Signal processing device and system for processing an induction signal of a magnetic positioning sensor

Abstract

The application discloses a signal processing device and system for processing an induction signal of a magnetic positioning sensor, and the signal processing device comprises: a preamplification circuit, which is used for amplifying the induction signal of the magnetic positioning sensor and suppressing a common-mode interference signal of the induction signal; a filter circuit, which is connected with the preamplification circuit and is used for filtering a signal output by the preamplification circuit at a preset cutoff frequency; a main amplification circuit, which is connected with the filter circuit and is used for amplifying a signal output after being filtered by the filter circuit; and a wave trap filter circuit, which is connected with the main amplification circuit and is used for eliminating noise in a signal output by the main amplification circuit. The application solves the technical problem of inaccurate positioning caused by low precision of the signal processing device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical equipment, in particular to a signal processing device and system for processing an induction signal of a magnetic positioning sensor. BACKGROUND

[0002] In an interventional surgery, it is important to obtain real-time position information of a medical device in a three-dimensional space in a human body. The application of a magnetic sensor can minimize the need for fluoroscopy during the surgery, and the magnetic sensor can be tracked without obstacles, and the tracking can be maintained even if the sensor is invisible.

[0003] The induction signal of the magnetic sensor needs to be processed to accurately position. The existing back-end sensor signal amplification circuit has few amplification and filtering modules for low-frequency alternating current signals, and the existing processing device has low integration, precision and sensitivity.

[0004] At present, no effective solution has been proposed for the above problems. SUMMARY

[0005] The embodiments of the present application provide a signal processing device and system for processing an induction signal of a magnetic positioning sensor to at least solve the technical problem of inaccurate positioning caused by low precision of the signal processing device.

[0006] According to an aspect of the embodiments of the present application, a signal processing device for processing an induction signal of a magnetic positioning sensor is provided, comprising: a preamplification circuit for amplifying the induction signal of the magnetic positioning sensor and suppressing a common-mode interference signal of the induction signal; a filter circuit connected with the preamplification circuit, for filtering a signal output by the preamplification circuit at a preset cutoff frequency; a main amplification circuit connected with the filter circuit, for amplifying a signal output by the filter circuit; and a wave trap filter circuit connected with the main amplification circuit, for eliminating noise in a signal output by the main amplification circuit.

[0007] According to an aspect of the embodiments of the present application, a medical system for magnetic positioning sensor tracking is also provided, comprising: a magnetic field generator for generating a magnetic field signal; an invasive medical device comprising an electromagnetic positioning sensor for sensing the magnetic field signal and outputting an induction signal; and the signal processing device according to any one of the above, for processing the induction signal led out by the magnetic positioning sensor.

[0008] In the embodiments of the present application, the wire twisting method is adopted to solve the technical problem of inaccurate positioning caused by low precision of the signal processing device, and has the beneficial effect of accurate positioning. BRIEF DESCRIPTION OF DRAWINGS

[0009] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0010] Figure 1 is a structural schematic diagram of a medical system for magnetic positioning sensor tracking according to an embodiment of the present application;

[0011] Figure 2A is a structural schematic diagram of a magnetic positioning sensor according to an embodiment of the present application;

[0012] Figure 2B is a perspective structural schematic diagram of a magnetic positioning sensor according to an embodiment of the present application;

[0013] Figure 3 is a structural schematic diagram of a magnetic core and coil according to an embodiment of the present application;

[0014] Figure 4A is a structural schematic diagram of another magnetic positioning sensor according to an embodiment of the present application;

[0015] Figure 4B is a structural schematic diagram of another magnetic positioning sensor according to an embodiment of the present application;

[0016] Figure 5 is a structural schematic diagram of a signal processing device according to an embodiment of the present application;

[0017] Figure 6A is a circuit diagram of a preamplifier circuit according to an embodiment of the present application;

[0018] Figure 6B is a circuit diagram of another preamplifier circuit according to an embodiment of the present application;

[0019] Figure 7 is a circuit diagram of a low-pass filter circuit according to an embodiment of the present application;

[0020] Figure 8 is a circuit diagram of a high-pass filter circuit according to an embodiment of the present application;

[0021] Figure 9 is a circuit diagram of a main amplifier circuit according to an embodiment of the present application;

[0022] Figure 10 is a circuit diagram of a notch filter circuit according to an embodiment of the present application.

[0023] Reference numerals: 12, magnetic field generator; 14, invasive medical device; 16, signal processing device; 142, magnetic positioning sensor; 144, catheter head; 146, catheter body; 148, connecting end; 1422, magnetic core; 1424, coil; 1426, sleeve 1426; 1428, wire; 1429, encapsulation layer; 1421, flexible insulation layer; 52, preamplification circuit; 54, filter circuit; 56, main amplification circuit; 58, wave trap filter circuit. DETAILED DESCRIPTION

[0024] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] Embodiment 1

[0027] According to an embodiment of the present application, a medical system for magnetic positioning sensor tracking is provided, as shown in Figure 1 The medical system includes a magnetic field generator 12, an invasive medical device 14 and a signal processing device 16, wherein the invasive medical device 14 includes a magnetic positioning sensor 142.

[0028] The magnetic field generator 12 is located near the subject for generating a magnetic field radiating in a preset direction. The magnetic field generator 12 can emit a magnetic field under the control of a console (not shown in the figure), or itself has a control panel and emits a magnetic field based on the control instructions received by the control panel itself.

[0029] The invasive medical device 14 can be, for example, a catheter, a sheath, or the like elongated medical instrument that can be inserted into a subject. The invasive medical device 14 in the present embodiment is a catheter as shown in FIG. 1, which includes a connection end 148, a catheter body 146, and a catheter head 144, wherein the catheter body 146 and the catheter head 144 are both made of flexible material. Of course, in other embodiments, they can also be made of rigid material. Figure 1 The connection end 148 is used to connect the magnetic positioning sensor and external devices, for example, to transmit the sensing signals of the magnetic positioning sensor to the signal processing device. The catheter head 144 is located at the end of the catheter away from the connection end 148.

[0030] The connection end 148 is used to connect the magnetic positioning sensor and external devices, for example, to transmit the sensing signals of the magnetic positioning sensor to the signal processing device. The catheter head 144 is located at the end of the catheter away from the connection end 148.

[0031] The magnetic positioning sensor 142 is disposed at the tip of the catheter head 144. The magnetic positioning sensor 142 can be connected to the outer end of the catheter head 144, or can be embedded in the outer end of the catheter head 144 in whole or in part, or can be attached to the outer end of the catheter head 144 by an adhesive, or can also be disposed inside the catheter head 144.

[0032] The magnetic positioning sensor 142 is capable of generating sensing signals, i.e. position data, based on the magnetic field generated by the magnetic field generator 12. These position data are transmitted to the signal processing device 16 via the connection end 148 through the wire 1428 of the magnetic positioning sensor 142.

[0033] The signal processing device 16 is used to amplify, filter, and the like process these position data received from the magnetic positioning sensor 142, eliminate the influence of disturbance signals from the external environment, so as to obtain the position of the magnetic positioning sensor 142 relative to the magnetic field generated by the magnetic field generator 12, and can also associate the position information with 2D or 3D images.

[0034] As shown in FIGS. 1, 2, and 3, the magnetic positioning sensor 142 includes a magnetic core 1422, a coil 1424 wound on the magnetic core 1422, a sleeve 1426, a wire 1428, and a packaging layer 1429. Figure 2A and 2B The sleeve 1426 can be a polyimide tube. In the present embodiment, the polyimide tube is sleeved outside the magnetic core 1422 on which the coil 1424 is wound, and the coil 1424 and the polyimide tube are filled with resin, for example, epoxy resin, for packaging. The two ends of the magnetic core 1422 are not wound with the coil 1424, and the two ends of the magnetic core 1422 not wound with the coil 1424 are also filled with resin, for example, epoxy resin, for packaging between the polyimide tube. In other embodiments, the polyimide tube can be replaced with other biocompatible tube materials.

[0035] Through the design of the above structure, the coil 1424 is wrapped and is not easy to be bent and broken, thereby ensuring the stability of the physical structure performance of the magnetic positioning sensor.

[0036] The magnetic core 1422 is made of high permeability material and has an elongated cylindrical shape. The high permeability material can be, for example, a ferromagnetic material or a mixture of ferromagnetic powder and other polymer binder which is flexible when cured.

[0037] The coil 1424 is adjacent to the outer surface of the magnetic core 1422. The coil 1424 is wound around the outer surface of the magnetic core 1422 in a circumferential direction. The coil 1424 is wound using wire with a diameter of less than 30 micrometers (pm), and the coil 1424 is designed to have a maximum outer diameter of 0.90 mm and a maximum length of 10.00 mm.

[0038] The existing magnetic positioning sensor has a size of more than 2 mm in length, width and height. In the present embodiment, the problem of large size of the magnetic positioning sensor in the prior art is solved by selecting wire with small diameter and small tolerance, and by controlling the number of layers of the coil 1424 to be within 6 layers and the number of turns to be within 3000 turns, so that the size of the magnetic positioning sensor is less than 1 mm in diameter.

[0039] In addition, in the present embodiment, a high-precision fully automated device is selected in the winding process, such as a winding machine with a wire arrangement precision of 0.001 mm, a feeding pitch precision of 0.001 mm and a winding width resolution of 0.001 mm.

[0040] In the present embodiment, the selection of the wire size and the precision of the wire arrangement machine ensures that the coil is wound uniformly and smoothly.

[0041] Reference is made to Figure 2A , 2B and Figure 3 The length of the magnetic core 1422 is 10% to 25% longer than the length of the coil 1424, and the two ends of the magnetic core 1422 are not wound with the coil. By this winding method, the inductance and the induced signal of the magnetic positioning sensor can be increased.

[0042] In the present embodiment, the coil 1424 is not wound at the two ends of the magnetic core 1422, so that the length of the coil 1424 is shorter than the length of the magnetic core 1422. In this way, the magnetic induction intensity at the center of the magnetic core 1422 is the largest and the sensitivity is the highest, while the magnetic induction intensity at the two ends is smaller than that at the center of the magnetic core 1422, thereby avoiding the edge effect.

[0043] On the other hand, the length of the coil 1424 cannot be too short, otherwise the length of the copper wire with the same number of turns will be too long, resulting in a large DC impedance and other parameters such as parasitic capacitance and AC impedance being deteriorated. In commercialized products, the length of the coil is generally 50% to 90% of the length of the magnetic core, or the ratio of the length of the coil to the length of the magnetic core is Generally between 0.1 and 0.8. In the present embodiment, the ratio of the length of the coil 1424 to the length of the magnetic core 1422 is set to be between 75% and 90%, and more preferably between 0.75 and 0.8.

[0044] When the ratio β of the length of the coil 1424 to the length of the magnetic core 1422 is set to be between 0.75 and 0.8, the inductance L is empirically given by: In the equation, μ0is the magnetic permeability of vacuum, μ c is the relative magnetic permeability of the magnetic core 1422, A c is the cross-sectional area of the coil 1424, b w is the length of the coil 1424, 1 is the length of the magnetic core 1422, and N is the number of turns of the coil 1424.

[0045] In the prior art, in a low frequency and weak magnetic field environment, the signal is weak and it is not possible to achieve positioning or the positioning accuracy is not high enough. In the present embodiment, by setting the ratio of the length of the coil 1424 to the length of the magnetic core 1422 to be between 0.75 and 0.8, the magnetic positioning sensor is able to achieve a large inductance and a large induced signal in a very small size, thereby enabling the positioning accuracy of the magnetic positioning sensor to be 1 mm.

[0046] The multiple of the enhancement of the induced signal μ app in the present embodiment is:

[0047]

[0048] In the equation, μ r is the initial magnetic permeability of the magnetic core 1422, and d is the effective diameter of the cross-sectional area of the magnetic core 1422. Obviously, in the case where the dimensions of the coil 1424 and the magnetic core 1422 are fixed, the larger the initial magnetic permeability μ r of the magnetic core 1422, the larger the multiple of the enhancement of the induced signal.

[0049] In the present embodiment, the selection of the magnetic core with high magnetic permeability and small diameter also enables the magnetic positioning sensor to achieve a large inductance and a large induced signal in a very small size.

[0050] The two wires 1428 leading from the magnetic core 1422 are electric wires with an insulating coating to prevent short-circuiting when the two wires are twisted together. The wire material from which the coil 1424 is made can be a high-conductivity metal conductor such as copper or the like. The coil 1424 has two end portions, from one of which two lead wires are drawn. The two lead wires of the coil 1424 are electrically connected to the signal processing device 16 via the two wires 1428, respectively. In the present embodiment, the lead wires and the wires 1428 are two, respectively, but in other embodiments, the lead wires and the wires 1428 can be multiple.

[0051] In this embodiment, the two wires 1428 are twisted wires. The fiber wire is added in the twisted wire, so that the wire 1428 reaches a larger tensile strength, and the magnetic positioning sensor is not easy to be broken in use.

[0052] In the prior art, the small size sensor is easy to be damaged in use, even if it is embedded in a rigid or flexible medical instrument. However, the above structure solves the problem that the magnetic positioning sensor is easy to be damaged in use.

[0053] In addition, in this embodiment, the wire 1428 uses a twisted wire, which can achieve the purpose of anti-interference. In another embodiment, silver wire can be added in the twisted wire to strengthen the shielding effect.

[0054] Figure 4A And 4B is a structure diagram of another magnetic positioning sensor according to the embodiment of the application. As shown in Figure 4A and 4B , the magnetic positioning sensor is different from the magnetic positioning sensor in Figure 2A and Figure 2B in that Figure 2A and Figure 2B The coil of the magnetic positioning sensor in Figure 4A and 4B is sleeved with a polyimide tube, and the coil and the polyimide tube are filled and packaged with epoxy resin, while the magnetic positioning sensor in and

[0055] is made by the following process: placing the coil-wound magnetic core in a tubular mold, then filling the mold with epoxy resin or polyurethane glue, and then assisting the setting by the mold, and then demolding after the epoxy resin or polyurethane glue is solidified. Figure 4A Figure 4B As shown in and

[0056] , the magnetic positioning sensor includes a magnetic core 1422, a coil 1424 wound circumferentially outside the magnetic core 1422, a flexible insulating layer 1421, and a wire 1428. The flexible insulating layer 1421 can be epoxy resin or polyurethane glue. The whole magnetic core 1422 can be made of a ferrous material, which can also be a ferromagnetic material. The coil 1424 can be a copper wire coil. Figure 4A 4B Specifically, the magnetic positioning sensor in and

[0057] is made by the following steps:The wire of the coil 1424 is wound outside the magnetic core 1422, i.e. the outer surface circumferentially surrounding the magnetic core 1422. In one embodiment, the wire of the coil 1424 can be wound outside the magnetic core 1422 such that the longitudinal ends of the coil 1424 are evenly distributed along the diameter of the central portion of the coil 1424.

[0058] Further, the magnetic core 1422 wound with the coil 1424 is encapsulated with a flexible insulating layer 1421, such as epoxy resin or polyurethane glue. The coating of the insulating material can be applied to any exposed part of the coil 1424 and the magnetic core 1422, which covers the outer surface of the exposed magnetic core 1422 and the coil 1424. For example, the magnetic core 1422 wound with the coil 1424 is shaped and cured with the assistance of a tubular mold using epoxy resin or polyurethane glue, and the mold is demolded after the epoxy resin or polyurethane glue solidifies, and finally forms a magnetic positioning sensor as shown in Figure 4A and 4B In other embodiments, the glue outside the coil, such as polyurethane glue, can be replaced with other biocompatible glue.

[0059] Figure 4A and 4B The structure and function of the coil 1424 and the magnetic core 1422 in the magnetic positioning sensor in Figure 2A and Figure 2B The structure and function of the coil 1424 and the magnetic core 1422 in the magnetic positioning sensor in

[0060] Through the design of the above structure, the coil 1424 is wrapped and is not easy to be bent and broken, which ensures the stability of the physical structure performance of the magnetic positioning sensor. In addition, by setting the flexible insulating layer 1421 to be flexible, the discomfort of the subject can be reduced when the invasive medical device invades the subject's body.

[0061] The magnetic positioning sensor provided by the embodiments of the present application has the following beneficial effects:

[0062] 1) The magnetic positioning sensor is small in size: the coil is wound with wire less than 30 microns (μm), and the outer diameter of the coil is controlled to be 0.90 mm max, and the length is controlled to be 10.00 mm max.

[0063] 2) High positioning accuracy: through the design of the wire, the selection of the magnetic core material, the selection of the ratio of the length of the magnetic core to the length of the coil, the selection of the material and design of the coil, and the selection of the coil winding machine, the sensor can achieve larger inductance and larger induction signal in a small size, thereby obtaining 1 mm high precision.

[0064] 3) In the process of use is not easy to be damaged: (1) twisted pair line added fiber line, so that the lead to a greater tensile strength, the sensor in the process of use lead is not easy to break; (2) the two structure scheme provided by the application, the coil is wrapped and not easy to be bent and broken, ensuring the stability of the physical structure performance of the sensor.

[0065] The embodiment of the application is directed to a medical application scene, and provides a magnetic positioning sensor which is extremely small in size, good in performance, high in sensitivity, stable in physical structure, and meets medical standards such as biological compatibility, can be embedded in a rigid or flexible medical instrument, and can stably generate a stable induction signal (voltage signal) in a changing low-frequency and weak magnetic field environment, thereby solving the technical problems of insufficient precision, weak signal generation, and inability to realize positioning in the prior art in a low-frequency and weak magnetic field environment.

[0066] The embodiment of the application also provides an invasive medical device, which can include a rigid invasive member and a magnetic positioning sensor having a magnetic core. The rigid invasive member has a distal end portion. The magnetic positioning sensor can be connected to the distal end portion of the rigid invasive member. The magnetic positioning sensor can include a magnetic core and a coil. The coil can circumferentially surround the elongated magnetic core.

[0067] The embodiment of the application also provides another invasive medical device, which can include a flexible invasive member and a magnetic positioning sensor having a magnetic core. The flexible invasive member has a distal end portion, and the magnetic positioning sensor can be connected to the distal end portion of the flexible invasive member. The magnetic positioning sensor can include a magnetic core having an outer surface, and a coil can circumferentially surround the outer surface of the magnetic core.

[0068] The magnetic core is in a hollow cylindrical shape. The hollow cylindrical magnetic core is relatively easy to install compared with a solid magnetic core, and the more stable the hollow magnetic core is, the better.

[0069] Figure 5 It is a structural schematic diagram of the signal processing device according to the embodiment of the application. As shown in Figure 5 The signal processing device includes a preamplification circuit 52, a filter circuit 54, a main amplification circuit 56, and a wave trap filter circuit 54.

[0070] The pre-amplification circuit 52 is used for amplifying the output signal of the magnetic positioning sensor and suppressing common-mode interference signal of the output signal, and the amplification multiple is set to 8-10 times; the filter circuit 54 is connected with the pre-amplification circuit 52, and is used for filtering the signal output by the pre-amplification circuit 52 at a preset cut-off frequency, for example, for performing 0.5Hz-100Hz low-pass and high-pass filtering; the main amplification circuit 56 is connected with the filter circuit 54, and is used for amplifying the signal output by the filter circuit 54 after filtering, and the amplification multiple is set to 60-100 times; the wave trap filter circuit 54 is connected with the main amplification circuit 56, and is used for eliminating noise introduced in the process of amplifying the signal output by the filter circuit 54 after filtering, for example, for filtering out 50Hz power frequency and harmonic components in the surrounding environment.

[0071] The pre-amplification circuit 52 is realized by an instrumentation amplifier chip AD620-U1 as shown in the following figure. Figure 6A The pins of the instrumentation amplifier chip AD620-U1 are set as follows: pin 1 is connected with pin 8 through resistor R3; pin 3 is connected with the input positive signal; pin 2 is connected with the input negative signal; pin 7 is connected with the positive power supply 5V; pin 5 is grounded; pin 4 is connected with the negative power supply 5V; and pin 6 is used as the output terminal of the pre-amplification circuit 52.

[0072] In another embodiment, the pre-amplification circuit 52 can also be as shown in the following figure. Figure 6B Pin 1 is connected with pin 8 through resistors R1, R2 and R3; pin 3 is connected with the input positive signal; pin 2 is connected with the input negative signal; pin 7 is connected with the positive power supply 5V; pin 5 is grounded; pin 4 is connected with the negative power supply 5V; and pin 6 is used as the output terminal of the pre-amplification circuit 52. In this way, the resistance selection can be facilitated, and there is basically no 6.66kΩ resistor in the existing resistors, and the parallel connection can have a 6.66kΩ resistor.

[0073] The filter circuit 54 includes a low-pass filter circuit 54 and a high-pass filter circuit 54.

[0074] The low-pass filter circuit is realized by an operational amplifier chip TL082-U2 as shown in the following figure. Figure 7 The pins of the operational amplifier chip TL082-U2 are set as follows: pin 2 is connected with pin 1; pin 3 is connected to pin 6 of the pre-amplification circuit 52 through resistors R5 and R4 in sequence, and pin 3 is connected with the ground through capacitor C4; pin 8 is connected with the positive power supply 5V; pin 4 is connected with the negative power supply 5V; and pin 1 is used as the output terminal of the low-pass filter, and is connected with capacitor C1 and resistor R4.

[0075] The high-pass filter circuit is realized by an operational amplifier chip TL082-U3 as shown in the following figure. Figure 8As shown, the high-pass filter circuit 54 is implemented by an operational amplifier chip TL082-U3. The pins of the operational amplifier chip TL082-U3 are set as follows: pin 2 is connected to pin 1; pin 3 is connected to pin 1 of the low-pass filter circuit 54 in sequence through capacitors C2 and C3, and pin 3 is connected to the ground through resistor R6; pin 8 is connected to the positive power supply 5V; pin 4 is connected to the negative power supply 5V; pin 1 is the output of the high-pass filter circuit 54, and is connected to capacitor C3 through resistor R7.

[0076] In other embodiments, the filter circuit in the present embodiment can also select other active filter circuits capable of implementing 0.5-100Hz high-pass and low-pass, such as active filter circuits designed based on integrated operational amplifiers such as LM358 and TLC2274.

[0077] The main amplification circuit 56 module is implemented by an operational amplifier chip OP07-U4 as shown. Figure 9 The pins of the operational amplifier chip OP07 are set as follows: pin 2 is connected to the ground through resistor R10, and pin 2 is connected to pin 6 through resistor R9; pin 3 is connected to pin 1 of the high-pass filter circuit 54, and is connected to the ground through resistor R15; pin 7 is connected to the positive power supply 5V; pin 4 is connected to the negative power supply 5V; and pin 6 is the output of the main operational amplifier circuit module.

[0078] The notch filter circuit 58 is implemented by an operational amplifier chip OP07 as shown. Figure 10 The notch filter circuit is a 50Hz notch filter circuit. The pins of the operational amplifier chip OP07 are set as follows: pin 3 is connected to the signal input; pin 2 is connected to pin 6 through resistor R11, and is connected to the ground through resistor R13; pin 7 is connected to the positive power supply 5V; pin 4 is connected to the negative power supply 5V; pin 6 is the output of the 50Hz notch filter, and is connected to the ground through resistors R11 and R13, and is connected to resistor R8 through capacitor C7.

[0079] In other embodiments, the notch filter circuit can also select a circuit structure domain design and chip that can make the signal amplified by the main amplification circuit perform 50Hz notch filtering, such as a notch filter circuit designed based on integrated operational amplifiers such as LM358 and TLC2274.

[0080] The magnetic field signal of the magnetic field generator is sensed by the magnetic induction sensor to obtain an induction signal, and the induction signal is sent to the preamplification circuit 52 for preliminary amplification. The common-mode interference signal of the induction signal is suppressed by the high-performance differential preamplification circuit 52, and the preliminary amplification multiple is 8 to 10 times. The induction signal, for example, an electrocardio signal, after the preliminary amplification by the preamplification circuit 52 is sent to the high-pass and low-pass filter circuits with a cutoff frequency of 0.5-100 Hz. Then, the signal after the filtering processing is input to the main amplification circuit 56 to realize 60 to 100 times amplification, so that the signal is amplified to the required range. In order to eliminate the noise introduced in the signal amplification process and filter out the 50 Hz power frequency signal in the signal, the signal after the main amplification is subjected to 50 Hz wave trapping, and finally output.

[0081] The existing back-end sensor signal amplification processing circuit has few amplification and filtering modules for low-frequency alternating current signals, and the integration, precision and sensitivity are not high enough. Through the above structure, the magnetic induction sensor signal is stably amplified by a specified multiple and filtering is completed, specifically, the amplification multiple is 500-1000 times, the signal-to-noise ratio is greater than 90 dB, and the out-of-band noise below 0.5 Hz and above 100 Hz and the power frequency noise near 50 Hz are filtered out, so that the accurate induction signal of the magnetic positioning sensor can be obtained.

[0082] In a preferred embodiment, the signal processing device can further include an error compensation processing module. The error compensation processing module will be described in detail below.

[0083] The biggest feature of the discrete Kalman filtering equation is recursion, but in actual application, most medical systems are continuous systems, so the system needs to be discretized first.

[0084] The discretization process is to discretize the system noise variance matrix Q of the continuous medical system, and the specific process is as follows:

[0085]

[0086] Where T is the calculation period of the filter, F represents the discrete Fourier function, Q represents the noise variance matrix of the continuous system, and Qk represents the discrete noise variance matrix.

[0087] In the same way, the discrete noise variance matrix V is discretized to obtain the discrete noise driving matrix V k .

[0088] After the error compensation processing module receives the signal output by the wave trap filter circuit 54, the signal is error compensated based on the discrete noise variance matrix and the noise driving matrix.

[0089] First, the error estimation coefficient K is determined. The error estimation coefficient K is based on the bias error F(t) of the magnetic positioning sensor, the noise variance matrix Qk of the discretized magnetic positioning sensor, the scale factor error U(t) of the magnetic positioning sensor, the measurement noise G(t) of the magnetic positioning sensor, and the discrete noise variance matrix V k is determined.

[0090] Specifically, K can be calculated by the following formula:

[0091] K=F(t)Q k +U(t)+G(t)V k

[0092] After the error compensation coefficient is calculated, error compensation is performed based on the error compensation coefficient:

[0093] E(t)=(F(t)Q k +U(t)+G(t)V k )I(t)

[0094] Where F(t) represents the bias error of the magnetic positioning sensor, Q k represents the noise variance matrix of the discretized magnetic positioning sensor, U(t) represents the scale factor error of the magnetic positioning sensor, G(t) represents the measurement noise of the magnetic positioning sensor, V k represents the discrete noise variance matrix, I(t) represents the amplified electrical signal, and E(t) represents the signal after error compensation.

[0095] A complete Kalman filter module, which acts as an error estimator, estimates the error accumulated in the last period in each support phase to obtain the error coefficient, thereby completing a closed-loop Kalman filter correction.

[0096] In this embodiment, the Kalman filter-based error correction algorithm estimates the amplified signal in real time to obtain the error estimation coefficient, and then compensates the amplified signal of the magnetic sensor using the error estimation coefficient, thereby suppressing the error accumulation of the system and improving the positioning accuracy of the system.

[0097] In a preferred embodiment, the signal processing device can further include a correction module for performing sliding mode surface correction on the signal after error compensation. The correction module will be described in detail below,

[0098] The magnetic positioning sensor can be regarded as a double-output tracking system, and the tracking error of the magnetic positioning sensor can be defined as

[0099] e(t)=X(t)-X d (t)

[0100] In the tracking error equation, X(t) is the magnetic field signal generated by the magnetic field generator, and X d (t) is the disturbance signal of the magnetic positioning sensor affected by the external environment.

[0101] According to the given tracking error, the proportional integral sliding surface is determined as follows:

[0102]

[0103] Where C is a constant coefficient matrix, B is a full rank matrix, t is the current time, A d is the noise matrix of the disturbance signal, and K d is the Hurwitz matrix.

[0104] The sliding surface based on the reaching law is selected, which has good robustness for the magnetic positioning sensor. Based on the above sliding surface, the signal after error compensation is corrected by the sliding surface, and the specific correction method is as follows:

[0105] E'(t) = E(t)(εsgns(t)-s(t))

[0106] Where E'(t) is the corrected signal, and ε is the correction factor.

[0107] In this embodiment, after error compensation, the signal is corrected again based on the sliding surface, so as to eliminate the disturbance of the external environment on the magnetic field induction signal, and to obtain more accurate induction signal, which provides the possibility for accurate calculation of position information.

[0108] The signal processing device provided by the embodiment of the application can amplify the output signal of the magnetic induction sensor with high precision, and at the same time complete filtering, error processing and correction processing, thereby providing a basis for the rear-end positioning system.

[0109] The embodiment of the application further provides the following configuration:

[0110] 1. A magnetic positioning sensor, comprising: a magnetic core, which is an elongated cylindrical shape; a coil, which is wound circumferentially on the outer surface of the magnetic core; and at least two wires 1428, which are led out from one end of the coil, wherein the at least two wires 1428 are twisted in the direction led out from the coil.

[0111] 2. The sensor according to item 1, wherein the sensor further comprises a sleeve 1426, which is used to sleeve the magnetic core wound with the coil.

[0112] 3. The sensor according to item 2, wherein the sleeve 1426 is a polyimide tube.

[0113] 4. The sensor of item 2, wherein the sleeve 1426 and the magnetic core with the coil wound thereon are encapsulated with resin.

[0114] 5. The sensor of item 1, wherein a layer of resin or glue is solidified in the circumference of the magnetic core with the coil wound thereon.

[0115] 6. The sensor of item 1, wherein the sensor is formed by using a tubular mold, filling the space between the mold and the magnetic core with the coil wound thereon with resin or glue, and demolding.

[0116] 7. The sensor of any one of items 1 to 6, wherein each of the at least two wires 1428 is a wire with a shielding effect greater than a shielding threshold and a tensile strength greater than a strength threshold.

[0117] 8. The sensor of any one of items 1 to 6, wherein the at least two wires 1428 are twisted pairs, or multi-stranded twisted wires with a shielding wire, or multi-stranded twisted wires with a fiber wire.

[0118] 9. The sensor of any one of items 1 to 6, wherein the wire diameter of the coil is less than a wire diameter threshold, and the tolerance of the coil is less than a tolerance threshold.

[0119] 10. The sensor of any one of items 1 to 6, wherein the coil is wound with a wire with a wire diameter less than 30 microns, the outer diameter of the coil is 0.9 millimeters, and the length of the coil is 10 millimeters.

[0120] 11. The sensor of any one of items 1 to 6, wherein the number of layers of the coil is less than 10 layers, and the number of turns of the coil is less than 3000 turns.

[0121] 12. The sensor of any one of items 1 to 6, wherein the length of the magnetic core is 10% to 25% longer than the length of the coil, and the two ends of the magnetic core are not wound with the coil.

[0122] 13. The sensor of any one of items 1 to 6, wherein the ratio of the length of the coil to the length of the magnetic core is determined based on the vacuum permeability of the magnetic core, the relative permeability of the magnetic core, the cross-sectional area of the coil, and the number of turns of the coil.

[0123] 14. The sensor of any one of items 1 to 6, wherein the initial permeability of the magnetic core is greater than a permeability threshold.

[0124] 15. An invasive medical device, comprising: the sensor of any one of items 1 to 15.

[0125] 16. A medical system for magnetic position sensor tracking, comprising: an invasive medical device according to item 15; and a signal processing device for processing a lead-out signal of the magnetic position sensor in the invasive medical device.

[0126] The embodiments of the present application also provide the following configurations:

[0127] 1. A signal processing device for processing an induced signal of a magnetic position sensor, comprising: a preamplification circuit for amplifying the induced signal of the magnetic position sensor and suppressing a common-mode interference signal of the induced signal; a filter circuit connected to the preamplification circuit for filtering a signal output by the preamplification circuit at a preset cutoff frequency; a main amplification circuit connected to the filter circuit for amplifying a signal output by the filter circuit; and a notch filter circuit connected to the main amplification circuit for eliminating noise in a signal output by the main amplification circuit.

[0128] 2. The signal processing device according to item 1, wherein the preamplification circuit comprises: a gain adjustment circuit for adjusting an amplification factor of the preamplification circuit, comprising a first resistor R1, a second resistor R2 and a third resistor R3, wherein the first resistor R1 and the second resistor R2 are connected in series and then connected in parallel with the third resistor R3, and two output ends are formed at two ends of the parallel connection; and an operational amplifier chip having two gain adjustment pins connected to the two output ends of the gain adjustment circuit, the operational amplifier chip amplifying the induced signal of the magnetic position sensor based on the adjustment of the gain adjustment circuit.

[0129] 3. The signal processing device according to item 2, wherein the filter circuit comprises: a low-pass filter circuit connected to the preamplification circuit for allowing a signal having a frequency lower than a first cutoff frequency in a signal output by the preamplification circuit to pass; and a high-pass filter circuit connected to the low-pass filter circuit for allowing a signal having a frequency higher than a second cutoff frequency in a signal filtered by the low-pass filter circuit to pass.

[0130] 4. The signal processing device according to item 3, wherein the low-pass filter circuit comprises: a low-pass dual operational amplifier chip having a positive input pin, a negative input pin and an output pin, wherein the positive input pin is connected to an output end of the preamplification circuit through a fifth resistor R5 and a fourth resistor R4, and the positive input pin is further connected to ground through a fourth capacitor C4, and the output pin is connected to the fourth resistor R4 through a first capacitor C1.

[0131] 5. The signal processing device of item 3, wherein the high-pass filter circuit comprises a high-pass dual operational amplifier chip having a positive input pin, a negative input pin and an output pin, the negative input pin is connected to the output pin, the positive input pin is connected to the output pin of the low-pass filter through a second capacitor C2 and a third capacitor C3 in sequence, and the positive input pin is connected to the ground through a sixth resistor R6.

[0132] 6. The signal processing device of item 1, wherein the main amplification circuit comprises a main operational amplifier chip, a negative input pin of the main operational amplifier chip is connected to the ground through a tenth resistor R10 and connected to an output pin through a ninth resistor R9, and a positive input pin of the main operational amplifier chip is connected to the output pin of the high-pass filter circuit and connected to the ground through a fifteenth resistor R15.

[0133] 7. The signal processing device of item 1, wherein an attenuation adjustment circuit is connected to the output end of the notch filter circuit, for adjusting the notch multiple of the bipolar operational amplifier; the bipolar operational amplifier is connected to the attenuation adjustment circuit, for eliminating the noise in the output signal of the main amplification circuit and filtering out the power frequency signal in the output signal of the main amplification circuit based on the adjustment of the attenuation adjustment circuit, and for notching the output signal of the main amplification circuit.

[0134] 8. The signal processing device of item 7, wherein the attenuation adjustment circuit comprises a fifth capacitor C5 and a sixth capacitor C6 connected in series, an eighth resistor R8 and a fourteenth resistor R14 connected in series, an eleventh resistor R11, a thirteenth resistor R13 and a twelfth resistor R12 connected in series, and a seventh capacitor C7, wherein the fifth capacitor C5 and the sixth capacitor C6 connected in series are connected in parallel with the eighth resistor R8 and the fourteenth resistor R14 connected in series, and are connected to the positive input pin of the bipolar operational amplifier after being connected in parallel; the negative input pin of the bipolar operational amplifier is connected to the output pin thereof through the eleventh resistor R11 and connected to the ground through the thirteenth resistor R13; the output pin is connected to the ground through the eleventh resistor R11 and the thirteenth resistor R13 and connected to the eighth resistor R8 through the seventh capacitor C7.

[0135] 9. The signal processing device of item 1, further comprising: an error compensation module connected to the notch filter circuit, for performing error compensation on the signal output by the notch filter circuit; and a correction module connected to the error compensation module, for correcting the signal after error compensation.

[0136] 10. A medical system for electromagnetic device tracking, comprising: a magnetic field generator for generating a magnetic field signal; an invasive medical device comprising an electromagnetic localization sensor for sensing the magnetic field signal and outputting a sensed signal; a signal processing device as claimed in any one of the items 1 to 9 for processing the sensed signal from the magnetic localization sensor.

[0137] The above-mentioned embodiment numbers of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0138] The integrated units in the above-mentioned embodiments, if realized in the form of software function units and sold or used as independent products, can be stored in the above-mentioned computer-readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the parts that make contributions to the prior art or the whole or part of the technical solutions can be embodied in the form of software products. The computer software product is stored in the storage medium and includes a plurality of instructions for causing one or more computer devices (which can be personal computers, servers or network devices, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application.

[0139] In the above-mentioned embodiments of the present application, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0140] In the several embodiments provided in the present application, it should be understood that the disclosed client can be implemented by other means. Among them, the above-mentioned device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed mutual units can be indirect coupling or communication connection through some interfaces, units or modules, and can be electrical or other forms.

[0141] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place or distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0142] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or software function unit.

[0143] The above merely preferred embodiments of the present application, it should be noted that for those of ordinary skill in the art, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements should also be considered within the scope of the present application.

Claims

1. A signal processing device for processing an induction signal of a magnetic positioning sensor, characterized in that The application relates to a magnetic positioning sensor signal processing circuit, which comprises the following parts: a pre-amplification circuit for amplifying the induction signal of the magnetic positioning sensor and suppressing the common-mode interference signal of the induction signal; a filter circuit connected with the pre-amplification circuit and used for filtering the signal output by the pre-amplification circuit at a preset cut-off frequency; a main amplification circuit connected with the filter circuit and used for amplifying the signal output after being filtered by the filter circuit; a wave trap filter circuit connected with the main amplification circuit and used for eliminating the noise in the signal output by the main amplification circuit; an error compensation module connected with the wave trap filter circuit and used for performing error compensation on the signal output by the wave trap filter circuit; a correction module connected with the error compensation module and used for correcting the signal after error compensation; wherein the correction comprises: regarding the magnetic positioning sensor as a double-output tracking system and defining the tracking error of the magnetic positioning sensor; determining a proportional-integral sliding mode surface according to the tracking error, and correcting the signal after error compensation based on the proportional-integral sliding mode surface; where the tracking error is e(t) = X(t) - X d (t), where X(t) is the magnetic field signal generated by the magnetic field generator, X d (t) is the disturbance signal affecting the magnetic localization sensor from the outside. Wherein, the proportional integral sliding mode surface is Wherein, c is a constant coefficient matrix, B is a full rank matrix, t is the current time, A d is a noise matrix of the disturbance signal, K d is a Hurwitz matrix; wherein the correction mode is: E'(t)=E(t)(epsilon sgn s(t)-s(t)) wherein E'(t) is the corrected signal and epsilon is a correction factor.

2. The signal processing device of claim 1, wherein, The pre-amplification circuit comprises: a gain adjustment circuit for adjusting the amplification multiple of the pre-amplification circuit, which comprises a first resistor R1, a second resistor R2 and a third resistor R3, wherein the first resistor R1 and the second resistor R2 are connected in series and then connected in parallel with the third resistor R3, and two output ends are formed at the two ends of the parallel connection; an operational amplifier chip having two gain adjustment pins, wherein the two gain adjustment pins are connected with the two output ends of the gain adjustment circuit, and the operational amplifier chip amplifies the induction signal of the magnetic positioning sensor based on the adjustment of the gain adjustment circuit.

3. The signal processing device of claim 2, wherein, The filter circuit comprises: a low-pass filter circuit connected with the pre-amplification circuit and used for allowing the signal with a frequency lower than a first cut-off frequency in the signal output by the pre-amplification circuit to pass through; a high-pass filter circuit connected with the low-pass filter circuit and used for allowing the signal with a frequency higher than a second cut-off frequency in the signal filtered by the low-pass filter circuit to pass through.

4. The signal processing device of claim 3, wherein The low-pass filter circuit comprises a low-pass double operational amplifier chip having a positive input pin, a negative input pin and an output pin, wherein the positive input pin is connected with the output end of the pre-amplification circuit through a fifth resistor R5 and a fourth resistor R4, and the positive input pin is also connected with the ground through a fourth capacitor C4, and the output pin is connected with the fourth resistor R4 through a first capacitor C1.

5. The signal processing device of claim 3, wherein, The high-pass filter circuit comprises a high-pass double operational amplifier chip having a positive input pin, a negative input pin and an output pin, wherein the negative input pin is connected with the output pin, the positive input pin is connected to the output pin of the low-pass filter in sequence through a second capacitor C2 and a third capacitor C3, and the positive input pin is connected with the ground through a sixth resistor R6.

6. The signal processing device of claim 1, wherein, The main amplification circuit comprises a main operational amplifier chip, a negative input pin of the main operational amplifier chip is connected with the ground through a tenth resistor R10 and connected with an output pin through a ninth resistor R9, a positive input pin of the main operational amplifier chip is connected with an output pin of the filter circuit and connected with the ground through a fifteenth resistor R15.

7. The signal processing device of claim 1, wherein The wave filter circuit comprises An attenuation adjustment circuit connected with an output end of the wave filter circuit, used for adjusting the wave multiple of the bipolar operational amplifier; A bipolar operational amplifier connected with the attenuation adjustment circuit, used for eliminating the noise in the output signal of the main amplification circuit and filtering the power frequency signal in the output signal of the main amplification circuit based on the adjustment of the attenuation adjustment circuit, and performing wave filtering on the output signal of the main amplification circuit.

8. The signal processing device of claim 7, wherein, The attenuation adjustment circuit comprises a fifth capacitor C5 and a sixth capacitor C6 connected in series, an eighth resistor R8 and a fourteenth resistor R14 connected in series, an eleventh resistor R11, a thirteenth resistor R13 and a twelfth resistor R12 connected in series, and a seventh capacitor C7, wherein The fifth capacitor C5 and the sixth capacitor C6 connected in series are connected in parallel with the eighth resistor R8 and the fourteenth resistor R14 connected in series, and connected with a positive input pin of the bipolar operational amplifier after being connected in parallel; a negative input pin of the bipolar operational amplifier is connected with an output pin thereof through the eleventh resistor R11 and connected with the ground through the thirteenth resistor R13; the output pin is connected with the ground through the eleventh resistor R11 and the thirteenth resistor R13 and connected with the eighth resistor R8 through the seventh capacitor C7.

9. A medical system for electromagnetic position sensor tracking, the system comprising: Comprise: A magnetic field generator for generating a magnetic field signal; An invasive medical device comprising an electromagnetic positioning sensor for sensing the magnetic field signal and outputting a sensing signal; The signal processing device according to any one of claims 1 to 8, for processing the sensing signal led out by the magnetic positioning sensor.

Images