Patent Publication Number: US-2010130818-A1

Title: Capsule-type endoscope capable of controlling frame rate of image

Description:
TECHNICAL FIELD 
     The present invention relates to an endoscope, and more particularly, to a capsule-type endoscope capable of controlling a frame rate of image. 
     BACKGROUND ART 
     A variety of methods for collecting medical information within a human body have been developed. 
     In general, an endoscope has been used for a method for collecting image information, one of medical information within the human body. Endoscope captures images inside the body and then transmits the captured images to an external device via a communication cable, such as conducting wires and optical fibers. However, if such cable is used in endoscope, even after the endoscope is inserted inside the body, the cable still remains in the mouth (oral cavity), thereby causing a great pain to a patient. In addition, the cable should be manipulated to adjust a region for image capture, thereby causing various side effects, such as damage in the internal organs inside the body, and the like. 
     In order to solve such problems, Given Imaging Ltd., an Israel-based company has recently developed a capsule-type endoscope, called the “PillCam.” If this capsule-type endoscope is swallowed by a patient, similar to a pill, it may transmit image data related to digestive organs inside the human body captured by an endoscope camera to an external receiver and thus to implement such image data on a monitor. 
     However, the capsule-type endoscope developed by Given Imaging Ltd., captures images at a fixed frame rate. The speed at which ingesta move within the body depends on the characteristic of each digestive organ within the body. Accordingly, every digestive organ cannot be captured by only one capsule-type endoscope. 
     That is, a fast frame rate is required to obtain image information related to an internal organ, such as the esophagus where ingesta move fast and frequently, thus to obtain image information therefor without any portion non-captured, whereas a slow frame rate is required in an internal organ, such as small intestine where ingesta move slowly and limitedly, thereby to efficiently obtain image information. 
     However, since the capsule-type endoscope developed by Given Imaging Ltd., provides a fixed frame rate, an exclusive capsule-type endoscope providing a frame work suitable for each digestive organ has been developed, which causes customers to consume many costs in order to examine every digestive organ. 
     DISCLOSURE OF INVENTION 
     Technical Solution 
     Therefore, it is an object of the present invention to control a frame rate of a capsule-type endoscope. 
     In detail, an object of the present invention is to control a frame rate of a capsule-type endoscope by determining a position of the capsule-type endoscope inserted into a body or information related to a movement of the capsule-type endoscope. 
     Here, the position of the capsule-type endoscope within the body may be determined by detecting a moving velocity/angular velocity of the capsule-type endoscope. That is, in general, since ingesta fast move in the esophagus but slowly move in small intestine, the moving velocity/angular velocity of the capsule-type endoscope is detected so as to determine the position of the capsule-type endoscope. 
     Alternatively, the position of the capsule-type endoscope within the body may be determined by calculating a similarity between a plurality of images captured. That is, a low similarity level indicates a fast movement of the capsule-type endoscope and a high similarity level indicates a slow movement thereof. Accordingly, in which digestive organ the capsule-type endoscope is located can be determined. 
     Alternatively, the position of the capsule-type endoscope within the body may be determined by using an energy level of a received signal. Also, it can be estimated in which organ the capsule-type endoscope is to be located after a certain time elapses according to an average resulting value known through experiments. 
     In one aspect of the present invention, a capsule-type endoscope capable of controlling a frame rate of image may comprise, a lens adapted to capture an image inside an animal body including a human body, a processor adapted to encode the image captured through the lens to output a signal and control a frame rate according to where the capsule-type endoscope is located within the body, and a transmitting unit adapted to transmit the signal from the processor. 
     Preferably, the processor may control the frame rate by itself or according to an external control signal. 
     In case of controlling the frame rate by itself, the processor drives a timer to check an elapsed time after the capsule-type endoscope is located within the body, so as to estimate the position of the capsule-type endoscope, thereby controlling the frame rate. 
     In case of controlling the frame rate according to the external control signal, the processor encodes a moving velocity of the capsule-type endoscope together with the image information for output, so as to determine the position of the capsule-type endoscope based upon the moving velocity outside the body, thereby controlling the frame rate outside the body. 
