JP2009000401A - Clothes with communication function, endoscope system and position estimation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the accuracy of estimated position information of a capsule endoscope. <P>SOLUTION: The clothes are equipped with a plurality of devices capable of wirelessly communicating with an external apparatus and have a control section capable of communicating with each of the devices; wherein the device has an identification information retention means, an external signal receiving means for receiving a transmission signal, a signal generation means for detecting a received timing and generating a timing signal based on the timing, and a transmission means for associating the timing signal with the identification information and transmitting them to the control par; and the control part has a position information retention means for retaining the position information of the respective devices associated with the identification information, a receiving means for receiving the timing signal, a position information acquisition means for acquiring the position information of a transmitter device based on the identification information associated with the received timing signal, and a position calculation means for calculating the position information of the external apparatus based on each of the received timing signals and the position information corresponding to each timing signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a garment with a communication function, in which a plurality of elements capable of wireless communication with an external device are mounted and provided with a control unit capable of communicating with each of the elements. Moreover, it is related with an endoscope system provided with such clothing with a communication function. The present invention also relates to a position estimation method for estimating the position of a capsule endoscope placed in a body cavity of a patient using a garment on which a plurality of elements capable of wireless communication with the capsule endoscope are mounted.

  As a device for diagnosing the inside of a patient's body, an electronic endoscope having an imaging element mounted on the tip of a flexible cable is widely known and put into practical use. The electronic endoscope sends an image signal obtained by the imaging device to a host device. Upon receiving the image signal, the host device performs predetermined processing and outputs it to the monitor. As a result, the inside of the patient's body cavity is displayed on the monitor, and the operator can diagnose the inside of the patient's body.

  In recent years, a capsule-shaped endoscope (hereinafter referred to as “capsule-type endoscope”) that communicates with a host device wirelessly, which is different from the electronic endoscope, has been proposed. Has been put to practical use. For example, Patent Document 1 below discloses an example of a system including a capsule endoscope.

Patent Document 1 below discloses an antenna array belt equipped with a plurality of antenna elements and a data recorder as a host-side device for wireless communication with a capsule endoscope. According to the following Patent Document 1, when each antenna element receives a signal transmitted from a capsule endoscope, the data recorder acquires information in the patient's body based on the signal and receives each of the received intensities. Measure. Then, the data recorder estimates the position of the capsule endoscope based on the measurement result, and executes a process according to the estimation result.
Japanese Patent Laid-Open No. 2003-19111

  However, the patient's body is composed of various substances such as bone, water, and fat, and is not uniform as a medium for propagating radio waves. Therefore, the attenuation rate of the transmission signal from the capsule endoscope varies depending on the constituent substance in the body interposed between the capsule endoscope and the antenna element. For this reason, the relationship between the pseudo distance between the capsule endoscope and the antenna element and the reception intensity is not constant and varies. As a result, depending on the position of the capsule endoscope, the pseudo distance includes many errors, and in this case, highly accurate estimated position information cannot be obtained.

  Accordingly, in view of the above circumstances, the present invention provides a clothing with communication function, an endoscope system, and a position estimation method capable of improving the accuracy of estimated position information of a capsule endoscope. It is said.

  A clothing with a communication function according to one embodiment of the present invention that solves the above problem is a clothing that includes a plurality of elements capable of wireless communication with an external device and includes a control unit that can communicate with each of the elements. The element of the clothing with a communication function of the present invention includes an identification information holding unit that holds its own identification information, an external signal receiving unit that receives a transmission signal transmitted from the external device, and a timing at which the transmission signal is received. And a signal generation unit configured to detect and generate a timing signal based on the detected timing, and a transmission unit configured to associate the identification information with the generated timing signal and transmit to the control unit. It is. Further, the control unit of the clothing with communication function of the present invention, the position information holding means for holding the position information of each element in association with the identification information, the receiving means for receiving the timing signal transmitted from each of the elements, Position information acquisition means for acquiring position information of a transmission source element based on the identification information associated with the received timing signal from the position information holding means, each of the received timing signals, and each of the timings And a position calculating unit that calculates position information of the external device based on the position information corresponding to the signal.

  According to such a configuration, it is possible to obtain the position information of the external device by calculating the pseudo distance between the external device and each element based on the propagation time of the radio wave. The propagation speed of radio waves has a relatively low dependence on the medium. Therefore, regardless of where the signal from the external device passes, the relationship between the pseudo-range between the external device and the element and the propagation time is kept relatively constant. For this reason, the error of the pseudo distance is reduced, and as a result, the position of the external device can be estimated with high accuracy.

  The signal generation unit may be configured to detect a time difference between the detected timing and a predetermined timing and generate a timing signal based on the detection result.

  The predetermined timing may be, for example, the rising timing of the internal clock of the element.

  In the clothing with a communication function, the control unit may be configured to deliver a predetermined signal to each of the elements, for example. In this case, the internal clock of the element is corrected based on the predetermined signal from the control unit, and the internal clocks of all the elements are synchronized.

