a capsule type endoscope according to a first embodiment of the present invention will be described below by referring to fig1 to 5 . fig1 is a diagrammatic view showing a capsule type endoscope 1 configured as a so - called compact camera . the endoscope has a light - transparent capsule body 2 serving as a protective outer shell . the capsule body 2 is formed as a case having such an outer configuration and size that it can be passed through the esophageal canal upon being swallowed via the mouth . a sealed storage chamber is created within the capsule body 2 . as shown in fig1 , the capsule body 2 has a cylindrical intermediate section axially elongated compared with its diameter . both the opposite end sections of the capsule body 2 , are each formed to have an axially outwardly extending hollow semispherical configuration with at least its outer surface smoothly formed . since the capsule body 2 is formed as being axially elongated compared with the diameter , it can be easily swallowed and the swallowing movement direction is readily liable to be guided toward the axial direction of the capsule body 2 . as shown in fig1 , various kinds of associated component parts are incorporated within the storage chamber of the capsule body . within the capsule body 2 are stored a substrate 3 , an image taking device having an image pickup element 4 and illuminating elements 5 mounted on the substrate , an image ( video ) signal processing circuit 6 , a memory 7 , an image ( video ) signal transmitting circuit 8 , a battery 9 , an antenna 10 , a position detecting means 11 , etc . as the image pickup element 4 use is made of a solid state image pickup element such as a c - mos and a ccd . as the illuminating elements 5 use is made of , for example , leds and so on . as shown in fig2 , the illuminating elements 5 are equidistantly arranged around the image pickup element 4 . each illuminating light emitted from the corresponding illuminating element 5 is radiated onto an image taking field through a transparent end wall of the capsule body 2 to illuminate the image taking field . the image pickup element 4 takes images in the illuminated image taking field . the image signal processing circuit 6 processes signals taken by the image taking element 4 in the image taking device to generate image signals . the signals are supplied to a memory 7 where these signals are once stored . the stored image signals are sequentially taken out by the image signal transmitting circuit 8 and sequentially converted to transmission signals . the transmission signals are sequentially transmitted via the antenna 10 to the outside by wireless . the battery 9 is used as a power source for each element , circuits and so on . the position detecting means 11 has a sensor for detecting an electromagnetic field at its site and detects the position of the capsule body 2 by the electromagnetic field detected by the sensor . for example , it responds to an external plate 12 , such as a magnetic plate or conductive plate , as will be set out below to detect the external plate 12 and decides its own position . further , it may be made to respond to an electromagnetic field generated in a magnetic coil if the external plate placed outside the living body is replaced by the magnetic coil . fig3 shows a receiver 15 located outside the living body . the receiver 15 receives / records image signals sent by a wireless transmission from the capsule type endoscope 1 . the receiver 15 includes a receiving antenna 16 , an image signal receiving circuit 17 and an image recording means ( memory ) 18 . the image signals received by the image signal receiving circuit 17 are recorded in the image recording means 18 . the image recording means 18 transmits the image signals to a monitor 19 where these images are monitored . the images taken can also be transmitted to a given image receiver at a remote site via a communication means such as the internet ( not shown ). it is to be noted that a program capable of a variable setting is provided for the image pickup element 4 ′ image information transmitting circuit 8 , image signal processing circuit 6 and memory 7 . the image taking rate by the image pickup element 4 , the transmission rate by the image information transmitting circuit 8 , the timing and time for allowing the storing of the image signals into the memory 7 through the image signal processing circuit 6 are arbitrarily set or variable by being programmable . these may be settable or variable even in such cases as to varying the program of a timer , etc ., in the capsule body 2 before swallowing the capsule body 2 , to vary a program by information from outside the living body after the capsule body 2 has been swallowed , or to vary both . in this case , a receiver 41 and antenna 42 are provided in the capsule body 2 as shown in fig1 to receive information for instructing a variation of the information contents . now , an explanation will be made below about how to use the capsule type endoscope 1 set out above . first , as shown in fig4 a , the external plate 12 is positioned in a manner to correspond to the esophageal canal 21 of a patient 20 and it is located on the external surface of the patient 20 . after this , the capsule type endoscope 1 is swallowed via the mouth with its axial direction guided toward the swallowing movement direction . as shown in fig4 a , the capsule type endoscope 1 passes through the esophageal canal 21 with its longitudinal axis direction guided toward the longitudinal direction