     In another aspect of the present invention, a capsule-type endoscope capable of controlling a frame rate of image may comprise a lens adapted to capture an image inside a digestive organ within an animal body including a human body, a processor adapted to encode the image captured by the lens for output, operate a timer for checking an elapsed time after the capsule-type endoscope is located within the body, and thusly determining in which digestive organ the capsule-type endoscope is located within the body, and to control the frame rate either according to the determined location or according to an external control signal received from the exterior, a transmitting unit adapted to transmit the image signal received from the processor, and a receiving unit adapted to receive the external control signal. 
     In still another aspect of the present invention, a capsule-type endoscope capable of controlling a frame rate of image may comprise a lens adapted to capture an image inside a body of an animal including human, a processor adapted to encode an image captured by the lens to output the signal and control the frame rate, and a transmitting unit adapted to transmit a signal from the processor. Here, the processor may control the frame rate according to a movement amount of the capsule-type endoscope. The movement amount may correspond to at least one or more of a moving velocity, an angular velocity and a moved distance of the capsule-type endoscope. In order to measure the movement amount, the capsule-type endoscope may further include one or more sensors adapted to measure the movement amount thereof. Also, the capsule-type endoscope may further include a receiving unit adapted to receive an external control signal for controlling the frame rate to provide to the processor. 
     In an aspect of the present invention, a diagnosis system may include a capsule-type endoscope located in a digestive organ of an animal including human, and adapted to capture an image of the digestive organ at different frame rates while moving in cooperation with the vermiculation of the digestive organ and encode the captured image information to output a signal, a receiver adapted to receive the signal of the image information from the capsule-type endoscope, a signal processing unit adapted to receive the signal of the image information from the receiver, determine where the capsule-type endoscope is located inside the digestive organ of the animal, and output a signal for controlling the frame rate of the capsule-type endoscope, and a transmitter adapted to receive the control signal from the signal processing unit and transmit the control signal to the capsule-type endoscope. 
     In an aspect of the present invention, a method for controlling a frame rate of image for a capsule-type endoscope may include checking an elapsed time after the capsule-type endoscope is located inside an animal body including a human body, performing a capturing by controlling the frame rate when the checked time corresponds to a preset time, and performing the capturing by controlling the frame rate according to an external control signal when the external control signal for controlling the frame rate is received. 
     In another aspect of the present invention, a method for controlling a frame rate of image for a capsule-type endoscope may include receiving a signal from the capsule-type endoscope located inside an animal body including a human body, determining where the capsule-type endoscope is located inside the animal body, and controlling the frame rate of the capsule-type endoscope according the determined position. 
     ADVANTAGEOUS EFFECTS 
     The present invention is implemented to determining where a capsule-type endoscope is located within a body and control a frame rate of image according to the determined position, thereby to capture images of every organ inside the body only by using one capsule-type endoscope. Also, the frame rate can be controlled so as to prevent battery consumption, and an amount of the captured images can also be controlled to thusly save time taken by a user to read such images. In addition, by controlling the frame rate of image, more accurate image capturing can be achieved at a portion suspected to be caught by a disease. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating a system including a capsule-type endoscope in accordance with the present invention; 
         FIG. 2  is a detailed view of the capsule-type endoscope of  FIG. 1 ; 
         FIG. 3  is a flowchart illustrating an operation of the capsule-type endoscope of  FIG. 2 ; 
         FIG. 4  is a flowchart illustrating an operation of a signal processing unit of  FIG. 1 ; 
         FIG. 5  is a flowchart illustrating a detailed operation of the signal processing unit of  FIG. 1 ; 
         FIG. 6  is an exemplary view illustrating one frame unit of an image captured by the capsule-type endoscope in accordance with the present invention; 
         FIG. 7  is an exemplary view illustrating several frames of an image captured by a capsule-type endoscope in accordance with the present invention; 
         FIG. 8  is an exemplary view illustrating a similarity between captured images; and 
         FIG. 9  is a graph illustrating the similarity between the captured images of  FIG. 8 . 
     
