AU2009201874A1 - Endoscope and method for operating the same - Google Patents

Description

A ustralian Patents Act 1990 - Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title Endoscope and method for operating the same The following statement is a full description of this invention, including the best method of performing it known to me/us: P/00/011 rin1 Uee--L-ZUUd-UU2o-Us-UU [0001] This application claims the benefit of the Patent Korean Application No. P2008-0118039, filed on November 26, 2008, which is hereby incorporated by reference as if fully set forth herein. BACKGROUND OF THE INVENTION Field of the Invention [0002] The present invention relates to endoscopes, and more particularly, to a capsule type endoscope and a method for operating the same. Discussion of the Related Art [0003] The endoscope is an instrument devised to insert in and observe an internal organ of a human body, a lesion of which is unable to see directly without an operation or autopsy. There are many kinds of endoscopes; a type called as a direct endoscope consist of one cylinder for observing the organ with a naked eye directly, a type which utilizes a lens system, a type which inserts a camera in the organ directly (such as stomach camera), fiberscope which uses fiberglass, and so on. Owing to leading development of endoscopes for a digestive track, specifically, stomach, in general, what is called as the endoscope indicates a stomach camera, or a stomach fiberscope. [0004] However, due to pain and unpleasant feeling of an examination with the endoscope, there are many cases when patients avoid the examination with the endoscope, and prefer 2 medication. According to this, the capsule type endoscope has been developed for complementing above disadvantage, particularly, for examination of diseases at a small intestine which is the longest in the digestive track. [0005) The capsule type endoscope is a micro-endoscope which is devised to enter into the stomach or the small intestine of a patient if the patient swallows it, for enabling a doctor to observe an inside of the digestive track of the patient by means of a video or computer monitor, directly. [0006] However, the related art capsule type endoscope has the following problems. [0007] The related art capsule type endoscope has a great power consumption due to a RF type image signal transmission. Therefore, the related art capsule type endoscope can not provide an enough time to examine an entire human body cavity (esophagus, stomach, small intestine, and large intestine) with a operating time period of 5 - 6 hours at the longest. [0008] In order to overcome above problem, a delayed turn on method is used mostly, in which the capsule type endoscope is turned on, by means of a timer built-in the endoscope inserted through a mouth of a person after a preset time period is passed, or when the endoscope recognizes an organ, such as the small intestine and large intestine. The recognition of the organ is made with reference to a 3 temperature of the organ, pH of the organ (by using a pH difference between organs of a human body), a shape of the organ (a diameter of the small intestine, and the large intestine), a pressure of the small intestine and the large intestine, and so on. [0009] However, the delayed turn on method has a disadvantage in that, because a time period of the capsule type endoscope passing through the organs of the human body, i.e., a digestion time period of the capsule type endoscope, is different between peoples, if the capsule type endoscope is turned on before the capsule type endoscope arrives, for, an example, to the large intestine, obtaining an image of the large intestine can not, but be failed. Moreover, there is another problem in that realization of the turn-on by recognition of the organ is difficult to put into practical application. That is, accurate organ recognition and location recognition is difficult to realize. [0010] And, different from the esophagus, the stomach, and the small intestine in the human body, a moving method of the endoscope is a problem at an ascending colon of the large intestine. Particularly, since the large intestine has a diameter greater than the small intestine, it is difficult to make the endoscope, transferred to the large intestine by peristalsis of the small intestine, to be moved by the peristalsis of the large intestine. 4 Ue-4L-ZUU-UU -- Ub-UU [0011] Moreover, the related art capsule type endoscope takes an image data from an inside of the human body with a camera built-in the capsule type endoscope, and transmits the image data to a receiver on an outside of the human body, for reproducing the image data on a monitor. Since the RF type signal transmission the capsule type endoscope employs has a great power consumption, operation time period is short, and various electronic waves on the outside of the human body can interfere therewith. Furthermore, since the RF type requires a radio transmitter having a modulation circuit for modulating the image signal into a RF signal and an antenna for transmission of the signal, the related art capsule type endoscope provided with the RF type signal transmission has a large volume, a high production cost, and is liable to harm the human body by the high frequency wave. [0012] The related art capsule type endoscope is also liable to tumble in the large intestine with the comparatively great diameter, resulting to take an image of, not an entire surface, but a portion of a surface of the inside of the large intestine. SUMMARY OF THE INVENTION [0013] Accordingly, the present invention is