of the esophageal canal 21 . when the capsule type endoscope 1 passes through the esophageal canal 21 , the position detecting means 11 of the capsule type endoscope 1 senses the external plate 12 and the image taking device starts its operation . the position detecting means 11 , while sensing the external plate 12 , decides that the capsule type endoscope 1 is situated in the esophageal canal 21 . as shown in fig4 a and 4b , while the capsule endoscope 1 is detected as being situated in the esophageal canal 21 , the illuminating elements 5 are lit and the image taking device is intermittently operated . the area of the esophageal canal 21 thus illuminated is thereby imaged by the image pickup element 4 many number of times . the capsule type endoscope 1 can pass through the esophageal canal 21 , usually within a very short time of one second . during this short time , the image pickup element 4 takes many frames of an image at high speeds , while scanning the entire area of the esophageal canal 21 . the minimum frame rate required for continuously scanning the entire area of the esophageal canal 21 is 5 frames / second . assume that the canal 21 is 30 cm long as in most cases , that the focal depth of the endoscope 1 is 6 cm and that it takes the endoscope 1 one second to pass the canal 21 . then , the minimum frame rate is given as : the length of the esophageal canal varies from person to person , and the focal depth of the endoscope 1 may change from time to time . if the endoscope 1 needs 0 . 5 seconds to pass through the canal 21 , the focal depth of the endoscope 1 is 1 cm , and 30 frames (= 30 ( cm )/ 1 ( cm )) must be taken , then the frame rate should be 60 frames / second . however , if the frame rate is less than 5 frames / second , for example 2 frames / second , it is not easy to set the focal depth at 10 cm or more . it is therefore hard to set the far point at 10 cm or more for tubular organs such as the esophageal canal . consequently , it would be difficult to observe the esophageal canal continuously . however hard the patient tries , he or she cannot swallow the capsule to move it continuously and slowly through the entire esophageal canal . in view of this , the imaging of the canal must be carried out at a frame rate of at least 5 frames / second to achieve continuous observation of the entire area of the esophageal canal 21 . further , the image signal processing circuit 6 sequentially processes those signals taken by the image pickup element 4 to generate image signals , and these image signals are stored in the memory 7 in realtime . for example , an image of a hundred thousand pixels is compressed under the jpeg system and those images corresponding to 30 frames are sequentially retained in the memory 7 . here , recording rate at which the generated image signal is stored in the memory 7 in realtime is given by v 1 . after the capsule type endoscope has dropped past the esophageal canal 21 into the stomach , the image taking operation is stopped because the position detecting means 11 ceases to detect the external plate 12 . thus , the capsule type endoscope 1 performs a high - speed image taking operation only during the time in which it passes through the esophageal canal . since the capsule type endoscope stops its image taking operation after it has dropped into the stomach and does not continue its image taking operation , the capacity of the memory 7 can be effectively utilized without wasting it . further , the remaining capacity of the memory 7 can be kept for another image taking operation . although the signals of those images taken by the image pickup element 4 of the image taking device have been once stored in the memory 7 , the image information items are sequentially read out of the memory 7 and wirelessly transmitted by the image signal transmitting circuit 8 to the outside of the living body via the antenna 10 . the operation of storing the signals of the images taken by the image pickup element 4 is continued without waiting for the completion of the transmission of the previous image information items by the image signal transmitting circuit 8 and these are sequentially stored in the memory 7 . incidentally , the transmitting speed v 2 by the image signal transmitting circuit 8 is as slow as a frame rate of two frames / second . however , the signals of the images taken by the image taking element 4 continue their storing operation relative to the memory 7 without waiting for the completion of the transmission operation . that is , since the image signal taking operation while allowing the transmitting operation is continued , a larger amount of image signals can be stored in the memory 7 . even if the transmitting rate v 2 is slower than the recording rate v 1 , it is possible to make the recording rate v 1 fairly rapid . further , the image signals stored in the memory 7 are wirelessly transmitted by the image signal transmitting circuit 8 to the outside of the living body via the antenna 10 in the order in which these image signals are stored . the operation of storing the image signals into the memory 7 and the transmitting operation by the image signal transmitting circuit 8 are carried out individually . a greater amount of image signals is stored for a shorter time period into the memory 7 and the image signals stored in the memory 7 are sequentially transmitted by the image signal transmitting circuit 8 to the outside of the living body in a wireless fashion . on the other hand , the receiver 15 externally installed