    
    
     MODE FOR THE INVENTION 
     Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a schematic view illustrating a system including a capsule-type endoscope in accordance with the present invention,  FIG. 2  illustrates the configuration of the capsule-type endoscope of  FIG. 1 , and  FIG. 3  is a flowchart illustrating an operation of the capsule-type endoscope of  FIG. 2 . 
     As shown in  FIG. 1 , the system according to the present invention may include a capsule-type endoscope  100  located inside a body  10 , a receiver  200  attached onto a skin of the body  10  to receive a signal from the capsule-type endoscope  100  for transfer, a signal processing unit  300  for processing the signal transferred from the receiver  200  and outputting a control signal, and a transmitter  400  for transmitting the control signal from the signal processing unit  300  into the capsule-type endoscope  100 . 
     First, a brief description of the present invention is given with reference to  FIG. 1  as follows. 
     The capsule-type endoscope  100  which can be located inside the human or animal body  10 , e.g., in a digestive organ, is configured to collect image information or a variety of information (e.g., internal images, pH (potential of hydrogen), temperature or electrical impedance, and the like) and transmit such information to the receiver  200  located on the skin of the body  10  through the body  10 . Here, the capsule-type endoscope  100  can either control its frame rate of image by itself according to where it is located inside the body  10 , namely, where it is located among esophagus, stomach, small intestine and large intestine, or control the frame rate according to the control signal from the signal processing unit  300 . Accordingly, a fast image capturing must be performed in a portion, such as the esophagus, in which the capsule-type endoscope  100  moves fast, thus to obtain image information without any missed portion. On the other hand, a slow image capturing is advantageous in a portion, such as small intestine rarely making a quick motion, in which the capsule-type endoscope  100  moves slowly. 
     The receiver  200  is configured to transfer the received information to the signal processing unit  300 . Here, the receiver  200  can store such signal for a certain time. That is, the receiver  200  may be attached onto the human or animal body as shown in  FIG. 1 , so as to store the signal received from the capsule-type endoscope  100  for a certain time. Accordingly, without going to the hospital, the human or animal can do an endoscopic examination and an endocrine examination with doing his own work as usual for several hours. 
     The signal processing unit  300  is configured to process and output the information. The signal processing unit  300  checks a current frame rate of the capsule-type endoscope  100 , and confirms where the capsule-type endoscope  100  is located within the body  100 , namely, in which of esophagus, stomach, small intestine and large intestine the capsule-type endoscope  100  is located. The signal processing unit  300  then transfers a control command (signal) for controlling the frame rate of the capsule-type endoscope  100  to the capsule-type endoscope  100  via the transmitter  400  according to the confirmation. 
     The capsule-type endoscope  100  will be described in detail with reference to  FIG. 2  as follows. The capsule-type endoscope  100  may include a lens  110 , a lighting unit  120  for illuminating light for capturing, a processor  130  for processing an image capturing by the lens  110  and controlling the frame rate of image, one or more sensors  140  for detecting where the capsule-type endoscope  100  is located inside the body  10  or collecting various information related to the inside of the body  10 , a transmitting unit  150 , a receiving unit  160 , transmitting electrodes  171  and  172 , and a receiving antenna  173 . Here, the one or more sensors  140  may optionally be included or not included. 
     The lens  110  allows a CMOS image sensor  131  within the processor  130  to capture an image (static image or dynamic image) of an object within the human or animal body  10 , for example, in a digestive organ. 
     The lighting unit  120  is configured to be connected to the processor  130 , thus to illuminate light when the lens  110  captures an image inside the body  10  under the control of the processor  130 . The lighting unit  120  may be implemented as one or more Light Emitting Diodes (LEDs). 
