Method and apparatus for authenticating three-dimensional objects

Abstract

A method for magnetic tracking of a flexible catheter device or a flexible elongate device, the method comprising: receiving, by a host server, a plurality of sensed values of a local magnetic field, the plurality of sensed values sensed by a corresponding plurality of sensors, wherein the host server is optionally comprised in a controller of the plurality of sensors, the plurality of sensors positioned along a flexible tube of a device, wherein the plurality of sensed values are at least partially due to at least one alternating magnetic field generated by at least one magnetic field generator, a source amplitude and a frequency of each alternating magnetic field provided to the host server; and calculating, by the host server, a position of the flexible tube based on the plurality of sensed values and the source amplitude and the frequency of each alternating magnetic field provided.

Description

Background Technology

[0001] Electromagnetic (EM) positioning systems are sometimes used in the medical field to track small catheters inside the body. The reason electromagnetic systems are well-suited for such applications is that the human body is permeable to electromagnetic near-fields. This allows for real-time tracking of catheters or any other instruments, inside or outside the body, without the need for visual contact or the use of any potentially harmful imaging modalities such as X-rays or computed tomography (CT).

[0002] Some known systems may include an electromagnetic field sensor / receiver and an electromagnetic field generator / transmitter that emits multiple different alternating (AC) electromagnetic fields, such as sinusoidal electromagnetic fields. The receiver typically receives a combination of multiple electromagnetic fields from the transmitter and distinguishes between the different fields, for example, by performing a Fast Fourier Transform (FFT) and / or a Discrete Fourier Transform (DFT) or any other suitable method. By analyzing the phase and / or amplitude, the receiver identifies a unique electromagnetic feature associated with a specific position and orientation, such as a specific six-degrees-of-freedom (6DOF) state, for example, three position coordinates and three orientation angles. In other systems, the electromagnetic feature is used only to recover five degrees of freedom (5DOF). In these systems, the sensor's roll angle is typically absent. In other systems, only the position (3DOF) can be solved and the sensor's orientation remains unknown.

[0003] To decompose and / or distinguish received field combinations and identify a unique 6DOF (or 5DOF) state of the monitored object, the transmitter needs to emit multiple electromagnetic sinusoidal field signals at carefully selected frequencies, for example, such that the sinusoidal field signals are orthogonal to each other. Some systems may include N transmitting coils that generate electromagnetic fields with different geometries. The number N should be large enough to identify the 6DOF (or 5DOF) state of the monitored object. In other systems, there may be a smaller number of coils that generate orthogonal (at the source) and / or other highly distinctive electromagnetic field signals. To facilitate field separation and improve system efficiency, the system typically uses high-frequency electromagnetic fields in kilohertz (kHz) frequencies.

[0004] In traditional electromagnetic tracking catheter setups, a catheter will have one or more microcoils placed at its tip. For example, three microcoils need to be placed at the tip of the catheter, traditionally orthogonally, and wires need to be pulled out to connect to an external DSP. Some specialized systems use a single coil instead of three orthogonal coils, but this requires a specialized electromagnetic field generator to generate many different unique fields, and it can only provide a maximum of five degrees of freedom for positioning (lacking roll angle). Generally, single-coil systems are inferior in accuracy and overall stability. The electromagnetic field generator produces a high-frequency (e.g., greater than 1 kHz) alternating magnetic field, which induces an electromotive force (EMF) (according to Faraday's law of induction) in the coils of the catheter. The coils are connected via wires to an external digital signal processor (DSP) unit, which is responsible for amplifying the induced voltage and then sampling it, for example, using an analog-to-digital (A2D) converter. Then, a dedicated processor analyzes the sensed signal, decomposes it into individual sinusoidal vibrations using FFT or DFT (or any other suitable method), and passes the DFT results to another processing stage, which is responsible for converting the calculated field vibrations into the position and orientation of the sensor relative to the field generator in three-dimensional space.

[0005] The DSP unit should include a high-quality, low-noise amplifier to amplify the minute voltage picked up on the microcoil so that the A2D converter can sample it with a good signal-to-noise ratio (SNR). Each such coil requires a separate processing channel with a dedicated high-quality amplifier and A2D input. Furthermore, maintaining a good SNR is difficult; even minimal noise can be amplified and obscure the signal of interest. For example, the wires connecting the coil to the DSP may form a loop through which some magnetic flux flows, thus picking up a certain amount of parasitic, unwanted signal from the transmitted field. This necessitates twisting the wires around the conduit. In addition to the wires, the connectors connecting the conduit to the DSP may also form an undesirable loop that can pick up a certain amount of parasitic signal. The complexity of such a system increases almost linearly with the number of sensors required (number of coils, number of twisted pairs, number of DSP input channels, including more expensive amplifiers and A2D). For all these reasons, one should understand why constructing a traditional electromagnetic conduit using multiple electromagnetic sensors is practically impractical.

[0006] Some devices (such as mobile phones) include an Inertial Measurement Unit (IMU), which provides motion and attitude information for the device. Typically, an IMU includes digital sensors such as a 3-axis accelerometer and a 3-axis gyroscope, and in many cases, a 3-axis magnetometer. The accelerometer senses acceleration in a local three-dimensional (3D) coordinate system. In a normal setup, the accelerometer primarily senses the gravity vector (plus some local linear acceleration that can be filtered out using various sensor fusion methods), thus detecting partial orientation, such as the device's screen (landscape / portrait). The gyroscope senses the device's angular velocity. In many applications, the data received from the accelerometer and gyroscope are combined to provide robust orientation tracking of the device. Because these two sensors have no reference other than gravity (pointing towards the sky), the orientation calculated from the accelerometer and gyroscope typically drifts slowly around the gravity vector. In this sense, orientation tracking based solely on the accelerometer and gyroscope is considered "drifting" because it lacks a stable reference. Magnetometers can be used to sense the direct current (DC) Earth's magnetic field, for example using Hall effect sensors, magnetoresistive sensors, magnetic induction sensors, and / or any other suitable sensor type. The sensed DC Earth magnetic field can be used to correct for drift in accelerometer and gyroscope orientation detection in Earth coordinates. However, magnetometer readings are often distorted by various elements in their environment, such as nearby metals (soft iron, hard iron distortion). Furthermore, low-cost magnetometer sensors are prone to bias calibration problems, i.e., the sensor's internal bias drifts over time. Therefore, in many applications, magnetometer data is ignored, and orientation is detected solely by accelerometers and gyroscopes, although the identified orientation typically drifts over time relative to Earth's north because magnetometer data is ignored and no other sensors are used as an additional reference for orientation. While IMUs are primarily used for orientation detection, they can also be used for relative positioning. Using sensor fusion methods, local acceleration (subtracting gravity) can be extracted from accelerometer readings. This can then be integrated over a short period to calculate the velocity of the device. Dual integration gives the relative position of the device. However, these methods are highly sensitive to bias noise and are therefore typically used only with high-end, high-precision IMU sensors or for very short time periods (e.g., for motion gesture detection). While an IMU can be used in normal settings to calculate a device's absolute orientation relative to Earth coordinates (using data from all three sensors: accelerometer, gyroscope, and magnetometer), no IMU reading provides positional information about the device relative to any absolute reference. To use an IMU for accurate absolute positioning, some external reference must be added. Summary of the Invention

[0007] In one aspect of some embodiments of the present invention, a method for magnetically tracking a flexible conduit device or a flexible elongated device is provided, characterized in that the method includes: receiving, via a host server, a plurality of sensed values ​​of a local magnetic field, the plurality of sensed values ​​being sensed by corresponding plurality of sensors; receiving, via a host server, a plurality of sensed values ​​of a local magnetic field, the plurality of sensed values ​​being sensed by corresponding plurality of sensors, wherein the host server is optionally included in a controller of the plurality of sensors, the plurality of sensors being positioned along a flexible tube of a device, wherein the plurality of sensed values ​​are at least partially caused by at least one alternating magnetic field generated by at least one magnetic field generator, the source amplitude and frequency of each alternating magnetic field being provided to the host server; and, via the host server, calculating a position of the flexible tube based on the plurality of sensed values ​​and the source amplitude and frequency of each provided alternating magnetic field.

[0008] Optionally, the method includes: receiving an instantaneous phase value of an alternating magnetic field from at least one magnetic field generator of an alternating magnetic field via a host server; associating the instantaneous phase value with at least some of a plurality of sensed values ​​received from the plurality of sensors via the host server; and calculating the positioning of the flexible tube based on the plurality of sensed values ​​and the associated instantaneous phase value via the host server.

[0009] Optionally, the association is based on a corresponding clock reading, which is shared or synchronized between the magnetic field generator, a controller of the plurality of sensors, and the host server.

[0010] Optionally, the instantaneous phase value is received from the at least one magnetic field generator at the full rate of a magnetometer located at the at least one magnetic field generator.

[0011] Alternatively, the clock reading can be shared via the magnetic field generator, or via a clock source shared between the magnetic field generator, a controller of the plurality of sensors, and the host server.

[0012] Optionally, the method includes receiving a vortex value of the alternating magnetic field at the source from the at least one magnetic field generator.

[0013] Optionally, the calculation includes calculating the position and orientation of each of the plurality of sensors.

[0014] Optionally, the calculation includes using an extended Kalman filter to fuse sensor data and impose a motion model or shape constraint on the calculation.

[0015] Optionally, at least one of the plurality of sensors is a sensor bundle, and the calculation includes accelerometer readings or gyroscope readings of the plurality of sensors corresponding to the sensor bundle.

[0016] Optionally, the calculation combines the known structural relationships between the plurality of sensors as a whole to calculate an estimate of the position, orientation, or curve of the tube.

[0017] Optionally, the plurality of sensed values ​​are at least partially caused by at least two alternating magnetic fields generated by at least two corresponding magnetic field generators.

[0018] Optionally, the at least two alternating magnetic fields operate at different frequencies.

[0019] Optionally, the at least two magnetic field generators share the same clock or have multiple synchronized clocks or share a clock source.