as shown in fig3 receives the image signals via the receiving antenna 16 which are transmitted from the capsule type endoscope 1 and the image signals are recorded via the image signal receiving circuit 17 into the image recording means 18 . further , the image signals are transmitted to the monitor 19 where these images are monitored or to an image receiver at a remote site through a communication means such as the internet ( not shown ). the position detecting means 11 as set out above detects the position of the capsule body 2 , and the image taking time , the times of image taking , and so on , are controlled . by doing so it is possible to adopt various kinds of image taking modes . for example , when the capsule body passes through the position corresponding to the external plate 12 , images are taken at a frame rate of 60 frames / second and , after the passage of the capsule body past that corresponding position , switching is made to a mode in which images are obtained at a frame rate of 2 frames / second . by doing so , proper image taking is carried out in accordance with each site . although , in the above - mentioned embodiment , the position detecting means 11 detects the external plate 12 to decide a position corresponding to the location of the capsule type endoscope 1 , this invention is not restricted thereto and it is also possible to decide the position of the capsule type endoscope with the use of other position detecting systems . further , the position detecting means as set out above may be comprised of a gyro , an acceleration sensor , a sensor for detecting the moving speed of the capsule body 2 , and so on . further , the position detected by the position detecting means 11 may be stored as position information in the memory 43 and the position information may be wirelessly transmitted to the outside by the transmitting unit 45 including an antenna 44 . still further , an adjusting unit 48 may be provided for adjusting the image taking rate by the image pickup element 4 , the on / off operation of the image taking , and so on , according to the position information of the capsule body 2 detected by the detecting means 11 as shown in fig1 . an explanation will be made below about a capsule type endoscope according to a second embodiment of the present invention by referring to fig6 . the capsule type endoscope 1 of this invention includes a built - in timer 31 in a capsule body 2 , and , by means of this timer 31 , the image taking time and the times of image taking by an image taking device , and so on , are controlled based both on its time data and according to a timer program . the remaining structure is the same as that of the first embodiment . based on the time data of the timer 31 and according to the timer program , the image taking time , the times of image taking , and so on , can be controlled and , by doing so , various modes of image taking can be adopted . for example , the capsule type endoscope 1 , after being passed through the esophageal canal 21 , is discharged via the anus past the stomach , the small intestine and the large intestine but it takes a whole day and night , unlike the passage of the capsule type endoscope through the esophageal canal , to move the capsule type endoscope through the stomach , the small intestine and the large intestine . for this reason , the image taking rate is varied or on / off operated according to a schedule initially set by the timer 31 and , by doing so , it is possible to effectively utilize a data retaining capacity in the memory 7 and also to reduce the wastage of the battery 9 for lighting illuminating means . an image taking examination can be made over the whole alimentary canal , including a gastrointestinal image taking examination after the capsule type endoscope has passed through the esophageal canal 21 . an explanation will be made below about a capsule type endoscope according to a third embodiment of the present invention by referring to fig7 . in the capsule type endoscope 1 according to this embodiment , the center of gravity , w , is located at or near a position corresponding to the image pickup element 4 . here , it is located on a longitudinal axis of the capsule body 2 at a position where the substrate 3 is situated . that is , the center of gravity , w , of the capsule type endoscope 1 is located at a forward site of the capsule body 2 on the image pickup element 4 side . the position of gravity , w is determined depending upon the shape and material of the capsule body 2 as well as the size and number of built - in component parts and their locations , and so on , and it is determined from the standpoint of these design considerations . since the center of gravity , w , of the capsule type endoscope 1 is located at the forward site of the capsule body 2 on the image pickup element 4 side , the capsule type endoscope 1 is easier to swallow and , after being swallowed , the direction of the capsule body 2 is stably guided and it is possible to stably and positively take images in the esophageal canal . an explanation will be made below about a capsule type endoscope according to a fourth embodiment of the present invention by referring to fig8 . in the capsule type endoscope 1 of the fourth embodiment , its capsule body 2 is so formed as to have a semi - spherical configuration at the forward end section as viewed from its longitudinal direction and the backward end section of the capsule body 2 is so formed as to be gradually tapered toward a backward direction . the forward end section of the capsule body 2 is larger in diameter than the backward end section . if the capsule body 2 is made thicker on the forward end side , then the center of gravity , w , of the capsule type endoscope 1 tends to be located toward the forward section of the capsule body 2 . since the capsule body 2 has such a shape as set out above , it is easier to swallow toward a predetermined direction . an explanation will be made below about a capsule type endoscope according to a fifth embodiment of the present invention by referring to fig9 . in the capsule type endoscope 1 according to this embodiment , its capsule body 2 is so formed as to have image taking devices incorporated at opposite longitudinal end portions . by so doing it is possible to take images at both the longitudinal forward and backward sections of the capsule body 2 . the respective image taking device is so formed as to have its corresponding image pickup element 4 and illuminating elements 5 mounted on a corresponding substrate 3 . according to the thus structured capsule type endoscope 1 , when the capsule body 2 is swallowed , it is possible to take images not only at its forward section but also at its backward section as viewed in its moving direction and , hence , to take more images corresponding to more sites of interest . in addition , it is also possible to take images corresponding to the inner wall sites of the esophageal canal from different directions . as a result , more reliability is ensured on diagnosis . since the backward sites can be taken as images when the capsule body 2 is swallowed , it is possible to take images at an important region of interest just at or near the exit opening of the esophagus into the stomach , in particular , immediately before , and just at the moment of , the dropping of the capsule body 2 into the stomach . an explanation will be made below about a capsule type endoscope according to a sixth embodiment of the present invention by referring to fig1 and 11 . in the capsule type endoscope 1 of this embodiment , a capsule body 2 has a soft flat tail 35 at its backward portion . according to the capsule type endoscope 1 having such a tail 35 , the capsule body 2 is easier to swallow and , when the capsule type endoscope 1 has been swallowed , the direction of the capsule body 2 is stably oriented by the tail 35 and it is possible to positively take images of the inner wall of the esophageal canal . it is to be noted that the present invention set out above is not restricted to the above - mentioned respective embodiments and can be applied to other modes of application . although , in the above - mentioned embodiments , the explanation has been made more about taking images of the inner wall of the esophageal canal , the object of the image taking is not restricted to the esophagus and the present invention can be applied to image taking of a region of interest to examine not only the esophagus but also those organs such as the stomach , the small intestine and the large intestine for any affected region of interest and its neighborhood . in this case , it is only necessary to set the position of the position detecting means and program of the timer to the region of interest . the present invention is not limited to the capsule type endoscope described above , which has a battery in the capsule body to supply power to the elements and circuits provided in the endoscope . rather , the invention may be applied to a capsule type endoscope shown in fig6 , in which a power receiver 46 is provided in the capsule body 2 . the receiver 46 continuously receives power that is supplied from the outside in the form of electromagnetic waves , for example , microwaves or light that passes through the living tissues and organs . further , a battery may be provided for storing electric power received by the power receiver 46 or may be made rechargeable . according to such a structure , the electric power can be continuously supplied in a contactless way from outside to the capsule type endoscope in a living body and there is the advantage that the capsule type endoscope in the living body can be positively operated for a long time . stated in more detail , the capsule body has a built - in power receiving means such as a power receiving antenna or a solar cell unit and , outside the living body , a power transmitting antenna or light emitting means as a light emitting plate / light emitting unit is arranged toward the inside of the living body . additional advantages and modifications will readily occur to those skilled in the art . therefore , the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein . accordingly , various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents .
a capsule - type endoscope comprising a capsule body , an image pickup element an illuminating elements , an image signal processing circuit , a memory , an image information transmitting circuit and an antenna for wireless transmission . the capsule body contains the pickup element , the illuminating elements , the processing circuit the memory , transmitting circuit and the antenna . while the capsule body remains in a living body , the image pickup element takes images of an interior of the living body . the processing circuit processes the image , generating image information . the memory stores the information . the transmitting circuit reads the information and supplies it to the antenna . the antenna transmits the information by radio , from the living body .