     The processor  130  controls the lighting unit  120  to illuminate light with an appropriate intensity of radiation when an image of an object is captured via the lens  110 . The processor  130  then encodes the image captured via the lens  110  to output to the transmitting unit  150 . The processor  130  can control a frame rate of image for the inside of the body  10  according to where the capsule-type endoscope  100  is located inside the body  10 . Such control of the frame rate of image may be achieved by the processor  130  itself or according to an external control signal. 
     In case of controlling the frame rate of image by itself, the processor  130  drives an internal timer to count a time elapsed after the capsule-type endoscope  110  is located inside the body  10 . Then, the processor  130  estimates in which the capsule-type endoscope is to be located inside the body  10  after a preset time elapses, and accordingly can control the frame rate of image. Here, the time of the timer may be set according to an average value resulted from many times of experiments. 
     Alternatively, in case of controlling the frame rate of image by itself, the processor  130  may obtain a moving velocity/angular velocity from the one or more sensors  140 , and check which internal organ corresponds to the obtained moving velocity/angular velocity, so as to enable the control of the frame rate. 
     In case of controlling the frame rate of image according to the external control signal, the processor  130  may receive a control signal from the signal processing unit  300  via the receiving unit  160  and controls the frame rate of image according to the control signal. Here, in order for the signal processing unit  300  to recognize where the capsule-type endoscope  100  is located inside the body  10 , the processor  130  may encode the information, e.g., the moving velocity/angular velocity, detected by the one or more sensors  140  together with the captured image, thus to output such encoded image to the transmitting unit  150 . Here, the information detected by the one or more sensors  140  may be included in a frame header as shown in  FIG. 6 . 
     Such processor  130  may concretely include a CMOS image sensor  131 , a controller  132 , and a clock generator  135 . 
     The CMOS image sensor  131  is configured to encode an image captured by the lens  110  to output a signal, thereby outputting such signal to the transmitting unit  150 . Here, the CMOS image sensor  131  may encode information, e.g., moving velocity/angular velocity, detected by the one or more sensors  140  together with the image. The information detected by the one or more sensors  140  may be encoded by being included in the frame header as shown in  FIG. 6 . The CMOS image sensor  131  may include not only the information from the one or more sensors  140  but also a current frame rate related information in the frame header as shown in  FIG. 6 , thus to encode together. 
     The controller  132  may include a timer  133  for counting a time according to a clock from the clock generator  135 , and a timing generator  134  for generating a capturing period signal according to the counting of the timer  133 . The timing generator  134 , as stated above, allows a prediction as to where the capsule-type endoscope  100  is to be located inside the body  10  after a preset time elapses according to the counting of the timer  133 , thus to generate a control signal for the capturing at an appropriate frame rate. 
     On the other hand, the transmitting unit  150  converts the encoded signal through the CMOS image sensor  131  into an electrical signal, so as to apply to two transmitting electrodes  171  and  172  via output lines. 
     The transmitting electrodes  171  and  172  are configured to come in contact with the inside of the body  10 , such that they can generate a potential difference therebetween according to data to be desirably sent, thus to allow a flow of conductive current via the body  10 . The current thusly flows from a transmitting electrode having a higher potential to another transmitting electrode having a lower potential via a certain path within the body  10 . Here, since the current flowing through the body  10  partially reaches the skin of the body  10 , receiving electrodes (not shown) of the receiver  200  attached onto the skin of the body  10  can induce a voltage from the current having reached the skin. 
     The receiving unit  160  is configured to transfer the control signals received from the transmitter  400  to the processor  130  via the receiving antenna  173 . Here, the receiving antenna  173  may be implemented in various manners, such as employing a coil. Here, the control signals may be a FINT signal, a Clk Sel signal, and an On/Off signal of the external control signal. Frame rates according to the control signals may be described as shown in Table 1 below. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Clk sel [1:0] = 00 
                 Clk sel [1:0] = 01 
                 Clk sel [1:0] = 10 
               
