Head space positioning method, device and system based on electrical impedance tomography

Abstract

The invention discloses a head space positioning method, device and system based on electrical impedance tomography, and the method comprises the steps: constructing a corresponding three-dimensional model according to the basic parameters of a flexible electrode cap, and carrying out the finite element meshing, and obtaining a three-dimensional mesh model; performing electric field distribution calculation on sampling points of the three-dimensional grid model according to a preset calculation rule to obtain corresponding touch electrode response information; generating a sensitive field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; performing projection matching according to the initial voltage data of the electrode pair and the sensitive field matrix to obtain projection matching information; and performing model training according to the projection matching information and the tensile deformation data of the flexible electrode cap to obtain a voltage feature-space coordinate mapping relation, and analyzing the induced voltage data of the electrode pair to obtain corresponding target coordinate information. According to the method, the voltage change of the flexible electrode cap is obtained and analyzed to obtain the coordinate information, and the positioning accuracy and stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of neural navigation, and particularly to a head space positioning method, device and system based on electrical impedance tomography, which cooperate with a touch pen through a flexible conductive material to achieve high-precision dynamic space coordinate tracking applied to the head, and are applicable to fields such as neurosurgical navigation, neuromodulation and medical rehabilitation. Background Art

[0002] Traditional neurosurgical navigation techniques (such as optical navigation and electromagnetic navigation) rely on rigid markers or external sensors. For example, it is necessary to fix optical markers or electromagnetic sensors on an individual's head, which has many limitations, increases the operation time, and is complex to operate; and tissue displacement during the operation is likely to cause positioning drift of the optical markers or electromagnetic sensors; if relying on precision optical components or customized equipment, the maintenance cost is high. The clinical application of existing non-invasive neuromodulation techniques (transcranial electrical stimulation, transcranial magnetic stimulation, transcranial ultrasound stimulation, transcranial light stimulation, etc.) also urgently requires an easy-to-use and accurate head space positioning method and system.

[0003] The existing positioning method of electrical impedance tomography (EIT) technology needs to indirectly calculate the target position through image reconstruction, and the single calculation time is significantly long. In addition, the EIT system usually uses a fixed electrode array, which cannot adapt to head deformation or electrode cap stretching, and the positioning accuracy is poor. Therefore, the existing technology has problems of poor positioning accuracy and too high application cost in head positioning applications. Summary of the Invention

[0004] Embodiments of the present invention provide a head space positioning method, device and system based on electrical impedance tomography, aiming to solve the problems of poor positioning accuracy and too high application cost existing in the methods for head positioning in clinical or scientific research applications of the existing technology.

[0005] In a first aspect, embodiments of the present invention provide a head space positioning method based on electrical impedance tomography. The method is applied to a positioning analysis terminal. The data acquisition unit in the positioning analysis terminal is respectively communicatively connected with a touch pen and a flexible electrode cap to implement data information transmission. The flexible electrode cap covers the outer surface of a three-dimensional head model. Wherein, the method includes: Construct a corresponding three-dimensional model according to the image segmentation information of an individual user and the basic parameters of the flexible electrode cap; Perform finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model; Calculate the electric field distribution of the sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain corresponding touch electrode response information; Generate a sensitivity field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; Perform projection matching on the initial voltage data of the electrode pair and the sensitive field matrix to obtain projection matching information; the initial voltage data is the voltage data of the electrode pair at each position in the flexible electrode cap touched by the touch pen. Perform model training based on the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - spatial coordinate mapping relationship. Analyze the induced voltage data of the electrode pair according to the regression model to obtain the corresponding target coordinate information; the induced voltage data is the voltage data of the electrode pair at a certain position in the flexible electrode cap touched by the touch pen.

[0006] In a second aspect, an embodiment of the present invention further provides a head spatial positioning device based on electrical impedance tomography. The device is configured in a positioning and analysis terminal. The data acquisition unit in the positioning and analysis terminal is respectively communicatively connected to the touch pen and the flexible electrode cap to achieve data information transmission. The flexible electrode cap covers the outer surface of a three - dimensional head model. The device is used to execute the head spatial positioning method based on electrical impedance tomography as described in the first aspect above. The device includes: A three - dimensional model construction module, configured to construct a corresponding three - dimensional model according to the image segmentation information of an individual user and the basic parameters of the flexible electrode cap. A three - dimensional grid model acquisition module, configured to perform finite - element meshing on the three - dimensional model to obtain a three - dimensional grid model. An electric field distribution calculation module, configured to calculate the electric field distribution of the sampling points in the three - dimensional grid model according to a preset calculation rule to obtain the corresponding touch electrode response information. A sensitive field matrix acquisition module, configured to generate a sensitive field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information. A projection matching information acquisition module, configured to perform projection matching on the initial voltage data of the electrode pair and the sensitive field matrix to obtain projection matching information; the initial voltage data is the voltage data of the electrode pair at each position in the flexible electrode cap touched by the touch pen. A regression model construction module, configured to perform model training based on the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - spatial coordinate mapping relationship. A target coordinate information acquisition module, configured to analyze the induced voltage data of the electrode pair according to the regression model to obtain the corresponding target coordinate information; the induced voltage data is the voltage data of the electrode pair at a certain position in the flexible electrode cap touched by the touch pen.

