KR100878719B1 - Method and system for data communication in human body and capsule-type endoscope used therein - Google Patents

Abstract

The present invention uses the human body as a conductor and the signal as the polarity of the voltage to transmit information to the external receiver through the human body at low frequency and low current, harmless to the human body, low power consumption, excellent reception sensitivity And a human body communication system. In addition, the present invention provides a low-cost, compact capsule endoscope that does not require a wireless transmitter and antenna as a sensing device used in a human body communication method and a human body communication system, and all circuits are integrated in a CMOS image sensor.

Description

TECHNICAL AND SYSTEM FOR DATA COMMUNICATION IN HUMAN BODY AND CAPSULE-TYPE ENDOSCOPE USED THEREIN}

The present invention relates to a method and system for transmitting data to the outside of the human body by a sensing device inserted into the human body for the purpose of collecting various medical information, specifically, the current generated by the sensing device flows through the human body to the human body The present invention relates to a human body communication method capable of transmitting data to the outside, a human body communication system, and a sensing device used therein.

Various sensing devices have been developed and used to collect medical information inside the human body. In addition to such information collection technology, a technology for transmitting collected information to the outside of the human body is very important.

As a general data transmission method, there is a communication cable method applied to an endoscope developed for the purpose of observing the internal condition of the stomach. In the communication cable method, a cable made of lead wire or optical fiber is inserted into the human body mainly through the throat of the patient. This communication cable method has the advantages of high reliability and excellent quality of data collected inside the human body, but there is a serious problem that it causes great pain to patients undergoing endoscopy.

In order to solve this problem, Given Imaging of Israel recently developed a capsule type endoscope called M2A. The capsule endoscope, like a pill, can be reproduced on a monitor by transmitting the image data inside the human body captured by the endoscope's camera just by swallowing it.

However, the capsule endoscope adopts a radio wave propagation method as a signal transmission method, 1) the power consumption is large, the operation time is shortened, 2) the reception sensitivity is deteriorated by the interference of various electromagnetic waves outside the human body, 3) It needs to have a wireless transmitter such as a modulation circuit for converting video signal into high frequency signal and an antenna for signal transmission, so it is bulky and the production cost increases. 4) The problem of harmful effects on the human body due to the use of high frequency. There is.

The present invention has been made to solve the above problems, an object of the present invention is to provide a human body communication method and a human body communication system that allows the sensing device put into the human body to transmit data to the outside of the human body as a conductor.

In addition, an object of the present invention is to provide a sensing device including a transmission electrode that can transmit data to the outside of the human body by generating a current in the human body to flow a current through the human body.

In order to achieve the above object, the human body communication method of the present invention is a human body communication method in which a sensing device inserted into a human body transmits a signal to the outside of a human body, and a potential difference is generated between transmission electrodes provided on a surface of the sensing device. And a current supplied from the transmitting electrode having a relatively high potential flows into the human body surface, flows into the human body surface, flows back into the human body, and sinks to the transmitting electrode having a relatively low potential, and a current flowing through the human body surface is And inducing a voltage between the receiving electrodes installed on the human body surface.

In addition, the human body communication system of the present invention is configured to include a sensing device including a transmitting electrode which is introduced into the human body to generate a potential difference, and a receiver installed on the human body surface to receive the current generated by the potential difference through the human body It is characterized by.

In addition, the sensing device of the present invention is an illumination element for irradiating the inside of the human body, a lens for focusing the light incident from the inside of the human body, a CMOS image sensor for generating an electrical signal from the light focused by the lens, and the illumination element And a housing for accommodating the lens and the CMOS image sensor, and a transmission electrode installed on a surface of the housing to which the electrical signal is applied.

As described above, the present invention is harmless to the human body and has low power consumption because it communicates with the human body using low frequency and low current as a conductor rather than a high frequency wireless method through an antenna, and attenuation is small in the human body and does not receive radio interference outside the human body. In addition, since the signal is transmitted with the polarity of the voltage, it is more resistant to noise, and thus has an excellent reception sensitivity.

In addition, the sensing device according to the present invention does not need a wireless transmitter and an antenna, and can provide a capsule endoscope with a small volume and low cost, and also has an effect of obtaining a good image by adding a memory in the future.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing for explaining a human body communication method and a human body communication system according to the present invention. As shown in FIG. 1, the sensing device 10 located in the human body 1, for example, the digestive tract, transmits information inside the human body to the receiver 20 located on the surface of the human body through the human body 2.