               
                   
                 2.5 Mhz 
                 5 Mhz 
                 10 Mhz 
               
               
                   
                 operation 
                 operation 
                 operation 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Frame 
                   
                 Frame 
                   
                 Frame 
                   
               
               
                   
                 Interval 
                 Frame 
                 Interval 
                 Frame 
                 Interval 
                 Frame 
               
               
                 FINT 
                 Time 
                 Rate 
                 Time 
                 Rate 
                 Time 
                 Rate 
               
               
                 [2:0] 
                 (ms) 
                 (fps) 
                 (ms) 
                 (fps) 
                 (ms) 
                 (fps) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 000 
                 2 
                 2.5 
                 1 
                 5.0 
                 0.5 
                 10.0 
               
               
                 001 
                 100 
                 2.0 
                 50 
                 4.0 
                 25 
                 8.0 
               
               
                 010 
                 200 
                 1.6 
                 100 
                 3.2 
                 50 
                 6.4 
               
               
                 011 
                 350 
                 1.3 
                 175 
                 2.6 
                 87.5 
                 5.2 
               
               
                 100 
                 500 
                 1.1 
                 250 
                 2.2 
                 125 
                 4.4 
               
               
                 101 
                 700 
                 0.9 
                 350 
                 1.8 
                 175 
                 3.6 
               
               
                 110 
                 1000 
                 0.7 
                 500 
                 1.4 
                 250 
                 2.8 
               
               
                 111 
                 1500 
                 0.5 
                 750 
                 1.0 
                 375 
                 2.0 
               
               
                   
               
            
           
         
       
     
     As stated above, the configuration of the capsule-type endoscope  100  has been described. Hereinafter, an operation of the capsule-type endoscope  100  will be described. 
     As shown in  FIG. 3 , when a certain time according to the counting of the timer  133  elapses (S 101 ), the capsule-type endoscope  100  recognizes to be located at a specific position within the body  10 , to control a frame rate accordingly (S 102 ). 
     Afterwards, the capsule-type endoscope  100  determines whether a control signal has been received from the signal processing unit  300  via the receiving unit  160  (S 103 ). If it is determined that the control signal has not been received, the capsule-type endoscope  100  proceeds back to the step S 101 . 
     If it is determined to have received the control signal, then the capsule-type endoscope  100  controls the frame rate according to the control signal (S 104 ). 
     As described above, the capsule-type endoscope  100  according to the present invention can control the frame rate according to the counting of the timer  133 . Also, it can control the frame rate according to the control signal when the control signal is received from the signal processing unit  300 . 
       FIG. 4  is a flowchart illustrating an operation of the signal processing unit  300  of  FIG. 1 . 
     As shown in  FIG. 4 , when data is received from the capsule-type endoscope  100  via the receiver  200  (S 201 ), then the signal processing unit  300  according to the present invention determines the position of the capsule-type endoscope  100  (S 202 ). 
     Then, the signal processing unit  300  checks a current frame rate of the capsule-type endoscope  100  (S 203 ). 
     The signal processing unit  300  then determines whether the frame rate of the capsule-type endoscope  100  should be controlled (S 204 ). 
     When the control of the frame rate is needed, the signal processing unit  300  calculates the frame rate (S 205 ), and outputs a control signal via the transmitter  400 , thereby transferring the control signal to the capsule-type endoscope  100  (S 206 ). 
       FIG. 5  is a flowchart illustrating a detailed operation of the signal processing unit of  FIG. 1 ,  FIG. 6  is an exemplary view illustrating one frame unit of an image captured by the capsule-type endoscope in accordance with the present invention,  FIG. 7  is an exemplary view illustrating several frames of an image captured by the capsule-type endoscope in accordance with the present invention,  FIG. 8  is an exemplary view illustrating a similarity between captured images, and  FIG. 9  is a graph illustrating the similarity between the captured images of  FIG. 8 . 
     As shown in  FIG. 5 , any one of three methods as follows can be employed to check the position of the capsule-type endoscope  100  (i.e., S 202 ). 
     As a first method, the determining of the position of the capsule-type endoscope  100  (S 202 ) can be achieved such that after separating image information and a frame header from frame-unit data as shown in  FIG. 6 , information (e.g., information related to the moving velocity/angular velocity of the capsule-type endoscope  100 ) detected by the aforesaid one or more sensors  140  are extracted from the frame header. That is, as stated above, since the capsule-type endoscope  100  includes the information detected by the one or more sensors  140  (e.g., information related to the moving velocity/angular velocity of the capsule-type endoscope  100 ) in the frame header of an image corresponding to the inside of the body  10 , and accordingly encodes and outputs the frame header together with such information, when extracting the information detected by the one or more sensors  140  from the frame header, the moving velocity of the capsule-type endoscope  100  can be detected. In general, ingesta move in each internal organ (e.g., esophagus, stomach, small intestine, large intestine, and the like) at different velocities. Therefore, once being known of the moving velocity of the capsule-type endoscope  100 , it is possible to recognize in which internal organ the capsule-type endoscope  100  is located. 
     As a second method, the determining of the position of the capsule-type endoscope  100  (S 202 ) can be achieved such that after separating image information and a frame header from frame-unit data as shown in  FIG. 6 , a similarity between a previous image (e.g., corresponding to  FIG. 8(   a )) and a current image (e.g., corresponding to  FIG. 8(   b )) can be checked to detect a moving velocity for detecting where the capsule-type endoscope  100  is located. 
     Here, the similarity may quantitatively represent how similar the previous image and the current image are. For a high similarity between the previous image and the current image, it denotes the capsule-type endoscope  100  moves fast while for a low similarity therebetween, it denotes the capsule-type endoscope  100  moves slowly. Such similarity may be represented by the following formula, assuming that n th  frame is N and n+1 th  frame is M. 
       Sum1 [n]=ΣAbs ( N[x,y] )− M[x,y] ) 
       Sum2 [n]=Σ ( N[x,y] )− M[x,y] ) 
       Similarity[ N ]=Sum1 [n ]*100/Sum2 [n]   
     where X denotes a coefficient of a horizontal axis, and y denotes a coefficient of a vertical axis. 
     Such calculation is performed per every frame. Accordingly, for the faster calculation, 10 frames are averaged, so as to perform the calculation per every 10 frame. 
     
