CN108827133B - Method for detecting pose of mobile magnetic source - Google Patents
Method for detecting pose of mobile magnetic source Download PDFInfo
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- CN108827133B CN108827133B CN201810620196.2A CN201810620196A CN108827133B CN 108827133 B CN108827133 B CN 108827133B CN 201810620196 A CN201810620196 A CN 201810620196A CN 108827133 B CN108827133 B CN 108827133B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
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- 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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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/003—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring position, not involving coordinate determination
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention provides a method for detecting the pose of a moving magnetic source. The magnetic field intensity of the driving magnet relative to the magnetic sensor under different poses is stored in advance to be used as a noise magnetic field; the driving magnet drives the moving magnetic source to be detected to move to a certain pose, and the controller determines the magnetic field intensity of the current noise magnetic field according to the relationship between the current pose of the driving magnet and the pre-stored pose of the driving magnet; measuring the total magnetic field intensity of the moving magnetic source to be measured in the current pose by using a magnetic sensor, obtaining the magnetic field intensity of the moving magnetic source by making a difference between the total magnetic field intensity and the magnetic field intensity of the current noise magnetic field, and calculating according to the magnetic field intensity of the moving magnetic source to obtain the pose of the current moving magnetic source. The invention can obtain the high-precision magnetic field signal of the moving magnetic source, thereby improving the pose detection precision.
Description
Technical Field
The invention relates to the technical field of magnetic field intensity, in particular to a method for detecting the pose of a moving magnetic source.
Background
The traditional colonoscopy uses a colonoscope for operation, and a doctor uses external force to control the colonoscope to enter the colon, so that the colonoscope is easy to touch the upper wall when turning in the intestinal tract, and the pain of a patient is increased. Therefore, capsule endoscopy technology has been developed, and currently used capsule endoscopes have small magnets inside the capsule, and external magnets are used to guide the capsule.
External magnet guided endoscopy capsules have significant advantages, including large range of motion, higher detection coverage, and ability to perform detection and treatment at a given location.
In the detection process, the position and the posture of the capsule need to be positioned, and the posture detection mainly detects a magnetic source embedded in the capsule through an external sensor so as to determine the posture of the capsule.
When the position and the posture are detected, the external driving magnetic field exists as noise and needs to be removed, and only the corresponding magnetic field value of the magnetic source in the capsule is reserved. However, the magnetic field signal obtained by the magnetic sensor includes a driving magnetic field signal and an effective magnetic source signal with a large specific gravity, and if the background magnetic field cannot be accurately removed, the detection result of the moving magnetic source must have a large error.
Disclosure of Invention
In view of this, the invention provides a method for detecting the pose of a moving magnetic source, which can obtain a high-precision magnetic field signal of the moving magnetic source, thereby improving the pose detection precision.
The specific embodiment of the invention is as follows:
a method for detecting the pose of a moving magnetic source adopts equipment comprising a driving magnet, a magnetic sensor and a controller; the magnetic sensors are distributed at two-dimensional or three-dimensional space points with known positions;
the detection method comprises the following steps: the magnetic field intensity of the driving magnet relative to the magnetic sensor under different poses is stored in advance to be used as a noise magnetic field; the driving magnet drives the moving magnetic source to be detected to move to a certain pose, and the controller determines the magnetic field intensity of the current noise magnetic field according to the relationship between the current pose of the driving magnet and the pre-stored pose of the driving magnet; measuring the total magnetic field intensity of the moving magnetic source to be measured in the current pose by using a magnetic sensor, obtaining the magnetic field intensity of the moving magnetic source by making a difference between the total magnetic field intensity and the magnetic field intensity of the current noise magnetic field, and calculating according to the magnetic field intensity of the moving magnetic source to obtain the pose of the current moving magnetic source.
Further, the specific method for determining the magnetic field strength of the current noise magnetic field is as follows:
if the current pose of the driving magnet is pre-stored, the magnetic field strength stored under the current pose of the driving magnet is adopted as the magnetic field strength of the current noise magnetic field;
under the condition that the current pose of the driving magnet is not prestored, if the difference of the magnetic field intensity of two adjacent prestored poses is smaller than a specified threshold value in the x, y and z directions of the sensors, carrying out interpolation operation by using the magnetic field intensity of the prestored poses, and taking a calculated value after interpolation as the magnetic field intensity of the current noise magnetic field; and if the difference between the magnetic field strengths of two adjacent prestored poses cannot be smaller than a specified threshold value in the x, y and z directions of the sensor, moving the driving magnet to the specified prestored pose, keeping the to-be-detected moving magnetic source still, and taking the magnetic field strength under the specified prestored pose as the magnetic field strength of the current noise magnetic field.
Further, the magnetic sensors are arranged in a two-dimensional or three-dimensional array.
Has the advantages that:
1. according to the invention, the intensity of the noise magnetic field is stored in advance, and then the corresponding noise magnetic field is removed in the detection process, so that the influence of the driving magnetic field and other background magnetic fields can be eliminated, and a high-precision magnetic field signal of the moving magnetic source is obtained, thereby improving the pose detection precision.
2. The magnetic sensors are arranged according to a two-dimensional or three-dimensional array, and the arrangement mode of the magnetic sensors is regular, so that the analysis and calculation are convenient, and the efficiency is improved.
Drawings
FIG. 1 is a flow chart of a method of the present invention;
FIG. 2 is a schematic diagram of a capsule and magnetic sensor array;
FIG. 3 is a schematic diagram of a magnetic sensor array measuring the attitude of a capsule position;
FIG. 4 is a schematic view of a drive magnet measurement position according to an embodiment;
FIG. 5 is a diagram of the background noise storage space of the second driving magnet according to the embodiment.
The method comprises the following steps of 1-a magnet to be detected, 2-a capsule, 3-a magnetic sensor, 4-a driving magnet, 5-a capsule motion area and 6-pre-storage of a pose.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The invention provides a method for detecting the pose of a moving magnetic source, and the adopted equipment comprises a driving magnet 4, a magnetic sensor 3 and a controller.
The mobile magnetic source to be detected comprises a magnet 1 to be detected and a capsule 2, the magnet 1 to be detected is embedded in the capsule endoscope to form the mobile magnetic source, and examination and treatment functions are performed in the stomach and intestine, as shown in figure 2.
The driving magnet 4 is located outside the human body and is a conventional magnet that guides the movement of the capsule 2 in the stomach and intestine by magnetic field force interaction, as shown in fig. 3.
The magnetic sensor array is located outside the human body, and can track the motion pose of the magnet 1 to be detected in the capsule 2, as shown in fig. 2, the arrangement form of the rectangular array is adopted, and the relative position between the magnetic sensors is known.
The driving magnet 4 is controlled by the robot to move, the position and the posture of the driving magnet 4 can be obtained by the feedback of an encoder arranged in the robot, and the magnetic sensor array is integrally arranged on a moving or static device, and the posture of the magnetic sensor array is known.
The controller is used for resolving the calculation.
The procedure of the detection method is shown in FIG. 1, and will be described below with reference to examples.
Example one
Step one, storing a noise magnetic field.
The driving magnet 4 is moved without the magnet 1 to be measured, the driving magnet 4 is made to have different positions and attitudes with respect to the magnetic sensor array, and the magnetic field strengths at the different positions and attitudes of the driving magnetic field are stored as the magnetic field strength of the noise magnetic field. As shown in fig. 4, an array coordinate system is established with the center of the magnetic sensor array as the origin, the plane of the magnetic sensor array is an XY plane, the direction perpendicular to the XY plane is a Z direction, the center coordinates of the array are (0,0,0), N poses of the driving magnet 4 fixed relative to the magnetic sensor array are set, N is not less than 1, the driving magnet 4 is placed at any position, the movement is stopped, and the pose is maintained. The coordinates of the N positions in the array coordinate system are recorded and set as (x)1n，y1n，z1n，α1，β1，γ1) Wherein N is 1, 2, … N, and x1n，y1n，z1nIs the position coordinate of the drive magnet 4 with respect to the magnetic sensor array, α1，β1，γ1The posture of the driving magnet 4 is constant. Under the conditions as described above, the reaction mixture,magnetic field measurement is carried out by sequentially using a magnetic sensor array, wherein the magnetic sensor array comprises A magnetic sensors 3, A is more than or equal to 3, or at least 5 magnetic field signals are provided, each magnetic sensor 3 is a three-axis sensor, the magnetic field intensity of the A magnetic sensors 3 in N positions of the driving magnet 4 is read, 3A magnetic field intensity coexists in one position of the driving magnet 4, the N positions of the driving magnet have 3A magnetic field intensity, the N positions of the driving magnet have 3A N magnetic field intensity, all the measured magnetic field intensity is used as the magnetic field intensity of a noise magnetic field, and the measured magnetic field intensity comprises geomagnetic signals of each position, signals respectively generated by the driving magnet 4 and other interference signals.
And step two, measuring the current magnetic field intensity by the magnetic sensor array.
The driving magnet 4 drives the capsule 2 to move in the capsule motion area 5, when the pose of the capsule 2 needs to be positioned by using an external magnetic sensor array, the controller determines the magnetic field intensity of the current noise magnetic field according to the relationship between the current pose coordinate of the driving magnet 4 and the prestored pose coordinate of the driving magnet 4, and if the current pose of the driving magnet 4 is prestored, the magnetic field intensity of the driving magnet 4 at the current pose is used as the magnetic field intensity of the current noise magnetic field;
if the current pose of the driving magnet 4 is not prestored, the driving magnet 4 is moved to the nearest prestored pose 6, the moving magnetic source to be detected is not moved at the moment, and the magnetic field intensity under the nearest prestored pose 6 is adopted as the magnetic field intensity of the current noise magnetic field. Then, the total magnetic field strength of the magnet 1 to be measured in the current pose is measured by using the magnetic sensor array, and the total magnetic field strength comprises the magnetic field strength of external background noise such as a driving magnet and the like and the magnetic field strength of the magnet 1 to be measured. A total of 3 x a magnetic field strengths were stored by the a 3-axis sensors.
And step three, removing the intensity of the noise magnetic field.
And (4) subtracting the magnetic field intensity of the current noise magnetic field from the total magnetic field intensity measured in the step (II), namely removing the geomagnetic signal, the magnetic field generated by the driving magnet 4 and other interference magnetic fields, and obtaining the magnetic field intensity distribution of the capsule 2, namely an effective signal for running a detection algorithm.
And step four, operating a pose detection algorithm.
And (3) running a detection algorithm by utilizing the magnetic field intensity distribution of the capsule 2 and not less than 5 magnetic field signals to calculate and obtain the current position and posture of the capsule 2.
Example two
Second embodiment as shown in fig. 5, the difference from the first embodiment is that when the noise magnetic field is stored in the first embodiment, the pose density of the driving magnet 4 is different, and it is required to ensure that the difference of the magnetic field strength in each direction x, y, and z is smaller than a specified threshold value in two adjacent pre-stored poses, and the density can be obtained through experiments. The selection of the specified threshold is related to the final required positioning accuracy. When the required position accuracy of the detection result is within 10mm and the attitude accuracy is within 5 degrees, the magnetic field difference between any adjacent storage position and attitude in each direction of x, y and z is not more than 100-300 mGs.
In the second step, the difference is that if the current pose of the driving magnet 4 is not prestored, two prestored poses which are closer to the current pose of the driving magnet relative to other prestored poses are judged; and performing interpolation operation by using the magnetic field strengths of the two pre-stored poses, and taking a calculated value after interpolation as the magnetic field strength of the current noise magnetic field.
The subsequent calculation method is consistent with the embodiment.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. A method for detecting the pose of a moving magnetic source is characterized in that the adopted equipment comprises a driving magnet, a magnetic sensor and a controller; the magnetic sensors are distributed at two-dimensional or three-dimensional space points with known positions;
the detection method comprises the following steps: the magnetic field intensity of the driving magnet relative to the magnetic sensor under different poses is stored in advance to be used as a noise magnetic field; the driving magnet drives the moving magnetic source to be detected to move to a certain pose, and the controller determines the magnetic field intensity of the current noise magnetic field according to the relationship between the current pose of the driving magnet and the pre-stored pose of the driving magnet; measuring the total magnetic field intensity of the moving magnetic source to be measured in the current pose by using a magnetic sensor, obtaining the magnetic field intensity of the moving magnetic source by making a difference between the total magnetic field intensity and the magnetic field intensity of the current noise magnetic field, and calculating according to the magnetic field intensity of the moving magnetic source to obtain the pose of the current moving magnetic source;
the specific method for determining the magnetic field strength of the current noise magnetic field comprises the following steps:
if the current pose of the driving magnet is pre-stored, the magnetic field strength stored under the current pose of the driving magnet is adopted as the magnetic field strength of the current noise magnetic field;
under the condition that the current pose of the driving magnet is not prestored, if the difference of the magnetic field intensity of two adjacent prestored poses is smaller than a specified threshold value in the x, y and z directions of the sensors, carrying out interpolation operation by using the magnetic field intensity of the prestored poses, and taking a calculated value after interpolation as the magnetic field intensity of the current noise magnetic field; and if the difference between the magnetic field strengths of two adjacent prestored poses cannot be smaller than a specified threshold value in the x, y and z directions of the sensor, moving the driving magnet to the specified prestored pose, keeping the to-be-detected moving magnetic source still, and taking the magnetic field strength under the specified prestored pose as the magnetic field strength of the current noise magnetic field.
2. The method for detecting the pose of a moving magnetic source according to claim 1, wherein the magnetic sensors are arranged in a two-dimensional or three-dimensional array.
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| CN109620104B (en) * | 2019-01-10 | 2021-04-02 | 深圳市资福医疗技术有限公司 | Capsule endoscope and positioning method and system thereof |
| CN109916287B (en) * | 2019-01-30 | 2020-11-27 | 西安维控自动化科技有限公司 | Planar displacement sensor based on magnetic induction, displacement detection method and system |
| CN110236474B (en) * | 2019-06-04 | 2020-10-27 | 北京理工大学 | Active magnetic control capsule robot detection system and detection method |
| US20220248943A1 (en) * | 2019-06-17 | 2022-08-11 | Shenzhen Sibernetics Co., Ltd. | Magnetic control device of capsule endoscope and method for controlling movement of capsule endoscope in tissue cavity |
| DE102019209035A1 (en) * | 2019-06-21 | 2020-12-24 | Infineon Technologies Ag | DETECTING A DISCRETE POSITIONAL RELATIONSHIP BETWEEN A MAGNETIC FIELD SENSOR AND A MAGNETIC FIELD SENSOR ARRANGEMENT |
| CN111486838B (en) * | 2020-04-13 | 2022-02-01 | 北京理工大学 | Method and device for establishing effective magnetic connection |
| CN111888634B (en) * | 2020-07-30 | 2021-06-15 | 浙江大学 | Automatic drug delivery system and method |
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| KR20080077182A (en) * | 2005-12-16 | 2008-08-21 | 올림푸스 가부시키가이샤 | System for detecting position in subject |
| CN101297756A (en) * | 2008-06-19 | 2008-11-05 | 大连理工大学 | Combined method of magnetic field and vision for locating gesture of medical micro type robot in vivo |
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| CN207366718U (en) * | 2017-09-05 | 2018-05-15 | 重庆金山医疗器械有限公司 | Space magnetic field detection device for the full attitude sensing system of variation magnetic field capsule |
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