directed to a capsule type endoscope and a method for operating the same. 5 UPP-ZZ-2UUU-UU~b-US-UU [0014] An object of the present invention is to provide a capsule type endoscope and a method for operating the same which can prevent the capsule type endoscope from taking only an image of a portion of an inside of an organ of a human body due to tumbling of the capsule type endoscope at the time the capsule type endoscope takes an image of the inside of the human body. [0015] Another object of the present invention is to provide a capsule type endoscope and a method for operating the same which can solve a problem in which the capsule type endoscope can not be moved peristalsis due to a large diameter of the large intestine. [0016] Another object of the present invention is to provide a capsule type endoscope and a method for operating the same which can solve the problem of a large volume, a high production cost, and possible harm to the human body by the high frequency wave of the related art capsule type endoscope. [0017] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed 6 out in the written description and claims hereof as well as the appended drawings. [0018] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a capsule type endoscope includes a plurality of optical windows facing directions different from one another, image obtaining units each positioned in rear of each of the plurality of optical windows for obtaining an image, signal transmission units each for transmission of the image obtained thus, and a control unit for forwarding first to third control signals for obtaining the image, wherein at least one of the control signals is delay turned on, and at least another one of the control signals is directly turned on. [0019] In another aspect of the present invention, a method for operating a capsule type endoscope includes the steps of obtaining image information on an object from at least opposite sides, converting the image information into an electric signal, applying a current to a housing of the capsule type endoscope and a surface of a human body by using the electric signal, and reproducing the image information by using the current applied to the surface of the human body. [0020] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are 7 UPP-ZZ-ZUUU-UU~b-US-UU intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS [0021] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: [0022] FIGS. 1A ~ 1C illustrate diagrams of capsule type endoscopes in accordance with preferred embodiments of the present invention, respectively. [0023] FIG. 2 illustrates a block diagram of a control unit in an endoscope in accordance with a preferred embodiment of the present invention. [0024] FIG. 3 illustrates signal transmission electrodes in an endoscope in accordance with preferred embodiments of the present invention, respectively. [0025] FIG. 4 illustrates a diagram for explaining a principle of a method for making communication with an endoscope in accordance with a preferred embodiment of the present invention. 8 UeY-44-ZUU0-UUzD-Ub-UU [0026] FIG. 5 illustrates a block diagram of a CMOS image sensor in an endoscope in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0027] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. [0028] In the attached drawings, thickness is enlarged for clearer expression of many layers and regions, and thickness ratios between the layers shown in the drawings do not represent actual thickness ratios. [0029] FIGS. 1A ~ 1C illustrate diagrams of capsule type endoscopes in accordance with preferred embodiments of the present invention, respectively. A capsule type endoscopes in accordance with a preferred embodiment of the present invention will be described with reference to FIGS. 1A ~ 1C. [0030] Referring to FIGS. 1A ~ 1C, the capsule type endoscope has two cameras 110 and 115 at opposite ends of a housing 100, and two illumination units 120 and 125 each for illumination of an object an image of which the camera 110 or 115 to take. The two cameras are provided at the opposite ends of the housing 100 for taking images of opposite sides 9 OPP-ZZ-2UU0-UU2'-US-UU of an object (mostly an organ of a human body), and the camera may be provided three or more than three directions. It is natural that apertures 110a and 115a are provided in front of the cameras 110 and 115, respectively. Lenses 110b and 115b are provided in front of the cameras 110 and 115 for focusing lights incident to the apertures 110a and 110b onto the cameras 110 and 115, respectively. In this instance, the cameras are an embodiment for taking an image, merely. The cameras 110 and 115 are mounted to opposite sides of the housing 100, and the mounting to the opposite ends of the housing 100 is only an embodiment. [0031] The housing 100 surrounds all components of a transmitter, such as sensors, battery, and PCB for protection, forms an exterior of the capsule together with dome shaped opposite ends joined thereto. Since the housing 100 is to be in direct contact with the human body, it is required that the housing 100 does not harm the human body, and is waterproof, and strong against dissolution and impact. The dome shaped opposite ends of the housing 100 have the apertures 110a and 115a for serving as windows enabling to see the organ in the human body, and it is natural that the apertures 110a and 115a are transparent and do not harm the human body. It is preferable that the camera 110 or 115, which obtains image information received through the aperture 110a or 115a, has an angle of view greater than 150 degrees, 10 UfeL~LUUOdUUZ-UZ-U with in general a focal distance of 5 ~ 10mm. It may be devised that the two cameras 110 and 115 take image information of the object at the same time or different times. [0032] Mounted in the housing 100, there is an image information processing unit 130. The image information processing unit 130 converts and processes the image information taken at the cameras 110 and 115 into an electrical signal. The image information processing unit 130 also serves as a controller for collecting and processing the image information taken at the two cameras 110 and 115. (0033] The image information processing unit 130 has a separate memory for storing specification of the cameras, the LED (light emitting diode) illumination units, and so on in the capsule type endoscope. According to this, at the time of reproduction of the images taken at the cameras, the image can be adjusted with reference to states of the cameras and the illumination units. [0034] The housing may have a signal transmission electrode 140 on a surface. The signal transmission electrode 140 may be mounted to the surface of the housing 100 electrically insulated from the housing 100 and the units mounted therein. [0035] Though not shown, the cameras 110 and 115 having CMOS image sensors mounted therein can store the image information of the object received through the apertures 110a 11 Ue-e6LUUb-UUzD-Ub-UU and 110b and the lenses 110b and 115b, respectively. The apertures 110a and 110b have non-reflective coating applied to an inside surface and an outside surface for making the lights from the illumination units 120 and 125 to illuminate the object well. [0036] The cameras 110 and 115 may have a battery 150 mounted therein for serving as a power source. The battery 150 is a silver oxide battery having a flat discharge voltage and harmless to the human body. [0037] The operation of the capsule type endoscope will be described in detail. [0038] Once a patient swallows down the capsule type endoscope, the capsule type endoscope enters into organs in the human body through the esophagus, and takes images of lesions at the organs in the human body and reproduces the images. [0039] In this instance, the light from the illumination unit 110 or 115 passes through the lens 110b or 115b and illuminates the object. The image information on the object passes through the lens 110b or 115b again, and taken at the CMOS image sensor, such as the camera 110 or 115. Then, the image processing unit 130 processes the image information by using various circuits therein and transmits the image information processed thus to the signal transmission electrode 140. In this instance, since images on opposite 12 sides of the housing 100 are obtainable from the cameras 110 and 115 mounted on opposite sides of the housing 100, and angle of views of the cameras 110 and 115 are 150 degrees respectively, almost all appearances of the inside of the organ through which the capsule type endoscope advances can be taken without missing. [0040] The capsule type endoscope 100 may have variable diameter. That is, it is required that the capsule type endoscope takes an image, not only of the small intestine, but also the large intestine. The small intestine has an average diameter of about 2.5cm, and the large intestine has a diameter of about 6 ~ 6.5cm. Therefore, the capsule type endoscope fabricated fit to the diameter of the small intestine is likely to tumble in the large intestine which has a diameter greater than the diameter of the small intestine. Particularly, the general advance preparation of emptying the large intestine by enema or the like for examination of the large intestine increases a possibility of the tumbling of the capsule type endoscope in the large intestine emptied thus. Though the capsule type endoscope of the present invention has cameras on opposite sides, it is still preferable that the tumbling of the capsule type endoscope is prevented for taking the image, securely. [0041] The large intestine, on an outer side of the small intestine, has a portion in a form of an ascending colon (in 13 UE--7-c-Z-UUd-UU23-US1-UU a form rising from a lower side to an upper side). Therefore, even if the capsule type endoscope enters into the large intestine, it is difficult to pass the ascending colon of the large intestine, easily. That is, since the large intestine does not make peristalsis always, it is required that the capsule type endoscope passes through the large intestine within a limit of an operation time period of the capsule type endoscope. Accordingly, if the housing has a variable diametric structure, the capsule type endoscope can fill up the large intestine fully, such that the capsule type endoscope can pass the large intestine within a comparatively short time period following the peristalsis. [0042] In this instance, as means for the housing to have the variable diametric structure, expandable members may be mounted to a surface of the housing. That is, as shown in FIG. 1B, the expandable members 160 may be mounted to the surface of the housing 100. A number of the expandable members 160 may be greater than shown in the drawing, and an extent of the expansion may also be greater than shown in the drawing. Though the expandable members 160 may be mounted to the surface of the housing sporadically, the expandable members 160 may form a layer on the surface of the housing 100 as shown in FIG. 1C. [0043] Though the embodiment shows the expandable members 160 mounted to the surface of the housing 100, it is apparent 14 UtetLL-ZUU0UUZ3-U1)-UU that the housing may also have