       
         
           
             
               AvgSimilarity 
                
               
                 [ 
                 k 
                 ] 
               
             
             = 
             
               
                 ∑ 
                 
                   n 
                   = 
                   1 
                 
                 10 
               
                
               
                 
                   Similarity 
                    
                   
                     [ 
                     
                       
                         k 
                         × 
                         10 
                       
                       + 
                       n 
                     
                     ] 
                   
                 
                 / 
                 10 
               
             
           
         
       
     
     On the other hand, in order to avoid errors, a variety of filters, e.g., Average, Median filter and the like, may be applied. 
     As such, the calculated similarity can be shown in a graph as shown in  FIG. 9 . 
     As a third method, the determining of the position of the capsule-type endoscope  100   
     (S 202 ) can be achieved by using an energy level of a signal received via the receiver  200 . For example, if plural pairs of receiving electrodes of the receiver  200  exist and the plural pairs of electrodes are divided to be attached to several portions on the skin of the body  10 , the position of the capsule-type endoscope  100  can be determined by searching for and comparing a database pre-stored with respect to each position, with the signal received via the plural pairs of electrodes. 
     In addition to the above methods, other methods for determining the position of the capsule-type endoscope may exist, which is obvious to those skilled in the art. Therefore, in order to prevent the concept of the present invention from being obscure, explanation thereof will be omitted. However, even if other methods for determining the position of the capsule-type endoscope are not described, it is apparent to those skilled in the art that the present invention may cover such methods within the claims of the present invention. 
     In the meantime, for checking the current frame rate (i.e., S 203 ), can be achieved by extracting the current frame rate from the frame header shown in  FIG. 6 , in case where the capsule-type endoscope  100  includes the current frame rate in the frame header when encoding the image. Also, the checking of the current frame rate (S 203 ) can be implemented either by calculating a time corresponding to a frame interval shown in  FIG. 7  or by calculating a time corresponding to one frame. For example, for a frame rate of 5 fps, the frame interval is 1 ms as can be seen in Table 1. For a frame rate of 4 fps, the frame rate is 50 ms. Therefore, the frame rate can be determined by measuring the frame interval. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described exemplary embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims