Multi-channel coil collaborative optimization method and device, storage medium and program product

Abstract

The invention discloses a multi-channel coil collaborative optimization method and device, a storage medium and a program product, and relates to the technical field of magnetic resonance imaging system coils. Firstly, a target optimization equation of the multi-channel coil is constructed according to a target field needing to be established, and then structural parameters of the multi-channel coil, weight parameters corresponding to coil performance and current of each coil unit are iteratively optimized according to the target optimization equation. Therefore, collaborative optimization between magnetic field performance parameters such as accuracy and symmetry of a magnetic field generated by the coil and coil performance parameters such as coil power loss, interaction among coil units and coil unit carrier surface coverage rate is realized. The multi-channel coil obtained through the method has higher magnetic field regulation and control flexibility, better magnetic field distribution symmetry, lower power loss and higher working efficiency on the premise that the accuracy of the magnetic field is guaranteed, and the comprehensive performance of the multi-channel coil is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of magnetic resonance imaging system coil technology, and specifically to a multi-channel coil collaborative optimization method, device, storage medium, and program product. Background Technology

[0002] Gradient coils in magnetic resonance imaging (MRI) systems are used for spatial encoding of magnetic resonance signals, including linear and nonlinear encoding, enabling precise localization of the scanned object. Shimming coils compensate for distorted magnetic fields, reducing artifacts caused by non-uniform main magnetic fields and improving image quality. Since MRI systems have limited imaging space, reducing coil volume allows for more examination space for the user, thereby reducing anxiety and panic caused by a confined environment. Therefore, minimizing coil volume is a crucial consideration in the application of MRI technology.

[0003] A multichannel coil consists of multiple coil units, and the magnetic field it generates is a linear superposition of the magnetic fields generated by all the coil units. By adjusting the multichannel coil, different magnetic field shapes can be obtained within the imaging range to meet the magnetic field requirements of spatial encoding and shimming. Therefore, multichannel coils have become a new coil hardware technology for reducing coil size.

[0004] However, high-performance multichannel coils require greater flexibility in magnetic field control, better symmetry in magnetic field distribution, lower power loss, and higher operating efficiency. These issues add difficulty to the design of high-performance multichannel coils. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a multi-channel coil collaborative optimization method, device, storage medium, and program product, which achieves collaborative optimization of the structural parameters and performance of multi-channel coils to improve the overall performance of multi-channel coils.

[0006] The first aspect discloses a multi-channel coil collaborative optimization method, wherein the multi-channel coil is composed of several coil units distributed on the surface of a coil carrier, and the method includes:

[0007] A first preset parameter combination of a multi-channel coil to be optimized is obtained, wherein the multi-channel coil to be optimized is set according to the first preset parameter combination, which includes at least one structural parameter and at least one weighting parameter; the unit magnetic field strength of the target magnetic field constructed by the multi-channel coil to be optimized is obtained, and the first current value of each coil unit is obtained according to the target optimization equation; the multi-channel coil to be optimized is determined according to the first current value of each coil unit and the unit magnetic field strength to determine whether it meets the preset constraint conditions. If it does, the first preset parameter combination is used as the optimization parameters of the multi-channel coil to be optimized.

[0008] As one possible implementation, the method further includes: if the multi-channel coil to be optimized does not meet the preset constraint conditions based on the first current value of each coil unit and the unit magnetic field strength, then a second preset parameter combination is obtained according to a preset iterative optimization algorithm, wherein the first preset parameter combination is different from the second preset parameter combination; the multi-channel coil to be optimized is reset according to the second preset parameter combination; the second unit magnetic field strength of the target magnetic field constructed by the reset multi-channel coil to be optimized and the second current value of each coil unit are obtained according to the target optimization equation; whether the multi-channel coil to be optimized meets the preset constraint conditions is determined based on the second current value of each coil unit and the second unit magnetic field strength; if it meets the constraint conditions, the second preset parameter combination is used as the optimization parameter of the multi-channel coil to be optimized; if it does not meet the constraint conditions, the next preset parameter combination is obtained according to the first preset iterative optimization algorithm, and a determination step on whether the preset constraint conditions are met is performed.

