Location determination system and location determination method

Abstract

This provides a novel configuration that improves the accuracy of positioning devices that are ingested orally and pass through the body. [Solution] A position determination system (100) for a device (101) that is ingested orally and passes through the body, comprising a device that outputs electromagnetic waves (W), a group of sensors (102) that detect the magnetic field strength of the electromagnetic waves output from the device passing through the body, and a determination device (103) that determines the position of the device within the body from the magnetic field strength of the electromagnetic waves detected by the sensors, wherein the electromagnetic waves output from the device have wavelengths defined such that the electric field and magnetic field behave independently of each other as they propagate from the body to the outside.

Description

Technical Field

[0001] The present disclosure relates to a positioning system and a positioning method.

Background Art

[0002] Patent Document 1 describes a system that detects a magnetic field generated by an in-vivo sensing device inside the body with an antenna arranged outside the body and identifies the position of the device based on the magnetic field strength. Non-Patent Document 1 describes a technique for identifying the position of an orally ingestible microdevice having a position recognition function using a magnetic field from outside the body and wirelessly monitoring it.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] One aspect of the present disclosure aims to provide a novel configuration for improving the positioning accuracy of a device that is orally ingested and passes through the body.

Means for Solving the Problems

[0006] To solve the above problems, a position determination system according to one aspect of the present disclosure is a position determination system for determining the position of a device that is taken orally and passes through the body, comprising: a device that outputs electromagnetic waves; a sensor that detects the magnetic field strength of the electromagnetic waves output from the device passing through the body; and a determination device that determines the position of the device within the body from the magnetic field strength of the electromagnetic waves detected by the sensor, wherein the electromagnetic waves output from the device have wavelengths defined such that the electric field and magnetic field behave independently of each other as they propagate from the body out of the body. [Effects of the Invention]

[0007] According to one aspect of this disclosure, a novel configuration can be provided that improves the accuracy of positioning a device that is ingested orally and passes through the body. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the configuration of the position determination system according to the embodiment of this disclosure. [Figure 2] This is a magnified view of the area surrounding the target space in Figure 1. [Figure 3] This graph shows the measurement results comparing propagation characteristics in a phantom and in air. [Figure 4] This flowchart shows the processing procedure for the position determination method according to the embodiment of this disclosure. [Figure 5] This is a schematic diagram showing a configuration for robot-assisted device movement and magnetic field strength detection. [Figure 6] This figure shows an example of a three-dimensional magnetic field strength model. [Figure 7] This is an explanatory diagram illustrating a modified example of the embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] [Summary of this disclosure] Devices that are ingested orally and pass through the body are being developed. These are also called "swallowable devices" and are used for medical and healthcare purposes.

[0010] One method for determining the position of a device within a living organism involves emitting electromagnetic waves from outside the organism into the organism, and the device detecting these waves to determine its position. However, with this method, the location of the device emitting the electromagnetic waves from outside the organism is fixed, making it difficult to accurately determine the position of a device moving within the organism moment by moment.

[0011] Furthermore, if an in-vivo device has the function of acquiring biological information, the device must also have the function of emitting electromagnetic waves to transmit the acquired biological information from inside the body to outside the body.

[0012] This disclosure describes a method for detecting electromagnetic waves emitted from a device within a living organism using sensors placed outside the body. Multiple sensors are used, and the location of the device is determined from the detection results of multiple sensors, for example, using triangulation technology.

[0013] Electromagnetic waves emitted from a device within a living body are separated into an electric field and a magnetic field, depending on the relationship between the communication distance and the wavelength of the electromagnetic wave, as described later. A sensor placed outside the living body detects the strength of the magnetic field, which is separated from the electric field and is not attenuated or affected when passing through the human body. Since the strength of the magnetic field detected by the sensor depends on the communication distance between the sensor and the device, the magnetic field strength obtained within the living body can be considered to be approximately the same as the magnetic field strength obtained in air.

[0014] Here, the experimental results obtained by the present inventors, which show that the magnetic field strength in electromagnetic waves can be considered to be the same between inside the body and in air, will be described. FIG. 3 is a graph showing the measurement results of the comparison of propagation characteristics in a phantom and in air. A phantom is an experimental model created to mimic the physical and electrical characteristics inside the body. In this experiment, a liquid phantom composed of a material having a dielectric constant, magnetic permeability, and electrical conductivity close to those of biological tissue was used. The shape and size of the phantom are designed to reproduce the conditions inside an actual human body.