[0007] In a third aspect, an embodiment of the present invention further provides a head space positioning system based on electrical impedance tomography. The system includes a positioning analysis terminal, a touch pen, and a flexible electrode cap; An excitation unit is disposed in the touch pen, and a circular electrode array composed of a plurality of electrode pairs is provided at the edge of the flexible electrode cap; A communication unit, an interaction unit, a power supply unit, a control unit, a data acquisition unit, a sensitive field modeling unit, a touch pen position reconstruction unit, and a visualization unit are disposed in the positioning analysis terminal; The communication unit, the interaction unit, the power supply unit, the sensitive field modeling unit, and the touch pen position reconstruction unit are all communicatively connected to the control unit, and the control unit is also communicatively connected to the excitation unit; The touch pen position reconstruction unit is communicatively connected to the sensitive field modeling unit and the visualization unit; the data acquisition unit is communicatively connected to the sensitive field modeling unit, the circular electrode array, and the excitation unit respectively; A memory is disposed inside the positioning analysis terminal. When the positioning analysis terminal executes the program stored on its internal memory, the steps of the head space positioning method based on electrical impedance tomography described in the first aspect above are implemented.

[0008] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the head space positioning method based on electrical impedance tomography described in the first aspect above are implemented.

[0009] An embodiment of the present invention provides a head space positioning method, device, and system based on electrical impedance tomography. The method includes: constructing a corresponding three-dimensional model according to the basic parameters of the flexible electrode cap and the image segmentation information of an individual user; performing finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model; calculating the electric field distribution of sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain corresponding touch electrode response information; generating a sensitive field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; performing projection matching on the initial voltage data of the electrode pairs and the sensitive field matrix to obtain projection matching information; performing model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a voltage feature - space coordinate mapping relationship and analyzing the induced voltage data of the electrode pairs to obtain corresponding target coordinate information. The above method improves the accuracy and stability in the positioning process by real-time monitoring of voltage changes by the flexible electrode cap and analyzing to obtain coordinate information. Description of the Drawings

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0011] Figure 1 It is a flowchart of the method for head space positioning based on electrical impedance tomography provided by the embodiments of the present invention; Figure 2 It is a schematic diagram of the application scenario of the method for head space positioning based on electrical impedance tomography provided by the embodiments of the present invention; Figure 3 It is an application effect diagram of the method for head space positioning based on electrical impedance tomography provided by the embodiments of the present invention; Figure 4 It is a device structure diagram of the flexible electrode cap provided by the embodiments of the present invention; Figure 5 It is a schematic block diagram of the head space positioning device based on electrical impedance tomography provided by the embodiments of the present invention; Figure 6 It is a schematic block diagram of the head space positioning system based on electrical impedance tomography provided by the embodiments of the present invention. Specific Embodiments

[0012] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0013] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0014] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0015] It should be further understood that the term "and / or" used in the specification and appended claims of the present invention refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0016] Please refer to Figure 1 and Figure 2 , as shown in the figure, an embodiment of the present invention application provides a head space positioning method based on electrical impedance tomography, which is applied to a positioning and analysis terminal 20, and this method is executed through an application software installed in the positioning and analysis terminal 20; a data acquisition unit 5 in the positioning and analysis terminal 20 is respectively communicatively connected to a touch pen 8 and a flexible electrode cap 6 to realize the transmission of data information. The specific application process is as Figure 3 shown. The flexible electrode cap 6 covers the outer surface of the three-dimensional head model 30. When the touch pen 8 touches a certain position of the flexible electrode cap 6, the electrode pairs arranged at the edge of the flexible electrode cap 6 can correspondingly sense voltage signals, and the data acquisition unit can collect the voltage signals generated by the electrode pairs, so as to realize the conversion of analog quantity to digital quantity and obtain corresponding voltage data. The positioning and analysis terminal 20 further analyzes and processes the voltage data, so as to obtain the accurate touch position of the touch pen 8 on the flexible electrode cap 6, that is, to obtain the target coordinate information. As Figure 1 shown, this method includes steps S110 to S170.