[0009] The second aspect discloses an electronic device including a processor and a memory, the memory storing a computer program that, when executed, implements the multi-channel coil collaborative optimization method disclosed in the first aspect or any possible implementation thereof.

[0010] The third aspect discloses a computer-readable storage medium storing a computer program or computer instructions that, when executed, implement the multi-channel coil collaborative optimization method disclosed in the first aspect or any possible implementation thereof.

[0011] The fourth aspect discloses a computer program product that, when run on a computer, causes the computer to perform the multi-channel coil collaborative optimization method disclosed in the first aspect or any possible implementation of the first aspect.

[0012] As can be seen from the above technical solutions, this invention has the following advantages: First, it constructs a target optimization equation for a multi-channel coil based on the established target field. Then, iteratively optimizes the structural parameters of the multi-channel coil, the weight parameters corresponding to the coil performance, and the current of each coil unit based on the target optimization equation. This achieves synergistic optimization between magnetic field performance parameters such as the accuracy and symmetry of the magnetic field generated by the coil, and coil performance parameters such as coil power loss, interaction between coil units, and surface coverage of the coil unit carrier. The coil obtained by this invention, while ensuring magnetic field accuracy, possesses stronger magnetic field control flexibility, better magnetic field distribution symmetry, lower power loss, and higher working efficiency, significantly improving the overall performance of the multi-channel coil. Attached Figure Description

[0013] Figure 1(a) is a schematic diagram of the principle of generating a magnetic field by a multi-channel coil provided in an embodiment of the present invention.

[0014] Figure 1(b) is a schematic diagram of the head-specific asymmetric multichannel coil provided in an embodiment of the present invention.

[0015] Figure 2(a) is a schematic diagram of the double-layer complementary rectangular multi-channel coil structure proposed in an embodiment of the present invention.

[0016] Figure 2(b) is a top view of the double-layer complementary rectangular multi-channel coil structure proposed in the embodiment of the present invention.

[0017] Figure 3 This is a surface unfolding diagram of the double-layer complementary rectangular multi-channel coil proposed in an embodiment of the present invention.

[0018] Figure 4 This is a flowchart of the multi-channel coil collaborative optimization method proposed in an embodiment of the present invention.

[0019] In the figure: multi-channel coil 101, coil unit 102, power amplifier 103, driving device 104, imaging area 105, axial direction 106, inner coil 201, gap between inner coil units 202, outer coil 203, gap between outer coil units 204, height of each row of inner coil units is 301-304, arc length of each column of inner coil units is 305-307, height of each row of outer coil units is 308-311, arc length of each column of outer coil units is 312-314. Detailed Implementation

[0020] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be thorough and complete.

[0021] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "up," "down," and similar expressions used herein are for illustrative purposes only and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0024] In one embodiment, to meet the need for improved performance of multi-channel coils in various aspects, this invention provides a multi-channel coil collaborative optimization method, device, storage medium, and program product. To better understand this invention, the principle of magnetic field generation by the multi-channel coil is first explained, as shown in Figure 1(a). In Figure 1(a), the multi-channel coil 101 consists of a series of coil units 102, which are fixed to the surface of a coil carrier. Each coil unit 102 is equipped with a power amplifier 103 for independent driving. By adjusting the current in the coil unit 102, different magnetic fields can be generated within the imaging region 105. Integrating all power amplifiers 103 into a single driving device 104 enables unified driving and control of the multi-channel coil 101. The requirements of different magnetic fields for spatial encoding and shimming in magnetic resonance imaging systems can be met using only one set of multi-channel coil structures. For example, a first-order linear field can be used for both linear encoding and shimming; a second-order nonlinear field can be used for both nonlinear encoding and shimming. Normally, the multi-channel coil 101 and the imaging area 105 are symmetrical in the axial direction 106. However, for head-specific coils, in order to fit the head contour more closely and improve the magnetic field strength, accuracy and range of action in the head imaging area, the multi-channel coil 101 and the imaging area 105 can be designed to be asymmetrical in the axial direction, as shown in Figure 1(b). In this case, it is easier to generate a non-uniform or asymmetrical magnetic field in the imaging area 105.