[0020] In another aspect of some embodiments of the present invention, a system for magnetically tracking a flexible conduit device or a flexible elongated device is provided, characterized in that the system comprises: at least one magnetic field generator, each magnetic field generator configured to generate an alternating magnetic field, wherein each alternating magnetic field has a defined source amplitude and frequency; a device comprising: a flexible tube; a plurality of sensors positioned along the flexible tube, each sensor configured to communicate a plurality of sensed values ​​of a local magnetic field; wherein the plurality of sensed values ​​are at least partially caused by the alternating magnetic field; and a host server configured to: receive the plurality of sensed values ​​of the local magnetic field from the corresponding plurality of sensors; and calculate a position of the flexible tube based on the plurality of sensed values ​​and the defined source amplitude and frequency, wherein optionally the host server is included in a controller of the plurality of sensors.

[0021] Optionally, the host server is configured to: receive an instantaneous phase value of the alternating magnetic field from the at least one magnetic field generator of the alternating magnetic field; associate the instantaneous phase value with at least some of the plurality of sensed values ​​received from the plurality of sensors via the host server; and calculate the positioning of the flexible tube based on the plurality of sensed values ​​and the associated instantaneous phase value via the host server.

[0022] Optionally, the association is based on a corresponding clock source reading, which is shared between the magnetic field generator, the controller of the plurality of sensors, and the host server.

[0023] Optionally, the device further includes a flexible printed circuit board (PCB) along the tube, wherein the plurality of sensors are positioned along the flexible printed circuit board.

[0024] Optionally, the flexible brush circuit board is wound in a spiral manner around one wall of the tube.

[0025] Optionally, the device further includes a communication bus configured to digitally transmit the plurality of sensed values ​​from the plurality of sensors to the host server.

[0026] Optionally, the communication bus includes up to four wires that can transmit digital data from the plurality of sensed values ​​from the plurality of sensors and provide power to the plurality of sensors.

[0027] Optionally, the at least one magnetic field generator includes an internal clock, and the at least one magnetic field generator is configured to share its clock reading with the plurality of sensors and the host server.

[0028] Optionally, the at least one magnetic field generator includes a magnetometer configured to detect the instantaneous phase value.

[0029] Optionally, the at least one sensor is a sensor bundle including an accelerometer or a gyroscope sensor.

[0030] Optionally, the system includes at least two magnetic field generators that generate at least two corresponding alternating magnetic fields, the at least two alternating magnetic fields operating at different frequencies.

[0031] Optionally, the at least two magnetic field generators share the same clock or have multiple synchronized clocks or share a clock source.

[0032] Optionally, the at least one magnetic field generator includes at least one permanent magnet and a motor device, the motor device rotating the permanent magnet at a defined frequency.

[0033] Optionally, the at least one magnetic field generator includes an electromagnetic coil that generates a sinusoidal electromagnetic field at a specific known frequency.

[0034] Optionally, the device includes a plurality of dipole magnets located between the plurality of sensors.

[0035] Optionally, the plurality of dipole magnets are positioned and oriented at equal distances, such that when the tube is in a straight line, the two dipole magnets located on either side of a sensor have opposite dipole directions. Attached Figure Description

[0036] The following figures illustrate some non-limiting example embodiments or features of the disclosed subject matter.

[0037] In the attached diagram:

[0038] Figure 1 This is a schematic diagram of a catheter tracking system for tracking via a digital magnetometer, according to some embodiments of the present disclosure;

[0039] Figure 2 This is a schematic diagram of an exemplary magnetic field generator / transmitter for tracking by a digital magnetometer, according to some exemplary embodiments of the present disclosure;

[0040] Figure 3 This is a schematic flowchart illustrating a method for tracking via a digital magnetometer according to some embodiments of the present disclosure;

[0041] Figure 4 This is a schematic diagram of a catheter according to some embodiments of the present disclosure;

[0042] Figure 5 This is a schematic diagram of a catheter device according to some other embodiments of the present disclosure; and

[0043] Figure 6 This is a schematic diagram of a catheter device according to some other embodiments of the present disclosure.

[0044] Referring now specifically to the accompanying drawings, it is emphasized that the details shown are exemplary and for the purpose of an illustrative discussion of embodiments of this disclosure. In this regard, the description taken in conjunction with the drawings will be readily apparent to those skilled in the art as to how embodiments of this disclosure can be practiced.

[0045] Identical or repeated or equivalent or similar structures, elements or parts appearing in one or more figures are generally labeled with the same reference numerals, and alternatively, additional letters or symbols may be used to distinguish similar entities or variations thereof, without repetition of labeling and / or description. References to previously presented elements are implied without requiring further reference to the accompanying drawings or descriptions in which they appear.

[0046] The dimensions of the components and features shown in the figures are chosen for ease of presentation or clarity and are not necessarily displayed to scale or in true perspective. For ease of presentation or clarity, some elements or structures are not shown or are only partially shown and / or shown from different perspectives or viewpoints. Detailed Implementation

[0047] Before explaining at least one embodiment of this disclosure in detail, it should be understood that the application of this disclosure is not necessarily limited to the construction details and arrangements of the components and / or methods set forth in the following description and / or methods and / or illustrated in the drawings and / or embodiments. This disclosure can have other embodiments or can be practiced or performed in various ways.

[0048] Some embodiments of this disclosure provide a magnetic full-curve catheter tracking system. A magnetic field generator / transmitter according to some embodiments of this disclosure can sense electromagnetic fields on multiple magnetometers placed along a flexible catheter. In some embodiments, the provided system may include at least one specialized magnetic field generator and / or use a specialized magnetic field generation and / or transmission method. A magnetic field generator / transmitter provided according to some embodiments of the invention may be composed of low-cost components.

[0049] The provided system can receive sensor readings of local electromagnetic field values ​​from the plurality of magnetometers and calculate the full-curve positioning of the catheter along its length based on the received readings. This contrasts with conventional electromagnetic field catheter tracking systems, which typically only track the catheter tip. In some embodiments, the provided system can calculate and / or identify 6DOF positioning, for example, based on the three-dimensional position and orientation of each magnetometer relative to the magnetic field generator based on its magnetic sensor readings. In some embodiments, the sensing radius of the magnetometers can be up to approximately 50 cm. Therefore, in some embodiments, the distance between the at least one magnetic field generator and the plurality of magnetometers can be up to 50 cm.

[0050] According to some embodiments, the provided system includes multiple digital magnetometers, such as off-the-shelf magnetic sensors, or magnetometers similar to or identical to those included in an IMU. In some embodiments, a complete IMU sensor bundle is used. The digital magnetometers may have a small footprint and / or size, suitable for insertion into catheters in various body cavities. For example, the magnetometers may be inserted into catheters and / or body cavities and / or catheter walls. For example, the multiple magnetometers (e.g., in an integrated circuit and / or silicon die) may be placed on a flexible printed circuit board (PCB) along the catheter. The multiple magnetometers may be packaged in, for example, a very small wafer-level ball grid array (BGA) package.

[0051] As mentioned throughout this specification, magnetometers typically operate at sampling rates on the order of hundreds of hertz (Hz), such as approximately 100 Hz and / or up to 500 Hz–1000 Hz. To use a direct-current (DC) magnetometer (a sensor for measuring DC magnetic fields) as an alternating-current (AC) magnetic sensor (a sensor for AC magnetic fields), the frequency of the sensed AC magnetic field may be significantly lower than the magnetometer's sampling rate, for example, by an order of magnitude. The sensed magnetic field should be within the detectable range of the DC magnetometer. For example, the sensed magnetic field should be approximately ten times more sensitive than the magnetometer when generated, taking into account noise levels, to facilitate detection by the magnetometer. For example, a DC magnetometer can sensitively detect magnetic fields between a few μT and several thousand μT (e.g., 1 to 4000 μT) with a resolution of approximately 0.1 μT. Since the strength of the magnetic field is inversely proportional to the cube of the distance between the dipole source and the receiver, the sensing range should have a coefficient of about 10 between the minimum and maximum distances, for example, 10 centimeters to 1 meter or 1 meter to 10 meters.

[0052] In some embodiments, the multiple magnetometers are placed along the same data bus and transmit the multiple sensed values ​​through the same data bus. For example, regardless of how many magnetometers are placed along the conduit and / or how much data is transmitted through the data bus, four or fewer wires need to be pulled along the conduit. This contrasts with conventional analog conduit tracking systems, which may require many wires that increase linearly with the number of magnetic sensors.

[0053] Some embodiments of the present invention provide a positioning calculation method that can calculate the full-curve positioning of the catheter at a rate greater than 30 Hz. This rate is suitable for most real-time medical applications. Therefore, some embodiments of the present invention provide a solution to the problem of obtaining real-time full-curve positioning of small-diameter catheters without the high cost of traditional electromagnetic sensors and DSPs. Additionally, in some embodiments, the provided system has low power consumption characteristics, such as at the receiving and transmitting ends, which allows a very small-footprint full-curve catheter positioning system to be operated wirelessly and / or on a battery.

[0054] The ability to construct a full-curve tracking catheter with low cost and uncomplicated construction, as provided by some embodiments of this disclosure, is important for many potential medical applications.

[0055] Now for reference Figure 1 , Figure 1This is a schematic diagram of a catheter tracking system 100 for tracking via a digital magnetometer, according to some embodiments of the present disclosure. According to some embodiments of the present disclosure, system 100 provides a solution for full-curve catheter positioning. System 100 may include a catheter 30, a hardware host server 10, and at least one magnetic field generator / transmitter 20, such as magnetic field generators / transmitters 20a and 20b. As described herein, system 100 can provide full-curve positioning of the catheter 30 along its length. In some embodiments of the present disclosure, the host server 10 is included in a controller within the catheter 30, for example, all functions of the host server 10 described herein are performed by a controller within the catheter 30. The terms controller and microcontroller are sometimes used interchangeably throughout the present disclosure and may also refer to or include a microprocessor.

[0056] The transmitter 20 can generate a magnetic field. For example, the transmitter 20 is an electromagnetic generator of the magnetic field, which includes, for example, at least one electromagnetic coil. Each magnetic field generator 20 can generate an alternating magnetic field. Each generated alternating magnetic field has a defined source amplitude and frequency. In some embodiments, the transmitter 20 may include a sensor that senses an instantaneous phase of the generated electromagnetic field or calculates the instantaneous phase of the generated electromagnetic field using a synchronized electromagnetic field generator driver and communicates it with the host server 10, for example, periodically, communicating the instantaneous phase value and a timestamp.

[0057] In some embodiments of this disclosure, the transmitter 20 may include at least one rotating magnet, such as Figure 2 As shown in more detail herein, in some embodiments, transmitter 20 may include a sensor that senses an instantaneous phase of the rotating magnet or calculates the instantaneous phase of the rotating magnet using a synchronized motor driver and communicates it with host server 10, for example, periodically, communicating the instantaneous phase value and a timestamp.

[0058] The conduit 30 may include a microcontroller 32, a flexible tube 36, and multiple magnetometer sensors 31, for example, along a flexible printed circuit board (PCB) (in) along the tube 36. Figure 4 (As shown in more detail below) is implemented on the tube 36. The magnetometer sensor 31 can be placed at multiple predetermined locations along the tube 36 and / or within predetermined distances between them. According to some embodiments, the magnetometer sensor 31 may be or include off-the-shelf magnetic sensors, for example, magnetic sensors similar to or identical to those included in an IMU or a separate off-the-shelf magnetic sensor. In some embodiments, each magnetometer sensor 31 may be or include a complete IMU sensor bundle.

[0059] Each of the plurality of magnetometer sensors 31 can sense a corresponding local magnetic field value generated by the magnetic field generated by the transmitter 20. The host server 10 / microcontroller 32 can receive magnetic field values ​​from the sensors 31, and / or the microcontroller 32 can transmit the sensed values ​​along with timestamps to the host server 10 / microcontroller 32. For example, the microcontroller 32 can receive and / or collect at least one local and transient magnetic field value from the corresponding at least one sensor 31, such as a value sensed at a certain moment, and transmit the collected value along with the corresponding timestamp, for example via USB, wireless communication, etc. For example, the microcontroller 32 can transmit the collected sensed values ​​and the identifier of the corresponding sensing sensor 31, for example for each sensed value. As described in more detail herein, the sensors 31 can be communicatively connected to the microcontroller 32 and / or the host server 10 via the same data bus 34 placed along the tube 36. In some embodiments of this disclosure, at least some of the functions of the host server 10 described throughout this specification are performed by the microcontroller 32. In some embodiments, all functions of the host server 10 are defined by reference to Figure 2 The microcontroller 32 and / or processor / controller 27 described herein shall execute this.

[0060] The flexible tube 36 can be positioned in various locations and can have various transient curve shapes, such as according to the shape of the body organ into which it is inserted and / or according to the obstacles encountered by the tube.

[0061] The host server 10 / microprocessor 32 may include at least one hardware processor 12 and / or at least one hardware memory 14. The memory 14 may include a tangible, non-transitory processor-readable storage medium storing processor-readable program instructions thereon for causing the processor 12 to perform various aspects of this disclosure. The system 100 may include a display device 16 configured to receive data and / or instructions from the host server 10 and display information based on the received data and / or instructions. The display device 16 may display, for example, navigation instructions to guide a physician to a point of interest within the body.

[0062] The magnetometer sensor 31 may be and / or include a digital sensor magnetometer configured to provide sensor digital outputs, and the magnetometer sensor may be low-cost and / or have a small footprint. In some embodiments, each of the plurality of sensors 31 may be or include a standard IMU, which may include a magnetometer, an accelerometer, and / or a gyroscope. The plurality of sensors 31 may be positioned along the same digital communication bus 34 and / or communicate sensor digital outputs to the microcontroller 32 and / or server 10 via the same digital communication bus 34. For example, the sensor 31 may sense local electromagnetic field values ​​simultaneously or within a very short time of a few milliseconds along the curve of the tube 36, and / or transmit these values ​​to the microcontroller 32 and / or server 10 via the same bus 34, for example simultaneously or within a very short time of at most a few milliseconds or tens of milliseconds. The host server 10 / microprocessor 32 can receive the sensed local magnetic field values ​​from the corresponding plurality of sensors 31, and / or can calculate the positioning of the flexible tube 36, for example, based on the sensed local magnetic field values ​​and the determined source amplitude and frequency of the magnetic field generated by the transmitter 20.

[0063] Each sensor 31 can be individually identified by the microcontroller 32 and / or the server 10. For example, the microcontroller 32 and / or the server 10 can associate each received electromagnetic field value with the corresponding sensor 31 that sensed that value. For example, the microcontroller 32 can send the sensed value along with an identifier code identifying the sensor that sensed the value to the server 10. In some embodiments, the sensed value and / or identifier code are sent along with a timestamp, which, for example, indicates the time of sample readout. As described in more detail herein, the host server 10 / microprocessor 32 can calculate the 6DOF position of the corresponding sensor based on the received sensed value and / or timestamp and / or phase data received from at least one generator 20, and / or calculate a full-curve position of the conduit 36 ​​based on the multiple sensed values ​​received from the multiple sensors 31. For example, such calculations can be performed by applying shape constraints and / or curve constraints. In some embodiments of the invention, system 100 may include any suitable number of sensors 31 along tube 36, for example without significantly increasing system complexity, such as because multiple sensors 31 transmit the sensed values ​​via the same data bus 34. For example, in some embodiments, a DSP input channel is not required to amplify, sample, and transmit the magnetic values ​​from the sensors 31 to the microcontroller 32 and / or server 10.

[0064] In some embodiments, system 100 is synchronized, for example, by sharing a clock among its components. For example, generator / transmitter 20 may include an internal clock and / or may share its clock readings with multiple sensors 31, microcontroller 32, and / or server 10 and / or other generators / transmitters, as described in more detail herein. In some embodiments of this disclosure, at least some components of system 100 synchronize their respective clocks with an external clock. Microcontroller 32 may receive its respective sensed values ​​from multiple sensors 31. For example, microcontroller 32 may receive sensed data sampled by multiple sensors 31 and written to data bus 34 via data bus 34. In some embodiments, microcontroller 32 transmits the data to host server 10, for example, along with a corresponding timestamp. For example, the timestamp may correspond to individual clock readings received from transmitter 20, or be based on another shared clock. Server 10 may receive data from transmitter 20 and multiple sensors 31 and / or synchronize the data according to the timestamp. For example, the shared clock or external clock may include a dedicated crystal oscillator connected to all devices, a USB hub clock shared among all devices connected to the USB hub, a clock generated by a radio frequency (RF) master source and shared among multiple RF devices, or a GPS clock sensed by at least some of the devices in system 100.

[0065] In some embodiments, transmitter 200 may use multiple electromagnetic coils to generate a low-frequency magnetic field. The frequency may be sufficient (e.g., up to 500 Hz) to perfectly match the sampling rate of the multiple sensors 31, such that the sensors 31 can sample the magnetic field at least at the minimum rate required to retain all the necessary information, such as the amplitude, frequency, and / or phase of the sensed magnetic field. In magnetometer sensitivity and / or signal-to-noise ratio (“SNR”) sensing, the generated magnetic field may be sufficiently strong within the sensing radius (e.g., stronger than 1 μT) to obtain high-quality samples. Sensors 31 may collect enough samples to perform a Discrete Fourier Transform (“DFT”) or similar algorithm to separate the generated magnetic field and resolve the 6DOF localization of the multiple sensors 31 and / or tube 36. In some cases, to provide a low-latency, high-speed 6DOF solution, phase information may be provided by transmitter 20 and synchronized between transmitter 20 and sensors 31 and / or microcontroller 32. In this way, the microcontroller 32 and / or the host server 10 can know the instantaneous phase of the generated alternating magnetic field and can generate a fast 6DOF solution (as explained herein) by using the synchronization phase information and timestamps in an extended Kalman filter setting.

[0066] As described in more detail in this article, for example, see references Figure 2According to some embodiments of the present invention, the magnetic field generator / transmitter 20 includes a rotating magnet and a rotation sensor, such as a magnetometer, which senses the instantaneous phase of the rotating magnet, for example, wherein the magnet is on its rotational track at a given moment. For example, the rotation sensor is configured to transmit instantaneous phase information to the server 10, for example, together with a corresponding timestamp of the clock reading, for example, at full rate.

[0067] For example, based on their matching timestamps, server 10 can correlate a specific phase state of the generated alternating magnetic field with corresponding local magnetic field readings received from multiple sensors 31, which are simultaneously sensed and / or transmitted along with the phase readings. Based on the magnetic field readings and the correlated instantaneous phase readings, server 10 / microprocessor 32 can calculate the full-curve duct positioning, for example, in real time. For example, the host server 10 / microprocessor 32 can receive an instantaneous phase value of the generated alternating magnetic field from at least one magnetic field generator 20 of an alternating magnetic field, correlate the instantaneous phase value with at least some of the multiple sense values ​​received from the multiple sensors 31, and / or calculate the positioning of the flexible tube 36 based on the multiple sense values ​​and the correlated instantaneous phase value.

[0068] It should be understood that system 100 may include multiple catheters 30, and server 10 may, for example, simultaneously calculate the full-curve catheter positioning of multiple catheters 30.

[0069] Now for reference Figure 2 , Figure 2 This is a schematic diagram of an exemplary magnetic field generator / transmitter 20 for tracking via a digital magnetometer, according to some exemplary embodiments of the present disclosure. The generator / transmitter 20 may include at least one permanent magnet 22, a processor / controller 27 having an internal clock 28 and a communication interface 29, a motor assembly 21, a magnetometer 25, and a power supply 24.

[0070] Some embodiments of the present invention do not require, as Figure 2 The configuration of the generator / transmitter 20 shown and described herein is subject to other suitable configurations, components, and / or structures of the generator / transmitter 20 according to some embodiments of the invention.

[0071] In some embodiments, the generator / emitter 20 generates a low-frequency electromagnetic field, for example, less than 60 Hz, with an intensity of, for example, about 1 μT or stronger, at a distance of about 1 meter from the transmitter. Typically, to generate such a strong field with alternating current according to Ampere's law, a very large and very power-consuming transmitter would be required. However, according to some embodiments of the invention, the generator / emitter 20 includes at least one permanent magnet 22 that generates the magnetic field. The magnetic field generated by the generator / emitter 20, through the magnetic field produced by at least one permanent magnet, can be approximately one hundred times stronger than a magnetic field generated by an alternating current from a transmitter of similar size, resulting in a very low-power transmitter. The material of the magnet is chosen to maximize the strength of the generated magnetic field relative to the size of the generator / emitter 20. For example, the generator / emitter 20 may include a rare-earth magnet, such as a neodymium magnet, or a magnet of another suitable material.

[0072] To generate an alternating magnetic field, in some embodiments of the invention, the magnet 22 is mounted on a rotating shaft and operates at a desired operating frequency f, for example by a motor device 21, such as a DC motor, or by a plurality of electromagnetic coils wound around the magnet 22, generating a weak alternating field strong enough to rotate the magnet around its center by the torque applied by them, or by a readily available electromagnetic single-axis coil placed near the magnet 22, strong enough to rotate the magnet by the torque applied by them, or any other suitable means. Thus, for example, rotating the magnet 22 results in an alternating (AC) magnetic field in the surrounding space. The magnetic field generated by rotating the magnet 22 can be represented as the superposition of two alternating magnetic fields of frequency f and orthogonal phase, and generated by two separate dummy coils x and y:

[0073]

[0074] Where φ(t) is the phase during the rotation of magnet 22. In a perfect setup, φ(t) = ωt, meaning the transmitter produces a completely fixed frequency ω = 2πf, but in more practical scenarios, this is only an approximation, which can be expressed as: B x It is the dipole magnetic field generated by the "x" virtual coil, B y It is the dipole magnetic field generated by the "y" virtual coil. In other words, B x B yThese are two magnetic fields corresponding to the virtual "x" and "y" axes of the rotating magnet 22, respectively. It should be understood that, according to some embodiments of the invention, the magnet 22 can be controlled to move according to other, for example, more complex motion models. For example, the magnet 22 can rotate about a time-varying axis. For example, the motion of the magnet 22 can include a combination of rotational motion about a fixed axis and a periodic linear motion parallel to said fixed axis. Other motion models are also within the scope of the invention. In some embodiments, a more complex motion model can add an additional orthogonal virtual coil "z", whose dipole field is represented as... Furthermore, it enhances position and orientation calculations. This also maintains the ability of the magnetometer 25 to detect the instantaneous position, such as phase, of the magnet 22.

[0075] In some embodiments, magnet 22 may be controlled by generator 20 to rotate about an additional secondary axis to obtain a more complex magnetic field sensed by receiver 20, thereby providing more information, for example, for position and orientation calculations. Magnetometer 25 may sense the correspondingly generated alternating magnetic field and accordingly calculate the instantaneous phase of magnet 22 in its rotational motion about the first and second axes, and send the calculated instantaneous phase to receiver 20. For example, cyclic motion of magnet 22 is generated by mounting magnet 22 and / or a first motor on a camshaft of a second motor. For example, by mounting magnet 22 on a shaft, cyclic motion about the first and second axes is applied to magnet 22, the shaft being freely rotatable and axially movable, and the shaft including a radial pin that engages in a groove in a surrounding sleeve. Optionally, the groove is in the shaft and the pin extends radially from the sleeve into the groove.

[0076] Processor / controller 27, such as a microcontroller / controller, can maintain motor 21 at a permanently desired frequency f and / or magnet 22 at a permanently desired frequency f. For example, a desired frequency f is inherent in and / or embedded in the hardware of controller 27 and / or transmitter 20. For example, motor device 21 can be a highly stable motor and / or a specially designed motor, for example, to operate according to a clock 28 of controller 27, or otherwise maintain a substantially constant frequency. In one embodiment, controller 27 can switch between various possible frequencies to maintain a closed feedback loop with magnetometer 25 (rotation sensor) having the transmitter, for example by maintaining a corresponding voltage level supplied to the motor, thereby causing the transmitter to generate an alternating field at a desired maintained frequency f. In some embodiments, controller 27 may include hardware and / or software components for changing said frequency f. The maintained frequency f can be transmitted to receiver / sensor 20, for example, via controller 27, such as via communication interface 29. The communication interface 29 may include a low-power radio transmitter / receiver, such as a 2.4 GHz transmitter / receiver, and / or a low-energy Bluetooth device, a WiFi communication device, a USB cable, or any other suitable communication device.

[0077] According to some embodiments of the invention, the magnetometer 25 may be located at a fixed position relative to the rotating magnet 22. The magnetometer 25 can sense the rotation period of the magnet 22 and the magnet 22, wherein the periodic magnet 22 is, for example, located at the instantaneous rotation phase φ(t) of the magnet 22. As shown in more detail herein, the rotation phase of the magnet 22 may include one or two rotation phases about corresponding one or two axes. The magnetometer 25 can provide a phase estimate of the magnet 22, for example by principal component analysis (PCA) of magnetic samples collected over many rotation periods, such as by extracting the axis of an ellipse plotted in a local coordinate system centered on the transmitter 20 by rotating the magnet 22, or any other suitable method for detecting the phase of the magnet 22, such as by optimizing the fitting of the ellipse to samples collected over many rotation periods of the rotating magnet. According to some embodiments of the invention, the magnetometer 25 is placed at and / or on the rotation axis of the rotating magnet. Due to symmetry, when the magnet rotates, the sensed magnetic field forms an approximate circle or ellipse at the position of magnetometer 25. The formed ellipse / circle can be identified, for example, by server 10 / microcontroller 32. For example, the ellipse / circle can be fitted to the periodic curve shape of the sensed magnetic field, for example, by host server 10 / microprocessor 32. For example, server 10 / microprocessor 32 can approximate the periodic curve shape of the sensed magnetic field as a circle and / or calculate the instantaneous phase state of the magnetic field generated within this circle.

[0078] The rotation frequency of magnet 22 can be significantly lower than the sampling rate of magnetometer 25, for example, in the range of approximately 100 Hz to 1000 Hz, allowing for a more accurate estimation of the rotation phase of magnet 22. Therefore, in some embodiments of the invention, the rotation frequency of magnet 22 is much lower than the sampling rate of magnetometer 25, for example, by an order of magnitude, which, depending on the sampling rate of magnetometer 25, can be as high as approximately 10 Hz to 100 Hz. Thus, processor / controller 27 can calculate the rotation phase of magnet 22 and / or transmit the calculated phase to receiver server 10, for example, via interface 29. In some embodiments, magnet 25 may be included in a sensor bundle, for example, in an IMU chip.

[0079] According to some embodiments of this disclosure, unlike conventional magnetic / electromagnetic field transmitter units, transmitter 20 can generate a magnetic field without using current to induce it. Transmitter 20 utilizes an existing magnetic field generated by permanent magnet 22. Therefore, transmitter 20 consumes significantly less power than conventional transmitter units, allowing it to operate for, for example, tens of hours on several standard batteries. Thus, the power supply 24 that can power transmitter 10 can be a low-power source, such as a disposable and / or rechargeable battery and / or any other suitable low-power source. Rotating the magnet using a standard DC motor or by a weak alternating field generated by a coil near the magnet, which applies torque to the magnet and causes it to rotate, consumes significantly less power than generating the same alternating field using a standard electromagnetic transmitter.

[0080] Now for reference Figure 3 , Figure 3 This is a schematic flowchart illustrating a method 300 for tracking via a digital magnetometer according to some embodiments of the present disclosure. As shown in block 310, server 10 can receive data from generator / transmitter 20 regarding an instantaneous phase of a generated alternating magnetic field, such as an instantaneous rotational phase of permanent magnet 22, or a corresponding clock reading of clock 28. For example, server 10 can receive the phase data from generator / transmitter 20 within a predetermined period and / or each time magnetometer 25 detects a phase of the generated alternating magnetic field. Additionally, server 10 can receive and / or extract the amplitude of the magnetic field generated at the source, i.e., at transmitter 20, such as from magnetometer 25 and / or through predefined calibration data stored in server 10.

[0081] As shown in box 320, server 10 can receive a sensed value of a local magnetic field, which is sensed by at least one of a plurality of sensors 31 along the flexible tube 36, the sensors sensing the magnetic field generated by generator / emitter 20. Since sensor 31 senses the generated magnetic field in its local coordinate system, the magnetic field reading is rotated according to its orientation relative to generator / emitter 20, for example, the following magnetic field measurement results are generated by sensor 31:

[0082] M RX (t)=R t (t)M(t)+M0

[0083] Where R is a 3x3 matrix representing the orientation of sensor 31 in the coordinates of generator / transmitter 20, M0 is a sensor bias of sensor 31, and M(t) is the generated magnetic field, for example, the ambient magnetic field is applied at the position of sensor 31 in the coordinates of generator / transmitter 20.

[0084] In some embodiments of the invention, where a single generator / transmitter 20 is included in the system 100, the local magnetic field at the location of one of the plurality of sensors 31 can be represented as the superposition of two alternating magnetic fields with frequency f and orthogonal phase, and generated by two separate virtual coils x and y of the transmitter 20:

[0085]

[0086] Where B0 is the environmental magnetic field (e.g., the Earth's magnetic field), B x B y This is due to the magnetic field generated by the virtual coil of the generator / transmitter 20. The position of sensor 31 at time t is given, and φ(t) is the sensing phase of generator / transmitter 20 at time t (e.g., sensed by magnetometer 25). Therefore, the sensed magnetic field M... RX (t) For example, the position and orientation of sensor 31 are transmitted and / or extracted via server 10, wherein phase φ(t) is received from generator / transmitter 20, and wherein time t is a shared reading of clock 28 or a shared reading of an external clock source shared among at least some components of system 100.

[0087] As shown in box 330, based on a corresponding shared clock reading from an external clock source shared between clock 28 or multiple components of system 100 (e.g., server 10 and sensors 31 and / or microcontroller 32), server 10 can correlate a sensed instantaneous phase of magnet 22 sensed and / or communicated by magnetometer 25 and / or generator / transmitter 20 with sensed magnetic field values ​​received from multiple sensors 31.

[0088] As shown in box 340, based on the received sensed magnetic field value and the phase of the associated magnet 22, server 10 can calculate the position and orientation of sensor 31 and / or the overall position, orientation, and / or the curvilinear positioning of tube 36, wherein sensor 31 provides, for example, a sensed magnetic field value for 6DOF or 5DOF positioning of each sensor 31. According to some embodiments, server 10 can be used to calculate accelerometer and / or gyroscope readings of corresponding sensors included in sensor 31 in some embodiments of this disclosure.

[0089] According to some embodiments of this disclosure, sensor 31 needs to have a minimum size and therefore may not include, for example, a gyroscope and / or accelerometer and / or other additional sensors. In this case, system 100 may include more than one generator / transmitter 20, such as generator / transmitter 20a and 20b, for example, to enable more accurate calculation of 6DOF or 5DOF positioning.

[0090] Both generators / emitters 20a and 20b can generate alternating magnetic fields, for example, at different frequencies (which are not necessarily orthogonal). Generators / emitters 20a and 20b can be located in a fixed position and orientation relative to each other, and / or in a relative position and / or relative orientation that can be calculated and / or adjusted, for example by manual and / or computer calibration.

[0091] Similar to a single generator / emitter 20, generators / emitters 20a and 20b can generate magnetic fields M1(t) and M2(t) respectively, which can be expressed as:

[0092]

[0093]

[0094] Among them These represent the positions of sensor 31 in the coordinates of transmitters 20a and 20b, respectively. φ1(t) and φ2(t) are the phases tracked by magnetometer 25 of transmitters 20a and 20b, respectively. x1 B y1 B is due to the magnetic field generated by the virtual coil of transmitter 20a. x2 B y2 The magnetic field is generated by the virtual coil of transmitter 20b. Generators / transmitters 20a and 20b can share the same clock and / or have synchronized clocks.

[0095] The magnetic field sensed by sensor 31 can be expressed as:

[0096]

[0097] Where R1 and R2 are 3x3 matrices, representing the orientation of sensor 31 in the coordinates of generator / emitter 20a and 20b, respectively; B0 is the ambient magnetic field (e.g., Earth's magnetic field); and M0 is a sensor bias of sensor 31. Since the positions of generator / emitter 20a and 20b are fixed relative to each other, R2 and / or It can be easily obtained from R1 and / or It can be deduced, and vice versa, for example, through simple relationships:

[0098] T 12 ·[R1; r1] = [R2; r2]

[0099] Where T 12 This is a known rigid transformation that converts the coordinates of transmitter 20a to the coordinates of transmitter 20b, and vice versa. Therefore, when system 100 includes two generators / transmitters 20a and 20b, it may not be necessary to solve for the two relative positions and two relative orientations for each sensor 31. Solving for the position and orientation relative to the first transmitter may be sufficient, and this can be converted to the coordinate system of the second transmitter. Therefore, server 10 can base its calculations on the received sensed magnetic field. The 6DOF position and orientation of sensor 31 are calculated using the phase and clock readings of the sensed magnetic field received from generators / transmitters 20a and 20b, for example, in a duct positioning algorithm implemented in server 10 / microcontroller 32.

[0100] It should be understood that the 6DOF positioning solution for sensor 31 and / or tube 36 is flexible enough and independent of any specific implementation, structure, and / or configuration of transmitter 20, as long as the instantaneously generated magnetic field at various locations in space is known. In a general setup, the magnetic field read by a sensor 31 can be described as:

[0101]

[0102] in, It is at point And the known generated magnetic field in the coordinates of the generator / emitter 20 at time t. For example, It can be modeled as a superposition of general sinusoidal electromagnetic coil fields of different frequencies, for example:

[0103]

[0104] in f is the magnetic field generated by the i-th electromagnetic coil. i It is the operating frequency of the i-th electromagnetic coil.

[0105] In some embodiments of this disclosure, a Kalman filter can be used to track the position and / or orientation state of sensor 31. By using the Kalman filtering algorithm, a faster refresh rate for updating the detection state of sensor 31 and better overall tracking performance can be obtained. It should be understood that in a positioning system based on a low-frequency magnetometer, where the sampling rate of sensor 31 can be, for example, between 100 Hz and 1000 Hz, the magnetic field frequency of transmitter 20 can be limited to approximately 10 to 100 Hz. In this case, a positioning algorithm that relies on decomposing the entire period of a sine wave into field amplitudes is destined to suffer from slow refresh rates and poor overall tracking performance, which is unacceptable for most medical applications. In some embodiments of this disclosure, server 10 addresses the slow refresh rate problem by using a Kalman filter algorithm incorporated into its catheter positioning algorithm, which in some embodiments can produce a refresh rate of at least 100 Hz, fast enough for most medical applications.

[0106] Server 10 can use a mathematical model to describe the motion of conduit 36. In some embodiments, server 10 can independently track each sensor 31. For example, server 10 can predict the state of sensor 31 in the next time frame, for example based on the state in a current time frame, and / or based on IMU sensor bundle measurements that can be used to correct the prediction. For example, a motion model can use a constant and / or damped velocity for the position and / or orientation of sensor 31. For example, server 10 can use the state vector of sensor 31 in a Kalman filter algorithm. The state vector can consist of multiple parameters, such as M0, B0, etc. Q, This could be a sensor bias, ambient magnetic bias, transmitter position in the 20 / 20a coordinate system, transmitter orientation in the 20 / 20a coordinate system (represented as a quaternion), transmitter velocity in the 20 / 20a coordinate system, and angular velocity in the local coordinate system (not to be confused with the frequency of the transmitting magnetic field, sometimes also represented by ω). The changes in M0 and B0 may be slow enough to be modeled as constants or close to constants. Deviations from constant velocity, such as the presence of linear acceleration and angular acceleration, and / or deviations from constant ambient magnetic field and sensor bias, can be modeled, for example, with the corresponding covariance matrix, as process noise.

[0107] After defining the state vector and its dynamic model, server 10 can predict a state vector of sensor 31 and / or the state covariance between consecutive time frames. The state vector can then be corrected based on the prediction to better fit newly acquired sensor magnetic field readings. For example, magnetic measurements are modeled as... The tracking state vector may produce a vector that deviates only from the latest sensed magnetic reading and contains only a small amount of random noise. Its standard deviation can be set according to its typical value, for example, from the datasheet of the corresponding magnetometer.

[0108] In some embodiments, the motion model used by server 10 is modular and / or scalable. For example, in the presence of optional accelerometer or gyroscope sensors, such as in sensor 31, the Kalman filter can be extended to include an additional state with linear acceleration. Accelerometer-gyroscope readings can be processed in an IMU fusion filter to distinguish between gravitational acceleration and linear acceleration. Then, during state vector correction, the calculated linear acceleration can be used as... The measured values ​​are input into the Kalman filter, while the gyroscope readings can be used as... The measured values. Additional accelerometer-gyroscope readings can significantly reduce filter latency and provide higher rates and more stable positioning.

[0109] In another configuration, instead of separating "classic" IMU-fused directional tracking with magnetometer-based 6DOF tracking, additional IMU data (accelerometer, gyroscope) can be combined with magnetometer readings into a unified extended Kalman filter. The state of this filter might be: (As described above). This unified filter can be represented by a constant (or damped) acceleration model to indicate its position. Each sensor 31 (magnetometer, optional accelerometer, and gyroscope) can provide measurements for the "update" step, where the state of the filter is needed to interpret all measurements. For example, magnetic measurements can use M0, B0, Q uses To explain, accelerometer measurements (the superposition of gravitational acceleration and linear acceleration) can be achieved by combining Q, To indicate, gyroscope measurements can be directly used Let me explain.

[0110] Using an extended Kalman filter to solve for the 6DOF localization of sensor 31 and / or tube 36 can be easily generalized to any type of transmitter 20, not limited to a reference. Figure 2 The transmitter 20 is described. The filter functions fully and provides a fast 6DOF solution, provided that the states can be used to interpret each magnetic measurement. This is an excellent characteristic of extended Kalman filters, where a high-quality solution for the states requires only the ability to model the measurements using those states.

[0111] For example, in the case of using an electromagnetic generator transmitter 20 that generates a magnetic field through an electromagnetic coil. A more general formula can be used instead:

[0112]

[0113] in The choice of transmitter 20 depends on the magnetic field generated by the transmitter being used. This makes the use of the extended Kalman filter for the 6DOF positioning solution of sensor 31 / tube 36 independent of the transmitter selection, which is very powerful and flexible for many general purposes.

[0114] According to some embodiments of this disclosure, server 10 may use known structural relationships between multiple sensors 31 in its conduit positioning algorithm to calculate an estimate of the position, orientation, and / or curve of the entire tube 36, for example, rather than calculating the position and / or orientation of each of the multiple sensors 31 individually.

[0115] Now for reference Figure 4 , Figure 4 This is a schematic diagram of a conduit 30 according to some embodiments of the present disclosure. The conduit 30 may include a flexible printed circuit board 33 located within and / or along the conduit 36. The flexible printed circuit board 33 may be communicatively connected to a microcontroller 32, for example via the same data bus 34, which may include a small number of wires 35, for example, two to four wires 35. For example, an inter-integrated circuit (I2C) may be used as a digital interface between the microcontroller 32 and a plurality of sensors 31 mounted along the flexible printed circuit board 33. In some embodiments, it requires only two wires 35 for data exchange between the sensors and the microcontroller 32, which may be advantageous for small conduits where a small number of wires should be maintained.