Referring to FIG. 1, a human body communication method in which a signal is transmitted from a sensing device 10 of a human body 1 to an external receiver 20 in a human body communication system according to the present invention will be described in detail. Various information collected by the sensing device 10 (for example, an image inside the human body, PH, temperature or electrical impedance) is converted into an electrical signal by a signal processing circuit inside the sensing device, and then output by the signal processing circuit. The potential difference is generated between the two transmitting electrodes 11 by being applied to the transmitting electrode 11 through a line. Since the transmitting electrode 11 is in contact with the inside of the human body 1 (that is, the transmitting electrode is electrically connected to the human body due to the body fluid in the digestive tract), the human body 2 is caused by the potential difference between the two transmitting electrodes 11. The current 3 flows through it. The current 3 flows out of the transmission electrode having a relatively high potential, flows through the human body 2 to the human body surface, and then flows back into the body 1 and sinks into the transmission electrode having a relatively low potential. At this time, the current flowing through the surface of the human body induces a voltage between the two receiving electrodes 21, so that the signal transmitted from the sensing device 10 located inside the human body 1 can be detected by the receiver 20 outside the human body. do. The receiver 20 processes the received signal and restores the image signal, and displays it on a monitor in real time or stores it in a memory.

2 illustrates various embodiments of the transmitting electrode 11 installed on the surface of the sensing device 10 used in the human body communication system according to the present invention. On the surface of the sensing device 10, two metal plates, that is, transmitting electrodes, are respectively connected to output lines of a signal processing circuit (to be described later) located inside the sensing device.

If the two transmitting electrodes are electrically isolated and the distance is far enough apart, the transmitting electrode can be formed at any position on the surface of the sensing device, but it is wrapped around the sensing device so that it is always in contact with the human body. It is preferable to be formed in a curved form.

2 (a) shows the structure of the transmitting electrode of the sensing device used in FIG. 1, wherein the transmitting electrode is composed of a first electrode and a second electrode respectively covering both ends of the sensing device. The transmitting electrode in (b) comprises a first electrode surrounding one end of the sensing device and a second electrode surrounding the other end of the sensing device in a band form. The transmitting electrode in (c) is composed of a first electrode and a second electrode which surround both ends of the sensing device in a band form. In addition, the transmitting electrode in (d) is composed of a first electrode and a second electrode symmetrically formed about the longitudinal axis of the sensing device.

Since the transmitting electrode is exposed to the inside of the human body, it should be a metal that is excellent in corrosion resistance and can be harmless to the human body to withstand reactive substances such as fire extinguishing fluid. In the embodiment of the present invention, SUS316L or gold was used as the metal having excellent corrosion resistance and harmless to the human body. In addition, in order to electrically isolate the transmitting electrode formed on the surface of the sensing device, the surface of the sensing device should be a non-conductive material that is harmless to the human body and does not conduct electricity. As a non-harmless insulator, plastic-based peaks, polyethylene, or polyflopropylene may be used, and in order to further improve harmlessness to the human body, Playlene coating may be used on the peak, polyethylene, or polyflopropylene.

Figure 3 shows the internal structure of the capsule endoscope as a sensing device used in the human body communication system of the present invention. The capsule endoscope used in FIG. 3 has a diameter of about 10 mm and a length of about 20 mm, and one end of the housing forming the outline of the capsule endoscope is formed of a dome-shaped light window 17, and the other end is a rectangular housing. It is formed of (18) and forms the bullet shape as a whole.

The light guide 17 of the capsule endoscope is made of a material through which light passes while being harmless to the human body, and the enclosure 18 is formed of an insulator that is harmless to the human body as a part including various elements to be described later. have. The light window 17 is sealed with the housing 18 so that, for example, the mucus of the digestive organs or the like is penetrated into the capsule endoscope, or the substance in the capsule endoscope does not leak into the human body.

As shown in FIG. 3, the capsule endoscope has an outer shape formed by a housing including a light window 17 and a housing 18, and includes an illumination element 12, a lens 13, and an inside of the housing 18. The CMOS image sensor 14 and the battery 15, and the transmission electrode 11 formed electrically isolated from the surface of the housing 18 are included.

First, a lens 13 is disposed behind the light window 17, and a CMOS image sensor 14 in which various circuits are integrated behind the lens 13 is disposed. The distance between the lens 13 and the CMOS image sensor 14 is adjusted so that light incident through the light window 17 can be focused on the surface of the CMOS image sensor 14. A plurality of lighting elements 12 are arranged in a donut-shaped arrangement between the lens 13 and the CMOS image sensor 14. In the embodiment of the present invention, four LEDs are used as the lighting device 12. In order to allow the light irradiated from the lighting device 12 to pass through the light window 17 to illuminate an object, an inner surface and an outer surface of the light window 17 have an anti-reflective coating. Behind the CMOS image sensor 14 is a battery 15 which acts as a power source. In the embodiment of the present invention, as the battery 15, a silver oxide battery having a flat discharge voltage and less harm to a human body is used.