a structure in which an entire housing expands. The expandable members 160 may not be distributed uniformly throughout the surface of the housing 100. In this instance, it is required that the expandable member 160 is devised such that the expandable member 160 has an increased volume when the expandable member 160 arrives at the large intestine so as to reduce density thereof. For an example, if liquid is filled in the expandable member 160, and the liquid is turned into gas in the large intestine, the increase of volume will be possible. [0044] Or, the expandable member 160 may expand by sensing a pressure of the large intestine or pH of the large intestine when the capsule type endoscope arrives at the large intestine passing through the stomach and the small intestine. Or, alternatively, the expandable members 160 may be expanded by a timer. It is also required that the capsule type endoscope has a diameter similar to the diameter of the large intestine when the expandable member 160 expands fully. [0045] Eventually, since the capsule type endoscope with the expandable members 160 has the expandable members 160 expanded after the capsule type endoscope enters in the large intestine, the capsule type endoscope is not likely to tumble in the large intestine. Moreover, since the capsule type endoscope fills the diameter of the large intestine fully when the expandable members 160 expand, the capsule type 15 UeeL LZUUd -UL _UI)UU endoscope can be moved by the peristalsis of the large intestine. [0046] The capsule type endoscope can be fabricated to have overall density to be equal to or greater than 0.7 and below 1. This is for providing floatability to the capsule type endoscope, wherein the floatability is making the capsule type endoscope to float on body fluid. This is for the capsule type endoscope to flow down easily following a flow of the body fluid. That is, in general, the capsule type endoscope is moved by the peristalsis or moves following the flow of the body fluid merely, but is not provided with any moving means for itself. [0047] Therefore, a time period of the capsule type endoscope for pass-through the stomach or the small intestine varies with a digestion capability, and a body constitution. Accordingly, if the capsule type endoscope is made to have a density of below unity, so that the capsule type endoscope flows down carried by water or the body fluid easily so as to arrive at the large intestine within a short time period. Moreover, if floated on the water, the capsule type endoscope can pass, not only through even the ascending colon easily when the capsule type endoscope enters in the large intestine, but also through the large intestine enlarged by making the patient to drink water of other solution, easily. 16 OPP-ZZ1-2UUb-UUzn-Ub-UU [0048] Though the capsule type endoscope has no problem in passing through the esophagus, the stomach, and the small intestine, since in general the esophagus, the stomach, and the small intestine have no ascending colon, moving means for the capsule type endoscope to pass through the large intestine is a significant issue. Therefore, it can be devised that the capsule type endoscope has density of about 0.7 - 1 when the capsule type endoscope enters in the large intestine. Moreover, if the density of the capsule type endoscope is made to be within above range in organs other than the large intestine, the organ pass through time period of the capsule type endoscope which varies from person to person can be made similar. That is, above system enables to shorten a body cavity pass through time period of the capsule type endoscope. [0049] It is natural that the capsule type endoscope has density varied depending on whether the expandable members are expanded or not. It is preferable that the density of the capsule type endoscope is within above range when the expandable members are expanded if structural characters of the organs are taken into account. [0050] In order to process image information on an object taken at the cameras on opposite sides of the housing, the capsule type endoscope has a control unit as described below. 17 [0051] FIG. 2 illustrates a block diagram of a control unit in an endoscope in accordance with a preferred embodiment of the present invention. A control unit in an endoscope in accordance with a preferred embodiment of the present invention will be described with reference to FIG. 2. [0052] The control unit mounted in the housing of the capsule type endoscope receives important information on an image sensor measured at the time of production of the capsule type endoscope and stores the information in control ASIC. The control unit transmits a control signal to the image sensors mounted to the opposite sides of the housing respectively by a method of 12C communication or the like. The control unit also processes the image signal (an input signal 3Mbps) taken at the image sensors, and forwards as an image signal greater than 6Mbps. The image sensor is a CMOS image sensor mounted to the camera. [0053] The control unit has 3 modes. In detail, BS(1.0) at a bit map denotes a boot sequence. If the boot sequence is 00, the control unit is in a basic mode which is in the delayed turn on method to turn on the capsule type endoscope automatically after a preset time period is passed. According to this, a time period can be adjusted according to setting of the timer. [0054] If the boot sequence is 01, the control unit is in a mode of double after single working, which is a mode in 18 Ut'r'L~LUUOUUJUZ-U I which the capsule type endoscope is swallowed through a mouth of a human body in a state only one of the CMOS sensors is turned on, and the other one of the CMOS sensors is turned on after a preset time period is passed. [0055] If the boot sequence is 10, the control unit is in a mode in which the capsule type endoscope is operated in a state both of the opposite side CMOS sensors are turned on from starting, i.e., in a direct turn on mode. In a case the capsule type endoscope is turned on directly, there is high necessity for operating one of the two cameras for saving power. [0056] By adjusting the turn on time period and time periods for operating the opposite two cameras of the capsule type endoscope having the three control modes, power consumption of the capsule type endoscope can be reduced, resulting to reduce an operating time period of the capsule type endoscope, at the end. [0057] Device and method for reproducing the image information from a signal from the signal transmission electrode will be described with reference to FIGS. 3 and 4. [0058] FIG. 3 illustrates signal transmission electrodes in an endoscope in accordance with preferred embodiments of the present invention, respectively. [0059] Referring to FIG. 3, there are one pair of signal transmission electrodes 140 mounted to the surface of the 19 Ue-L-LUV-UULO-U-UU housing 100. In detail, one pair of the signal transmission electrodes 140 are mounted on opposite sides of the housing 100 in shapes of bands respectively. Since the signal transmission electrodes 140 are exposed to the inside of the human body, it is required that the signal transmission electrodes 140 are formed of a metal having a good corrosion resistance for enduring to reactive substances, such as digestive fluid and harmless to the human body. [0060] In the embodiment, as a material for the signal transmission electrodes 140, stainless steel or gold is used as the metal having a good corrosion resistance and harmless to the human body. Moreover, in order to isolate the signal transmission electrodes 140 from the surface of the housing 100 electrically, it is required that the surface of the housing 100 is formed of a non-conductive material which is harmless to the human body and conducts no electricity. As a non-conductive material harmless to the human body, there are Peek, polyethylene, or polypropylene in a group of plastic, and in order to enhance the harmlessness to the human body, a playlene coating may be applied to the Peek, polyethylene, or polypropylene. [0061] FIG. 3 illustrates signal transmission electrodes in an endoscope in accordance with preferred embodiments of the present invention, respectively. 20 OPP-ZZ-2UUd-UUZb-US;-UU [0062] The capsule type endoscope introduced to the inside of human body transmits a data to an outside of the human body by using the human body as a conductive substance. In more detail, the capsule type endoscope generates a current in the human body and makes the current to flow through the body, for transmission of the data to the outside of the human body. [0063] Referring to FIG. 4, the capsule type endoscope 410 located in the human body, for an example, in the digestive track, transmits information on the inside of the human body to a receiver 430 on a surface of the human body. [0064] It will be described in detail. [0065] The cameras mounted to the housing of the capsule type endoscope introduced to the inside of the human body obtain image information on an object in at least two directions. In this instance, the obtaining of the image information on an object is made simultaneously by taking images of the object at the same time with the cameras on opposite sides of the housing of the capsule type endoscope. As described before, at least one of the cameras can be turned on after a preset time period is passed. [0066] Then, the image information is converted into an electric signal. The electric signal is applied to the housing of the capsule type endoscope and the surface of the human body. In detail, pieces of information (for an example, 21 images, pH, temperatures, or electric impedance, and so on of the inside 300 of the human body) collected by the capsule type endoscope 410 is converted into electric signals by the CMOS image sensor in the capsule type endoscope 410, and applied to the signal transmission electrodes 140 through the image information processing unit 130. [0067] The current flows through the surface of the human body owing to a voltage difference between the signal transmission electrode 140 and a signal receiving electrode 440, and the image information can be reproduced by using the current. It will be described in detail. Therefore, the signal transmission electrode is in contact with the inside of the human body 400, and the current 430 flows through the human body 400 owing to the voltage difference between the signal transmission electrode 140 and the signal receiving electrode 240. In this instance, the current 430 flows from the signal transmission electrode 140 having a relatively high voltage to the surface of the human body through the human body 400, passes through the signal receiving electrode 440, and flows back to the signal transmission electrode 140 having a relatively low voltage through the inside of the human body again 400 again. [0068] The current on the surface of the human body is applied to the signal receiving electrode, to reproduce the image information. It will be described in detail. The 22 current flowing through the surface of the human body forms a voltage difference between the two signal receiving electrodes 440, such that the signal from the capsule type endoscope 410 in the human body 400 is sensed at the signal receiving electrode 440 on the outside of the human body 400 at the end. By processing the signal received at the signal receiving electrode 440 to restore the image signal, the image can be displayed on a monitor in real time or store in a memory. (0069] In this instance, both images taken from the organ with the cameras mounted to the opposite sides of the housing may be displayed at the same time. It is preferable that the images are taken at the same time. [0070] FIG. 5 illustrates a block diagram of a CMOS image sensor in an endoscope in accordance with a preferred embodiment of the present invention. The CMOS image sensor in an endoscope in accordance with a preferred embodiment of the present invention will be described with reference to FIG. 5. [0071] Referring to FIG. 5, the CMOS image sensor 540 includes a pixel array 500 for taking and storing the image signal, a reading circuit 510 for retrieving a signal from each of pixels in succession, an encoding circuit 520 for encoding the signal from the reading circuit 510, a switching circuit 530 for forwarding the signal encoded at the encoding circuit 520 through two output lines, a current limiting 23 Ue-L-ZUUb-UUL3-Ub-UU circuit 540 for regulating a current value so that a current of an intensity harmful to the human body does not flow, a control circuit 550 for controlling processing of the signal and operation of the illumination unit 520, and an oscillating circuit 560 for determining an operation frequency. [0072] The pixel array 500 has 320x240 pixels for taking an image signal of high resolution, and it is made that the image signal stored is processed by one frame per each second. The control circuit 550 determines a gray scale of the inside of the human body with reference to the light incident on the pixel array 500, to operate the illumination unit 520 for 5 200 microseconds variably, for taking the image signal with the pixel array 500 during the while. By doing thus, even if each of the image frames is taken instantaneously, the brightness of the image becomes good. The PSK method is employed as the encoding method, which is simple, but resistant against the noise. [0073] The switching circuit 530 receives the signal from the encoding circuit 520, so that the switching circuit 530 applies a positive voltage to the first output line 540a and grounds the second output line 540b if the signal is '1', and the switching circuit 530 grounds the first output line 540a and applies a positive voltage to the second output line 540b and if the signal is '0' . By above system, the signal is 24 Ue-4L6-ZUU0-UUZ -Ub-UU transmitted, not by amplitude of the voltage, but by polarity of voltage, so that the signal is more resistant to the noise. [0074] The current limiting circuit 540 serves that a current higher than 5mA can not flow to the human body. In the embodiment, resistors are connected in series to each of the output lines 540a and 540b of the switching circuit 530 to make the current limiting circuit 540. For an example, in a case a power source has 10 volts, if the current limiting circuit is made by connecting 10000 of resistors to each of the output lines in series, the current flowing through the human body can not exceed 5mA even if the signal transmission electrodes are short circuited owing to very low resistance of the human body. In addition to this, if high frequency components are removed from the signal transmitted through the human body and electric conformity with the human body is sought by connecting a capacitor to each of the resistors in parallel, an excellent signal transmission can be achieved. [0075] The signal passed through the current limiting circuit 540 is applied to the two signal transmission electrodes 510 finally through above paths taking the human body as a path, and therefrom is transmitted to the outside of the human body. Therefore, though hundreds of MHz of high frequency signal is required in an electronic wave communication system used presently, the present invention permits to transmit the image signal taken by the capsule 25 Ue-Z-zUUb-UUz-U'--UU type endoscope to the outside of the human body even with a 10MHz low frequency signal. [0076] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. [0077] As has been described, the capsule type endoscope and the method for operating the same of the present invention have the following advantage. [0078] First, the capsule type can be moved within organs having diameters different from each other by peristalsis and the like, and the three mode operation and the body communication system reduces power consumption of the capsule type endoscope even if a plurality of cameras are used, which enables use of the capsule type endoscope for a long time period, permitting to take images of lesion at the large intestine after the capsule type endoscope is introduced to the human body. [0079] Second, the use of the body communication system dispenses with an antenna in view of structure, which enables to reduce a volume of the housing, and to dispense with a high frequency which is harmful to the human body. 26 [0080] Third, the variable diameter of the capsule type endoscope prevents the housing from tumbling at the time of taking images of an inside organ of the human body, particularly the large intestine, and, even if the tumbling takes place, the cameras on opposite sides of the housing of the capsule type endoscope enables to take images of an entire organ. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 27