[0116] In an exemplary configuration, the flexible printed circuit board 33 may have eight, five, ten, or any suitable number of sensors 31 mounted thereon, all connected to the same I2C bus (e.g., serial data and serial clock lines). In some embodiments, the microcontroller 32 is connected to the flexible printed circuit board 33 using a four-wire shielded cable, for example, including voltage and / or ground lines. The microcontroller 32 may provide voltage and / or ground to the multiple digital sensors 31, for example, attached to two data lines, for readings of digital measurements of the sensors 31. The microcontroller 32 may, for example, read the multiple sensors 31 sequentially and transmit the sensor readings to the server 10, for example, via wired and / or wireless communication. In a slightly different configuration, five wires 35 may be used to connect the microcontroller 32 and the flexible printed circuit board 33 and / or the sensors 31. For example, additional data lines may be added. For example, some of the multiple sensors 31 may use a first data line, while other sensors 31 may use a second data line. Thus, for example, the microcontroller 32 may sample and / or read some of the multiple sensors 31 simultaneously, thereby reducing the overall I2C sampling time, for example. For example, with two parallel data lines, the sampling time can be reduced by half.

[0117] The design of the flexible printed circuit board 33 and / or the positioning of the sensor 31 thereon can provide the position and / or orientation of the sensor 31, for example, when the flexible printed circuit board 33 is straight. For example, during manufacturing, the printed circuit board 33 may be attached inside and / or along the tube 36, for example, in a manner that determines the position and / or orientation of the sensor 31, for example, relative to the tube 36. The server 10 can be calibrated to provide the server 10 with the initial 6DOF orientation and / or position of the sensor 31, for example, the 6DOF orientation and / or position of the sensor 31 when the tube 36 is straight. The initial 6DOF orientation and / or position data, together with information about the rigidity and / or flexibility constraints of the tube 36, can be incorporated as shape constraints into the conduit positioning algorithm. For example, based on the incorporated shape constraints, two adjacent sensors 31 cannot point in opposite directions.

[0118] Thus, a more complex positioning algorithm considering shape constraints can make system 100 both compact and robust. Solving for the 6DOF position and / or orientation of all sensors 31 while imposing physical shape constraints on the full curve shape of the conduit 36 ​​can fundamentally reduce the number of parameters in the motion model and, therefore, prevent, for example, overfitting of the measurement data. By using the shape constraints, server 10 can avoid erroneous calculation of the position and / or orientation of the sensors 31 due to noise or distorted measurements, because the position and / or orientation solutions must conform, for example, to the position and / or orientation solutions of adjacent sensors 31, so that they together describe a smooth, physically plausible conduit 36.

[0119] A common challenge of electromagnetic positioning systems is achieving the highest possible accuracy in the presence of magnetic distortion. For low-frequency systems, the primary distortion is caused by objects made of ferromagnetic materials. In hospital settings, these can be found in the frame of a patient's bed or as part of instruments used by physicians during medical procedures, such as surgical tools. When a positioning system does not account for magnetic distortion, it can be highly inaccurate (position error > 1 cm) and may be unsuitable for medical use. Magnetic distortion devices can be categorized into static distortion devices, whose position can be fixed relative to the system, and dynamic distortion devices, which can be moved between and / or during medical procedures. A static magnetic distortion device is an object that can be fixed relative to the magnetic field generator during the deployment of the positioning system and will remain permanently fixed for the lifetime of the positioning system. In some embodiments of this disclosure, static distortion can be addressed through a magnetic mapping process, in which the magnetic field in the induction radius around the transmitter 20 is no longer assumed to be a perfect dipole field, but is instead “mapped” offline using a calibrated sensor 31 and later solved by a real-time solver to determine the precise 6DOF position and orientation, even under distorted fields. In some embodiments, server 10 may take dynamic distortion into account by incorporating distortion into the localization algorithm, for example, to provide an accurate solution.

[0120] Different methods can be used to compensate for dynamic magnetic field distortion. One approach is to incorporate a physical distortion model into the sensing magnetic field model of sensor 31. If each sensor 31 is solved independently, this addition of parameters can lead to less robust solutions, even with more than one transmitter 20, because the solver can overfit the 6DOF and distortion model parameters to the measured sensor 31 data. For this reason, the solver should be constrained to parameters that have “mechanical significance,” both in terms of the solution geometry of sensor 31 in conduit 36 ​​and the geometric characteristics of the distortion field. Another approach to addressing dynamic distortion can include imposing shape constraints on the full curve shape of conduit 36. The 6DOF orientation and position solutions calculated by server 10 may not deviate significantly from the actual position and orientation of sensor 31 along the curve of conduit 36, for example, because they are regularized by shape constraints, as described above. While dynamic distortion is often a local artifact that distorts position and orientation calculations in entirely different ways, the applied shape constraints will ensure that the position and / or orientation solutions of multiple sensors 31 remain meaningful in terms of the fully solved curve of conduit 36. Due to the applied shape constraints, the adverse effects of distortion will be naturally reduced.

[0121] Several methods exist for imposing shape constraints in the positioning algorithm. One option is to approximate the shape of the conduit as a set of line segments 37, each segment 37 having a sensor 31 at its end. It is assumed that the orientation of each sensor 31 relative to its surrounding conduit and its distance to its adjacent receiver are fixed and known, for example, through calibration by the positioning algorithm. Therefore, according to some embodiments of this disclosure, the entire conduit curve can be modeled using a set of 6DOFs that may belong to one of the plurality of sensors 31, such as a first sensor 36 along the tube 36, for example, the one closest to the server 10 and / or microcontroller 32 in the communication path, and for each sensor 31, two spherical angles correspond to the bending of the conduit in the line segment 37 between sensor 31 and the preceding (e.g., adjacent) sensor 31, and / or an additional angle represents an internal twist of the tube 36 in the corresponding line segment 37. In some embodiments of the invention, the printed circuit board 33 includes a thinner portion 33a, for example, between a plurality of sensors 31, the thinner portion starting, for example, from a portion of the printed circuit board 33 where the sensors 31 are located, for example, to enhance the flexibility and / or bendability of the printed circuit board 33 in the portion 33a.

[0122] Now for reference Figure 5 This is a schematic diagram of a conduit 30a according to some embodiments of the present disclosure. In some embodiments, a flexible printed circuit board 33 is wound in a spiral manner around the inner or outer wall of the conduit 36 ​​and / or along the inner or outer wall of the conduit 36, such as... Figure 5 As shown, for example, to improve the flexibility and / or bendability of the conduit 30a, the conduit 36 ​​together with the printed circuit board 33. As described in more detail herein, for example, refer to Figure 6 The printed circuit board 33 may carry multiple dipole magnets, for example, further to the sensor 31 and / or the data bus 34.

[0123] Therefore, in some embodiments, the number of parameters in the conduit shape is significantly reduced from the 6DOF orientation and position of each sensor 31 to the 6DOF orientation and position of a first sensor 31 plus three angles for each additional sensor 31. In this approach, the solved orientations and positions of the sensor 31 are less prone to overfitting, for example due to the hard constraint assuming a fixed distance between the sensors 31 and, for example, a fixed orientation of each sensor 31 relative to a specific surrounding segment of the tube 36. Another approach is to use a soft model where the positions and orientations of the sensors 31 relative to previous (e.g., adjacent) sensors 31 are parameterized by a regularization term to penalize the parameters, for example:

[0124]

[0125] Where: r i ri+1 These are the positions of two continuous sensors 31, and This is the calibration distance between two consecutive sensors 31. Alternatively, inequalities can be used to limit the solved distance to a certain range, for example: This model, which takes into account the parameters of sensor 31, can be formalized in a single extended Kalman filter.

[0126] Another possible approach is to solve for the orientation and / or position of sensor 31, for example using a single solver. This could involve fitting a mechanical model to the curve of conduit 36 ​​in line segment 37 between multiple sensors 31, then forcing a single sensor 31 as close as possible to its relevant position and orientation along the curve of conduit 36. This could be achieved, for example, by fitting a low-order polynomial between the solved positions of the multiple sensors 31, and then using the model positions of the sensors 31 as a (noisy) position measurement against the single solver. Another more general approach is to describe the curve of conduit 36 ​​as a general curve with some energy function that encodes the shape constraints of the conduit (e.g., position and orientation smoothing constraints, distances along the curve between sequential sensors, etc.). The curve of conduit 36 ​​can then be fitted to noisy or distorted measurements of sensor 31 via nonlinear optimization, while minimizing the error of sensor 31 and the energy function of the curve of conduit 36. Alternating between single sensor 31 positioning calculations and full curve fitting calculations could be advantageous, as it allows for parallel computation. Instead of solving the full curve shape of tube 36 as a whole within a potentially huge extended Kalman filter, this task can be broken down into smaller subtasks, such as solving the localization of each sensor 31 individually, and then the sub-results can be glued together in the form of a final tube curve fit.

[0127] In some embodiments, the number of degrees of freedom of the system can also be reduced by assuming that the ambient magnetic field (e.g., the Earth's magnetic field) is uniform along the duct curve. The ambient magnetic field to be solved is denoted by B0 above and is solved independently for each sensor in the duct (in the transmitter's coordinate system). By assuming that the ambient magnetic field is uniform along the duct, B0 can be solved jointly for all sensors in the duct, thereby reducing the number of degrees of freedom of the system and reducing the risk of overfitting. Intuitively, sharing B0 among sensors imposes constraints on the relative orientations between the sensors (along with the constraints on the relative positions of the sensors, along with the constraints on the overall duct shape). In cases where magnetic field distortion exists, assuming that B0 is uniform along the entire duct may be incorrect; in these cases, the ambient magnetic field is deformed and may vary slowly in space, especially along the duct curve. In such cases, a softer assumption can be used, assuming that B0 is almost constant between adjacent sensors. This soft assumption can be expressed as an energy function and minimized in a least-squares sense (as part of the optimization of the full duct solver): It requires solving for adjacent sensors. The ambient magnetic fields are similar to each other. In all the above cases, the solution B0 is no longer independent for each sensor, but is bundled together to impose some constraints on the sensors along the central direction of the conduit.

[0128] In another embodiment, instead of simply using the natural environment's magnetic field (e.g., Earth's) to constrain the sensor's 6DOF solution, an artificial, constant magnetic field can be generated by adding small magnets along the duct curve. By placing the magnets in known positions and orientations, the B0 of any given configuration of the complete duct curve can be fully predicted. B0 may also depend on the relative position and orientation of the sensors (which is also uniquely defined by shape smoothness constraints), as each such different configuration may project additional DC magnetic fields (e.g., essentially zero-frequency fields) onto each sensor along the curve by a combination of small magnets with different positioning and orientations. By knowing the exact position and orientation of each built-in magnet in each full-curve configuration, the B0 of each sensor can be predicted, thereby further reducing the number of degrees of freedom of the system.

[0129] Now for reference Figure 6 , Figure 6This is a schematic diagram of a conduit 30b according to some embodiments of the present disclosure. The conduit 30a may include a plurality of dipole magnets 38 located between sensors, for example, at equal distances. For example, the dipole magnets 38 are oriented such that when the conduit 36 ​​is straight, two magnets 38 located on either side of sensor 31 have opposite dipole orientations. When the conduit 36 ​​is straight, each sensor can sense the superposition of perfectly aligned positive and negative dipole fields, thus canceling out the contributions of the two magnets located on either side of sensor 31, and therefore, for example, B0 sensed by sensor 31 may essentially consist only of the Earth's magnetic field. When the conduit begins to bend, the contribution of the two magnets located on either side of sensor 31 may increase linearly with C sin(α), where α is the bending angle and C is some known constant depending on the relative position and strength of the magnets 38. In this example, it is clear how B0 encodes more information about the relative orientation between adjacent sensors. By incorporating a magnet 38 along the conduit, as in this example, more effective constraints can be achieved relative to the sensor orientation compared to using only the Earth's magnetic field, in terms of signal-to-noise ratio (by incorporating a relatively strong magnet), reliability (the incorporated magnet is less prone to magnetic field distortion), and geometry (for specific applications, the magnet is placed in a carefully chosen orientation to adjust the constraints as needed).

[0130] In some embodiments of the invention, system 100 can be used for organ deformation tracking in minimally invasive surgery. For example, full-curve catheter positioning can be used to track deformations imposed on internal organs by some external means. For example, during laparoscopic surgery, tools may be used to manipulate organs to the point that it is difficult to distinguish which parts of the organ are visible in a live laparoscopic video. For this reason, visual markers are sometimes used; at the start of the surgery, markers are placed on known anatomical landmarks on the organ's surface before any manipulation is performed. They are then visually tracked throughout the procedure and used as registration references to achieve a certain anatomical positioning, even if the organ may be highly manipulated and deformed compared to its initial known state.

[0131] Unfortunately, in some surgeries, such as laparoscopic lung surgery, localization is crucial for identifying hidden blood vessels, and the lung surface does not contain sufficient visual information to place anatomical markers (i.e., well-known markers indicating their location within the anatomical structures). Furthermore, due to the highly flexible form of the lung, tracking anatomical features on the lung surface does not necessarily extend well to tracking important intrapulmonary anatomical features such as airways and blood vessels; the surface does not necessarily predict the internal state of the lung well. Finally, visual markers and optical tracking systems are susceptible to occlusion, motion blur, 3D computation problems, and other drawbacks, making most optical-based systems unsuitable for high-precision laparoscopic guidance.

[0132] The newly invented full-curve flexible catheter tracking method easily solves the problem of flexible registration: In the preoperative phase, one or more flexible catheters are inserted into a known airway using a bronchoscope. Each catheter remains stationary relative to the anatomical structure (described below) and provides full-curve positioning for airways near certain regions of interest (ROIs). All important anatomical features within a ROI can then be displayed in real-time by employing real-time registration between the fully tracked catheters and preoperative CT scans. During laparoscopic surgery, the catheters (or catheters) are bent and twisted, but still maintain their anatomical position within certain known airways. The catheters (or catheters) can then be used as a framework for the lungs, tracked in real-time, and can provide smooth, real-time, and flexible registration between important anatomical features taken from preoperative CT and real-time deformed lung features. By placing an additional sensor on the laparoscopic camera, these anatomical features can be displayed as an overlay of real-time laparoscopic video, thus providing guidance for laparoscopic lung surgery that is inherently fully real-time and flexible.

[0133] To keep the catheter stationary relative to the anatomical structure, especially in organs containing tubes (blood vessels or airways), it should be attached to the anatomical tube. The attachment should be distal, allowing the catheter to track the organ from its distal end and allowing the organ to extend or contract freely. Attachment can be achieved using a balloon or hook, or through friction with the tissue. For the catheter to conform to the anatomical structure without deformation, it needs to be highly flexible. Flexibility is achieved by using a flexible plastic tube in the catheter's axial structure. Reducing the rigidity of the flexible printed circuit board (PCB) is also important. The rigidity of the flexible PCB material comes from the stiffness of the polyimide, the number of PCB layers, and the amount of copper used. Increased flexibility can be achieved through the geometry of the PCB, for example, by reducing the width of the PCB 33 between the sensors 31, and / or by arranging the conductors in a zigzag manner and cutting the PCB 33 parallel to the zigzag path to reduce rotational stiffness.

[0134] In some embodiments of the invention, system 100 can be used for electromagnetic navigation bronchoscopy (ENB). A fully-curved real-time catheter localization offers significant advantages in registration accuracy within the ENB procedure. Rather than relying solely on past catheter tip samples, which are often “noisy” due to respiratory and cardiac activity, the entire catheter is always visible in the system and can be used as a whole for registration between the transmitter 20 coordinates and the airway map. The very specific curvature and shape of the catheter within the airway can serve as a complete curve indicating to the system the most probable location of the catheter within the airway. Its shape can be matched to the map and serves as a unique signature of its anatomical location within the airway. For initial registration, full-curve localization provides more samples during unsupervised lung surveys compared to catheter tip only—a complete path can be drawn in the transmitter 20 coordinates and matched to the map in an unsupervised manner, thus improving the stability and accuracy of registration. For adaptive registration, the fully localized catheter curve can be matched to the airway within a region of interest (ROI) until the most probable airway is found. This allows for better adaptation to changes in breathing and body posture; full-curve localization is instantaneous, unlike history-based methods where accumulated samples within a time window may deform differently over time (e.g., if they were acquired at different respiratory stages). Another form of adaptive registration is also possible, where full-curve localization can be used for lung skeletalization and as a fundamental component of flexible, deformable lung models. By analyzing the full curve of the duct, it is possible to understand how certain major airways through which the duct passes deform, and then extrapolation models can be used to infer how the surrounding areas deform.

[0135] Furthermore, catheter manipulation can become easier: it's not uncommon for doctors to encounter difficulties when attempting sharp turns with a catheter inside the lung. The doctor then tries pulling, rotating, and pushing the catheter repeatedly, based on feedback from a single sensor received from the system. With full-curve positioning, the doctor can see the complete curve of the catheter and better understand how the applied force translates into distal catheter movement under the pressure of surrounding tissue. Based on this greater amount of feedback, the doctor can generate more precise steering gestures, which translate into accurate, desired distal movement with less trial and error.

[0136] Furthermore, full-curve positioning facilitates registration with other methods, such as fluoroscopy. During fluoroscopy, the entire length of the catheter is visible in the X-ray image due to the radiopaque nature of the catheter. In traditional electromagnetic positioning systems, only the tip is visible. In this situation, it is difficult for physicians to match the fluoroscopic image with the image displayed by the positioning system. With full-catheter positioning, the entire length of the catheter is visible in both the fluoroscopic image and the magnetic positioning system, making it easier for physicians to match between different modes.

[0137] In some embodiments of this disclosure, system 100 can be used for electromagnetically guided colonoscopy, where full catheter localization has proven advantageous.

[0138] It should be understood that some embodiments of the present invention are applicable to any elongated flexible body, and not only to catheters, but also have desired variations.

[0139] Some embodiments of this disclosure may include systems, methods, and / or computer program products. A computer program product may include a tangible, non-transitory computer-readable storage medium (or medium) having computer-readable program instructions thereon for causing a processor to perform aspects of this disclosure. The computer-readable program instructions for performing operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or objects written in any combination of one or more programming languages, including any object-oriented programming language and / or a traditional procedural programming language.

[0140] In the context of some embodiments of this disclosure, terms such as “operation” or “execution” are used by way of example and not limitation, and also imply capabilities such as “operable” or “executable”, respectively.

[0141] Conjugate terms such as “properties of things” imply the properties of things unless they are clearly apparent from their context.

[0142] The terms "processor" or "computer" or their systems are used herein in the general context of the art, such as a general-purpose processor, or a portable device, such as a smartphone or tablet computer, or a microprocessor, or a RISC processor, or a DSP, which may include additional elements, such as memory or communication ports. Optionally or additionally, the terms "processor" or "computer" or their derivatives mean means capable of executing provided or incorporated programs and / or capable of controlling and / or accessing data storage devices and / or other devices, such as input and output ports. The terms "processor" or "computer" also mean multiple processors or computers that are connected, and / or linked and / or otherwise communicate with each other, and may share one or more other resources, such as memory.

[0143] The terms “software,” “program,” “software process,” “process,” “software code,” “code,” or “application” are used interchangeably depending on their context and refer to one or more instructions or electronic circuits for performing a series of operations that typically represent an algorithm and / or other process or method. Such a program is stored in or on a medium such as random access memory (RAM), read-only memory (ROM), or a disk, or embedded in circuitry accessible and executable by a device such as a processor or other circuitry. The processor and the program may at least partially constitute the same device, such as an electronic gate array, like a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC), designed to perform a programmed sequence of operations, optionally including or connected to a processor or other circuitry.

[0144] The terms “configuration” and / or “adjustment” used for an objective or variations thereof mean the use of at least one software and / or electronic circuit and / or auxiliary device that is designed and / or implemented and / or operable to achieve the objective.

[0145] Devices that store and / or include programs and / or data constitute articles of art. Unless otherwise stated, programs and / or data are stored in or on non-transitory media.

[0146] When electrical or electronic equipment is made public, it is assumed that a suitable power source is used for its operation.

[0147] Flowcharts and block diagrams illustrate the architecture, functionality, or operation of possible implementations of systems, methods, and computer program products according to various embodiments of the subject matter of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of program code, including one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative embodiments, the operations shown or described may occur in different orders or combinations, or as concurrent operations rather than sequential operations, to achieve the same or equivalent effects.

[0148] All means or steps in the following claims, plus the corresponding structures, materials, actions, and equivalents of the functional elements, are intended to include any structure, material, or action for performing a function in combination with other claimed elements as specifically claimed. As used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context clearly indicates otherwise. Further understanding is that the terms “comprising,” “including,” and / or “having,” and other variations of these terms, when used in this specification, designate the stated features, integers, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.

[0149] Unless otherwise stated, the terminology used herein should not be construed as limiting and is for the purpose of describing particular embodiments only and is not intended to limit the disclosed subject matter. Although certain embodiments of the disclosed subject matter have been illustrated and described, it is clear that this disclosure is not limited to the embodiments described herein. Many modifications, alterations, variations, substitutions, and equivalents are not excluded.

Claims

1. A method for magnetically tracking a flexible device, said flexible device being a flexible conduit device or a flexible elongated device, said flexible device comprising a tip and a body, characterized in that, The method includes: A host server receives multiple sensed values ​​of a local magnetic field, which are sensed by a plurality of corresponding digital DC magnetometers positioned along the flexible device on at least one of the tip and the body of the flexible device. The plurality of sensed values ​​are at least partially caused by at least one alternating magnetic field generated by at least one magnetic field generator; and The host server calculates a position of the flexible device based on the multiple sense values ​​and the source amplitude and frequency of each alternating magnetic field. The calculations include calculating the three-dimensional position and orientation of each of the plurality of digital DC magnetometers relative to the alternating magnetic field; The plurality of digital DC magnetometers are located on the same digital communication bus; and At least one of the alternating magnetic fields has a frequency lower than the sampling rate of each of the plurality of digital DC magnetometers.

2. The method as described in claim 1, characterized in that: The host server is included in a controller of the plurality of digital DC magnetometers.

3. The method as described in claim 1, characterized in that: The method includes: The host server receives an instantaneous phase value of an alternating magnetic field from at least one magnetic field generator, wherein the instantaneous phase value is received from the at least one magnetic field generator at the full rate of a magnetometer located at the at least one magnetic field generator. The host server associates the instantaneous phase value with at least some of the plurality of sensed values ​​received from the plurality of digital DC magnetometers, wherein the association is based on a corresponding clock reading shared among the magnetic field generator, a controller of the plurality of digital DC magnetometers, and the host server, and wherein the clock reading is shared either through the magnetic field generator or through a clock source shared among the magnetic field generator, the controller of the plurality of digital DC magnetometers, and the host server; and The host server calculates the positioning of the flexible device based on the plurality of sensed values ​​and the associated instantaneous phase values.

4. The method as described in claim 1, characterized in that: The calculation, incorporating the known structural relationships among the plurality of digital DC magnetometers, is used as a whole to calculate an estimate of the position, orientation, or curve of the flexible device.

5. The method as described in claim 1, characterized in that: The plurality of sensed values ​​are at least partially caused by at least two alternating magnetic fields generated by at least two corresponding magnetic field generators, wherein the at least two magnetic field generators share the same clock or have multiple synchronized clocks or share a clock source.

6. The method as described in claim 5, characterized in that: The at least two alternating magnetic fields operate at different frequencies.

7. The method as described in claim 1, characterized in that: The calculation includes applying a shape constraint to the flexible device based on the calculation of the positioning of the flexible device.

8. The method as described in claim 1, characterized in that: The host server is included in a controller of the flexible conduit device.

9. The method as described in claim 1, characterized in that: The frequency is as high as 500 Hz.

10. The method as described in claim 1, characterized in that: The frequency is from 10 Hz to 100 Hz.

11. The method as described in claim 1, characterized in that: The flexible device includes multiple digital IMU sensors.

12. The method as described in claim 11, characterized in that: The plurality of digital IMU sensors are located on the tip of the flexible device and along the body of the flexible device.

13. The method as described in claim 11, characterized in that: The multiple digital IMU sensors are located on the same digital communication bus.

14. The method as described in claim 11, characterized in that: The plurality of digital IMU sensors are placed at multiple predetermined locations along the flexible device.

15. The method as described in claim 11, characterized in that: The plurality of digital IMU sensors are placed along the flexible device at a predetermined distance.

16. The method as described in claim 1, characterized in that: The source amplitude and frequency of each alternating magnetic field are provided to the host server.

17. The method as described in claim 1, characterized in that: The method also includes calculating an estimate of the flexible device's position along a full curve along its length.

18. A system for magnetically tracking a flexible device, said flexible device being a flexible conduit device or a flexible elongated device, characterized in that, The system includes: At least one magnetic field generator, each magnetic field generator being configured to generate an alternating magnetic field; A flexible device includes: a tip and a body, a plurality of digital DC magnetometers, the plurality of digital DC magnetometers being positioned along the flexible device on at least one of the tip and the body of the flexible device, each digital DC magnetometer being configured to communicate a plurality of sensed values ​​of a local magnetic field. Wherein, the plurality of sensed values ​​are at least partially caused by the alternating magnetic field; and A host server, configured to be used for: Receive the plurality of sensed values ​​of the local magnetic field from the corresponding plurality of digital DC magnetometers; and A position of the flexible device is calculated based on the multiple sensed values, source amplitude, and frequency. The calculations include calculating the three-dimensional position and orientation of each of the plurality of digital DC magnetometers relative to the alternating magnetic field; The plurality of digital DC magnetometers are located on the same digital communication bus; and At least one of the alternating magnetic fields has a frequency lower than the sampling rate of each of the plurality of digital DC magnetometers.

19. The system as described in claim 18, characterized in that: The host server is included in a controller of the plurality of digital DC magnetometers.

20. The system as described in claim 18, characterized in that: The host server is configured to: Receive an instantaneous phase value of the alternating magnetic field from at least one magnetic field generator of the alternating magnetic field; The host server associates the instantaneous phase value with at least some of the multiple sensing values ​​received from the multiple digital DC magnetometers, the association being based on a corresponding clock source reading shared between the magnetic field generator, a controller of the multiple digital DC magnetometers, and the host server. as well as The host server calculates the positioning of the flexible device based on the plurality of sensed values ​​and the associated instantaneous phase values.

21. The system as described in claim 18, characterized in that: The device also includes a flexible printed circuit board along the tube, wherein the plurality of digital DC magnetometers are positioned along the flexible printed circuit board.

22. The system as described in claim 21, characterized in that: The flexible brush circuit board is spirally wound around one wall of the flexible device.

23. The system as described in claim 18, characterized in that: The device further includes a communication bus configured to digitally transmit the plurality of sensed values ​​from the plurality of digital DC magnetometers to the host server.

24. The system as described in claim 23, characterized in that: The communication bus includes up to four wires that can transmit digital data from the plurality of sensed values ​​of the plurality of digital DC magnetometers and provide power to the plurality of digital DC magnetometers.

25. The system as described in claim 18, characterized in that: The at least one magnetic field generator includes one or more of an internal clock and a magnetometer, and the at least one magnetic field generator is configured to share its clock reading with the plurality of digital DC magnetometers and the host server, the magnetometer being configured to detect instantaneous phase values.

26. The system as described in claim 18, characterized in that: The system includes at least two magnetic field generators that generate at least two corresponding alternating magnetic fields, the at least two alternating magnetic fields operating at different frequencies, wherein the at least two magnetic field generators share the same clock or have multiple synchronized clocks or share a clock source.

27. The system as described in claim 18, characterized in that: The at least one magnetic field generator includes at least one permanent magnet and a motor device, the motor device rotating the permanent magnet at a defined frequency.

28. The system as described in claim 18, characterized in that: The device includes multiple dipole magnets located between the plurality of digital DC magnetometers.

29. The system as described in claim 18, characterized in that: The at least one magnetic field generator includes one or more transmitting coils that generate electromagnetic (EM) fields of different geometries.

30. The system as described in claim 18, characterized in that: The flexible catheter device is wireless.

31. The system as described in claim 18, characterized in that: The calculation includes applying a shape constraint of the flexible tube to the calculated positioning of the flexible device.

32. The system as described in claim 18, characterized in that: The host server is included in a controller of the flexible conduit device.

33. The system as described in claim 18, characterized in that: The frequency is as high as 500 Hz.

34. The system as described in claim 18, characterized in that: The frequency is from 10 Hz to 100 Hz.

35. The system as described in claim 18, characterized in that: The flexible device includes multiple digital IMU sensors.

36. The system as described in claim 35, characterized in that: The plurality of digital IMU sensors are located on the tip of the flexible device and along the body of the flexible device.

37. The system as described in claim 35, characterized in that: The multiple digital IMU sensors are located on the same digital communication bus.

38. The system as described in claim 35, characterized in that: The plurality of digital IMU sensors are placed at multiple predetermined locations along the flexible device.

39. The system as described in claim 35, characterized in that: The plurality of digital IMU sensors are placed along the flexible device at a predetermined distance.

40. The system as described in claim 18, characterized in that: The source amplitude and frequency of each alternating magnetic field are provided to the host server.

41. The system as described in claim 18, characterized in that: The host server is also configured to calculate an estimate of the flexible device's position along a full curve of its length.

Images