  In the clothing with a communication function, the control unit may further include, for example, a reference setting unit that sets, as a reference element, an element that satisfies a predetermined condition. In this case, the position calculation means calculates the phase difference between the reception timings of the transmission signals between the timing signal of the reference element and the timing signals of other elements. Next, a pseudo distance difference between the reference element and each of the other elements with respect to the external device is calculated based on the calculated phase difference. Then, the position information of the external device is calculated using each of the calculated pseudo distance differences and each of the position information held in the position information holding means.

  Moreover, in the clothes with a communication function, the elements and the control unit are mounted on, for example, a signal-transmittable sheet, and communication between each element and between each element and the control unit is performed based on a 2D-DST algorithm. It may be configured as described above.

  In the above-mentioned clothing with a communication function, the position calculating means, for example, calculates the position information of the external device when the timing signal received by the receiving means is greater than or equal to a predetermined number, and the timing signal satisfies the predetermined number. If not, it may be determined that an error has occurred and the position information of the external device is not calculated.

  Moreover, the said clothing with a communication function may be further provided with the position measurement means which measures each position of an element, for example. In this case, the position information holding unit holds the measured position information in association with the identification information of each element.

  An endoscope system according to an aspect of the present invention that solves the above problems includes a capsule endoscope that is inserted into a body cavity of a patient and wirelessly transmits information in the patient's body, and the communication function A system comprising a garment having a communication function for wirelessly communicating with a capsule endoscope by an element.

  According to such a configuration, it is possible to obtain the positional information of the capsule endoscope by calculating the pseudo distance between the capsule endoscope and each element based on the propagation time of the radio wave. The propagation speed of radio waves has a relatively low dependence on the medium. Therefore, regardless of where the signal from the capsule endoscope passes, the relationship between the pseudo-range between the capsule endoscope and the element and the propagation time is kept relatively constant. For this reason, the error of the pseudo distance is reduced, and as a result, the position of the capsule endoscope can be estimated with high accuracy.

  The capsule endoscope may have, for example, an image signal generation unit that generates an image signal by imaging the inside of the body cavity and transmits the image signal wirelessly. In this case, the signal generation means included in the element detects the timing of receiving the image signal.

  In addition, a position estimation method according to one aspect of the present invention that solves the above-described problem is a capsule placed in a body cavity of a patient using a garment on which a plurality of elements capable of wireless communication with a capsule endoscope are mounted. This is a method for estimating the position of a mold endoscope. The position estimation method according to the present invention monitors the transmission power of the capsule endoscope installed at the specified position and transmits the first signal, and monitors the reception power of each of the elements to monitor each of the elements. A timing detection step for detecting a timing at which the first signal is received in a step, a pseudo distance calculation step for calculating a pseudo distance between the specified position and each of the elements based on the detection result, and the calculated A position information acquisition step for acquiring position information of each element based on the pseudo distance, and each of the elements receives a second signal from the capsule endoscope inserted into the body cavity and detects the reception timing thereof Receiving timing detection step, timing information collecting step for collecting information on the detected reception timing, information on the collected reception timing and each element Based on the position information of a method comprising a position calculation step of calculating the position information of the capsule endoscope.

  According to such a method, it is possible to obtain the position information of the capsule endoscope by calculating the pseudo distance between the capsule endoscope and each element based on the propagation time of the radio wave. The propagation speed of radio waves has a relatively low dependence on the medium. Therefore, regardless of where the signal from the capsule endoscope passes, the relationship between the pseudo-range between the capsule endoscope and the element and the propagation time is kept relatively constant. For this reason, the error of the pseudo distance is reduced, and as a result, the position of the capsule endoscope can be estimated with high accuracy. Further, according to the above method, the position information of each element that changes depending on the patient's body shape can be acquired in advance before the capsule endoscope is inserted, so that the accuracy of the estimated position information of the capsule endoscope is further improved. To do. Further, according to the above method, the position information of each element can be acquired using the capsule endoscope. Therefore, there is no need to prepare a dedicated device for measuring the position of each element, which is advantageous in terms of cost.

  ADVANTAGE OF THE INVENTION According to this invention, the clothing with a communication function which can improve the precision of the estimated position information of a capsule endoscope, an endoscope system, and a position estimation method are provided.

  Hereinafter, an endoscope system according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an endoscope system 10 according to an embodiment of the present invention. As shown in FIG. 1, the endoscope system 10 includes an external processing system 300 including a capsule endoscope 100, a jacket 200 with an antenna, and a PC (Personal Computer) with a monitor. By using the endoscope system 10 of the present embodiment, the surgeon can observe and diagnose aspects of the body of the patient 1.

  FIG. 2 is a block diagram showing the configuration of the capsule endoscope 100. As shown in FIG. The configuration and function of the capsule endoscope 100 will be described with reference to FIG.

  As shown in FIG. 2, the capsule endoscope 100 is a capsule-shaped endoscope that is inserted into a body cavity of a patient 1. The capsule endoscope 100 includes a power supply unit 102, a control unit 104, a memory 106, two illumination units 108, an objective optical system 110, a solid-state imaging device 112, a transmission / reception unit 114, and an antenna unit 116.

  The power supply unit 102 is a built-in battery that supplies power to each component. The control unit 104 is an IC chip for comprehensively controlling each component. The memory 106 is a storage medium that stores various data and programs. The illumination unit 108 is a light source that illuminates the body cavity. The objective optical system 110 is an objective lens for observing the inside of a body cavity. The solid-state imaging device 112 is for imaging a body cavity, and is, for example, a CCD (Charge Coupled Device) or a C-MOS (Complementary Metal Oxide Semiconductor). The transmission / reception unit 114 is a communication interface for performing communication with an external device. The antenna unit 116 is an element for transmitting and receiving radio waves.

  When the capsule endoscope 100 is turned on and inserted into the body cavity of the patient 1, the illumination unit 108 illuminates the body cavity. The light reflected by the wall in the body cavity enters the objective optical system 110 and forms an image.

  The solid-state image sensor 112 is installed such that its light receiving surface is positioned on the image side focal plane of the objective optical system 110. Accordingly, the light imaged by the power of the objective optical system 110 is received by the solid-state image sensor 112. The solid-state image sensor 112 photoelectrically converts the received light to generate an image signal.

  The transmission / reception unit 114 modulates the generated image signal and transmits the modulated image signal to the outside via the antenna unit 116. The image signal transmitted from the antenna unit 116 is received by the jacket 200 with the antenna.

  Next, the jacket 200 with an antenna will be described.

  The antenna-equipped jacket 200 is a jacket worn by the patient 1 to diagnose the inside of the body. For example, JP 2004-328409 A, JP 2005-245937 A, non-patent literature (Celcross, Inc. 2D-DST (2 Dimension- Diffusive Signal-Transmission) disclosed on January, 2009], the Internet, <http://www.cellcross.co.jp/technology.html>, etc. Yes. As described in these publications, in 2D-DST technology, each of a plurality of elements (hereinafter referred to as “DST chips”) scattered on a sheet serves as a signal relay point, Transmit in packets towards the ground.

  As shown in FIG. 1, the DST chip 230 is arranged in a matrix over the entire area of the antenna-equipped jacket 200. The DST chip 230 is a chip for executing 2D-DST, and does not require a wired cable or a copper foil pattern to communicate with other elements. Therefore, in the jacket with antenna 200, the DST chip 230 can be arranged with a high degree of freedom, and its flexibility and durability are comparable to those of ordinary clothes. Further, since the DST chip 230 is a chip having a very small size, high-density mounting is possible.

  FIG. 3 is a cross-sectional view taken along the line AA in FIG. AA sectional view is a sectional side view of jacket 200 with an antenna including DST chip 230. As shown in FIG. 3, the antenna-equipped jacket 200 includes two signal layers (a signal layer 210 and a ground layer 212), an insulating layer 214 for insulating these signal layers from each other, and these signal layers and the outside. Insulating layers 216 and 218 for insulating each other are composed of a total of five layers. These layers are stacked in the order of the insulating layer 216, the ground layer 212, the insulating layer 214, the signal layer 210, and the insulating layer 218. The DST chip 230 is embedded in these layer structures so as to straddle the ground layer 212 and the insulating layer 214. The laminated structure of the jacket with antenna 200 has various forms. For example, there are layers in which layers for supplying power to each DST chip 230 are independent.

  Note that the signal layer 210 and the ground layer 212 are made of, for example, a conductive rubber or a cloth woven with a conductor, and have flexibility and conductivity. The insulating layers 214, 216, and 218 are made of, for example, an insulating rubber, an insulating film, an insulating cloth, and the like, and have flexibility and insulating properties. Each DST chip 230 is grounded by a ground layer 212 and can transmit a signal to other elements using the signal layer 210 as a medium.

  FIG. 4 is a block diagram showing the configuration of the DST chip 230. As shown in FIG. 4, the DST chip 230 includes a control unit 231, an antenna 232, a transmission / reception unit 233, a memory 234, and a communication unit 235. The DST chip 230 achieves a predetermined function using these components.

  The functions achieved by the DST chip 230 are roughly divided into two. One is a communication function. The communication function is achieved by the control unit 231 and the transmission / reception unit 233 operating in cooperation. Specifically, the transmission / reception unit 233 communicates with the capsule endoscope 100 via the antenna 232 under the control of the control unit 231. Thereby, for example, power is supplied from the DST chip 230 to the capsule endoscope 100, and the image signal is transferred from the capsule endoscope 100 to the DST chip 230. The control unit 231 temporarily stores the image signal from the capsule endoscope 100 in the memory 234.

  Another function achieved with the DST chip 230 is the function of performing 2D-DST. This function is achieved by the control unit 231, the memory 234, and the communication unit 235 operating in cooperation. The memory 234 stores, for example, an algorithm for executing 2D-DST, its own address, and the like. The communication unit 235 is a communication interface that connects each DST chip 230. The control unit 231 executes the above algorithm to perform 2D-DST, and transmits the image signal to another DST chip 230 via the communication unit 235. By performing 2D-DST in each DST chip 230, the image signal is transmitted toward a predetermined destination. Here, the predetermined destination in the present embodiment is the control unit 220.

  The control unit 220 will be described. As shown in FIG. 1, the control unit 220 is provided in a jacket 200 with an antenna. FIG. 5 is a block diagram showing the configuration of the control unit 220. The control unit 220 includes a control unit 221, a power supply 222, a communication unit 223, a memory 224, a signal processing unit 225, and an interface unit 226.

  The control unit 220 performs overall control for each DST chip 230. This is achieved by the control unit 221, the power source 222, the communication unit 223, and the memory 224 operating in cooperation. The control unit 221 performs overall control of the control unit 220. The communication unit 223 is a communication interface for causing the control unit 220 to communicate with the DST chip 230. The memory 224 stores, for example, an algorithm for executing 2D-DST and various data. The control unit 221 executes the above algorithm and controls the communication unit 223 to communicate with the DST chip 230. In the communication, an address is assigned to each DST chip 230 and information on a path for transmitting the image signal is provided. In addition, the control unit 221 supplies the drive current from the power supply 222 to each DST chip 230 via the signal layer 210.

  The control unit 220 processes a transmission signal from the DST chip 230, that is, an image signal, to generate a video signal in a predetermined format. Then, the generated video signal is output to the external processing system 300. This is achieved by the control unit 221, the signal processing unit 225, and the interface unit 226 operating in cooperation. The signal processing unit 225 performs predetermined processing on the image signal under the control of the control unit 221 and converts the image signal into a video signal that can be displayed by the external processing system 300. The video signal generated by the signal processing unit 225 is output to the external processing system 300 via the interface unit 226.

  The external processing system 300 is, for example, a well-known PC, and uses a video signal from the control unit 220 to display the state of the body cavity of the patient 1 on the monitor, or to perform analysis processing and display the analysis result on the monitor. can do. The analysis here refers to, for example, a state different from the normal state (normal portion) by analyzing the surface shape in the body cavity, the distribution of each color component of the image information, etc. based on the image information obtained from the video signal. This indicates that the part of is extracted. Thereby, based on a large amount of acquired image information, a candidate for a part that seems to be abnormal can be picked up in advance, and the diagnosis can be speeded up.

  Here, in the jacket with antenna 200 of the present embodiment, the position of the capsule endoscope 100 can be estimated based on the image signal received by each DST chip 230. This will be described in detail below.

  In order to execute the process of estimating the position of the capsule endoscope 100 (hereinafter referred to as “position estimation process”), first, the coordinate information of each DST chip 230 needs to be measured before diagnosis. This is because the jacket 200 with the antenna is worn so as to fit the patient's body, and the positional relationship of each DST chip 230 changes depending on the patient's body shape. FIG. 6 is a diagram for explaining processing for measuring coordinate information of each DST chip 230 (hereinafter referred to as “chip position measurement processing”). FIG. 7 shows a flowchart of the chip position measurement process. The chip position measurement process is executed by the control unit 220.

  The target of the chip position measurement process is all DST chips 230 mounted on the antenna-equipped jacket 200. Here, in order to make the drawing easy to understand, two DST chips (more precisely, the positions of two DST chips are used). ) Only is illustrated and described. Further, the actual chip position measurement process measures the three-dimensional coordinate information of the DST chip 230. However, in FIG. 6, the contents of the two-dimensional coordinate information are only described for the sake of clarity. In FIG. 6, it is assumed that one DST chip 230 is located at each of points A and B. For convenience of explanation, the numbers of “DST chip 230A” and “DST chip 230B” are given to the DST chips 230 located at points A and B, respectively. In the subsequent paragraphs and drawings, the same rule is used for numbering.

First, (After i.e. the posture of the patient 1 to the state at diagnosis) the patient 1 for example, After aging the examination table or the like, the operator placed a predetermined transmission source to a defined position P _1. The predetermined transmission source is a device that can communicate with the control unit 220 and has a function of transmitting a reference signal. The predetermined transmission source transmits a reference signal in response to a user operation or at every predetermined timing.

The predetermined transmission source may be, for example, a dedicated device for measuring the position of each DST chip 230, or the capsule endoscope 100 itself. In the latter case, there is no need to prepare a dedicated device, which is advantageous in terms of cost. In addition, it is assumed that the specified position P ₁ and other specified positions to be described later are known positions for the control unit 220.

  As shown in FIG. 7, the control unit 220 monitors the transmission timing at which a predetermined transmission source transmits a reference signal and the reception timing at which each DST chip 230 receives the reference signal (Step 1, hereinafter, details). Step is abbreviated as “S” in the document and drawings).

  Specifically, in the processing of S1, the control unit 220 monitors the transmission power of a predetermined transmission source and the reception power of each DST chip 230, and transmits the information at the time when the transmission power becomes a first threshold value or more. Information at the time when the timing and received power are equal to or higher than the second threshold is acquired as the reception timing. Next, based on the acquired timing information, the propagation time of the reference signal from the predetermined transmission source to each DST chip 230 is calculated. Note that the control unit 220 also acquires an address from each DST chip 230 together with the reception timing information. The control unit 220 can identify which DST chip 230 each reception timing is by acquiring the address of each DST chip 230.

After calculating each propagation time, the control unit 220 calculates a pseudo distance between a predetermined transmission source and each DST chip 230 based on the calculation result (S2). Thus, as shown in FIG. 6 (a), DST chip 230A is found to be located from the defined position _{P 1} on the circumference _{C A} separated by pseudorange _{d A.} Further, DST chip 230B is seen to be located on the circumference _{C B} away from the prescribed position _{P 1} by pseudorange _{d B.}

Next, the operator placed a predetermined transmission source to a defined position P _2. Then, similarly to the above, the control unit 220 monitors the timing of the predetermined transmission source and each DST chip 230 (S3), and then calculates the pseudo distance based on the monitoring result (S4). Thus, as shown in FIG. 6 (b), the control unit 220, the position of the DST chip 230A comprises a circumferential _{C A,} pseudoranges from a defined position _{P 2 d A} 'apart circumferentially _{C A'} It is obtained from the calculation result that it is either the point of intersection, that is, point A or point A ′. Also, that the position of the DST chip 230B includes a circumferential _{C B,} the intersection of the defined position _{P 2} and the 'circumference _{C B} separated by' pseudorange _{d B,} that is, either point B or point B ' Is obtained from the calculation result.

  Here, either point A or point A ′ (and point B or point B ′) indicates a position on the antenna-equipped jacket 200, and the other indicates a position clearly separated from the antenna-equipped jacket 200. Become. Here, the points A and B indicate positions on the jacket 200 with an antenna, and the points A ′ and B ′ indicate positions that are clearly separated from the jacket 200 with an antenna. In this case, the control unit 220 truncates the position information of the points A ′ and B ′ and specifies the positions of the DST chips 230A and 230B as the points A and B (S5).

  Following the process of S5, the control unit 220 performs a known coordinate conversion process so that the position information of each DST chip 230 is adapted to a predetermined coordinate system (S6), and ends the chip position measurement process.

  Through the processing described above, the control unit 220 acquires coordinate information of all the DST chips 230. The acquired coordinate information is stored in the memory 224, for example, in association with the corresponding address.

  In addition, in order to obtain the three-dimensional coordinate information, a predetermined transmission source may be installed at another specified position, and processing similar to S1 and 2 (or S3 and 4) may be executed. In this case, the control unit 220 can further narrow down the position of each DST chip 230 to two points in the three-dimensional space based on the obtained pseudo distance. Here again, the control unit 220 can specify the position of each DST chip 230 at one point by discarding the information of the position clearly separated from the jacket 200 with the antenna.

  As an alternative to the process of S5, the position of each DST chip 230 can be narrowed down from 2 points to 1 point by executing the same process as S1 and 2 (or S3 and 4) once more.

  In the above embodiment, the predetermined transmission source is sequentially installed at each specified position. However, in another embodiment, the predetermined transmission source may be installed at each predetermined position in advance. In this case, the work of installing a predetermined transmission source is omitted, so that the chip position measurement process is quickly performed.

  When the chip position measurement process is completed and the position of each DST chip 230 is measured, the capsule endoscope 100 is inserted into the body cavity of the patient 1 and diagnosis is started. And a position estimation process is also performed with a diagnosis start. FIG. 8 shows a flowchart of chip-side position estimation processing executed by each DST chip 230. FIG. 9 shows a flowchart of unit side position estimation processing executed by the control unit 220. In the present embodiment, each DST chip 230 and the control unit 220 operate in cooperation, whereby the estimated position of the capsule endoscope 100 can be obtained.

  In the present embodiment, the estimated position information of the capsule endoscope 100 is acquired using the internal clock of each DST chip 230. Therefore, in order to obtain estimated position information with higher accuracy, it is desirable that the internal clocks be synchronized. However, there are individual differences in the internal clock. For this reason, each internal clock is normally in a state where it is not synchronized, and even if it is synchronized, it gradually shifts with time. In the present embodiment, in order to solve the above problem, the timing of the internal clock of each DST chip 230 is periodically synchronized using a clock adjustment signal described below.

  As shown in FIG. 9, the control unit 220 refers to a first counter (not shown) built in itself and determines whether or not it is time to transmit a clock adjustment signal (S21). When the count value of the first counter is a predetermined value, it is determined that it is time to transmit the clock adjustment signal (S21: YES). Next, a clock adjustment signal is transmitted to each DST chip 230 (S22). The first counter is always incremented during execution of the unit side position estimation process of FIG. 9, and is reset at the start and return of the unit side position estimation process.

  As shown in FIG. 8, each DST chip 230 determines whether or not a clock adjustment signal from the control unit 220 has been received (S11). If it is determined that the clock adjustment signal has been received (S11: YES), the internal clock (more precisely, the internal clock of the control unit 231) is adjusted based on the received clock adjustment signal (S12), The process proceeds to S13. If it is determined that the clock adjustment signal has not been received (S11: NO), the DST chip 230 proceeds to the process of S13 without executing the process of S12.

  Here, FIG. 10 shows the relationship between the clock adjustment signal and the internal clock of each DST chip 230. In FIG. 10, three DST chips, DST chips 230A, 230B, and 230C, are shown as representatives. In FIG. 10, the vertical axis represents amplitude and the horizontal axis represents time. 10A shows the waveform of the clock adjustment signal, and FIGS. 10B, 10C, and 10D show the waveforms of the internal clocks of the DST chips 230A, 230B, and 230C, respectively.

  Each DST chip 230 has a different distance from the control unit 220. Therefore, each DST chip 230 has a different signal transmission delay amount. In the present embodiment, it is assumed that each DST chip 230 holds an offset value of a delay amount corresponding to itself, and executes various processes with reference to the offset value. In the following paragraphs, each process will be described on the premise that the delay amount is offset (that is, the delay amount is not considered) in order to avoid complicated description.

Time _{T 1} of the FIG. 10 is a timing each DST chip 230 receives a clock adjusting signal. As shown in FIG. 10 (b) to (d), the time T ₁ before, in a state in which individual difference of each internal clock is not of synchronization due. However, when the clock adjustment signal in each DST chip 230 at time T ₁ is being received, the DST chip 230 performs clock correction to match the rising timing of both the internal clock and the clock adjustment signal. Thereby, the internal clock of each DST chip 230 is in a synchronized state.

  The predetermined value in the first counter is a value that is considered so that the deviation amount of each internal clock does not exceed a predetermined allowable range. Therefore, each internal clock is corrected before the amount of deviation from each other exceeds a predetermined allowable range. As a result, each internal clock is substantially always synchronized.

  The capsule endoscope 100 periodically transmits a predetermined signal after being inserted into the body cavity of the patient 1. As shown in FIG. 8, each DST chip 230 waits to receive the predetermined signal in a state where the internal clock is synchronized (S13). The predetermined signal referred to here may be, for example, the image signal or a reference signal for position estimation processing.

  When each DST chip 230 receives the predetermined signal from the capsule endoscope 100 (S13: YES), each DST chip 230 compares the reception timing with an internal clock to detect a phase difference. Specifically, the DST chip 230 generates another clock higher than the internal clock, counts the clock, compares the reception timing with the internal clock, and detects the phase difference. Next, a signal in which the detected phase difference information is associated with its own address is generated (S14, the signal generated here is referred to as a “phase difference signal”). Each DST chip 230 transmits the generated phase difference signal to the control unit 220 (S15), and returns the chip side position estimation process of FIG.

  FIG. 11 is a diagram for explaining the phase difference detected by each DST chip 230. FIGS. 11A, 11B, and 11C show the relationship between the received power of the predetermined signal of the DST chips 230A, 230B, and 230C and the internal clock, respectively. In FIG. 11, the vertical axis indicates amplitude, and the horizontal axis indicates time. Further, in each of FIGS. 11A, 11B, and 11C, the upper stage indicates the internal clock, and the lower stage indicates the reception power of the predetermined signal.

As shown in FIG. 11, the phase difference is a phase difference between the rising timing of the internal clock and the rising timing at the start of reception of the predetermined signal. The DST chips 230A, 230B, and 230C detect the phase differences pd _a , pd _b , and pd _c , respectively. The internal clock has a sufficiently long period so that all the DST chips 230 receive the predetermined signal within the same period in time.

  The control unit 220 increments a second counter (not shown) by 1 every time one phase difference signal is received. Then, as shown in FIG. 9, it is determined at every predetermined timing whether or not n or more phase difference signals are received with reference to the counter (that is, whether or not the count value of the counter is n or more). (S23). The predetermined timing here is a timing set so as not to receive the phase difference signal from the same DST chip 230 a plurality of times. Therefore, n always matches the number of DST chips 230 that are the source of the phase difference signal.

  If the control unit 220 determines that the received phase difference signals are n or more (S23: YES), the control unit 220 executes the position calculation process of S24. On the other hand, if it is determined that the number of received phase difference signals is less than n (S23: NO), it is determined that the unit side position estimation process in FIG. 9 is an error (S25), and the unit side position is determined. Return the estimation process. The counter is reset to “0” when the unit side position estimation process is returned. Also, n is “4”, for example, when obtaining three-dimensional estimated position information.

  FIG. 12 is a diagram for explaining the position calculation process of S24. In the process of S24, the control unit 220 calculates the current estimated position of the capsule endoscope 100 based on each received phase difference signal. Note that the actual position calculation processing calculates a three-dimensional position, but FIG. 12 is similar to FIG. 6 and only describes the two-dimensional position. With reference to FIG. 12, the position calculation process in S24 will be described.

  In the process of S24, the control unit 220 first sets a DST chip 230 that satisfies a predetermined condition as a reference chip. In this embodiment, it is assumed that the DST chip 230A is set as the reference chip. The predetermined conditions here include, for example, the prescribed DST chip 230, the DST chip 230 corresponding to the phase difference signal first received by the control unit 220, and the DST chip having the highest reception intensity. 230. In the case of the last condition, for example, it is necessary to associate reception intensity information with the phase difference signal.

After the reference chip setting, the control unit 220 obtains a virtual hyperbola in which the capsule endoscope 100 can be located based on the phase difference signal and coordinate information of the reference chip and each DST chip 230. In FIG. 12 (a), it shows a hyperbola _{h 1} obtained based on the phase difference signal DST chips 230A and 230B. Figure 12 (b), shows a hyperbola _{h 2} obtained on the basis of the phase difference signal DST chip 230A and 230C. The hyperbola h ₁ is a locus of points where the difference in distance from the points A and B is constant. Further, hyperbola h ₂ is the locus of points the point A, the difference in the distance from C is constant.

Specifically, the control unit 220 determines the difference between the phase differences pd _a and pd _b (that is, the time when the radio wave from the capsule endoscope 100 arrives at the DST chip 230A and the time when the radio wave arrives at the DST chip 230B. The difference between the distance from the capsule endoscope 100 to the DST chip 230A and the distance from the capsule endoscope 100 to the DST chip 230B is calculated. Next, a first function, that is, a hyperbola h ₁ is acquired based on the coordinate information of the DST chips 230A and 230B and the distance difference. Further, the control unit 220, DST performs the same processing with respect to the chip 230A and 230C, to obtain a second function namely hyperbola _{h 2.}

The capsule endoscope 100 is located on the hyperbola h ₁ and also on the hyperbola h ₂ . That is, the capsule endoscope 100 is located at either the intersection P ′ ₁ or P ′ ₂ . Here, normally, the coordinate information of one intersection point indicates a position in the body cavity of the patient 1, and the coordinate information of the other intersection point indicates a position clearly separated from the patient 1. Since the capsule endoscope 100 is located in the body cavity of the patient 1, the control unit 220 excludes the latter coordinate information. Then, the former coordinate information is acquired as the current estimated position information of the capsule endoscope 100, and the unit side position estimation process of FIG. 9 is returned.

  The control unit 220 transmits the estimated position information acquired in the unit side position estimation process to the external processing system 300. The external processing system 300 executes various processes using the received estimated position information.

In order to acquire the three-dimensional estimated position information of the capsule endoscope 100, a hyperbola of the DST chip 230A and another DST chip 230 may be obtained. In this case, the control unit 220 can narrow down the estimated position of the capsule endoscope 100 to two points in the three-dimensional space based on the hyperbola h ₁ and h ₂ and the further obtained hyperbola. Again, the control unit 220 can specify the estimated position of the capsule endoscope 100 as one point by discarding the coordinate information of the intersection that is clearly separated from the patient 1.

  As described above, in this embodiment, the propagation time of radio waves is used to calculate the pseudo distance between the capsule endoscope 100 and each DST chip 230. The propagation speed of radio waves has a relatively low dependence on the medium. Therefore, even if the transmission signal from the capsule endoscope 100 passes through any place in the body, the relationship between the pseudo distance between the capsule endoscope 100 and the DST chip 230 and the propagation time is relatively long. Kept constant. For this reason, the error of the pseudo distance is reduced, and as a result, the position of the capsule endoscope 100 can be estimated with high accuracy.

  In the present embodiment, the chip position measurement process of FIG. 7 is executed prior to the diagnosis. Thereby, as described above, the position estimation process of the capsule endoscope 100 can be executed using the highly accurate position information of each DST chip 230. For this reason, the position of the capsule endoscope 100 can be estimated with higher accuracy.

  The above is the embodiment of the present invention. The present invention is not limited to these embodiments and can be modified in various ranges. For example, the target of the chip position measurement process in FIG. 7 may not be all DST chips 230 as in the present embodiment, but may be only a specific DST chip 230.

  As the number of received phase difference signals in the process of S23 in FIG. 9 increases, more hyperbolas can be obtained. Also, the more hyperbola used to calculate the position estimate in the process of S24, the more accurate the estimated position can be obtained by reducing the pseudorange error. Therefore, when the reception state of each DST chip 230 is good, the estimated position information of the capsule endoscope 100 may be calculated using the phase difference signals of all the DST chips 230.

  In FIG. 10, the frequency of the clock adjustment signal and each internal clock are the same, but the frequency of the clock adjustment signal is not limited to this. The frequency of the clock adjustment signal may be a frequency whose one cycle is longer than the longest delay time (largest delay amount) in all the DST chips 230.

It is a block diagram showing composition of an endoscope system of an embodiment of the invention. It is a block diagram showing composition of a capsule type endoscope of an embodiment of the invention. It is AA sectional drawing of FIG. It is the block diagram which showed the structure of the DST chip | tip of embodiment of this invention. It is the block diagram which showed the structure of the control unit of embodiment of this invention. It is a figure for demonstrating the chip position measurement process which a control unit performs in embodiment of this invention. It is a flowchart which shows the chip | tip position measurement process which a control unit performs in embodiment of this invention. It is a flowchart which shows the chip | tip side position estimation process which a DST chip | tip performs in embodiment of this invention. It is a flowchart which shows the unit side position estimation process which a control unit performs in embodiment of this invention. It is a figure which shows the relationship between the clock adjustment signal of embodiment of this invention, and the internal clock of each DST chip. It is a figure for demonstrating the phase difference detected with the DST chip | tip of embodiment of this invention. It is a figure for demonstrating the position calculation process of S24 of FIG.

Explanation of symbols

100 Capsule type endoscope 200 Jacket 230 with antenna DST chip 300 External processing system

Claims (11)

A plurality of elements capable of wireless communication with an external device are mounted, and in a clothing with a communication function including a control unit capable of communicating with each of the elements,
The element is
Identification information holding means for holding the identification information of the self,
External signal receiving means for receiving a transmission signal transmitted from the external device;
Signal generating means for detecting the timing of receiving the transmission signal and generating a timing signal based on the detected timing;
Transmission means for associating the identification information with the generated timing signal and transmitting it to the control unit,
The controller is
Position information holding means for holding the position information of each of the elements in association with the identification information;
Receiving means for receiving timing signals transmitted from each of the elements;
Position information acquisition means for acquiring position information of a transmission source element based on the identification information associated with the received timing signal from the position information holding means;
With a communication function, comprising: each of the received timing signals; and position calculation means for calculating position information of the external device based on the position information corresponding to each of the timing signals. Clothing.   The clothing with a communication function according to claim 1, wherein the signal generation unit detects a time difference between the detected timing and a predetermined timing, and generates a timing signal based on the detection result.   The clothing with a communication function according to claim 2, wherein the predetermined timing is a rising timing of an internal clock of the element. The control unit distributes a predetermined signal to each of the elements,
4. The communication function according to claim 3, wherein an internal clock of the element is corrected based on the predetermined signal from the control unit, and the internal clocks of all the elements are synchronized. Clothing. The control unit further includes reference setting means for setting an element satisfying a predetermined condition as a reference element,
The position calculating means includes
Calculating the phase difference of the reception timing of the transmission signal between the timing signal of the reference element and each of the timing signals of the other elements;
Calculate a pseudo-range difference between the reference element and each of the other elements with respect to the external device based on the calculated phase difference,
5. The position information of the external device is calculated using each of the calculated pseudo distance differences and each of the position information held in the position information holding means. Clothing with a communication function as described in any one.   The element and the control unit are mounted on a sheet capable of signal transmission, and communication between each element and between each element and the control unit is performed based on a 2D-DST algorithm. The clothing with a communication function in any one of Claims 1-5.   The position calculating means calculates position information of the external device when the timing signal received by the receiving means is equal to or greater than a predetermined number, and determines that an error occurs when the timing signal is less than the predetermined number. The position information of an external device is not calculated, The clothing with a communication function in any one of Claims 1-6 characterized by the above-mentioned. Further comprising position measuring means for measuring the position of each of the elements;
The clothing with a communication function according to any one of claims 1 to 7, wherein the position information holding unit holds the information on the measured position in association with the identification information of each of the elements. . A capsule endoscope that is inserted into a patient's body cavity and wirelessly transmits information in the patient's body; and
9. A garment with a communication function according to claim 1, further comprising a garment with a communication function that wirelessly communicates with the capsule endoscope by the element. Endoscopic system. The capsule endoscope has an image signal generation means for imaging the inside of the body cavity and generating an image signal, and transmits the image signal wirelessly,
The endoscope system according to claim 9, wherein the signal generation unit detects timing of receiving the image signal. In a position estimation method for estimating the position of a capsule endoscope placed in a body cavity of a patient, using a garment in which a plurality of elements capable of wireless communication with the capsule endoscope are mounted,
The timing at which the first signal is transmitted by monitoring the transmission power of the capsule endoscope installed at the specified position, and the reception power of each of the elements is monitored, and the first signal is received at each of the elements. A timing detection step for detecting the received timing;
A pseudo distance calculating step for calculating a pseudo distance between the specified position and each of the elements based on the detection result;
A position information acquisition step of acquiring position information of each of the elements based on the calculated pseudo distance;
A reception timing detection step in which each of the elements receives a second signal from the capsule endoscope placed in the body cavity and detects the reception timing;
A timing information collecting step for collecting information on the detected reception timing;
A position estimation method comprising: a position calculation step of calculating position information of the capsule endoscope based on the collected information regarding reception timing and position information of each of the elements.

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