[0025] The magnetic field performance of a multi-channel coil includes the accuracy and symmetry of the magnetic field generated by the coil, while its structural performance includes the flexibility of the magnetic field generation, system power loss, and coil efficiency. Improving the flexibility of the magnetic field generation by a multi-channel coil can be achieved by increasing the coverage of coil units on the coil carrier surface. This increased surface coverage can be achieved through a multi-layered, complementary coil structure. Specifically, coil units 102 are no longer distributed on the same layer but can be distributed across multiple layers along the carrier. The positions of the coil units between layers and the gaps between coil units form a complementary distribution pattern; that is, the gaps between coil units in the same layer are covered by coil units in other layers, resulting in a multi-layered complementary coil structure. Since the coil units 102 will act on the imaging region 105 through the gaps, this compensates for the lack of magnetic field action on the imaging region 105 caused by the gaps, thereby improving the flexibility and freedom of the magnetic field generation by the multi-channel coil. Improving the symmetry of the magnetic field generated by the coil can be achieved by constraining the maximum asymmetry value of the magnetic field in the imaging region 105; the smaller this value, the better the symmetry of the surface magnetic field distribution. Coil power loss and coil efficiency can be achieved by constraining the coil power and the mutual inductance coupling coefficient between coil units. The smaller the mutual inductance coupling coefficient between coil units, the less interaction occurs, and the higher the coil efficiency. This invention significantly improves the flexibility, symmetry, and efficiency of the generated magnetic field by synergistically optimizing factors such as the accuracy and symmetry of the magnetic field generated by the coil, coil power loss, interaction between coil units, and carrier surface coverage. It also effectively reduces system power loss and improves the overall performance of the coil.

[0026] In one embodiment, the present invention discloses a multi-channel coil collaborative optimization method, such as... Figure 4 As shown, it specifically includes:

[0027] S101. Obtain a first preset parameter combination of the multi-channel coil to be optimized, wherein the multi-channel coil to be optimized is set according to the first preset parameter combination, and the first preset parameter combination includes at least one structural parameter and at least one weight parameter.

[0028] It should be noted that the optimization design method of the present invention covers the systematic design of multi-channel coil structural parameters and coil unit current. The structural parameters include the shape (e.g., rectangle, circle, irregular polygon), size (e.g., arc length, height), distribution method (e.g., array type, non-array type), and number of distribution layers of the coil unit.

[0029] The weighting parameters are used to constrain various performance characteristics of the multi-channel coil to be optimized, ensuring that the optimized coil's performance better meets practical requirements. Specifically, the weighting parameters can be the symmetry of the magnetic field generated by the multi-channel coil, as well as the weights corresponding to the coil's magnetic field generation flexibility, system power loss, and coil efficiency. Co-optimization refers to the coordinated optimization between magnetic field performance parameters such as accuracy and symmetry of magnetic field generation and coil performance parameters such as coil power loss, interaction between coil units, and surface coverage of the coil unit carrier. Based on the Tikhonov regularization method, an objective optimization equation is established, with parameters other than magnetic field accuracy used as regularization terms. The weights of relevant performance parameters are adjusted by optimizing the weighting coefficients.

[0030] Specifically, in one embodiment, the first preset parameter combination includes at least a first weight parameter corresponding to the surface coverage of the coil unit carrier and a second weight parameter corresponding to the maximum asymmetry value of the magnetic field, which is used to constrain the flexibility and magnetic field symmetry of the multi-channel coil to be optimized.

