Positioning system and method for permanent magnet target in gastrointestinal tract

Abstract

The invention provides a positioning system and method for a permanent magnet target in a gastrointestinal tract. The positioning system comprises a magnetic source, a magnetic sensor array and a processing module, the magnetic source is used for generating a magnetic field; the magnetic sensor array is used for measuring the magnetic field intensity in the space; and the processing module acquires magnetic field intensity data, and further performs spatial position and orientation calculation of the target by using the magnetic moment and magnetic field intensity data of the magnetic source based on a magnetic dipole model and a magnetic moment theory. By means of the innovative magnetic field induction technology and the magnetic dipole model, the problems that in the prior art, positioning of an electronic capsule in the gastrointestinal tract is insufficient in precision, large in external interference, difficult in posture information obtaining, incapable of meeting the requirement for precise diagnosis and treatment in modern medical treatment and the like are solved, and permanent magnet target positioning in the gastrointestinal tract can be achieved.

Description

Technical Field

[0001] The present application relates to the field of magnetic field positioning technology applied in the fields of biomedicine and virtual reality, and in particular to a positioning system and method for a permanent magnet target in the gastrointestinal tract. Background Art

[0002] With the rapid development of miniaturization and wireless communication technology, the application of miniature devices (such as wireless capsule endoscopes) in the gastrointestinal tract has gradually become an important topic in medical research and clinical practice. Wireless capsule endoscopes are portable, non-invasive medical devices that can perform image acquisition and monitoring inside the gastrointestinal tract. However, the precise positioning and navigation of such devices in the body still face many challenges, which is crucial to their diagnostic effectiveness and ease of use.

[0003] In the prior art, the positioning methods in the gastrointestinal tract are, for example: Radio signal positioning technology: Radio signal positioning technology locates the capsule by arranging receivers inside or outside the body. However, since the radio signal is strongly attenuated by tissues and fluids when propagating in the body, the accuracy and reliability of this method are limited, which results in poor positioning accuracy in the gastrointestinal tract.

[0004] Based on this, a new technical solution is needed. Summary of the invention

[0005] In view of this, the present application provides a system and method for positioning a permanent magnet target in the gastrointestinal tract.

[0006] This application provides the following technical solutions:

[0007] According to the present application, a positioning system for a permanent magnet target in the gastrointestinal tract includes a magnetic source, a magnetic sensor array, and a processing module;

[0008] The magnetic source is used to generate a magnetic field;

[0009] The magnetic sensor array is used to measure the magnetic field strength in space;

[0010] The processing module collects magnetic field strength data, and then calculates the spatial position and orientation of the target based on the magnetic dipole model and magnetic moment theory using the magnetic moment and magnetic field strength data of the magnetic source.

[0011] Preferably, the processing module includes a control unit, a storage unit and a data processing unit;

[0012] The magnetic sensor array includes a plurality of Hall effect magnetic sensors installed at spatial coordinate positions, and the plurality of Hall effect magnetic sensors are used to respectively measure magnetic field intensity components at different spatial coordinate positions;

[0013] The control unit synchronously collects magnetic field strength data, and converts the collected magnetic field strength data into digital signals;

[0014] The storage module stores the magnetic field strength data converted into digital signals;

[0015] The data processing unit calculates the three-dimensional spatial position and azimuth of the target based on the magnetic dipole model and magnetic moment theory.

[0016] Preferably, the magnetic source comprises at least one permanent magnet; the direction and magnitude of the magnetic dipole moment vector of the permanent magnet are used to calculate the orientation and position of the target;

[0017] The magnetic field intensity component is used to infer the position of the magnetic source and the direction of the magnetic dipole moment.

[0018] Preferably, the data processing unit iteratively solves the spatial position and attitude information of the magnetic source by minimizing the error between the measured data and the magnetic dipole model predicted data based on a magnetic field inversion algorithm.

[0019] Preferably, the data processing unit uses a magnetic dipole model to express the magnetic field at any point in space and derive the three-dimensional position of the target object;

[0020] Among them, using the magnetic dipole model, the expression of the magnetic field at any point in space is:

[0021]

[0022] is the unit vector of distance; m is the magnetic dipole moment; is the distance from the magnetic dipole to the sensor; The vector representing the distance; s = (x, y, z) is the spatial coordinate of the sensor; x, y, z are the three coordinate values ​​of the sensor space; B is the magnetic field strength; μ0 is the vacuum permeability.

[0023] Preferably, the data processing unit minimizes the deviation between the magnetic field value actually measured by the magnetic sensor array and the theoretical predicted value through an error function, and calculates the three-dimensional position and orientation of the target;

[0024] The error function is defined to measure the magnetic field B actually measured by the magnetic sensor array. i The magnetic field predicted by theory Deviation between:

[0025]

[0026] Magnetic dipole moment m = (a, b, c) is the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes respectively; N represents the number of magnetic sensors; and E represents the deviation value.

[0027] The embodiments of this specification also provide a method for positioning a permanent magnet target in the gastrointestinal tract, using any of the above-mentioned positioning systems for a permanent magnet target in the gastrointestinal tract, comprising the following steps:

[0028] Data measurement steps: measuring the magnetic field strength in space through a magnetic sensor array;

[0029] Processing steps: Collect magnetic field strength data, and then calculate the spatial position and orientation of the target based on the magnetic dipole model and magnetic moment theory using the magnetic moment and magnetic field strength data of the magnetic source.

[0030] Preferably, the processing step comprises the following steps:

[0031] Control processing steps: synchronously collect magnetic field strength data, and convert the collected magnetic field strength data into analog signals to digital signals;

[0032] Storing step: storing the magnetic field strength data converted into digital signals;

[0033] Data processing steps: Calculate the three-dimensional spatial position and azimuth of the target based on the magnetic dipole model and magnetic moment theory.

[0034] Preferably, in the data processing step, based on a magnetic field inversion algorithm, the spatial position and attitude information of the magnetic source are iteratively solved by minimizing the error between the measured data and the magnetic dipole model predicted data.

[0035] Preferably, the data processing step includes: using a magnetic dipole model to express the magnetic field at any point in space and deriving the three-dimensional position of the target object;

[0036] Among them, using the magnetic dipole model, the expression of the magnetic field at any point in space is:

[0037]

[0038] is the unit vector of distance; m is the magnetic dipole moment; is the distance from the magnetic dipole to the sensor; The vector representing the distance; s = (x, y, z) is the spatial coordinate of the sensor; x, y, z are the three coordinate values ​​of the sensor space; B is the magnetic field strength; μ0 is the vacuum permeability;

[0039] The error function is used to minimize the deviation between the magnetic field value measured by the magnetic sensor array and the theoretical predicted value, and the three-dimensional position and orientation of the target are calculated;

[0040] The error function is defined to measure the magnetic field B actually measured by the magnetic sensor array. iThe magnetic field predicted by theory Deviation between:

[0041]

[0042] Magnetic dipole moment m = (a, b, c) is the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes respectively; N represents the number of magnetic sensors; and E represents the deviation value.

[0043] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the present application include at least:

[0044] This application uses innovative magnetic field sensing technology and magnetic dipole models to solve the problems in the existing technology, such as insufficient accuracy in positioning electronic capsules in the gastrointestinal tract, greater external interference, and difficulty in obtaining posture information, which cannot meet the needs of modern medicine for precise diagnosis and treatment. It can achieve the positioning of permanent magnet targets in the gastrointestinal tract. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 This is the structural diagram of the positioning system;

[0047] Figure 2 This is a block diagram of a positioning system using the PIC18 chip as an example;

[0048] Figure 3 This is the flow chart of the acquisition module.

[0049] Figure 4 Schematic diagram defining the position and orientation of a permanent magnet. DETAILED DESCRIPTION

[0050] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0051] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0052] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0053] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0054] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0055] In view of this, the applicant conducted in-depth research and improvement exploration on target positioning in the gastrointestinal tract and found that in the prior art, positioning in the gastrointestinal tract mainly relies on the following technical means:

[0056] Radio signal positioning technology: Radio signal positioning technology locates the capsule by placing receivers inside or outside the body. However, the accuracy and reliability of this method are limited because radio signals are strongly attenuated by tissues and fluids when propagating in the body. In addition, the transmission and reception of radio signals require a large amount of power consumption, which may affect the service life and performance of the capsule. Therefore, in practical applications, radio signal positioning technology faces challenges such as signal attenuation, interference, and power consumption.

[0057] Magnetic field sensing technology: Magnetic field sensing technology uses magnetic field strength measurement to locate targets. Traditional magnetic field positioning methods are based on the magnetic dipole model, which regards permanent magnets as magnetic dipoles and infers the position of the target by measuring the magnetic field strength generated by the target. The advantage of this method is that it can achieve positioning under low power consumption conditions, but its accuracy and response speed are still limited. The main challenges faced by traditional magnetic field positioning technology include: a) Magnetic field interference: Other magnetic substances in the body and external interference sources may affect magnetic field measurements, resulting in positioning errors. b) Positioning accuracy: Positioning methods based on magnetic dipole models often face the problem of insufficient accuracy in practical applications, especially in the presence of multiple targets or complex environments. c) Computational complexity: The calculation of magnetic field strength involves complex mathematical modeling and inversion calculations, which increases the computational burden of the system and the difficulty of real-time processing.

[0058] Ultrasound positioning technology: Ultrasound positioning technology determines the target position by emitting and receiving ultrasonic signals. This technology usually involves arranging ultrasonic transmitters and receivers inside or outside the body, and calculating the distance of the target by measuring the propagation time or phase change of ultrasonic waves. The advantages of ultrasonic positioning are its high time resolution and low interference, but there are also the following challenges: a) Penetration depth limitation: The depth of ultrasonic wave propagation in the body is limited, especially in thicker tissue layers, and the signal attenuates faster. b) Impact of environmental changes: Changes in the internal environment (such as tissue density and fluid distribution) can affect the speed and direction of ultrasonic wave propagation, thereby affecting positioning accuracy.

[0059] Inertial navigation technology: Inertial navigation technology measures the acceleration and angular velocity of a target to infer its position and direction. This usually involves building an accelerometer and gyroscope into the target, and estimating the target's trajectory by integrating the acceleration and angular velocity data. The advantage of inertial navigation technology is that it can provide high-frequency positioning updates and good real-time performance, but its main challenges are: a) Cumulative error: Inertial navigation technology is susceptible to cumulative errors. Over time, the errors will continue to accumulate and affect positioning accuracy. b) High power consumption: High-precision inertial sensors usually require higher power consumption, which puts additional requirements on the design of wireless capsule devices.

[0060] Nevertheless, existing technologies still face many challenges in improving positioning accuracy, reducing power consumption and dealing with magnetic field interference. Therefore, optimizing magnetic field positioning technology, especially in practical operation in biomedical applications, remains an important issue to be solved.

[0061] In recent years, researchers have proposed some innovative methods based on traditional magnetic field positioning technology to improve positioning accuracy and robustness, including: a) Multi-sensor fusion technology: by arranging multiple sensors to form an array, measuring the magnetic field strength at different positions, thereby improving positioning accuracy. Multi-sensor fusion can reduce the measurement error of a single sensor and improve the system's adaptability to environmental changes by optimizing the arrangement and measurement strategy of the sensor. b) Optimizing the magnetic field model: Optimizing the magnetic dipole model for factors such as magnetic field interference and non-ideal magnetic sources in practical applications. The optimized model not only improves the accuracy of the calculation, but also enhances the system's adaptability in complex environments. c) Algorithm improvement: Advanced data processing algorithms (such as Kalman filtering, particle filtering, etc.) are used to process positioning data. These algorithms improve the robustness to noise and interference by fusing sensor data with dynamic models, thereby improving the positioning accuracy and stability of the system. The positioning method based on the magnetic dipole model proposed in this application further optimizes the magnetic field model and sensor array design to achieve higher-precision three-dimensional spatial positioning and orientation detection, thereby improving the actual application effect of wireless capsule endoscopy.

[0062] Based on this, the technical solutions provided by the embodiments of the present application are described below in conjunction with the accompanying drawings.

[0063] The embodiments of this specification provide a positioning system for a permanent magnet target in the gastrointestinal tract, such as Figure 1 , Figure 2 as well as Figure 3 As shown, it includes a magnetic source, a magnetic sensor array and a processing module.

[0064] The magnetic source is used to generate a magnetic field. Specifically, the magnetic source is configured to generate a stable magnetic field, which is generated by one or more permanent magnets. The magnetic dipole moment vector m of each permanent magnet is known, and its direction and magnitude can be used to calculate the orientation and position of the target.

[0065] The magnetic sensor array is used to measure the magnetic field strength in space. Specifically, the magnetic sensor array includes multiple Hall effect magnetic sensors installed at spatial coordinate positions. The array is composed of multiple Hall effect magnetic sensors, and the sensors are arranged at known spatial coordinate positions. Each sensor can measure the magnetic field strength components at different points in space respectively. These components are used to infer the position of the magnetic field source and the direction of the magnetic dipole moment.

[0066] The processing module collects magnetic field strength data, and then calculates the spatial position and orientation of the target based on the magnetic dipole model and magnetic moment theory, using the magnetic moment and magnetic field strength data of the magnetic source. The arrangement position of the sensor array of the present application is known, and the magnetic field data collected by it is combined with the magnetic dipole model for multi-sensor fusion to improve positioning reliability.

[0067] In one embodiment, the processing module includes a control unit, a storage unit and a data processing unit.

[0068] The control unit synchronously collects magnetic field strength data and converts the collected magnetic field strength data from analog signals to digital signals. Specifically, the control unit includes a microprocessor, such as PIC18F4520, which is responsible for synchronously collecting magnetic field data of the sensor array, converting the analog signal of the sensor into a digital signal through an ADC module (Analog-to-Digital Converter Module) and storing it in a storage module.

[0069] The storage module stores the magnetic field strength data converted into digital signals. Specifically, the storage module includes an SD card as a storage device for storing the magnetic field data collected from the control unit to facilitate subsequent data processing. The microprocessor is used to receive and process the output signals of multiple Hall effect sensors, convert these analog signals into digital signals and store them in the SD card.

[0070] The data processing unit calculates the three-dimensional spatial position and azimuth of the target based on the magnetic dipole model and magnetic moment theory. Specifically, the data processing unit imports the data in the SD card into an external computing device, and calculates the spatial position and orientation of the target object based on the magnetic dipole model and magnetic moment, that is, imports the SD card data after the acquisition into the external computing device, and derives the target position and orientation based on the magnetic dipole model and magnetic moment theory, combined with the magnetic field strength measured by the sensor array.

[0071] In one embodiment, the magnetic source includes at least one permanent magnet; the direction and magnitude of the magnetic dipole moment vector of the permanent magnet are used to calculate the orientation and position of the target; and the magnetic field intensity component is used to infer the position of the magnetic source and the direction of the magnetic dipole moment.

[0072] In one embodiment, the data processing unit uses a data processing algorithm to calculate the three-dimensional position coordinates and azimuth of the target object based on the magnetic dipole model using the magnetic moment direction of the magnetic source and the magnetic induction intensity collected by the sensor array. Specifically, the data processing algorithm: based on the magnetic field inversion algorithm, by minimizing the error between the measured data and the magnetic dipole model predicted data, iteratively solves the spatial position and attitude information of the magnetic source.

[0073] In one embodiment, the data processing unit uses a magnetic dipole model to express the magnetic field at any point in space and deduce the three-dimensional position of the target object.

[0074] Specifically, refer to Figure 4 , the data processing unit uses the magnetic dipole model to express the magnetic field at any point in space and derives the three-dimensional position of the target object; wherein, using the magnetic dipole model, the expression of the magnetic field at any point in space is:

[0075]

[0076] is the unit vector of distance; m is the magnetic dipole moment; is the distance from the magnetic dipole to the sensor; The vector representing the distance; s = (x, y, z) is the spatial coordinate of the sensor; x, y, z are the three coordinate values ​​of the sensor space; B is the magnetic field strength; μ0 is the vacuum permeability (μ0 = 4π×10 -7 T·m / A). When the permanent magnet is located at the origin (0, 0, 0) of the spatial coordinate system, (x, y, z) is the spatial position coordinate of the sensor.

[0077] In one embodiment, the data processing unit minimizes the deviation between the magnetic field value actually measured by the magnetic sensor array and the theoretical predicted value through an error function, and calculates the three-dimensional position and orientation of the target.

[0078] Specifically, the target is, for example, a capsule. The data processing unit minimizes the deviation between the magnetic field value actually measured by the sensor and the theoretical predicted value through an error function, and finally calculates the three-dimensional position and orientation of the capsule.

[0079] Among them, refer to Figure 4 , define the error function to measure the magnetic field B actually measured by the magnetic sensor array i The magnetic field predicted by theory Deviation between:

[0080]

[0081] The magnetic dipole moment m = (a, b, c) represents the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes respectively; N represents the number of magnetic sensors; and E represents the deviation value.

[0082] Reference Figure 2 This application takes into account that the positioning of the diagnostic electronic capsule is a real-time positioning, which must have definite time information. This also lays the foundation for the subsequent data processing unit to provide correct and effective data information. Therefore, the DS1307 real-time clock chip is selected in the hardware design to obtain valid time information by reading and writing related control words.

[0083] Reference Figure 3 The working process of the magnetic positioning system is as follows: the sensor array collects the magnetic field data of the permanent magnet and obtains the signal representing the magnetic field strength. After the CD4067 analog selection switch (one of the channels is selected for connection through the circuit control signal to realize signal switching and selection, it is often used as a multi-channel signal selector in the signal acquisition system, allowing the system to select one or more sensors from multiple signals for acquisition and processing.), the signal is conditioned (the signal representing the magnetic field strength is very small and susceptible to interference, so it is necessary to consider filtering before acquisition). PGA204 is used as a first-stage amplifier circuit, with an internal integrated subtractor to filter out the DC bias voltage (external interference). PGA205 further amplifies and adjusts (fine-tunes) the signal. In high-precision applications such as medical instruments, multi-stage amplification and calibration are usually required to ensure the accuracy and stability of the signal. Finally, the output signal is converted by the AD module inside the microcontroller (that is, the ADC mentioned in the article, which is responsible for converting the collected analog quantity into digital quantity), and its numerical data is stored in the SD card.

[0084] The embodiments of this specification also provide a method for positioning a permanent magnet target in the gastrointestinal tract, such as Figure 1 , Figure 2 as well as Figure 3 As shown, using any of the above-mentioned positioning systems for permanent magnet targets in the gastrointestinal tract includes the following steps:

[0085] Data measurement steps: measure the magnetic field strength in space through a magnetic sensor array. Specific data collection: collect the magnetic induction intensity generated by the magnetic source through a Hall effect magnetic sensor array arranged in space.

[0086] Processing steps: Collect magnetic field strength data, and then calculate the spatial position and orientation of the target based on the magnetic dipole model and magnetic moment theory using the magnetic moment and magnetic field strength data of the magnetic source.

[0087] In one embodiment, the processing step includes the following steps:

[0088] Control processing steps: synchronously collect magnetic field strength data, and convert the collected magnetic field strength data from analog signals to digital signals. Specific signal processing: the analog signal output by the sensor or sensor array is converted into a digital signal through the ADC module of the control unit and stored in the SD card.

[0089] Storage step: storing the magnetic field strength data converted into digital signals. Specifically, the collected digital signals are stored in an SD card.

[0090] Data processing steps: Calculate the three-dimensional spatial position and azimuth of the target based on the magnetic dipole model and magnetic moment theory. Specific data analysis: After the data collection is completed, the SD card data is imported into the computing device, and based on the magnetic dipole model and magnetic moment theory, the sensor position and the measured magnetic field strength are used to deduce the target position and azimuth.

[0091] In one embodiment, in the data processing step, based on a magnetic field inversion algorithm, the spatial position and attitude information of the magnetic source is iteratively solved by minimizing the error between the measured data and the magnetic dipole model predicted data.

[0092] In one embodiment, the data processing step includes: using a magnetic dipole model to express the magnetic field at any point in space, and deriving the three-dimensional position of the target object; wherein, using the magnetic dipole model, the expression of the magnetic field at any point in space is:

[0093]

[0094] is the unit vector of distance; m is the magnetic dipole moment; is the distance from the magnetic dipole to the sensor; The vector representing the distance; s = (x, y, z) is the spatial coordinate of the sensor; x, y, z are the three coordinate values ​​in the sensor space; B is the magnetic field strength; μ0 is the vacuum permeability. The target is, for example, a capsule.

[0095] The error function is used to minimize the deviation between the measured magnetic field value of the magnetic sensor array and the theoretical predicted value, and the three-dimensional position and orientation of the target are calculated.

[0096] Specifically, the spatial position of the magnetic source is iteratively solved by minimizing the error between the actual magnetic field value measured by the sensor array and the theoretical magnetic field value. The error function is defined to measure the magnetic field B actually measured by the magnetic sensor array. i The magnetic field predicted by theory Deviation between:

[0097]

[0098] Magnetic dipole moment m = (a, b, c) is the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes; N represents the number of magnetic sensors; E represents the deviation value. The target is, for example, a capsule.

[0099] Attitude calculation: The attitude parameters of the target object are calculated through the magnetic field inversion algorithm and the direction of the magnetic moment. The direction of the magnetic dipole moment is used in the derivation to calculate the attitude information of the target object, including: the object orientation derived from the magnetic field strength data measured by the sensor combined with the magnetic dipole model; the attitude parameters of the target object are calculated based on the magnetic moment and the measured magnetic field distribution. The attitude parameter derivation is achieved through the spatial distribution of the magnetic moment direction and the magnetic field strength, and the orientation information is expressed in Euler angles or quaternions.

[0100] The present application provides a method for positioning a permanent magnet target in the gastrointestinal tract, which involves target positioning based on magnetic dipole theory and is suitable for three-dimensional spatial positioning and posture derivation of diagnostic electronic capsules. The system includes a magnetic source composed of permanent magnets, a Hall effect magnetic sensor array, a control unit, a storage module and a data processing unit. Through the magnetic sensor array arranged at a known spatial position, the magnetic induction intensity data generated by the magnetic source is collected, and the magnetic dipole model and magnetic moment theory are used, combined with the spatial position of the sensor, to deduce the target position and orientation, and the magnetic field strength is measured by an external magnetic sensor array to reversely infer the position and orientation of the target, so as to achieve reliable target positioning. The system adopts multi-sensor data fusion technology, which significantly improves the positioning reliability and can be applied to the clinical application of gastrointestinal examination and diagnostic electronic capsules.

[0101] The positioning method of permanent magnet targets in the gastrointestinal tract based on the magnetic dipole model of the present application is applied to the magnetic field positioning system for three-dimensional spatial positioning and posture derivation of diagnostic electronic capsules. The positioning method of diagnostic electronic capsules based on magnetic field sensing of the present application can effectively improve the accuracy of positioning and posture derivation of diagnostic electronic capsules, while achieving efficient data processing and storage to meet the reliability requirements in modern medicine.

[0102] The present invention can accurately calculate the three-dimensional position and posture of the target object by adopting the magnetic dipole model and multi-sensor fusion technology, and is particularly suitable for the positioning of diagnostic and therapeutic electronic capsules in the gastrointestinal tract. The arrangement of multiple Hall effect magnetic sensors ensures the multi-point collection of magnetic field data, and combined with the magnetic field inversion algorithm, the positioning accuracy is significantly improved. The system has high practicality in medical applications, and can obtain the position information of diagnostic and therapeutic electronic capsules in the patient's body in real time, providing reliable technical support for subsequent precision medical diagnosis and treatment. The present application has certain advantages in improving the positioning and posture derivation accuracy of diagnostic and therapeutic electronic capsules, and has broad application prospects.

[0103] The embodiments of this specification also provide a design of a positioning system for a permanent magnet target in the gastrointestinal tract, and introduce a three-dimensional positioning system for a gastrointestinal tract diagnosis and treatment electronic capsule based on a permanent magnet and its implementation method. The arrangement of the system is as follows:

[0104] Design and configuration of magnetic source: The magnetic source of this system uses one or more permanent magnets, which are placed in the gastrointestinal diagnostic and therapeutic electronic capsule. The magnetic dipole moment vector of each permanent magnet is known, and its direction and magnitude are determined by the position of the capsule and the physical properties of the magnetic moment. The selection of permanent magnets takes into account the following factors: Stability and reliability of the magnetic source: Neodymium iron boron (NdFeB) magnets are selected, which have strong magnetic field strength and stable magnetism to ensure that the magnetic field in the body is not easily disturbed by the outside world. The size and weight of the permanent magnet: To ensure the normal movement of the capsule in the gastrointestinal tract, the permanent magnet is small in size and light in weight to avoid additional burden on the patient.

[0105] Arrangement of magnetic sensor array: The system uses a Hall effect magnetic sensor array to collect the magnetic field generated by the permanent magnet. The sensor array consists of multiple sensors, each of which is installed at a known spatial coordinate position and can measure different components of the magnetic field separately. The arrangement of sensors takes into account the spatial coverage and data accuracy, including: Spatial distribution: The sensor array is installed around the patient's body, and the spatial position of each sensor is known to ensure that the complete distribution information of the magnetic field can be collected. Number of sensors: Multiple sensors (such as 15 Hall effect sensors) are selected, each of which can measure the magnetic field strength at different points in three-dimensional space, providing sufficient data to achieve accurate calculation of the position of the permanent magnet.

[0106] Control unit and signal acquisition: The control unit is composed of a microprocessor (such as PIC18F4520), which is used to receive the output signal of the magnetic sensor array and convert the analog signal into a digital signal through its built-in ADC module.

[0107] Synchronous signal acquisition: The microprocessor is responsible for coordinating the signal acquisition of multiple sensors to ensure that the data of all sensors are acquired at the same time point to avoid data errors caused by asynchrony.

[0108] Data storage: The digital signal of the control unit is stored through the SD card storage module. The SD card is used to save a large amount of data generated during long-term monitoring and facilitate subsequent data processing.

[0109] Data processing and position derivation: After data collection is completed, the data in the SD card is imported into an external computing device (such as a PC), and the three-dimensional position and orientation of the target object are deduced based on the magnetic dipole model and magnetic moment theory.

[0110] Magnetic dipole model: The system uses the magnetic dipole model to calculate the magnetic field distribution of the magnetic field source at any point in space. The expression of the magnetic field at any point in space is:

[0111]

[0112] in, is the unit vector of distance; is the distance from the magnetic dipole to the sensor, m = (a, b, c) represents the magnetic dipole moment, and is the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes respectively.

[0113] Error minimization: Through the magnetic field inversion algorithm, the measured magnetic field strength is compared with the theoretically predicted magnetic field, and the spatial position and attitude of the magnetic source are iteratively solved using the method of minimizing the error. The error function is defined as:

[0114]

[0115] Where N is the number of sensors, B measured，i is the magnetic field measured by the i-th sensor, B calculated，i is the magnetic field calculated according to the magnetic dipole model.

[0116] Attitude derivation: After obtaining the position of the target object, the system can also deduce the attitude of the target object based on the direction of the magnetic moment. The attitude parameters are derived through the magnetic field distribution and magnetic moment direction measured by the sensor. The specific steps are as follows:

[0117] Azimuth calculation: The azimuth of the target object is calculated through the relationship between the magnetic moment and the magnetic field strength.

[0118] Posture parameter derivation: The posture information is represented in the form of Euler angles or quaternions, which are further used for display and analysis in medical images.

[0119] The embodiments of this specification also provide experimental verification of the application of the positioning system based on the magnetic dipole model to the electronic capsule. To verify the effectiveness of the system, the system is applied to the electronic capsule positioning experiment in a simulated gastrointestinal environment in this embodiment. The experimental device includes a capsule equipped with a neodymium iron boron permanent magnet, a Hall effect magnetic sensor array, and a data processing device. The experimental steps are as follows:

[0120] Capsule motion trajectory design: In the experiment, a capsule was designed to move along the gastrointestinal tract, with a permanent magnet embedded inside the capsule. The capsule moves along a predetermined trajectory, and the sensor array collects the magnetic field changes generated during the capsule's movement.

[0121] Magnetic field data acquisition: The Hall effect magnetic sensor array is installed outside the experimental device and arranged along the capsule movement path. The magnetic field data collected by each sensor is synchronously processed by the microprocessor and stored in the SD card. The frequency of data acquisition is set to 10Hz to ensure sufficient time resolution.

[0122] Data processing and result verification: After the experiment, the collected data were imported into the PC, and the three-dimensional position of the capsule during movement was derived using the magnetic dipole model and inversion algorithm.

[0123] By comparing with the actual trajectory, it is verified whether the experimental results meet the needs of clinical applications.

[0124] The present specification also provides an application of the system in actual medical treatment, and introduces the operation process of the system in actual gastrointestinal examination:

[0125] Patient preparation: Before the gastrointestinal examination, the patient wears an electronic capsule with a permanent magnet. After the capsule enters the gastrointestinal tract, the magnetic field sensor collects the position changes of the capsule in the gastrointestinal tract.

[0126] Data collection and analysis: The sensor collects the magnetic field data generated by the capsule in real time and stores the data in the SD card. After the inspection, the data is imported into an external device for 3D positioning and posture derivation.

[0127] Result display and diagnosis: Through data processing and posture deduction, doctors can observe the movement path of the capsule in three-dimensional images and conduct a more detailed analysis of internal lesions of the gastrointestinal tract.

[0128] The present application provides a target object positioning system in the gastrointestinal tract based on a magnetic dipole model. As a diagnostic electronic capsule positioning system based on a magnetic dipole model, it includes a magnetic field positioning system, which is applied to the three-dimensional spatial positioning and posture derivation of the diagnostic electronic capsule. It can significantly improve the positioning reliability of the diagnostic electronic capsule and has important application value in medical imaging and precision diagnosis.

[0129] In this specification, the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and the relevant parts can be referred to the partial description of the previous embodiments.

[0130] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A positioning system for a permanent magnet target in the gastrointestinal tract, characterized in that: It includes a magnetic source, a magnetic sensor array and a processing module; The magnetic source is used to generate a magnetic field; The magnetic sensor array is used to measure the magnetic field strength in space; The processing module collects magnetic field strength data, and then calculates the spatial position and orientation of the target based on the magnetic dipole model and magnetic moment theory using the magnetic moment and magnetic field strength data of the magnetic source.

2. The positioning system for permanent magnet targets in the gastrointestinal tract according to claim 1, characterized in that: The processing module includes a control unit, a storage unit and a data processing unit; The magnetic sensor array includes a plurality of Hall effect magnetic sensors installed at spatial coordinate positions, and the plurality of Hall effect magnetic sensors are used to respectively measure magnetic field intensity components at different spatial coordinate positions; The control unit synchronously collects magnetic field strength data, and converts the collected magnetic field strength data into digital signals; The storage module stores the magnetic field strength data converted into digital signals; The data processing unit calculates the three-dimensional spatial position and azimuth of the target based on the magnetic dipole model and magnetic moment theory.

3. The positioning system for permanent magnet targets in the gastrointestinal tract according to claim 2, characterized in that: The magnetic source includes at least one permanent magnet; the direction and magnitude of the magnetic dipole moment vector of the permanent magnet are used to calculate the orientation and position of the target; The magnetic field intensity component is used to infer the position of the magnetic source and the direction of the magnetic dipole moment.

4. The positioning system for permanent magnet targets in the gastrointestinal tract according to claim 2, characterized in that: The data processing unit is based on a magnetic field inversion algorithm and iteratively solves the spatial position and attitude information of the magnetic source by minimizing the error between the measured data and the magnetic dipole model predicted data.

5. The positioning system for permanent magnet targets in the gastrointestinal tract according to claim 4, characterized in that: The data processing unit uses a magnetic dipole model to express the magnetic field at any point in space and derive the three-dimensional position of the target object; Among them, using the magnetic dipole model, the expression of the magnetic field at any point in space is: is the unit vector of distance; m is the magnetic dipole moment; is the distance from the magnetic dipole to the sensor; The vector representing the distance; s = (x, y, z) is the spatial coordinate of the sensor; x, y, z are the three coordinate values ​​of the sensor space; B is the magnetic field strength; μ0 is the vacuum permeability.

6. The positioning system for permanent magnet targets in the gastrointestinal tract according to claim 5, characterized in that: The data processing unit minimizes the deviation between the magnetic field value actually measured by the magnetic sensor array and the theoretical predicted value through an error function, and calculates the three-dimensional position and orientation of the target; The error function is defined to measure the magnetic field B actually measured by the magnetic sensor array. i The magnetic field predicted by theory Deviation between: The magnetic dipole moment m = (a, b, c) is the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes respectively; N represents the number of magnetic sensors; and E represents the deviation value.

7. A method for positioning a permanent magnet target in the gastrointestinal tract, characterized in that: The positioning system for a permanent magnet target in the gastrointestinal tract according to any one of claims 1 to 6 comprises the following steps: Data measurement steps: measuring the magnetic field strength in space through a magnetic sensor array; Processing steps: Collect magnetic field strength data, and then calculate the spatial position and orientation of the target based on the magnetic dipole model and magnetic moment theory using the magnetic moment and magnetic field strength data of the magnetic source.

8. The method for positioning a permanent magnet target in the gastrointestinal tract according to claim 7, characterized in that: The processing steps include the following steps: Control processing steps: synchronously collect magnetic field strength data, and convert the collected magnetic field strength data into analog signals to digital signals; Storing step: storing the magnetic field strength data converted into digital signals; Data processing steps: Calculate the three-dimensional spatial position and azimuth of the target based on the magnetic dipole model and magnetic moment theory.

9. The method for positioning a permanent magnet target in the gastrointestinal tract according to claim 8, characterized in that: In the data processing step, based on the magnetic field inversion algorithm, the spatial position and attitude information of the magnetic source are iteratively solved by minimizing the error between the measured data and the magnetic dipole model predicted data.

10. The method for positioning a permanent magnet target in the gastrointestinal tract according to claim 9, characterized in that: The data processing step includes: using a magnetic dipole model to express the magnetic field at any point in space and deriving the three-dimensional position of the target object; Among them, using the magnetic dipole model, the expression of the magnetic field at any point in space is: is the unit vector of distance; m is the magnetic dipole moment; is the distance from the magnetic dipole to the sensor; The vector representing the distance; s = (x, y, z) is the spatial coordinate of the sensor; x, y, z are the three coordinate values ​​of the sensor space; B is the magnetic field strength; μ0 is the vacuum permeability; The error function is used to minimize the deviation between the magnetic field value measured by the magnetic sensor array and the theoretical predicted value, and the three-dimensional position and orientation of the target are calculated; The error function is defined to measure the magnetic field B actually measured by the magnetic sensor array. i The magnetic field predicted by theory Deviation between: The magnetic dipole moment m = (a, b, c) is the orientation of the target; a, b, c represent the projection components of the magnetization direction of the permanent magnet on the three coordinate axes respectively; N represents the number of magnetic sensors; and E represents the deviation value.

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