[0015] The two graphs in FIG. 3 represent the magnetic field strength in electromagnetic waves radiated from a device present in the phantom and the magnetic field strength in electromagnetic waves radiated from a device present in air, respectively. The device radiated electromagnetic waves at a frequency of 11.3 MHz. From the graph, it was confirmed that the magnetic field propagation characteristics in the phantom and in air are almost the same, and the influence of biological tissue on magnetic field propagation is limited. From this experimental result, it was shown that the magnetic field in the 10 MHz band has a negligible difference in attenuation between inside the body and in air, and is extremely effective for position estimation using magnetic fields.

[0016] Here, this electromagnetic wave in the 10 MHz band can be regarded as a quasi-static magnetic field that approximates a static magnetic field in which the magnetic field does not change with time among the electric field and magnetic field constituting the electromagnetic wave. Also, for this electromagnetic wave in the 10 MHz band, since the magnetic field can be regarded as a quasi-static magnetic field, it can be said that the electric field and the magnetic field act independently of each other. However, this "can be regarded as a quasi-static magnetic field" means that it holds at a communication distance between a device present inside the body and a sensor arranged outside the body, for example, about 30 cm (a distance based on the diameter of a general biological torso), when electromagnetic waves propagate from inside the body to outside the body in the present disclosure.

[0017] Note that electromagnetic waves travel at the speed of light (about 3×10 8Since it propagates at (m / s), the wavelength of electromagnetic waves in the 10 MHz band is approximately 30 m. Assuming the size of the living body, that is, the diameter of the torso of the living body is 30 cm, the communication distance between the sensor disposed outside the living body and the device existing inside the living body is at most 30 cm. It is preferable to set the wavelength of the electromagnetic wave to be 10 times or more the communication distance, and it is preferable to set it to 1,000 times or less from the viewpoint of information transmission for transmitting the biological information acquired by the device via the electromagnetic wave outside the living body.

[0018] Furthermore, in the present disclosure, a three-dimensional magnetic field intensity map representing the intensity distribution of the magnetic field radiated from the device in the air is created.

[0019] The space in the air is divided into a rectangular parallelepiped lattice, and the device is placed in each rectangular parallelepiped. By sequentially moving the device and recording the intensity of the magnetic field detected by the sensor in each rectangular parallelepiped, a three-dimensional magnetic field intensity map representing the magnetic field intensity distribution of the space in the air is created.

[0020] The finer the rectangular parallelepiped in the space is divided, the more detailed the magnetic field distribution can be obtained. However, when the number of divisions is increased, the number of movements of the device and the number of detections by the sensor become extremely large. In the present disclosure, for example, by interpolating data between adjacent positions using machine learning, a detailed three-dimensional magnetic field intensity model can be efficiently created. As a result, it is possible to obtain a detailed three-dimensional magnetic field intensity model without increasing the amount of work.

[0021] As described above, in the present disclosure, by referring to this three-dimensional magnetic field intensity model, the positioning accuracy when the orally ingested device passes through the living body can be improved.

[0022] 〔Embodiment〕 (Schematic configuration of the positioning system) Hereinafter, the positioning system according to the embodiment of the present disclosure will be described in detail with reference to the drawings.

[0023] Figure 1 is a diagram showing the configuration of a position determination system 100 according to an embodiment of the present disclosure. As shown in Figure 1, the position determination system 100 comprises a device 101 and a sensor determination device 103 (hereinafter collectively referred to as "sensor group 102").

[0024] Device 101 is taken into the living organism H by oral ingestion. Subsequently, device 101 moves through the living organism H. Device 101 has the function of acquiring biological information related to the living organism H while inside the living organism H.

[0025] Furthermore, device 101 has the function of radiating electromagnetic waves W in all directions. The radiation of electromagnetic waves W may be used to transmit biological information acquired within the living organism H to the outside of the living organism H. Device 101 may also have a transmission function to transmit the acquired biological information to the outside of the living organism H via electromagnetic waves W. If the electromagnetic waves W are in the 10 MHz band, biological information can be efficiently transmitted to the outside of the living organism H.