[0031] Furthermore, to improve optimization efficiency, this invention can also perform selective optimization on certain structural parameters, that is, pre-set some parameters while optimizing uncertain parameters. For example, the number of coil layers, the number of coil units, the structure of the coil units, the number of turns, and the positional distribution can be pre-set, and only the size of the coil units can be optimized, thereby effectively reducing the optimization complexity and computation time without significantly affecting performance.

[0032] In addition, when optimizing coil structure and weighting coefficients and other related parameters, the structural parameters and weighting parameters are updated and iterated simultaneously. At this time, all parameters will be obtained through a preset iterative optimization algorithm.

[0033] S102. Obtain the unit magnetic field strength of the target magnetic field constructed by the multi-channel coil to be optimized, and obtain the first current value of each coil unit according to the target optimization equation.

[0034] Specifically, regarding the setting of the target magnetic field, a single target field or multiple target fields can be selected as the optimization target according to the actual imaging requirements, so as to flexibly adapt to the magnetic field requirements of different coding application scenarios. For example, in linear coding, a linear magnetic field distributed along the three directions of x, y, and z is required, namely the X, Y, and Z gradient fields. If only the X gradient field needs to be generated, then there is only one target field, i.e., a single target field; if three gradient fields need to be generated simultaneously, then there are three target fields, i.e., multiple target fields. As another example, when shimming, a magnetic field with the same amplitude and opposite direction to the distortion field (composed of harmonic terms of spherical harmonic functions) needs to be generated. If only one set of distortion fields needs to be compensated, then the target field is a single target field; if different sets of distortion fields need to be compensated according to different locations, then the target field is a multiple target field.

[0035] Wherein, the unit magnetic field strength is the magnetic field strength generated by the multi-channel coil structure in the imaging region 105 under the action of a unit current, and the unit magnetic field strength matrix B MC This represents the magnetic field generated at the i-th target field point when the l-th coil unit is supplied with a unit current (1A). There are a total of M target field points and L coil units. The target field points are set within the imaging area, and the specific settings can be determined according to actual needs.

[0036] Specifically, the steps for obtaining the first current value of each coil unit based on the target optimization equation include:

[0037] According to the second preset iterative optimization algorithm, multiple combinations of current values ​​corresponding to each coil unit are obtained. The combination of current values ​​corresponding to the coil unit that makes the target optimization equation reach the minimum value is used as the first current value of each coil unit. Each coil unit corresponds to a current value, and the current values ​​corresponding to different coil units may be the same or different.

[0038] It should be noted that, based on factors such as algorithm complexity, optimization time, and expected results, the second preset iterative optimization algorithm can flexibly select appropriate optimization algorithms, including but not limited to least squares, genetic algorithms, and particle swarm optimization. Both the same algorithm and different algorithms can be used to achieve the best balance between efficiency and performance in the optimization process. Specifically, the corresponding current value combinations for each coil unit can be obtained based on existing optimization algorithms until the current value combination that minimizes the target optimization equation is obtained.

[0039] S103. Determine whether the multi-channel coil to be optimized meets the preset constraint conditions based on the first current value of each coil unit and the unit magnetic field strength. If it does, use the first preset parameter combination as the optimization parameters of the multi-channel coil to be optimized.

[0040] In another embodiment, determining whether the multi-channel coil to be optimized meets preset constraints based on the first current value of each coil unit and the unit magnetic field strength includes:

[0041] The target value δ is determined based on the first current value of each coil unit and the unit magnetic field strength. The target value δ is used to represent the maximum magnetic field error of the multi-channel coil to be optimized.

[0042] If the target value δ is less than the preset value, then the preset constraint condition is considered to be satisfied.

[0043] Specifically, the accuracy of the magnetic field generated by the multi-channel coil is represented by the maximum magnetic field error δ:

[0044] (1)

[0045] In the formula, B MC Let I be the unit magnetic field strength matrix, and I be the coil element current vector, represented as [I1, I2, ..., I...]. L ] T B tg Let [B] be the target field magnetic field intensity vector, denoted as [B] tg1 B tg2 B tgM ] T The target value δ can be calculated using the above formula. When the target value δ is less than the preset value, it means that the accuracy of the magnetic field generated by the multi-channel coil to be optimized, expressed as the maximum magnetic field error δ, is less than the preset value, thus meeting the requirements for the accuracy of the multi-channel coil's magnetic field. The preset value can be set according to the actual needs of the target field and is not specifically limited here.