[0017] S110. Construct a corresponding three-dimensional model according to the image segmentation information of the individual user and the basic parameters of the flexible electrode cap.

[0018] By combining the image segmentation information of the individual user with the basic parameters of the flexible electrode cap, a corresponding three-dimensional model is constructed. Here, the three-dimensional model is a virtual three-dimensional model. Specifically, based on the image segmentation information, the virtual model of the flexible electrode cap is placed on the high-precision three-dimensional head mold corresponding to the image segmentation information, and the virtual model of the flexible electrode cap is fused with the three-dimensional head mold corresponding to the image segmentation information based on the basic parameters of the flexible electrode cap, so as to construct a composite model including tissue conductivity (σ) and relative permittivity distribution as the corresponding three-dimensional model. Among them, the basic parameters of the flexible electrode cap include electrode cap size, electrode spacing, electrode diameter, material conductivity, etc.; the values of each parameter in the basic parameters can be obtained through actual measurement or experimental measurement. For example, the conductivity of the conductive material in the electrode cap can be calibrated through experimental measurement (such as the conductive material is an Ag / AgCl coating, and its conductivity can be calibrated to ) through measurement. In this three-dimensional model, the touch pen model can be simplified to a point current source, the virtual position of the touch pen model can be dynamically bound to the coordinate system of this three-dimensional model, and the node parameters of the three-dimensional head mold and each virtual component in the three-dimensional model are set. The virtual components include the touch pen model and the flexible electrode cap model.

[0019] In a specific embodiment, before step S110, the method further includes the steps of: receiving brain image data of an individual user, performing segmentation processing on the brain image data according to a preset segmentation model to obtain corresponding initial segmentation information; performing segmentation optimization processing on the initial segmentation information according to a preset segmentation optimization model to obtain corresponding image segmentation information; and using the image segmentation information as the basic data for constructing the three-dimensional head model.

[0020] The brain image data of the individual user can be imported into a positioning and analysis terminal. The brain image data can be MRI / CT image data. When performing segmentation processing on the brain image data according to the preset segmentation model, anisotropic diffusion filtering can be specifically used to eliminate image noise while retaining tissue edge features. Then, a segmentation model integrating a deep learning framework (such as U-Net, nnU-Net) is used to perform brain tissue segmentation on the denoised image, and the scalp, skull, cerebrospinal fluid, gray matter, and white matter are automatically segmented based on the pre-trained segmentation model to obtain the initial segmentation information.

[0021] When performing segmentation optimization processing on the initial segmentation information through a preset segmentation optimization model, such as jointly using the cross-entropy loss function and the Dice coefficient to perform segmentation optimization on the initial segmentation information to optimize the segmentation accuracy and obtain more accurate image segmentation information. This image segmentation information can be used as the basic data for constructing the three-dimensional head model, and the three-dimensional head model is a three-dimensional entity structure simulating the head of the individual user.

[0022] S120: Performing finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model.

[0023] Performing finite element meshing on the three-dimensional model obtained in the above steps to further obtain a three-dimensional mesh model. Finite element meshing is to divide specific meshes in the three-dimensional model to obtain a three-dimensional mesh model containing mesh information.

[0024] In a specific embodiment, step S120 includes the following steps: performing mesh division on the sensing area of the three-dimensional model according to a preset finite element model to obtain corresponding mesh division information; determining the three-dimensional coordinate positions of each mesh according to the position parameters of each mesh in the mesh division information; and adding the mesh division information and the three-dimensional coordinate positions to the three-dimensional model to obtain a corresponding three-dimensional mesh model.

[0025] Specifically, the sensing area of the three-dimensional model can be meshed according to a preset finite element model. The finite element model includes unstructured tetrahedral meshes and mesh size parameters. For example, if the mesh size in the size parameters is set to 0.1 mm, then unstructured tetrahedral meshes can be used and combined with this size parameter to mesh the sensing area of the three-dimensional model to obtain meshing information, thereby ensuring the accuracy of electric field calculation. Further, the three-dimensional coordinate positions of each mesh can be determined according to the position parameters of each mesh in the meshing information. Specifically, the center point coordinates of the mesh can be calculated according to the position parameters of the mesh. Taking the center point coordinates as the origin, a perpendicular line is drawn perpendicular to the plane where the mesh is located. The intersection coordinates of this perpendicular line and the virtual model of the flexible electrode cap in the three-dimensional model are the three-dimensional coordinate positions of the mesh. The obtained meshing information and three-dimensional coordinate positions are added to the three-dimensional model to obtain a three-dimensional mesh model.

[0026] S130. Calculate the electric field distribution of the sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain corresponding touch electrode response information.

[0027] After meshing, the electric field distribution of the sampling points in the three-dimensional mesh model can be calculated according to a preset calculation rule to obtain corresponding touch electrode response information. The sampling points in the three-dimensional mesh model are also the touch positions corresponding to the touch of the touch pen. For example, if the sensing area is divided into a 100×100 mesh in the three-dimensional mesh model, 10,000 touch positions can be correspondingly obtained, and one touch position corresponds to one sampling point. The electric field distribution is calculated for each sampling point respectively, and the voltage response value corresponding to each sampling point can be obtained. Then, the voltage response values of all sampling points constitute the touch electrode response information of the three-dimensional mesh model.

[0028] In a specific embodiment, step S130 includes the following steps: Calculate the spatial electric potential of the three-dimensional mesh model according to the calculation rule and the basic parameters to obtain corresponding spatial electric potential distribution information; Obtain the voltage response values of the electrode pairs adjacent to the sampling point when the touch pen contacts the sampling point according to the spatial electric potential distribution information to obtain the touch electrode response information.

[0029] Specifically, the spatial electric potential of each sampling point can be calculated respectively according to the calculation rule and the basic parameters of the flexible electrode cap; The finite element equation is configured in the calculation rule, and the spatial electric potential distribution information induced by the touch pen at different sampling points in the three-dimensional mesh model under the excitation of a preset voltage value is obtained by solving based on the material conductivity and the preset voltage value. According to the spatial electric potential distribution information, further calculate the voltage response value V of the electrode pair adjacent to the sampling point in the electrode array when the touch pen (position (X, Y, Z)) contacts the sampling point. ij(X, Y, Z), so as to obtain touch electrode response information.

[0030] S140. Generate a sensitivity field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information.

[0031] Generate a sensitivity field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the obtained touch electrode response information. Specifically, each sampling point in the three-dimensional grid model can be traversed, and a corresponding sparse sensitivity field matrix S is generated according to the correspondence between the sampling points and the electrode pairs and the touch electrode response information, where S ∈ R M×N (M is the number of electrode pairs, and N is the number of spatial sampling points). When generating the sensitivity field matrix S, the matrix needs to be processed to obtain a data structure consistent with the actual position, and the sensitivity field matrix S is compressed and stored through singular value decomposition (SVD) to reduce the real-time calculation complexity.

[0032] S150. Perform projection matching according to the initial voltage data of the electrode pairs and the sensitivity field matrix to obtain projection matching information.

[0033] Perform projection matching according to the initial voltage data of the pairs and the sensitivity field matrix to obtain projection matching information. Among them, the initial voltage data is the voltage data of the touch pen touching the electrode pairs at each position in the flexible electrode cap.

[0034] The initial voltage data includes the voltage data corresponding to each position, so a set of voltage data corresponds to one position; feature extraction can be performed on the initial voltage data, vector features are extracted from each group of voltage data, and the vector features are projected and matched with the sensitivity field matrix S, so as to obtain the projection matching information corresponding to each position.

[0035] S160. Perform model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - spatial coordinate mapping relationship.

[0036] Model training can be performed according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - spatial coordinate mapping relationship. Specifically, a lightweight machine learning method can be used for model training to establish a regression model based on the voltage feature - spatial coordinate mapping relationship; the stretching deformation data is added during the model training process, and the robustness can be enhanced by adding the stretching deformation data during the model training process. The stretching deformation data is also the simulated data of the electrode cap stretching deformation, and the simulated data of the electrode cap stretching deformation is obtained by acquiring voltage - position pairs in the deformation scenario generated by finite element simulation.

[0037] S170. Analyze the induced voltage data of the electrode pair according to the regression model to obtain the corresponding target coordinate information.

[0038] In the actual application process of spatial positioning, the electrode pairs at the edge of the electrode cap can be monitored in real time to obtain the induced voltage data, and the induced voltage data of the electrode pair can be analyzed according to the regression model constructed in the above steps to obtain the corresponding target coordinate information. Among them, the induced voltage data is the voltage data of the touch pen touching a certain position of the flexible electrode cap.

[0039] In a specific embodiment, step S170 includes the following steps: Extract the corresponding voltage vector features from the induced voltage data; Map the voltage vector features according to the voltage feature - spatial coordinate mapping relationship in the regression model to analyze and obtain the corresponding initial coordinate position as the corresponding target coordinate information.

[0040] Specifically, the voltage vector features can be extracted from the induced voltage data, that is, the principal component extraction is performed on the voltage vector V of the induced voltage data collected in real time real to obtain the voltage vector features. Map the voltage vector features according to the obtained voltage feature - spatial coordinate mapping relationship, so as to realize the coordinate position analysis of the voltage vector features and obtain the initial coordinate position, which can be used as the target coordinate information.

[0041] In a specific embodiment, after mapping the voltage vector features according to the voltage feature - spatial coordinate mapping relationship in the regression model to analyze and obtain the corresponding initial coordinate position, it further includes: compensating the initial coordinate position according to the preset position compensation strategy and the induced voltage data to obtain the corresponding compensated coordinate position as the target coordinate information.

[0042] To further improve the accuracy of obtaining the coordinate position, after obtaining the initial coordinate position, the initial coordinate position can also be compensated. Estimate the deformation amount of the flexible electrode cap through the induced voltage data, so as to realize the position compensation of the initial coordinate position and obtain a more accurate compensated coordinate position for use as the target coordinate position.

[0043] In a specific embodiment, compensating the initial coordinate position according to the preset position compensation strategy and the induced voltage data to obtain the corresponding compensated coordinate position as the target coordinate information includes: obtaining the voltage gradient change information at the edge position in the induced voltage data; performing compensation calculation on the voltage gradient change information according to the position compensation strategy to obtain the corresponding position compensation value; compensating the initial coordinate position according to the position compensation value to obtain the corresponding compensated coordinate position.

[0044] Specifically, the voltage gradient change information at the edge position in the sensed voltage data can be obtained. This voltage gradient change information is also the voltage gradient change information of the electrode pairs at the edge of the electrode cap monitored in real time. The obtained voltage gradient change information is compensated and calculated through a position compensation strategy. The compensation strategy can be a Kalman Filter operation. The voltage gradient change information is compensated and calculated through the Kalman Filter to obtain the estimated deformation amount ΔX as the corresponding position compensation value. Then, the initial coordinate position can be compensated through this position compensation value. Specifically, the estimated deformation amount can be fed back to the above regression model, and the estimated deformation amount and the initial coordinate position are comprehensively analyzed based on this regression model to achieve position compensation. The finally output compensated coordinate position is: X final = X pred + ΔX, X pred is the initial coordinate position, and X final is the compensated coordinate position.

[0045] In the head space positioning method based on electrical impedance tomography disclosed in the above embodiments, the method includes: constructing a corresponding three-dimensional model according to the basic parameters of the flexible electrode cap; performing finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model; calculating the electric field distribution of the sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain the corresponding touch electrode response information; generating a sensitivity field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; performing projection matching on the initial voltage data of the electrode pairs and the sensitivity field matrix to obtain projection matching information; performing model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a voltage feature - space coordinate mapping relationship and analyzing the induced voltage data of the electrode pairs to obtain the corresponding target coordinate information. The above method monitors the voltage change in real time through the flexible electrode cap and analyzes to obtain the coordinate information, improving the accuracy and stability in the positioning process.

[0046] An embodiment of the present invention further provides a head space positioning device based on electrical impedance tomography. The head space positioning device based on electrical impedance tomography is configured in a positioning and analysis terminal; the head space positioning device based on electrical impedance tomography is used to execute any one of the above embodiments of the head space positioning method based on electrical impedance tomography. Specifically, please refer to Figure 5 , Figure 5 which is a schematic block diagram of the head space positioning device based on electrical impedance tomography provided by an embodiment of the present invention.

[0047] As shown in Figure 5As shown, the head spatial positioning device 100 based on electrical impedance tomography includes a three-dimensional model construction module 110, a three-dimensional grid model acquisition module 120, an electric field distribution calculation module 130, a sensitive field matrix acquisition module 140, a projection matching information acquisition module 150, a regression model construction module 160, and a target coordinate information acquisition module 170.

[0048] The three-dimensional model construction module 110 is used to construct a corresponding three-dimensional model according to the image segmentation information of the individual user and the basic parameters of the flexible electrode cap. The three-dimensional grid model acquisition module 120 is used to perform finite element meshing on the three-dimensional model to obtain a three-dimensional grid model. The electric field distribution calculation module 130 is used to calculate the electric field distribution of the sampling points in the three-dimensional grid model according to a preset calculation rule to obtain corresponding touch electrode response information. The sensitive field matrix acquisition module 140 is used to generate a sensitive field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information. The projection matching information acquisition module 150 is used to perform projection matching on the initial voltage data of the electrode pairs and the sensitive field matrix to obtain projection matching information; the initial voltage data is the voltage data when the touch pen touches the electrode pairs at various positions on the flexible electrode cap. The regression model construction module 160 is used to perform model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - space coordinate mapping relationship. The target coordinate information acquisition module 170 is used to analyze the induced voltage data of the electrode pairs according to the regression model to obtain corresponding target coordinate information; the induced voltage data is the voltage data when the touch pen touches the electrode pairs at a certain position on the flexible electrode cap.

[0049] In the head spatial positioning device based on electrical impedance tomography provided by the embodiments of the present invention, it is used to execute the above-mentioned head spatial positioning method based on electrical impedance tomography, construct a corresponding three-dimensional model according to the basic parameters of the flexible electrode cap; perform finite element meshing on the three-dimensional model to obtain a three-dimensional grid model; calculate the electric field distribution of the sampling points in the three-dimensional grid model according to a preset calculation rule to obtain corresponding touch electrode response information; generate a sensitive field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; perform projection matching on the initial voltage data of the electrode pairs and the sensitive field matrix to obtain projection matching information; perform model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain the voltage feature - space coordinate mapping relationship and analyze the induced voltage data of the electrode pairs to obtain corresponding target coordinate information. The above method monitors the voltage change in real time through the flexible electrode cap and analyzes to obtain coordinate information, improving the accuracy and stability in the positioning process.

[0050] The embodiment of the present application also discloses a head spatial positioning system based on electrical impedance tomography, as Figure 6 shown. The system includes a positioning and analysis terminal 20, a touch pen 8, and a flexible electrode cap 6. An excitation unit 7 is disposed in the touch pen 8, and a ring electrode array composed of multiple electrode pairs is provided at the edge of the flexible electrode cap 6. A communication unit 9, an interaction unit 10, a power supply unit 11, a control unit 1, a data acquisition unit 5, a sensitive field modeling unit 4, a touch pen position reconstruction unit 2, and a visualization unit 3 are disposed in the positioning and analysis terminal 20. The communication unit 9, the interaction unit 10, the power supply unit 11, the sensitive field modeling unit 4, and the touch pen position reconstruction unit 2 are all communicatively connected to the control unit 1, and the control unit 1 is further communicatively connected to the excitation unit 7. The touch pen position reconstruction unit 2 is communicatively connected to the sensitive field modeling unit 4 and the visualization unit 3. The data acquisition unit 5 is communicatively connected to the sensitive field modeling unit 4, the ring electrode array, and the excitation unit 7 respectively. A memory is disposed inside the positioning and analysis terminal. When the positioning and analysis terminal executes the program stored in its internal memory, the positioning and analysis terminal can execute the steps included in the head spatial positioning method based on electrical impedance tomography.

[0051] The data acquisition unit is used to collect the voltage signals of the ring electrode array on the electrode cap, and is equipped with an anti-interference design to realize weak signal induction. The data acquisition unit is also connected to the excitation unit and can receive the synchronous trigger signal generated by the touch pen touching the electrode cap.

[0052] As Figure 4 shown, the flexible electrode cap 6 is worn on the head similar to a traditional electroencephalogram cap, and is specifically made by laminating and combining an electrode patch array 64, conductive fiber sutures 63, conductive silicone 62, and soft fabric 61. In this embodiment, the conductive fiber sutures 63 are used to stitch and fix the electrode patch array 64 and the conductive silicone 62, and a layer of soft fabric 61 is provided at the bottom. The conductive silicone 62 is a stretchable conductive material, and electrode pairs are arranged in a circular pattern at the edge of the conductive silicone 62 to form a ring electrode array. The soft fabric 61 directly contacts the scalp to improve wearing comfort, and at the same time adapts to head deformation and maintains electrical contact stability.

[0053] The specific application process is as Figure 2 shown. The subject wears the flexible electrode cap, and data is collected when the touch pen touches the top of the electrode cap. When the touch pen of this embodiment contacts the flexible electrode cap, different electric field distributions and real-time coordinates are generated when the touch pen is at different positions on the head. The positioning and analysis terminal with a visualization unit on the right can perform real-time visualization display on the obtained target coordinate information.

[0054] The excitation unit is used to transmit the excitation trigger state. It can send a synchronous trigger signal containing frequency parameters and current intensity parameters to the data acquisition unit through its own wireless communication module to ensure the timing consistency of current excitation and voltage measurement.

[0055] The touch pen includes a contact detection module, which integrates a pressure sensing unit and an electrode impedance detection unit. When the contact pressure between the pen tip and the electrode cap reaches the set threshold and the contact impedance is lower than the critical value, it drives the excitation unit to generate a synchronous trigger signal.

[0056] In a preferred embodiment of the present invention, the touch pen position reconstruction unit is used to analyze the data collected by the data acquisition unit. By analyzing the voltage distribution of the electrode array when the touch pen applies an excitation current at different positions on the electrode cap, the spatial position of the touch pen is obtained through conversion.

[0057] The touch pen position reconstruction unit can solve the position information based on the touch pen position solving method, which is as follows: First, wear the flexible electrode cap on the head of the subject, connect the flexible electrode cap containing the electrode array to the acquisition front-end module of the data acquisition unit. After connection, place the touch pen at the relevant position on the electrode cap. The trigger module of the acquisition unit receives the trigger signal, and the data acquisition unit will collect the voltage data of the electrode pairs under the excitation of the touch pen unit and then transmit it to the touch pen position reconstruction unit for data processing. Use FPGA hardware to accelerate data processing. According to the sensitive field matrix obtained by the sensitive field modeling unit, combine the fast matching algorithm or the lightweight machine learning model to shorten the position calculation time, and at the same time extract the deformation parameters of the voltage change at the edge of the electrode cap to dynamically correct and compensate the positioning error caused by deformation. Finally, give the specific position (X, Y, Z) of the touch pen on the electrode cap at this time.

[0058] The visualization unit is used to display the electric field generated when the touch pen is at different positions on the electrode cap and the real-time coordinates of the touch pen in real-time three dimensions. High-performance graphics interfaces such as OpenGL or Vulkan can be used for three-dimensional rendering, combined with a user-friendly GUI (Graphical User Interface) to achieve intuitive operation and visualization.

[0059] The power supply unit is used to supply energy for the system to work. It is mainly composed of a power conditioning circuit, adopting a modular power supply system, including circuit modules such as an AC / DC conversion module and a DC / DC voltage regulation module, as well as a backup battery pack.

[0060] The communication unit is used for the system to communicate with the outside. The communication method is wired communication or wireless Bluetooth WIFI communication. Wired communication uses an Ethernet or USB interface, and wireless communication uses a Wi-Fi or Bluetooth module.

[0061] The interaction unit is used for users to set and interact with the system functions. The interaction method adopts an interaction interface including a liquid crystal touch display screen, an LED display screen, buttons and touch keys, and provides operation guidance and system feedback through an intuitive user interface.

[0062] In another embodiment of the present invention, a computer-readable storage medium is provided. The computer-readable storage medium can be a volatile or non-volatile computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps included in the above-mentioned head space positioning method based on electrical impedance tomography are implemented.

[0063] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described devices, apparatuses and units can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here. Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0064] In several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. Units with the same function can also be aggregated into one unit. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed couplings or direct couplings or communication connections to each other can be indirect couplings or communication connections through some interfaces, devices or units, and can also be electrical, mechanical or other forms of connection.

[0065] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention.

[0066] In addition, in each embodiment of the present invention, the functional units may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware or in the form of software functional units.

[0067] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product. This computer software product is stored in a computer-readable storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The foregoing computer-readable storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROMs), magnetic disks, or optical discs.

[0068] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A head space positioning method based on electrical impedance tomography, characterized in that, The method is applied to a positioning and parsing terminal. The data acquisition unit in the positioning and parsing terminal is respectively communicatively connected to a touch pen and a flexible electrode cap to achieve the transmission of data information. The flexible electrode cap covers the outer surface of a three-dimensional head model. The method includes: Construct a corresponding three-dimensional model according to the image segmentation information of an individual user and the basic parameters of the flexible electrode cap; Perform finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model; Calculate the electric field distribution of the sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain corresponding touch electrode response information; Generate a sensitivity field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; Perform projection matching on the initial voltage data of the electrode pairs and the sensitivity field matrix to obtain projection matching information; the initial voltage data is the voltage data of the touch pen touching the electrode pairs at various positions in the flexible electrode cap; Perform model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - space coordinate mapping relationship; Analyze the induced voltage data of the electrode pairs according to the regression model to obtain corresponding target coordinate information; the induced voltage data is the voltage data of the touch pen touching the electrode pairs at a certain position in the flexible electrode cap.

2. The head spatial positioning method based on electrical impedance tomography according to claim 1, wherein The performing finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model includes: Perform mesh division on the induction area of the three-dimensional model according to a preset finite element model to obtain corresponding mesh division information; Determine the three-dimensional coordinate positions of each mesh according to the position parameters of each mesh in the mesh division information; Add the mesh division information and the three-dimensional coordinate positions to the three-dimensional model to obtain a corresponding three-dimensional mesh model.

3. The head space positioning method based on electrical impedance tomography according to claim 1 or 2, characterized in that The calculating the electric field distribution of the sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain corresponding touch electrode response information includes: Perform spatial electric potential calculation on the three-dimensional mesh model according to the calculation rule and the basic parameters to obtain corresponding spatial electric potential distribution information; Obtain the voltage response values of the electrode pairs adjacent to the sampling points when the sampling points are in contact with the touch pen according to the spatial electric potential distribution information to obtain the touch electrode response information.

4. The head space positioning method based on electrical impedance tomography according to claim 3, characterized in that, The analyzing the induced voltage data of the electrode pairs according to the regression model to obtain corresponding target coordinate information includes: Extract corresponding voltage vector features from the induced voltage data; Map the voltage vector features according to the voltage feature - space coordinate mapping relationship in the regression model to analyze and obtain corresponding initial coordinate positions as corresponding target coordinate information.

5. The head space positioning method based on electrical impedance tomography according to claim 4, characterized in that After mapping the voltage vector features according to the voltage feature - space coordinate mapping relationship in the regression model to analyze and obtain corresponding initial coordinate positions, it further includes: Perform position compensation on the initial coordinate positions according to a preset position compensation strategy and the induced voltage data to obtain corresponding compensated coordinate positions as the target coordinate information.

6. The head space positioning method based on electrical impedance tomography according to claim 5, characterized in that Performing position compensation on the initial coordinate position according to the preset position compensation strategy and the induced voltage data to obtain a corresponding compensated coordinate position as the target coordinate information includes: Obtaining the voltage gradient change information at the edge position in the induced voltage data; Performing compensation calculation on the voltage gradient change information according to the position compensation strategy to obtain a corresponding position compensation value; Performing position compensation on the initial coordinate position according to the position compensation value to obtain a corresponding compensated coordinate position.

7. The method for head spatial positioning based on electrical impedance tomography according to claim 6, wherein The method further includes: Receiving the brain image data of an individual user, and performing segmentation processing on the brain image data according to a preset segmentation model to obtain corresponding initial segmentation information; Performing segmentation optimization processing on the initial segmentation information according to a preset segmentation optimization model to obtain corresponding image segmentation information; the image segmentation information serves as the basic data for constructing the three-dimensional head model.

8. A head space positioning device based on electrical impedance tomography, characterized in that The device is configured in a positioning and analysis terminal. The data acquisition unit in the positioning and analysis terminal is respectively communicatively connected to the touch pen and the flexible electrode cap to implement data information transmission. The flexible electrode cap covers the outer surface of the three-dimensional head model. The device is used to execute the head space positioning method based on electrical impedance tomography according to any one of claims 1-7. The device includes: A three-dimensional model construction module, configured to construct a corresponding three-dimensional model according to the image segmentation information of an individual user and the basic parameters of the flexible electrode cap; A three-dimensional mesh model acquisition module, configured to perform finite element meshing on the three-dimensional model to obtain a three-dimensional mesh model; An electric field distribution calculation module, configured to perform electric field distribution calculation on the sampling points in the three-dimensional mesh model according to a preset calculation rule to obtain corresponding touch electrode response information; A sensitive field matrix acquisition module, configured to generate a sensitive field matrix corresponding to the sampling points and the electrode pairs in the flexible electrode cap according to the touch electrode response information; A projection matching information acquisition module, configured to perform projection matching on the initial voltage data of the electrode pairs and the sensitive field matrix to obtain projection matching information; the initial voltage data is the voltage data when the touch pen touches the electrode pairs at various positions in the flexible electrode cap; A regression model construction module, configured to perform model training according to the projection matching information and the stretching deformation data of the flexible electrode cap to obtain a regression model based on the voltage feature - spatial coordinate mapping relationship; A target coordinate information acquisition module, configured to analyze the induced voltage data of the electrode pairs according to the regression model to obtain corresponding target coordinate information; the induced voltage data is the voltage data when the touch pen touches an electrode pair at a certain position in the flexible electrode cap.

9. A head space positioning system based on electrical impedance tomography, characterized in that, The system includes a positioning and analysis terminal, a touch pen, and a flexible electrode cap; An excitation unit is configured in the touch pen, and a ring electrode array composed of multiple electrode pairs is provided at the edge of the flexible electrode cap; A communication unit, an interaction unit, a power supply unit, a control unit, a data acquisition unit, a sensitive field modeling unit, a touch pen position reconstruction unit, and a visualization unit are configured in the positioning and analysis terminal; The communication unit, the interaction unit, the power supply unit, the sensitive field modeling unit, and the touch pen position reconstruction unit are all communicatively connected to the control unit, and the control unit is also communicatively connected to the excitation unit; The touch pen position reconstruction unit is communicatively connected to the sensitive field modeling unit and the visualization unit; the data acquisition unit is communicatively connected to the sensitive field modeling unit, the annular electrode array, and the excitation unit respectively; The positioning and analysis terminal is internally configured with a memory. When the positioning and analysis terminal executes the program stored in its internal memory, the steps of the method for head space positioning based on electrical impedance tomography according to any one of claims 1-7 are realized.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, the steps of the method for head space positioning based on electrical impedance tomography according to any one of claims 1-7 are realized.

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