[0026] The sensor group 102 is positioned outside the living organism H. Each sensor 102-1 to 102-4 included in the sensor group 102 detects the strength of the magnetic field in the electromagnetic wave W emitted from device 101. Each sensor 102-1 to 102-4 included in the sensor group 102 is, for example, a three-axis magnetic field sensor capable of detecting magnetic field strength. Each sensor 102-1 to 102-4 is positioned to accurately detect the magnetic field in the electromagnetic wave W emitted from device 101 located in space B. Each sensor 102-1 to 102-4 is capable of detecting magnetic field strength corresponding to the three axes of the X, Y, and Z directions, thereby determining the position of device 101 in three dimensions. The arrangement of each sensor 102-1 to 102-4 included in the sensor group 102 is optimized to enable highly accurate position estimation using, for example, triangulation techniques.

[0027] Each sensor 102-1 to 102-4 is equipped with a communication function to quickly and reliably transmit detected magnetic field strength data to the determination device 103. Communication is performed either by wired or wireless communication. This enables the determination device 103 to reliably and efficiently perform real-time position tracking.

[0028] Now, let's explain the arrangement of the sensor group 102.

[0029] In Figure 1, a rectangular parallelepiped-shaped space (hereinafter referred to as the "target space") B is defined. The target space B represents the range in which the position determination system 100 can determine the position of the device 101 within the living organism H. As shown in Figure 1, the target space B is defined to include the lower region of the digestive tract of the living organism H. However, the region included in the target space B is not limited to the lower region of the digestive tract of the living organism H.

[0030] Figure 2 is an enlarged view of the area surrounding the target space B in Figure 1. Note that the X, Y, and Z directions in Figures 1 and 2 are defined based on the same coordinate system. Furthermore, the X, Y, and Z directions in Figures 3 and beyond are also defined based on the same coordinate system as in Figures 1 and 2.

[0031] As shown in Figure 2, each of the sensors 102-1 to 102-4 included in the sensor group 102 is positioned on one of the four sides in the Z direction of the rectangular parallelepiped shape that constitutes the target space B. Specifically, each of the sensors 102-1 to 102-4 is installed near the midpoint of the four sides along the Z direction.

[0032] Each of the sensors 102-1 to 102-4 in the sensor group 102 detects the strength of the magnetic field in the electromagnetic wave W emitted from the device 101 located within the target space B.

[0033] The determination device 103 receives and analyzes the magnetic field strength in the electromagnetic wave W detected by the sensor group 102. Based on this analysis, the determination device 103 calculates the position of the device 101 within the living organism H. This makes it possible to determine the precise position of the device 101.

[0034] The decision device 103 has multiple hardware and software configurations. The decision device 103 includes a processor 201, memory 202, input device 206, output device 207, and input / output interface (I / F) 208.

[0035] The processor 201 executes the model creation application 203 and the position determination application 204, which will be described later. The processor 201 employs, for example, a high-performance multi-core processor to enable real-time processing. The processor processes the data received from the sensor group 102 quickly and accurately.

[0036] Memory 202 stores the model creation application 203, the location determination application 204, and the 3D magnetic field strength model 205. Memory 202 is composed of, for example, RAM or flash memory. In this specification, "memory" refers to a storage device that has the function of recording or holding information, and its form and structure are not limited to a specific technology. Examples of memory 202 include semiconductor memory, magnetic recording devices, optical recording devices, cloud storage, and other storage technologies. Any of these, as long as they have the function of recording and holding the model creation application 203, the location determination application 204, and the 3D magnetic field strength model 205, fall under the definition of "memory" in this specification. In this specification, by interpreting "memory" in such a broad sense, flexibility is ensured to accommodate a variety of applications without limiting the technical scope of the present invention. For this reason, it is made clear that the expression "memory" is not limited to a specific storage technology or device.

[0037] The input device 206 is, for example, a touchscreen, a physical keyboard, or a port for connecting an external device. The output device 207 is, for example, equipped with a high-resolution display that visually displays real-time location information and analysis results. Furthermore, the input device 206 may be equipped with a USB port or an HDMI® port for outputting data to an external system.

[0038] The input / output interface 208 is responsible for communication between the sensor group 102 and external systems. Wired communication uses Ethernet® ports and serial ports. Wireless communication uses Wi-Fi® and Bluetooth®. Data from the sensor group 102 is transmitted to the processor 201 via wired or wireless communication.

[0039] When the processor 201 executes the position determination application 204, it references the 3D magnetic field strength model 205 based on the detection results from the sensor group 102 to estimate the position of the device 101. This position estimation uses advanced algorithms, such as fingerprinting technology. Specifically, the position of the device 101 is determined with high accuracy by comparing the magnetic field strength distribution detected by the sensor group 102 with the 3D magnetic field strength model 205. This position estimation enables real-time position tracking of the device 101.

[0040] When the processor 201 executes the model creation application 203, it creates a detailed 3D magnetic field strength model 205 based on the 3D magnetic field strength map acquired from the sensor group 102. For example, interpolation and machine learning techniques are used to create the 3D magnetic field strength model 205. Interpolation allows for the estimation of undetected areas between detection positions, enabling the construction of a more precise model. Furthermore, machine learning is used to further improve the accuracy of the information obtained from the sensor group 102, thereby enhancing the accuracy of position determination. The 3D magnetic field strength model 205 is referenced when determining the position of the device 101.

[0041] (Positioning method) Figure 4 is a flowchart showing the processing procedure of the position determination method according to the embodiment of this disclosure. Below, we will first describe steps S101 to S103 included in the procedure for creating a three-dimensional magnetic field strength model 205, and then describe steps S104 to S105 included in the procedure for determining the position of the device 101 located within the biological body H.

[0042] Steps S101 to S103 shown in Figure 4 are steps included in the procedure for creating the 3D magnetic field strength model 205. This procedure involves detecting the magnetic field strength of electromagnetic waves W emitted from a device 101 present in a space B defined in the air (hereinafter referred to as the "non-biological space"), creating a 3D magnetic field strength map of the detection results for the entire non-biological space B, and then applying interpolation processing, machine learning, etc., to create the 3D magnetic field strength model 205.

[0043] On the other hand, steps S104 to S105 are procedures performed when the orally ingested device 101 passes through the living body H. In these procedures, the magnetic field strength of the electromagnetic waves W emitted from the device 101 present in the target space B defined within the living body H is detected, and the position of the device moving through the living body H is determined by using the detection results and a pre-created three-dimensional magnetic field strength model 205.

[0044] Furthermore, although steps S101 to S105 are described as a series of procedures in Figure 4, this disclosure is not limited to this series of procedures. For example, the procedure for creating the three-dimensional magnetic field strength model 205 in steps S101 to S103 and the procedure for determining the position of the device 101 in steps S104 to S105 do not necessarily have to be performed consecutively. That is, after the procedure for creating the three-dimensional magnetic field strength model 205 is completed, the procedure for determining the position of the device 101 may be performed at a later date when the device 101 is actually ingested orally.

[0045] In short, when determining the position of device 101, it is possible to use a pre-created three-dimensional magnetic field strength model 205.

[0046] Step S101: A non-biological space B, defined as a rectangular parallelepiped in the air, is prepared and divided into a grid. The magnetic field strength in each rectangular parallelepiped is detected by the sensor group 102, and a three-dimensional magnetic field strength map is created. Here, the arrangement of the sensor group 102 for the non-biological space B defined in the air substantially coincides with the arrangement of the sensor group 102 for the target space B defined within the biological space H in the position determination procedure described later. Furthermore, the target space B and the non-biological space B substantially coincide in terms of shape, dimensions, size, and volume.

[0047] However, this "match" does not mean a perfect match. It is considered a "match" if, in detecting the magnetic field strength, the detection errors of each sensor 102-1 to 102-4 included in the sensor group 102 do not affect either the creation of the 3D magnetic field strength model 205 or the position determination of the device 101.

[0048] In this specification, the space B defined in the air when creating the three-dimensional magnetic field strength model 205 is referred to as the "non-biological space," and the space B defined within the biological H when locating the device 101 moving within the biological H is referred to as the "target space." These two spaces differ only in the location in which they are defined; their shapes, dimensions, etc., are substantially the same as described above. Therefore, from the viewpoint of the purpose for which each is defined, they can be considered the same space. For these reasons, in this specification, the same symbol "B" is used for both the non-biological space and the target space.

[0049] When arranging the sensor group 102 in a non-biological space B defined in the air, a support member should be used to support each sensor 102-1 to 102-4 and fix the position of each sensor 102-1 to 102-4. The support member can be fixed to a fixed object such as the floor or a table. This arrangement enables high-precision acquisition of data necessary for creating a three-dimensional magnetic field strength map.

[0050] Figure 5 is a schematic diagram showing the configuration for the robot 500 to move the device 101 and detect the magnetic field strength. The robot 500 has a multi-axis arm with multiple joints, and a gripping member 501 for grasping the device 101 is provided at its tip. The gripping member 501 has the function of precisely adjusting the position and orientation of the device 101 and determining its position in each rectangular parallelepiped within the target space B.

[0051] The controller (not shown) that controls the robot 500 stores coordinate data that divides the target space B into multiple rectangular parallelepipeds. Based on this coordinate data, the controller moves the device 101 to a target position within each rectangular parallelepiped and has a function to optimize the movement path so that the sensor group 102 can efficiently detect the magnetic field strength.

[0052] Specifically, the robot 500 starts its movement from the origin O of the target space B and scans the XY plane in a predetermined scanning pattern. Once the scanning of one XY plane is complete, the robot 500 moves the device 101 in the Z direction and performs the same scanning in the next XY plane. By repeating this operation, the device 101 is accurately positioned in all the rectangular parallelepipeds in the target space B.

[0053] The detection of magnetic field strength by the sensor group 102 in each rectangular parallelepiped is represented as data where the magnetic field strength in the sub-plane shown as b in the figure is stacked.

[0054] Step S102: The obtained magnetic field strength data is sent to processor 201 and used to create a three-dimensional magnetic field strength map.

[0055] Step S103: The obtained magnetic field strength data may lack continuity between adjacent rectangular parallelepipeds. Interpolation of data between adjacent regions is performed to create a continuous and smooth magnetic field distribution.

[0056] Figure 6 shows an example of the 3D magnetic field strength model 205. The 3D magnetic field strength model 205 represents the magnetic field strength distribution in each rectangular parallelepiped within the target space B. The magnetic field strength is indicated by the intensity of the color of each rectangular parallelepiped, with darker colors indicating a stronger magnetic field and lighter colors indicating a weaker magnetic field.

[0057] The 3D magnetic field strength model 205 is created based on magnetic field strength data detected by the sensor group 102, and achieves a smooth and continuous distribution, for example, through interpolation between adjacent rectangular parallelepipeds.

[0058] To further refine the interpolated 3D magnetic field strength model 205, machine learning algorithms are applied. These machine learning algorithms include techniques that utilize pattern recognition and regression analysis models to create detailed magnetic field distributions estimated from measured data.

[0059] The completed three-dimensional magnetic field strength model 205 is recorded in the memory 202 of the determination device 103.

[0060] Step S104: The sensor group 102 detects the magnetic field strength in the electromagnetic wave W emitted from device 101 in real time and transmits the detected data to the determination device 103. The sensor group 102 is positioned on the outer surface of the biological body H with respect to the target space B defined within the biological body H. Since the biological body H is not usually rectangular in shape, support members for position adjustment may be used to substantially match the position of the sensor group 102 in air with the position of the sensor group 102 outside the biological body. The sensor group 102 positioned in this manner collects data necessary for determining the position of device 101 with high accuracy.

[0061] Step S105: The processor 201 of the determination device 103 compares the magnetic field strength data acquired from the sensor group 102 with a three-dimensional magnetic field strength model 205 recorded in the memory 202. Specifically, it uses techniques such as fingerprinting or machine learning to analyze which position in the three-dimensional magnetic field strength model 205 the data acquired from the sensor group 102 corresponds to. This comparison allows for highly accurate determination of the position of device 101.

[0062] The location information of device 101 determined by the analysis is displayed and transmitted to a display or external system via the output device 207. This makes it possible to understand the movement path and current location of device 101 within the living organism H.

[0063] [Variation] Modifications of the embodiments of this disclosure are described below. For the sake of convenience, components having the same function as those described in the above embodiments are denoted by the same reference numerals, and their descriptions are not repeated.

[0064] In the above embodiment, the position of the device 101 within the living organism H is determined, but in addition to the position, at least one of the orientation or posture of the device 101 may also be determined. Furthermore, when determining at least one of the orientation or posture of the device 101, it is preferable to incorporate at least one detector for detecting the orientation or posture of the device 101, such as a gyro sensor, an accelerometer, or a magnetic sensor, into the device 101. If each of the sensors 102-1 to 102-4 included in the sensor group 102 is a 3-axis magnetic field sensor, incorporating a gyro sensor or the like into the device 101 makes it possible to reduce the number of 3-axis magnetic field sensors required compared to when at least one of the orientation or posture of the device 101 is determined using only 3-axis magnetic field sensors.

[0065] Alternatively, a three-dimensional magnetic field strength model 205 may be created that takes into account at least one of the orientation or attitude of the device 101. At least one of the orientation or attitude of the device 101 may be detected using data output from a gyro sensor or the like incorporated in the device 101, and the three-dimensional magnetic field strength model 205 may be created using the detection result.

[0066] Furthermore, the arrangement of the sensor group 102 is not limited to the midpoints of the four sides in the Z direction of space B. For example, it may be arranged near the midpoints of the four sides in the X or Y direction. It is also possible to arrange each of the sensors 102-1 to 102-4 included in the sensor group 102 at the four vertices of any face constituting space B. Moreover, the number of sensors included in the sensor group 102 is not limited to four, and can be increased or decreased according to the accuracy of the 3D magnetic field strength model 205.

[0067] More specifically, the sensors 102-1 to 102-4 included in the sensor group 102 do not necessarily need to be arranged on the same plane. Furthermore, the arrangement of these sensors 102-1 to 102-4 can be set to any position and is not limited to an arrangement that forms a specific shape such as the rectangular parallelepiped described in the above embodiment. The arrangement of each sensor 102-1 to 102-4 can be flexibly set according to the characteristics of the space being measured and the requirements for measurement accuracy.

[0068] Furthermore, while the sensor group 102 contained four sensors in the above embodiment, the embodiments of this disclosure are not limited to four sensors. For example, as shown in Figure 7, the sensor group 102A may contain eight sensors. In this case, each sensor 102A-1 to 102A-8 is positioned at one of the eight vertices of the rectangular parallelepiped shape in the target space B. By arranging eight sensors in this way, the position determination accuracy of the device 101 can be improved. It should be noted that the creation procedure for the three-dimensional magnetic field strength model 205, as described using Figures 5 and 6 in the above embodiment, does not change even if the number of sensors is changed from four to eight. Only the number of detected data increases with the increase in the number of sensors, and processing using this increased data can be performed in the same way as when there are four sensors.

[0069] Furthermore, the determination device 103 does not necessarily need to have the model creation application 203 built-in. For example, a separate dedicated model creation device may be provided, the 3D magnetic field strength model 205 may be created using this dedicated model creation device, and the created 3D magnetic field strength model 205 may be recorded in the memory 202 of the determination device 103.

[0070] Furthermore, the decision device 103 does not necessarily need to have the model creation application 203 and the position determination application 204 built-in; it may be configured to perform processing using the model creation application 203 and the position determination application 204 stored on the cloud. In this case, the decision device 103 is equipped with a network interface that can communicate with the cloud and retrieves and uses the necessary data and applications from the cloud. By placing the model creation application 203 and the position determination application 204 on the cloud, the processing load is distributed, the hardware configuration of the decision device 103 is reduced, and the cost efficiency of the entire position determination system 100 is improved.

[0071] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments and modifications described above are also included in the technical scope of this disclosure.

[0072] 〔summary〕 A position determination system according to Embodiment 1 of the present invention is a position determination system for determining the position of a device that is ingested orally and passes through the body, comprising: a device that outputs electromagnetic waves; a sensor that detects the magnetic field strength of the electromagnetic waves output from the device passing through the body; and a determination device that determines the position of the device within the body from the magnetic field strength of the electromagnetic waves detected by the sensor, wherein the electromagnetic waves output from the device have wavelengths defined such that the electric field and magnetic field behave independently of each other as they propagate from the body out of the body.

[0073] The above configuration provides a novel configuration that improves the accuracy of positioning a device that is ingested orally and passes through the body.

[0074] The position determination system according to aspect 2 of the present invention, in aspect 1 above, comprises a memory storing a three-dimensional magnetic field strength model in which the magnetic field strength of electromagnetic waves output from the device placed in each rectangular parallelepiped in a non-biological space divided into a rectangular grid, which is a space different from the inside of a living body, is three-dimensionally represented, and a processor that, when the position determination device determines the position of the device inside the body, estimates the position of the device inside the body based on the three-dimensional magnetic field strength model stored in the memory and the magnetic field strength of electromagnetic waves detected by the sensor, wherein the position of the device estimated by the processor is the position of the device determined by the position determination device.

[0075] According to the above configuration, by referring to a three-dimensional magnetic field strength model, the accuracy of positioning a device ingested orally as it passes through the body can be improved.

[0076] In the third aspect of the present invention, the position determination system, as described in aspect 2, is such that the device is taken into the body by oral ingestion and acquires biological information while moving within the body, and the biological information acquired by the device is transmitted from the body to the outside of the body via electromagnetic waves output from the device.

[0077] According to the above configuration, biological information can be transmitted to the outside of the living body via electromagnetic waves.

[0078] In the position determination system according to aspect 4 of the present invention, in aspect 2 above, when the non-biological space is considered to be the body of a living organism, it is preferable that the position of a sensor located outside the body of the living organism and the position of a sensor located outside the non-biological space substantially coincide when determining the position of a device inside the body of the living organism.

[0079] A position determination method according to aspect 5 of the present invention is a position determination method for determining the position of a device that is ingested orally and passes through the body, and includes a detection step of detecting the magnetic field strength of electromagnetic waves output from the device passing through the body, and a determination step of determining the position of the device within the body from the magnetic field strength of the electromagnetic waves detected in the detection step, wherein the electromagnetic waves output from the device have wavelengths defined such that the electric field and magnetic field behave independently of each other when propagating from the body to the outside of the body.

[0080] The above configuration provides a novel configuration that improves the accuracy of positioning a device that is ingested orally and passes through the body.

[0081] In the position determination system according to embodiment 6 of the present invention, in embodiment 2 or 4 above, the device incorporates a detector for detecting at least one of the orientation or orientation of the device, and the three-dimensional magnetic field strength model further represents in three dimensions the detection data output from the detectors incorporated in the devices arranged in each rectangular parallelepiped in the non-biological space.

[0082] According to the above configuration, in addition to the position of the device within the living body, at least one of the orientation or posture of the device can also be determined. [Explanation of symbols]

[0083] 100 Positioning System 101 devices 102 Sensor Group 102-1, 102-2, 102-3, 102-4 sensors 103 Determination device 201 Processor 202 memory 203 Model Creation Applications 204 Location Determination Applications 205-dimensional magnetic field strength model 206 Input device 207 Output device 208 Input / Output Interfaces 500 robots 501 Gripping member

Claims

1. A positioning system for a device that is ingested orally and passes through the body, which determines the position of the device within the body. Devices that emit electromagnetic waves, A sensor that detects the magnetic field strength of electromagnetic waves emitted from the device as it passes through the body, A determination device that determines the position of the device within the body from the magnetic field strength of the electromagnetic waves detected by the aforementioned sensor. Equipped with, A position determination system in which electromagnetic waves emitted from the aforementioned device have wavelengths defined such that the electric and magnetic fields behave independently of each other as they propagate from inside to outside the body.

2. The determination device is, A memory that stores a three-dimensional magnetic field strength model in which the magnetic field strength of electromagnetic waves output from the device placed in each rectangular prism is represented three-dimensionally in a non-biological space that is a space different from the living body and is divided into a rectangular grid, When the determination device determines the position of the device within the body, a processor estimates the position of the device within the body based on the three-dimensional magnetic field strength model stored in the memory and the magnetic field strength of the electromagnetic waves detected by the sensor. It has, The position determination system according to claim 1, wherein the position of the device estimated by the processor is the position of the device determined by the determination device.

3. The aforementioned device is taken into the body by oral ingestion and acquires biological information while moving within the body. The location determination system according to claim 2, wherein the biological information acquired by the device is transmitted from inside the body to outside the body via electromagnetic waves output from the device.

4. The position determination system according to claim 2, wherein, when the non-living space is considered to be the body of a living organism, the position of a sensor located outside the body of the living organism and the position of a sensor located outside the non-living space substantially coincide when determining the position of a device within the body of the living organism.

5. A method for determining the position of a device that is ingested orally and passes through the body, A detection process for detecting the magnetic field strength of electromagnetic waves emitted from a device passing through the body, A determination step is made to determine the position of the device within the body based on the magnetic field strength of the electromagnetic waves detected in the above detection step. Includes, A position determination method wherein the electromagnetic waves output from the device have wavelengths defined such that the electric field and magnetic field behave independently of each other as they propagate from inside the body to outside the body.

6. The device incorporates a detector for detecting at least one of the orientation or attitude of the device. The position determination system according to claim 2 or 4, wherein the three-dimensional magnetic field strength model further represents in three dimensions the detection data output from the detectors incorporated in the devices arranged within each rectangular parallelepiped in the non-biological space.

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