered differential signals to the digital recovery circuit Capsule endoscopic imaging receiver further comprising a comparator configured to 11. The method of claim 10,
The comparator receives the first filtered differential signal from the band pass filter through a first comparator coupling capacitor and receives the second filtered differential signal from the band pass filter through a second comparator coupling capacitor Capsule endoscopic imaging receiver. Capsule endoscope image transmitter for photographing an image inside the body, obtaining image information based on the captured image, and outputting first and second differential signals including the obtained image information, respectively; and
Capsule endoscopic image receiver,
The capsule endoscopy image receiver comprises:
a receiving electrode unit configured to receive the first and second differential signals from the capsule endoscope image transmitter through a human body communication channel;
an analog amplifier configured to receive the first and second differential signals from the receiving electrode and output first and second amplified differential signals based on the received first and second differential signals; and
and a signal restoration unit configured to receive the first and second amplified differential signals from the analog amplification unit and to restore the image information based on the received first and second amplified differential signals,
The analog amplifier includes:
a first amplifier configured to output the first amplified differential signal based on the first differential signal;
a second amplifier configured to output the second amplified differential signal based on the second differential signal; and
connected between the first inverting input terminal of the first amplifier and the second inverting input terminal of the second amplifier, and obtain a differential signal amplification gain in which a high frequency component of the first and second amplified differential signals is higher than a low frequency component A capsule endoscopy device comprising an input impedance configured to 13. The method of claim 12,
The receiving electrode unit includes a first receiving electrode configured to receive the first differential signal and a second receiving electrode configured to receive the second differential signal,
The capsule endoscopy image transmitter comprises:
an image sensor that captures the image inside the body and outputs an image signal including the acquired image information;
a signal driver receiving the image signal from the image sensor and outputting the first and second differential signals based on the image signal;
a first transmitting electrode configured to receive the first differential signal from the signal driver and output the first differential signal to the first receiving electrode through the human body communication channel; and
and a second transmitting electrode configured to receive the second differential signal from the signal driver and output the second differential signal to the second receiving electrode through the human body communication channel. 14. The method of claim 13,
The first transmission electrode receives the first differential signal from the signal driver through a first current limiting resistor,
The second transmitting electrode receives the second differential signal from the signal driver through a second current limiting resistor.

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