[0046] In another embodiment, the present invention further includes the following steps:

[0047] S104. If the multi-channel coil to be optimized does not meet the preset constraint conditions based on the first current value of each coil unit and the unit magnetic field strength, then the second preset parameter combination is obtained according to the first preset iterative optimization algorithm, wherein the first preset parameter combination is different from the second preset parameter combination.

[0048] It should be noted that the first preset iterative optimization algorithm can flexibly select appropriate optimization algorithms, including but not limited to least squares method, genetic algorithm, particle swarm optimization, etc. Both the same algorithm and different algorithms can be used to achieve the best balance between efficiency and performance in the optimization process. Specifically, different combinations of preset parameters can be obtained through existing algorithms until the multi-channel coil to be optimized satisfies the preset constraints. It is important to note that the first and second preset iterative optimization algorithms can be the same algorithm or different algorithms, with adaptive selection based on the different optimization objectives.

[0049] S105. The multi-channel coil to be optimized is reset according to the second preset parameter combination;

[0050] S106. Obtain the second unit magnetic field strength of the target magnetic field constructed by the reconfigured multi-channel coil to be optimized, and obtain the second current value of each coil unit according to the target optimization equation;

[0051] S107. Determine whether the multi-channel coil to be optimized meets the preset constraint conditions based on the second current value and the second unit magnetic field strength of each coil unit. If it does, then use the second preset parameter combination as the optimization parameters of the multi-channel coil to be optimized.

[0052] S108. If not satisfied, continue to obtain the next preset parameter combination according to the preset iterative optimization algorithm, and perform the determination step of whether the preset constraints are satisfied.

[0053] It should be further explained that this application finds the optimal parameter combination that meets the performance requirements of the target field by iteratively optimizing the parameter combination of the multi-channel coil to be optimized.

[0054] In another embodiment, when the target magnetic field is a single target field, the target optimization equation specifically includes:

[0055] (2)

[0056] Where |||2 is the second-order norm, representing the error between the actual magnetic field strength at the target field point in the imaging region and the target magnetic field strength, and I is the coil element current vector, denoted as [I1, I2, ..., I... L ] T B MC B is the unit magnetic field strength matrix. tg Let [B] be the target field magnetic field intensity vector, denoted as [B] tg1 B tg2 B tgM ] T λ1-λ4 are weighting coefficients used to adjust the proportion of the regularization term in the optimization equation, min represents the minimum value, η represents the surface coverage of the coil unit carrier, v represents the maximum asymmetry value of the magnetic field, k represents the mutual inductance coupling coefficient, and p represents the power loss.

[0057] This invention achieves synergistic optimization between magnetic field performance parameters such as accuracy and symmetry of magnetic field generation by multi-channel coils and coil performance parameters such as coil power loss, interaction between coil units, and surface coverage of coil unit carrier. Based on the Tikhonov regularization method, an objective optimization equation is established, with parameters other than magnetic field accuracy as regularization terms. The weights of relevant performance parameters are adjusted by optimizing the weight coefficients.

[0058] Furthermore, the specific representations of each performance parameter in the above formula are as follows:

[0059] The surface coverage η of the coil unit carrier is the ratio of the effective area of ​​the coil unit to the surface area of ​​the coil carrier, specifically expressed as:

[0060] (3)

[0061] Among them, S MC S and S represent the effective area and surface area of ​​the multi-channel coil unit distributed on the carrier surface, respectively.

[0062] The asymmetry of the magnetic field generated by the multi-channel coil is represented by the maximum asymmetry value v, which is the maximum value of the difference between the absolute value of the maximum and minimum magnetic field values ​​at the target field point. