CN114532943B - Positioning system and computer equipment of wireless capsule endoscope based on magnetic drive - Google Patents
Positioning system and computer equipment of wireless capsule endoscope based on magnetic drive Download PDFInfo
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- CN114532943B CN114532943B CN202210268943.7A CN202210268943A CN114532943B CN 114532943 B CN114532943 B CN 114532943B CN 202210268943 A CN202210268943 A CN 202210268943A CN 114532943 B CN114532943 B CN 114532943B
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
- A61B1/00147—Holding or positioning arrangements
- A61B1/00158—Holding or positioning arrangements using magnetic field
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
- A61B1/00064—Constructional details of the endoscope body
- A61B1/00105—Constructional details of the endoscope body characterised by modular construction
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
- A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
- A61B1/041—Capsule endoscopes for imaging
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
- A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
- A61B1/273—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor for the upper alimentary canal, e.g. oesophagoscopes, gastroscopes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/005—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 with correlation of navigation data from several sources, e.g. map or contour matching
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
- A61B2560/04—Constructional details of apparatus
- A61B2560/0462—Apparatus with built-in sensors
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0219—Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/06—Arrangements of multiple sensors of different types
- A61B2562/066—Arrangements of multiple sensors of different types in a matrix array
Abstract
The application is applicable to the technical field of medical equipment, and provides a positioning system of a wireless capsule endoscope based on magnetic drive and computer equipment, wherein the computer equipment is used for executing the following operations: receiving magnetic field data measured by an external sensor array and biaxial rotation data measured by an inertial sensor inside the capsule; calculating a capsule magnetic field theoretical value on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array; calculating a theoretical value of the driver magnetic field at each sensor based on the position data of the extracorporeal driver and the external sensor array; calculating capsule magnetic field components generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the theoretical value of the magnetic field of the driver; and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component, thereby realizing the real-time and accurate positioning of the wireless capsule endoscope.
Description
Technical Field
The application belongs to the technical field of medical equipment, and particularly relates to a positioning system of a wireless capsule endoscope based on magnetic driving and computer equipment.
Background
The wireless capsule endoscope technology is used for complete digestive tract examination and has the characteristics of no pain, no invasion and the like. The wireless capsule endoscope is a capsule-like micro-robot, and is provided with an illumination module, a camera module, an image processing module, a wireless transmission module, and the like. After swallowed by a patient and entering the digestive tract of a human body, the wireless capsule endoscope can shoot images in vivo and transmit the images to the outside of the body in real time. A doctor or a computer can make a disease diagnosis based on the received image.
In the process of using the wireless capsule endoscope to carry out the digestive tract examination, the wireless capsule endoscope is accurately positioned in real time, and the correctness of the final diagnosis result is ensured. In general, a six-dimensional pose consisting of a three-dimensional position and a three-dimensional rotation of the wireless capsule endoscope can be used to describe the precise location of the wireless capsule endoscope in the alimentary tract. However, in the prior art, the real-time positioning of the wireless capsule endoscope is usually only capable of solving five-dimensional poses of the wireless capsule endoscope at most. For example, in the positioning technology of the wireless capsule endoscope based on magnetic driving, an external permanent magnet is used for driving the wireless capsule endoscope embedded with a permanent magnet, then the superposed magnetic field of the external permanent magnet and the permanent magnet in the capsule is measured through a magnetic sensor, and then the real-time five-dimensional pose of the wireless capsule endoscope is obtained through calculation. Some researchers estimate the advancing direction of the wireless capsule endoscope by adopting a five-dimensional pose sequence measured within a period of time so as to obtain the six-dimensional pose of the wireless capsule endoscope, but the method cannot intuitively obtain the three-dimensional rotation of the wireless capsule endoscope relative to a world coordinate system at each moment, and because the measured value within a period of time is required to estimate the sixth-dimensional pose, the positioning frequency of the wireless capsule endoscope is greatly reduced, and the adverse effect on the digestive tract examination is easily brought. Therefore, in the course of using the wireless capsule endoscope to perform the alimentary canal examination, how to accurately estimate the six-dimensional pose of the wireless capsule endoscope in real time is a difficult problem to be solved urgently by those skilled in the art.
Disclosure of Invention
In view of this, the present application provides a positioning system and a computer device for a wireless capsule endoscope based on magnetic driving, so as to estimate the six-dimensional pose of the wireless capsule endoscope during the examination of the digestive tract, and realize real-time and accurate positioning of the wireless capsule endoscope.
A first aspect of the application provides a magnetically-driven wireless capsule endoscope-based positioning system, the system comprising a wireless capsule endoscope, an extracorporeal driver, an external sensor array, and a computer device communicatively connected to the wireless capsule endoscope, the extracorporeal driver, and the external sensor array, respectively; wherein, permanent magnets are respectively arranged in the wireless capsule endoscope and the extracorporeal driver, and an inertial sensor is also arranged in the wireless capsule endoscope; the computer device is configured to perform the following operations:
receiving magnetic field data measured by the external sensor array and biaxial rotation data of the wireless capsule endoscope measured by the inertial sensor during the process that the extracorporeal driver drives the wireless capsule endoscope to move;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
A second aspect of the present application provides a magnetically-driven wireless capsule endoscope-based positioning device, comprising:
the measurement data receiving module is used for receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope in the process of driving the wireless capsule endoscope to move by an extracorporeal driver;
a position data determination module for determining position data of the extracorporeal driver and the external sensor array, respectively;
the capsule magnetic field theoretical value calculation module is used for calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
a driver magnetic field theoretical value calculation module, configured to calculate a driver magnetic field theoretical value of a permanent magnet embedded in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
a capsule magnetic field component calculation module for calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and the six-dimensional pose solving module is used for solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
A third aspect of the application provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor when executing the computer program implementing the following operations:
in the process that an external driver drives a wireless capsule endoscope to move, receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
A fourth aspect of the present application provides a computer-readable storage medium storing a computer program which, when executed by a processor, performs the operations of:
in the process that an external driver drives a wireless capsule endoscope to move, receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
A fifth aspect of the present application provides a computer program product which, when run on a computer, causes the computer to perform the operations of:
in the process that an external driver drives a wireless capsule endoscope to move, receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
Compared with the prior art, the method has the following advantages:
according to the method, the external sensor array is adopted for measuring magnetic field data, the inertial sensor arranged in the wireless capsule endoscope is adopted for measuring biaxial rotation data, the capsule magnetic field component generated by the permanent magnet arranged in the wireless capsule endoscope is extracted by calculating the magnetic field theoretical value of the permanent magnet in the external driver and the magnetic field theoretical value of the permanent magnet arranged in the wireless capsule endoscope on each sensor of the external sensor array, so that the six-dimensional pose of the wireless capsule endoscope can be accurately estimated, the high-precision and high-update-rate positioning can be realized in a larger three-dimensional working space, and the real-time performance and the accuracy of the positioning are ensured.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the embodiments or the description of the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a schematic diagram of a positioning system for a magnetically driven wireless capsule endoscope according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a wireless capsule endoscope provided by an embodiment of the present application;
FIG. 3 is a schematic diagram of a positioning algorithm for a wireless capsule endoscope based on magnetic drive provided by an embodiment of the present application;
FIG. 4 is a schematic diagram of the position of an extracorporeal driver and a wireless capsule endoscope provided by an embodiment of the present application relative to a world coordinate system;
FIG. 5 is a schematic diagram of a magnetic field model and sensor measurement for positioning according to an embodiment of the present disclosure;
FIG. 6 is a schematic diagram of a positioning device of a wireless capsule endoscope based on magnetic drive provided by an embodiment of the application;
fig. 7 is a schematic diagram of a computer device according to an embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
The technical solution of the present application will be described below by way of specific examples. It should be noted that, in the embodiments of the present application, when a "capsule" is referred to separately, the "capsule" is referred to as a "wireless capsule endoscope".
Referring to fig. 1, a schematic diagram of a positioning system of a magnetic drive-based wireless capsule endoscope is shown, which includes a examining table, a mechanical arm, a wireless capsule endoscope, an extracorporeal drive, an external sensor array, and a computer device.
Wherein the robotic arm is positioned near the examination couch and the end effector thereof may be used to mount an extracorporeal drive. The extracorporeal driver may be located over the examination bed and consists of a cylindrical permanent magnet wrapped in a spherical plastic casing. The plastic shell and the permanent magnet, and the mechanical arm end effector and the external driver can be rigidly connected. The structures may be rigidly connected, for example, by means of 3D printing.
As shown in fig. 2, which is a schematic view of a wireless capsule endoscope provided in an embodiment of the present application, the wireless capsule endoscope shown in fig. 2 is further provided with a cylindrical permanent magnet and an inertial sensor (IMU) in addition to a conventional camera module, an illumination module, a wireless communication module, a microprocessor module, and a button battery. The inertial sensor can be used for estimating two-degree-of-freedom rotation of the capsule in the human body relative to a fixed world coordinate system to obtain two-axis rotation data. In the embodiment of the application, the magnetizing direction of the permanent magnet arranged in the capsule can be consistent with the geometric axis direction of the capsule.
In the present embodiment, the external sensor array may be located below and on both sides of the examination table. As shown in fig. 1, the external sensor arrays under and on both sides of the examination bed may be a single-layer or multi-layer planar structure, each external sensor array includes a plurality of sensors, and the plurality of sensors of each external sensor array are arranged in a matrix. For example, each external sensor array under and on both sides of the examination bed comprises 100 sensors, which may be arranged in a 10 × 10 matrix. These sensors are magnetic sensors that can be used to measure three-dimensional magnetic field data at their location.
As shown in fig. 1, the external sensor arrays on both sides of the examination table may be mounted on a guide rail, by which the distance between the external sensor arrays on both sides of the examination table may be adjusted. For example, the distance between the external sensor arrays on the two sides can be reduced by moving the external sensor arrays on the two sides to the middle of the examination bed through the guide rails; on the contrary, the external sensor arrays on the two sides are moved to the outside of the examining table through the guide rail, so that the distance between the external sensor arrays on the two sides can be increased. Like this, can adjust external sensor array's three-dimensional workspace to adapt to the patient of different sizes, guarantee that external sensor array's workspace can cover patient's whole abdominal region.
As shown in fig. 1, the system further includes a computer device, which can be connected to the examining table, the mechanical arm, the wireless capsule endoscope, the extracorporeal driver, and the external sensor array in a communication manner, and the computer device can be operated by a worker to send a control command to the mechanical arm, collect and process position tracking data of the mechanical arm, magnetic field data measured by the external sensor array, biaxial rotation data measured by the inertial sensor in the capsule, and the like, and calculate and display a real-time positioning tracking result of the capsule based on the above data.
In the embodiment of the application, relevant programs and algorithms of magnetic driving and magnetic positioning can be stored in computer equipment, real-time driving control and real-time six-dimensional pose estimation are carried out on the capsule through modeling of a superposed magnetic field of a permanent magnet arranged in an extracorporeal driver and a permanent magnet driven in the capsule and combining a nonlinear least square optimization algorithm with boundary constraint, and the real-time accurate positioning of the six degrees of freedom of the wireless capsule endoscope is realized.
Specifically, referring to fig. 3, a schematic diagram of a positioning algorithm of a wireless capsule endoscope based on magnetic drive provided by an embodiment of the present application is shown, and the computer device in fig. 1 can output an accurate six-dimensional pose of the wireless capsule endoscope in real time by executing the algorithm flow shown in fig. 3.
The following describes in detail a process of outputting an accurate six-dimensional pose of the wireless capsule endoscope in real time by the computer device executing the algorithm flow with reference to the algorithm flow shown in fig. 3.
In the embodiment of the present application, before executing the algorithm flow shown in fig. 3, the computer device may first construct a world coordinate system for subsequent position data acquisition.
Fig. 4 is a schematic diagram showing a position of an extracorporeal driver and a wireless capsule endoscope provided by an embodiment of the present application relative to a world coordinate system. In FIG. 4, the world coordinate system { W } may be first defined as the robot arm base center, and the six-dimensional pose of the capsule may be defined by the three-dimensional position
And a three-dimensional rotation matrix R c And epsilon SO (3). Wherein R is c May include a first angle, a second angle, and a third angle. The first, second and third angles may be defined by angles alpha, beta of the capsule coordinate system sequentially rotated around the x-axis, y-axis and z-axis of the world coordinate system,
expressed as: r c = Rot (z, γ) Rot (y, β) Rot (x, α). Because the inertial sensor built in the capsule can measure the accurate two-dimensional direction angle (beta) in real time, the unknown quantity of the pose of the capsule is the three-dimensional position p c And the direction angle γ, containing four unknown parameters. Assuming that the magnetic moment direction of the capsule coincides with the z-axis of its own coordinate system, the magnetic moment direction of the capsule can be obtained from the above parameters.
On the other hand, for the established world coordinate system { W }, the computer device may determine the position data of the extracorporeal driver and the external sensor array, respectively, i.e., the position data of each sensor of the extracorporeal driver and the external sensor array, respectively, in the world coordinate system.
In the present embodiment, it is assumed that the external sensor array shown in fig. 1 includes N sensors in totalSensors, the position data of each sensor in the world coordinate system can be expressed as (p) 1 ,…,p N ). Since a spherical extracorporeal drive of known dimensions is rigidly connected to the robotic arm's end-effector, and the default robotic arm can estimate the position and orientation of the end-effector in real-time through a known forward kinematics model, the six-dimensional pose (p) of the extracorporeal drive can be considered a ,R a ) Can also be measured in real time, the six-dimensional pose (p) a ,R a ) I.e. the position data of the extracorporeal drive in the world coordinate system.
In an embodiment of the application, the computer device may receive magnetic field data measured by the external sensor array and biaxial rotation data of the wireless capsule endoscope measured by the inertial sensor during the process that the extracorporeal driver drives the wireless capsule endoscope to move.
The magnetic field data may refer to magnetic field data actually measured by each sensor in the external sensor array. Since the external sensor array shown in fig. 1 includes N sensors in total, the position of each sensor in the world coordinate system is (p) 1 ,…,p N ) Then the magnetic field data measured by the external sensor array can be represented as the matrix B = [ B ] 1 ,…,b N ]. Each value in the matrix B is a reading of the sensor at each location. The two-axis rotation data is a two-dimensional direction angle (alpha, beta), which can be directly measured by an inertial sensor built in the capsule.
As shown in FIG. 3, the computer device may be configured to determine the position data (p) of the external sensor array based on the two-axis rotation data (α, β) measured by the inertial sensor and the position data (α, β) of the external sensor array 1 ,…,p N ) And calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array.
In a specific implementation, due to the position (p) of each sensor in the world coordinate system 1 ,…,p N ) As known, the theoretical magnetic field of the permanent magnet in the capsule on the ith sensor can be calculated according to a magnetic dipole model
The combination of the theoretical values of the magnetic field of the permanent magnets in the capsule on the N sensors can then be represented as a matrix B c (p c ,γ；α,β)＝[b c1 ,…,b cN ]。
On the other hand, the computer device may also be based on position data (p) of the extracorporeal drive a ,R a ) And position data (p) of the external sensor array 1 ,…,p N ) And calculating the theoretical value of the magnetic field of the driver on each sensor of the external sensor array by the permanent magnet built in the external driver.
In the concrete implementation, the theoretical magnetic field b of the permanent magnet in the in-vitro driver on the ith sensor can be obtained according to the magnetic dipole model under the assumption that the magnetic moment direction of the permanent magnet in the in-vitro driver is coincident with the z-axis of the self coordinate system ai Further, it can be found that the combination of the magnetic field theoretical values of the permanent magnet embedded in the extracorporeal driver on the N sensors can be expressed as a matrix B a ＝[b a1 ,…,b aN ]。
Typically, in practical applications, there is a certain magnetic field in the environment, and each sensor in the external sensor array has a range limitation and is noisy, which factors have a non-negligible impact on the capsule positioning algorithm. In particular, on the one hand, the earth magnetic field and other magnetic sources may exist in the application environment, and therefore, the measurement estimation of the environmental magnetic field needs to be performed in advance, and the sensor data needs to be preprocessed to remove the environmental magnetic field. On the other hand, because the volume of the permanent magnet built in the extracorporeal driver is much larger than that of the permanent magnet in the capsule, when the extracorporeal driver is closer to the external sensor array, the part of the sensors closest to the extracorporeal driver may be saturated, resulting in inaccurate magnetic field measurement values. Furthermore, since the sensors inevitably have noise and limited resolution, sensors located at a greater distance from the capsule may not be able to acquire a sufficient signal-to-noise ratio to obtain an effective measurement of the capsule magnetic field. Therefore, to ensure that the six-dimensional pose of the capsule is calculated using sensor data that is not saturated and has a sufficient signal-to-noise ratio, it is necessary to identify and remove saturated sensor data as well as capsule magnetic field measurement data that is below the sensor noise. In view of the above, the embodiments of the present application may perform pre-processing and post-processing on the magnetic field data measured by the multi-layer stereo external sensor array. The magnetic field data are preprocessed to remove the influence of the geomagnetic field and other magnetic sources on the measurement data in the application environment, and the magnetic field data are post-processed to remove the influence of the noise of the sensor on the subsequent positioning.
In embodiments of the present application, the pre-processing of the magnetic field data by the computer device may be done prior to receiving the magnetic field data measured by the external sensor array and the two-axis rotation data of the wireless capsule endoscope measured by the inertial sensor.
In response to the problem of geomagnetic fields and other magnetic sources that may be present in the application environment, the extracorporeal driver and wireless capsule endoscope may first be removed from the current workspace. Then, the control starts the external sensor array and receives the data B measured by the external sensor array env And calculating an environment magnetic field estimation value. When the extracorporeal driver and the wireless capsule endoscope are located in the working space, after the computer device receives the magnetic field data measured by the external sensor array, the computer device can subtract the environmental magnetic field estimated value by using the received magnetic field data to obtain new magnetic field data.
Illustratively, during endoscopy using a wireless capsule, it is assumed that the magnetic field data returned by the external sensor array at any time is the matrix B = [ B ] 1 ,…,b N ],
The ambient magnetic field B is subtracted from B env Is used as new magnetic field data B ← B-B env And a subsequent positioning algorithm is performed using the new magnetic field data.
Aiming at the problem that the part of the sensors closest to the extracorporeal drive can reach saturation, so that the measured value of the magnetic field is inaccurate, the computer device can respectively calculate the measured magnetic field data of each sensor aiming at each sensor of the external sensor array; if the magnetic field data measured by any sensor is larger than the preset magnetic field value, the magnetic field data measured by the sensor can be deleted. The size of the preset magnetic field value can be determined according to the measuring range of the sensor.
Illustratively, assume the sensor range is b max The magnetic field data returned by the external sensor array at any moment is a matrix B = [ B = [ [ B ] 1 ,…,b N ]Then for i e {1, \8230;, N }, we can calculate | b i Value of |, b i ‖≥b max The column measurement B is removed from the matrix B i Therefore, saturated sensor measurement data are removed, and the accuracy of magnetic field measurement data used for a subsequent algorithm is improved. As shown in fig. 1, because the multi-layer three-dimensional sensor array is used in the embodiment of the present application, when a capsule is close to a sensor array on one side and is saturated, sensors on a lower layer and other planes which are not saturated can still provide accurate magnetic field measurement results, so that effective positioning in a larger three-dimensional working space can be realized.
Fig. 5 is a schematic diagram of a magnetic field model and a sensor measurement for positioning according to an embodiment of the present disclosure. In FIG. 5, b total For the magnetic field data actually measured by a sensor in the external sensor array, the data being represented by the magnetic field b a And b c And (4) superposing to obtain the product. Wherein, b a Representing the magnetic field generated by a permanent magnet in an extracorporeal drive, b c Representing the magnetic field generated by the permanent magnet within the capsule. As can be seen from fig. 5, the magnetic field data measured by each sensor in the external sensor array is the result of the vector superposition of the magnetic field generated by the permanent magnet in the extracorporeal drive and the magnetic field generated by the permanent magnet in the capsule, i.e.: b is a mixture of total ＝b a +b c 。
Therefore, in order to accurately calculate the magnitude of the magnetic field generated at each sensor by the permanent magnet inside the capsule, it is necessary to remove the magnetic field component generated by the permanent magnet driven outside the body from the magnetic field data measured by the sensors, thereby extracting the capsule magnetic field component.
In the embodiment of the present application, the computer device may determine B = [ B ] from magnetic field data measured by the external sensor array 1 ,…,b N ]And driveTheoretical value of actuator magnetic field B a ＝[b a1 ,…,b aN ]And calculating capsule magnetic field components generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data.
In a specific implementation, for each sensor of the external sensor array, the magnetic field data measured by each sensor is respectively subtracted by the theoretical value of the magnetic field of the driver corresponding to the sensor, so as to obtain the capsule magnetic field component generated at each sensor by the permanent magnet built in the wireless capsule endoscope.
Illustratively, the magnetic field data returned by the external sensor array is the matrix B = [ B ] 1 ,…,b N ]And the capsule magnetic field component B 'in the magnetic field data' c It can be obtained by subtracting the theoretical value of the magnetic field of the extracorporeal drive from the total measurement, namely: b' c ＝B-B a ＝[b 1 ,…,b N ]-[b a1 ,…,b aN ]＝[b c1 ′,…,b cN ′]。
As previously mentioned, sensors that are located at a greater distance from the capsule may also fail to acquire a sufficient signal-to-noise ratio to obtain an effective measurement of the capsule's magnetic field due to the inevitable noise they have and the limited resolution. Thus, the influence of sensor noise on the positioning process can be removed by post-processing the magnetic field data measured by the external sensor array.
In an embodiment of the present application, the computer device may determine a noise value of the sensor, and then for each sensor of the external sensor array, if a capsule magnetic field component generated by the permanent magnet within the capsule at a certain sensor is less than or equal to the noise value, the capsule magnetic field component corresponding to the sensor may be deleted.
Illustratively, assume the sensor noise is b noise The measured value of the capsule magnetic field component extracted by the processing at any time is B' c ＝[b c1 ′,…,b cN ′]Then for i e {1, \8230;, N }, i | b can be calculated ci Value of' | l, if b | | | ci ′||≤b noise Then can be from matrix B' c In which the column of measured values b is removed ci ', wherebyAnd the capsule magnetic field measurement data with low signal-to-noise ratio is removed, and the accuracy of the magnetic field measurement data for the subsequent algorithm is improved.
As shown in fig. 3, after the theoretical value of the capsule magnetic field is obtained by calculation using the magnetic dipole model and the component of the capsule magnetic field is accurately calculated through the processes of preprocessing, post-processing and the like, the computer device can solve the six-dimensional pose of the wireless capsule endoscope based on the theoretical value of the capsule magnetic field and the component of the capsule magnetic field.
In the embodiment of the application, the six-dimensional pose of the wireless capsule endoscope is formed by three-dimensional positions
And a three-dimensional rotation matrix R c And epsilon SO (3). Wherein R is c The biaxial rotation data in the element of SO (3) is measured by an inertial sensor in the capsule, and the solution of the six-dimensional pose of the wireless capsule endoscope can be regarded as the solution of unknown parameters in the six-dimensional pose, namely the three-dimensional position p c And an orientation angle gamma. Wherein, the direction angle gamma is the angle of the wireless capsule endoscope rotated around the z axis of the world coordinate system by the capsule coordinate system. The unknown parameters and biaxial rotation data obtained by the measurement of the inertial sensor jointly form a real-time six-dimensional pose of the wireless capsule endoscope.
In the embodiment of the application, the unknown parameters in the six-dimensional pose of the wireless capsule endoscope can be solved by adopting a least square method based on the capsule magnetic field theoretical value and the capsule magnetic field component. I.e. minimizing the sum of the squares of the errors between the magnetic field data measured by the external sensor array and the theoretical magnetic field values.
In specific implementation, the following formula can be adopted to solve the unknown variable p in the six poses of the capsule c ,γ：
In practical application, because the capsule is positioned in a human body, the possible positions of the capsule have a certain range, in order to avoid obtaining a solution which is not in line with practical limiting conditions by adopting a least square method and improve the safety of a system, the problem can be modeled into a nonlinear optimization problem with boundary constraint.
In embodiments of the present application, boundary constraints for three-dimensional locations may be determined, which may be related to the workspace size of the wireless capsule endoscope. The above-mentioned working space may be a volume space sufficient to cover the entire abdominal region of the patient under examination, i.e. the capsule may only be present in this volume space. Specifically, a cubic area may be selected as the working space according to the body size of the patient. The working space is set, so that the solution of the positioning algorithm can be facilitated, the solution range is reduced, the problem that the wrong solution is easy to occur is prevented, and the safety of the system is improved.
Then, the computer equipment can solve the capsule magnetic field theoretical value and the capsule magnetic field component by adopting a least square method based on the determined boundary constraint condition to obtain the optimal estimation of the unknown parameters. That is, the optimal estimate for the unknown parameters can be modeled as a non-linear optimization problem with boundary constraints:
s.t.p c ∈S,
wherein, the first and the second end of the pipe are connected with each other,
the working space is set manually, and the numerical size can be specifically determined by combining the body size of the patient and the external sensor array.
By solving the above nonlinear least squares estimation problem with boundary constraint, p can be obtained c Optimal estimation of gammaAnd the accurate six-dimensional pose of the infinite capsule endoscope in the human body is obtained.
In the embodiment of the present application, since the direction angle γ is a function with a period of 2 π, after solving the direction angle γ, it can be transformed into a main period of (- π, π).
According to the embodiment of the application, the internal inertial measurement positioning and the external magnetic positioning are combined, wherein the internal positioning only adopts a miniature low-power-consumption inertial sensor to provide two-axis rotation data, and the power consumption is far lower than that of a common internal positioning mechanism, so that the volume and the weight of a capsule are reduced, the internal space of the capsule is saved, and the utilization rate of a battery is improved; the external positioning adopts a large multilayer three-dimensional sensor array arranged below and on two sides of the examining table, the structure is simple and easy to install, a large and adjustable three-dimensional working space can be provided, an examinee is not required to be placed in a fixed sensor array structure, adverse effects on the magnetic driving and the examining process of the capsule can be avoided, and the real-time accurate positioning in the large working space can be realized.
Secondly, in the positioning system provided by the embodiment of the application, the mechanical arm operates the spherical external driver, the capsule is controlled to move in the body by changing the magnetic field of the permanent magnet in the external driver, the device is very simple and easy to install, and compared with the driving device depending on the electromagnetic coil in the prior art, the device is smaller and lighter, and can provide larger working space; the spherical surface is also more suitable for contacting with the body surface of a patient, and the safety risk is reduced.
Thirdly, the embodiment of the application establishes a mathematical model for the magnetic field of the permanent magnet of the external driver and the magnetic field of the passive magnet in the capsule, controls the capsule by the permanent magnet of the external driver, senses the superimposed magnetic field by the external sensor array, senses the rotation of the capsule by the inertial sensor in the capsule, and carries out real-time six-dimensional pose positioning on the capsule by a nonlinear optimization algorithm, thereby not only ensuring that the positioning algorithm is not influenced by the driving magnetic field, but also ensuring that the positioning result is more intuitive and realizing higher positioning frequency.
Referring to fig. 6, a schematic diagram of a positioning device of a wireless capsule endoscope based on magnetic drive provided by an embodiment of the present application is shown, and the device may specifically include: a measurement data receiving module 601, a position data determining module 602, a capsule magnetic field theoretical value calculating module 603, a driver magnetic field theoretical value calculating module 604, a capsule magnetic field component calculating module 605 and a six-dimensional pose solving module 606, wherein:
the measurement data receiving module 601 is configured to receive magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope in a process in which the extracorporeal driver drives the wireless capsule endoscope to move;
a position data determination module 602 for determining position data of the extracorporeal driver and the external sensor array, respectively;
a capsule magnetic field theoretical value calculation module 603, configured to calculate a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
a driver magnetic field theoretical value calculation module 604, configured to calculate a driver magnetic field theoretical value of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
a capsule magnetic field component calculation module 605, configured to calculate a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and a six-dimensional pose solving module 606, configured to solve the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
In this embodiment of the application, the location data determining module 602 is specifically configured to: and respectively determining the position data of each sensor of the extracorporeal driver and the external sensor array in a preset world coordinate system.
In this embodiment of the application, the measurement data receiving module 601 is further configured to: after the extracorporeal driver and the wireless capsule endoscope are removed from a working space, controlling to start the external sensor array and receive an environmental magnetic field estimated value measured by the external sensor array; and the environment magnetic field estimation value is used for subtracting the environment magnetic field estimation value from the magnetic field data to obtain new magnetic field data after the computer equipment receives the magnetic field data measured by the external sensor array.
In this embodiment, the measurement data receiving module 601 is further configured to: for each sensor of the external sensor array, respectively calculating magnetic field data measured by each sensor; and if the magnetic field data measured by any sensor is greater than or equal to the preset magnetic field value, deleting the magnetic field data measured by the sensor.
In the embodiment of the present application, the capsule magnetic field component calculation module 605 is specifically configured to: and for each sensor of the external sensor array, subtracting the theoretical value of the magnetic field of the driver corresponding to the sensor from the data of the magnetic field measured by each sensor to obtain the capsule magnetic field component generated by the permanent magnet built in the wireless capsule endoscope at each sensor.
In the embodiment of the present application, the capsule magnetic field component calculation module 605 is further configured to: determining a noise value of the sensor; and for each sensor of the external sensor array, if the capsule magnetic field component generated by the permanent magnet built in the wireless capsule endoscope at the sensor is less than or equal to the noise value, deleting the capsule magnetic field component corresponding to the sensor.
In this embodiment of the application, the two-axis rotation data is a first angle and a second angle of the wireless capsule endoscope that are respectively rotated by a capsule coordinate system around an x-axis and a y-axis of a preset world coordinate system, and the six-dimensional pose solving module 606 is specifically configured to: and solving unknown parameters in the six-dimensional pose of the wireless capsule endoscope by adopting a least square method based on the capsule magnetic field theoretical value and the capsule magnetic field component, wherein the unknown parameters comprise the three-dimensional position of the wireless capsule endoscope and a third angle of the wireless capsule endoscope, the third angle is formed by the capsule coordinate system of the wireless capsule endoscope rotating around the z axis of a preset world coordinate system, and the unknown parameters and the two-axis rotation data jointly form the real-time six-dimensional pose of the wireless capsule endoscope.
In this embodiment of the present application, the six-dimensional pose solving module 606 is further configured to: determining boundary constraints for the three-dimensional location, the boundary constraints relating to a workspace size of the wireless capsule endoscope; and solving the capsule magnetic field theoretical value and the capsule magnetic field component by adopting a least square method based on the boundary constraint condition to obtain the optimal estimation of the unknown parameter.
In an embodiment of the present application, the six-dimensional pose solving module 606 is further configured to: and transforming the solved third angle into a main period, wherein the main period is (-pi, pi).
It should be noted that, as for the device embodiment, since it is basically similar to the system embodiment described above, the description is relatively simple, and the relevant points can be referred to the description of the system embodiment.
Referring to fig. 7, a schematic diagram of a computer device provided in an embodiment of the present application is shown. As shown in fig. 7, a computer device 700 in the embodiment of the present application includes: a processor 710, a memory 720, and a computer program 721 stored in said memory 720 and operable on said processor 710. The processor 710, when executing the computer program 721, implements the functions implemented by the computer device in the various embodiments of the magnetic drive-based wireless capsule endoscope positioning system described above. For example, the computer device 700, when communicatively connected to a wireless capsule endoscope, an extracorporeal driver, and an external sensor array, respectively, the processor, when executing the computer program, may perform the following operations:
receiving magnetic field data measured by the external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope in the process that the extracorporeal driver drives the wireless capsule endoscope to move;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
In one implementation, the computer program 721 may be partitioned into one or more modules/units that are stored in the memory 720 and executed by the processor 710 to accomplish the present application. The one or more modules/units may be a series of computer program instruction segments capable of performing certain functions, which may be used to describe the execution of the computer program 721 in the computer device 700. For example, the computer program 721 may be divided into a measurement data receiving module, a position data determining module, a capsule magnetic field theoretical value calculating module, a driver magnetic field theoretical value calculating module, a capsule magnetic field component calculating module, and a six-dimensional pose solving module, each of which functions as follows:
the measurement data receiving module is used for receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope in the process that the extracorporeal driver drives the wireless capsule endoscope to move;
a position data determination module for determining position data of the extracorporeal driver and the external sensor array, respectively;
the capsule magnetic field theoretical value calculation module is used for calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
the driver magnetic field theoretical value calculation module is used for calculating a driver magnetic field theoretical value of a permanent magnet arranged in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
the capsule magnetic field component calculation module is used for calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the theoretical value of the magnetic field of the driver;
and the six-dimensional pose solving module is used for solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
The computing device 700 may be a desktop computer, a cloud server, or other computing device. The computer device 700 may include, but is not limited to, a processor 710, a memory 720. Those skilled in the art will appreciate that fig. 7 is merely an example of a computing device 700 and is not intended to limit the computing device 700 and that additional or fewer components than those shown, or some combination of components, or different components may be included in the computing device 700, e.g., the computing device 700 may also include input output devices, network access devices, buses, etc.
The Processor 710 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 720 may be an internal storage unit of the computer device 700, such as a hard disk or a memory of the computer device 700. The memory 720 may also be an external storage device of the computer device 700, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), etc. provided on the computer device 700. Further, the memory 720 may also include both internal storage units and external storage devices of the computer device 700. The memory 720 is used for storing the computer program 721 and other programs and data required by the computer device 700. The memory 720 may also be used to temporarily store data that has been output or is to be output.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (14)
1. A magnetically-driven wireless capsule endoscope-based positioning system, comprising a wireless capsule endoscope, an extracorporeal driver, an external sensor array, and a computer device communicatively coupled to the wireless capsule endoscope, the extracorporeal driver, and the external sensor array, respectively; wherein, permanent magnets are respectively arranged in the wireless capsule endoscope and the extracorporeal driver, and an inertial sensor is also arranged in the wireless capsule endoscope; the computer device is configured to perform the following operations:
receiving magnetic field data measured by the external sensor array and biaxial rotation data of the wireless capsule endoscope measured by the inertial sensor during the process that the extracorporeal driver drives the wireless capsule endoscope to move;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
2. The system of claim 1, wherein the external sensor arrays are located below and on both sides of the examination table, the external sensor arrays on both sides and below are in a single-layer or multi-layer planar structure, each layer of the external sensor array comprises a plurality of sensors, and the plurality of sensors of each layer of the external sensor array are arranged in a matrix.
3. The system of claim 2, wherein the two side external sensor arrays are mounted on a guide rail, and a distance between the two side external sensor arrays is adjusted by the guide rail.
4. The system of claim 1, wherein the separately determining position data for the extracorporeal driver and the external sensor array comprises:
and respectively determining the position data of each sensor of the extracorporeal driver and the external sensor array in a preset world coordinate system.
5. The system of any of claims 1-4, wherein the computer device is further configured to, prior to receiving the magnetic field data measured by the external sensor array and the two-axis rotation data of the wireless capsule endoscope measured by the inertial sensor, perform the following:
after the external driver and the wireless capsule endoscope are removed from a working space, controlling to start the external sensor array, receiving magnetic field values measured by the external sensor array, and calculating an environment magnetic field estimated value; and the environment magnetic field estimated value is used for subtracting the environment magnetic field estimated value from the received magnetic field data measured by the external sensor array by the computer equipment to obtain new magnetic field data when the extracorporeal driver and the wireless capsule endoscope are positioned in a working space.
6. The system of claim 5, wherein after receiving the magnetic field data measured by the external sensor array and the biaxial rotation data of the wireless capsule endoscope measured by the inertial sensor, the computer device is further configured to:
for each sensor of the external sensor array, respectively calculating magnetic field data measured by each sensor;
and if the magnetic field data measured by any sensor is greater than or equal to the preset magnetic field value, deleting the magnetic field data measured by the sensor.
7. The system according to any one of claims 1-4 or 6, wherein said calculating a capsule magnetic field component in said magnetic field data generated by a permanent magnet built into said wireless capsule endoscope based on said magnetic field data measured by said external sensor array and said actuator magnetic field theoretical value comprises:
and for each sensor of the external sensor array, subtracting the theoretical value of the magnetic field of the driver corresponding to the sensor from the data of the magnetic field measured by each sensor to obtain the capsule magnetic field component generated by the permanent magnet built in the wireless capsule endoscope at each sensor.
8. The system of claim 7, wherein after calculating capsule magnetic field components in the magnetic field data generated by permanent magnets built in the wireless capsule endoscope based on the magnetic field data measured by the external sensor array and the actuator magnetic field theoretical values, the computer device is further configured to:
determining a noise value of the sensor;
and for each sensor of the external sensor array, if the capsule magnetic field component generated by the permanent magnet built in the wireless capsule endoscope at the sensor is less than or equal to the noise value, deleting the capsule magnetic field component corresponding to the sensor.
9. The system of any one of claims 1-4, 6 or 8, wherein the two-axis rotation data is a first angle and a second angle of rotation of the wireless capsule endoscope by a capsule coordinate system around an x-axis and a y-axis of a preset world coordinate system, respectively, and the solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component comprises:
and solving unknown parameters in the six-dimensional pose of the wireless capsule endoscope by adopting a least square method based on the capsule magnetic field theoretical value and the capsule magnetic field component, wherein the unknown parameters comprise the three-dimensional position of the wireless capsule endoscope and a third angle of the wireless capsule endoscope, the third angle is formed by the capsule coordinate system of the wireless capsule endoscope rotating around the z axis of a preset world coordinate system, and the unknown parameters and the two-axis rotation data jointly form the real-time six-dimensional pose of the wireless capsule endoscope.
10. The system of claim 9, wherein solving the unknown parameters in the six-dimensional pose of the wireless capsule endoscope using a least squares method based on the theoretical capsule magnetic field values and the capsule magnetic field components comprises:
determining boundary constraints for the three-dimensional location, the boundary constraints relating to a workspace size of the wireless capsule endoscope;
and solving the capsule magnetic field theoretical value and the capsule magnetic field component by adopting a least square method based on the boundary constraint condition to obtain the optimal estimation of the unknown parameter.
11. The system of claim 9, wherein after solving for the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical values and the capsule magnetic field components, the computer device is further configured to:
and transforming the solved third angle into a main period, wherein the main period is (-pi, pi).
12. A magnetically-actuated wireless capsule endoscope-based positioning device, comprising:
the measurement data receiving module is used for receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope in the process that the extracorporeal driver drives the wireless capsule endoscope to move;
a position data determination module for determining position data of the extracorporeal driver and the external sensor array, respectively;
the capsule magnetic field theoretical value calculation module is used for calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
the driver magnetic field theoretical value calculation module is used for calculating a driver magnetic field theoretical value of a permanent magnet arranged in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
the capsule magnetic field component calculation module is used for calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the theoretical value of the magnetic field of the driver;
and the six-dimensional pose solving module is used for solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
13. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor when executing the computer program performs the operations of:
receiving magnetic field data measured by an external sensor array and biaxial rotation data of a wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope in the process that a wireless capsule endoscope is driven by an extracorporeal driver to move;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
14. A computer-readable storage medium storing a computer program, the computer program when executed by a processor performing the operations of:
in the process that an external driver drives a wireless capsule endoscope to move, receiving magnetic field data measured by an external sensor array and biaxial rotation data of the wireless capsule endoscope measured by an inertial sensor built in the wireless capsule endoscope;
determining position data of the extracorporeal driver and the external sensor array, respectively;
calculating a capsule magnetic field theoretical value of a permanent magnet built in the wireless capsule endoscope on each sensor of the external sensor array according to the biaxial rotation data and the position data of the external sensor array;
calculating a theoretical value of a driver magnetic field of a permanent magnet built in the extracorporeal driver on each sensor of the external sensor array according to the position data of the extracorporeal driver and the position data of the external sensor array;
calculating a capsule magnetic field component generated by a permanent magnet built in the wireless capsule endoscope in the magnetic field data according to the magnetic field data measured by the external sensor array and the driver magnetic field theoretical value;
and solving the six-dimensional pose of the wireless capsule endoscope based on the capsule magnetic field theoretical value and the capsule magnetic field component.
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