Briefly referring to the internal operation of the capsule endoscope, the CMOS image sensor 14 captures an image of an object from the light emitted from the illumination device 12 through the lens 13, and the CMOS image sensor 14 captures the captured image. After the signal is processed through various circuits therein, a signal is applied to the transmission electrodes connected to the two output lines 16, and as described above, the signal is sensed by the external reception electrode using the human body as a conductor.

4 shows a circuit configuration diagram of the CMOS image sensor 14 for explaining the operation principle of the capsule endoscope in more detail.

As shown in FIG. 4, the CMOS image sensor 14 includes a pixel array 100 for capturing and storing an image signal, a reading circuit 110 for sequentially extracting a signal of each pixel, and an output of the reading circuit 110. Encoding circuit 120 for encoding the signal, switching circuit 130 for transmitting the signal encoded by the encoding circuit 120 using two output lines, the current to adjust the current value so that the current of a harmful size to the human body does not flow The limiting circuit 140 includes a control circuit 150 for controlling the operation of the signal processing and lighting device 12, and an oscillating circuit 160 for determining an operating frequency.

In the embodiment of the present invention, the pixel array 100 allows a high resolution video signal to be captured as the number of pixels is 320 × 240, and the stored video signal is sequentially processed one frame per second, thereby reducing the cost and volume of the memory. Adoption was excluded. In addition, the control circuit 150 determines the degree of contrast inside the human body based on the brightness of the light incident on the pixel array 100, and operates the lighting device 12 for 5-200 msec. To be captured by the array 100. By doing in this way, each video frame is captured at an instant and the brightness is excellent. The coding scheme adopts the PSK scheme which is simple and has a strong noise resistance.

The switching circuit 130 receives a signal from the encoding circuit 120 and applies a positive voltage to the first output line 16a when the signal is "1", and grounds the second output line 16b to "0". In this case, the first output line 16a is grounded and a positive voltage is applied to the second output line 16b. In this way, the signal is transmitted by the polarity of the voltage rather than the magnitude of the voltage, thereby making it more resistant to noise.

The current limiting circuit 140 serves to prevent a current of 5 mA or more flowing through the human body. In an embodiment of the present invention, a current limiting circuit (2) is connected to each of the two output lines 16 of the switching circuit 130 in series. 140). In other words, when the power supply voltage is 3 volts and the current limiting circuit is configured by connecting 300Ω resistors in series to each of the two output lines, the current flowing in the human body does not exceed 5 mA even if the resistance of the human body is short. I can't. In addition, by connecting a capacitor in parallel to each resistor to remove the high-frequency components of the signal transmitted to the human body to achieve an excellent signal transmission by electrical matching with the human body.

The signal passing through the current limiting circuit 140 is finally applied to the two transmitting electrodes 11 through the human body and transmitted to the outside of the human body. In the conventional radio communication method, a high frequency signal of several hundred MHz is required, but in the present invention, even a low frequency signal of 10 MHz may transmit an image signal captured by the capsule endoscope to the outside of the human body.

1 is an embodiment for explaining a human body communication method according to the present invention.

Figure 2 is a perspective view showing various embodiments of the transmission electrode installed on the surface of the sensing device used in the human body communication system according to the present invention.

3 is a cross-sectional view of a sensing device used in a human body communication system according to the present invention.

4 is a circuit diagram showing an internal configuration of a CMOS image sensor of a sensing device.

<Code Description of Main Parts of Drawing>

10: sensing device 11: transmitting electrode

12 lighting device 13 lens

14 CMOS Image Sensor 15 Battery

16 output line 17 light window

18 receiver 20 receiver

21: receiving electrode 100: pixel array

110: reading circuit 120: coding circuit

130: switching circuit 140: current limiting circuit

150: control circuit 160: oscillation circuit

Claims (4)

In the human body communication method in which the capsule endoscope inserted into the human body transmits a signal to the outside of the human body, Generating a potential difference between two transmission electrodes provided on a surface of the capsule endoscope; A current is supplied into the human body from the transmission electrode having a relatively high potential among the two transmission electrodes to flow on the human body surface; Inducing a voltage between the two receiving electrodes provided on the human body surface by the current flowing through the human body surface; And the current inducing a voltage between the two receiving electrodes flows back into the human body and sinks to a transmitting electrode having a relatively low potential among the transmitting electrodes. The method of claim 1, wherein the capsule endoscope transmits a current from one electrode of the transmitting electrode to the other electrode when the signal to be transmitted is a digital signal "1" and reverses when the signal to be transmitted is a digital signal "0". Human body communication method characterized in that for changing the polarity of the transmission electrode by flowing a current from the other electrode to one electrode. The human body communication method according to claim 1, wherein a resistance is connected to each of the transmitting electrodes in series to limit the magnitude of the current. The human body communication method according to claim 3, further comprising a capacitor connected in parallel to each of said resistors.

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