Claims (14)

1. A capsule type endoscope comprising: a plurality of optical windows facing directions different from one another; image obtaining units each positioned in rear of each of the plurality of optical windows for obtaining an image; signal transmission units each for transmission of the image obtained thus; and a control unit for forwarding first to third control signals for obtaining the image, wherein at least one of the control signals is delay turned on, and at least another one of the control signals is directly turned on.

2. The capsule type endoscope as claimed in claim 1, wherein the first control signal is a control signal which is delay turned on for obtaining signals form opposite sides.

3. The capsule type endoscope as claimed in claim 1, wherein the second control signal is a control signal which is directly turned on for obtaining an image from one side. 28 OPP-ZZ-2UU8-UU25-US-UU

4. The capsule type endoscope as claimed in claim 1, wherein the third signal is a control signal which is directly turned on for obtaining images from opposite sides.

5. The capsule type endoscope as claimed in claim 1, further comprising an expandable portion.

6. The capsule type endoscope as claimed in claim 1, having density of 0.7 ~ unity.

7. The capsule type endoscope as claimed in claim 1, wherein the signal transmission units are at least two electrodes.

8. The capsule type endoscope as claimed in claim 5, wherein the expandable portion is formed of silicone.

9. A method for operating a capsule type endoscope comprising the steps of: obtaining image information on an object from at least opposite sides; converting the image information into an electric signal; 29 OPP-ZZ-2008-0025-US-UU applying a current to a housing of the capsule type endoscope and a surface of a human body by using the electric signal; and reproducing the image information by using the current applied to the surface of the human body.

11. The method as claimed in claim 10, wherein the step of obtaining image information includes the step of taking image information of the object simultaneously by image obtaining units mounted to at least two sides of the housing of the capsule type endoscope, respectively.

12. The method as claimed in claim 11, wherein at least one of the image obtaining units is turned on after a preset time period is passed.

13. The method as claimed in claim 10, wherein the step of applying a current to a housing of the capsule type endoscope and a surface of a human body includes the step of applying the electric signal to a surface of the housing to apply the electric current to the surface of the human body by a voltage difference between the first electrode and the second electrode on the surface of the human body. 30 OPP-ZZ-2UU-UU25-US-UU

14. The method as claimed in claim 10, wherein the step of reproducing the image information includes the step of applying a current to the surface of the human body by a current on the surface of the human body, and the image information is reproduced by the current.

15. The method as claimed in claim 10, further comprising the step of expanding a diameter of the housing at a specific location of an inside of the human body. 31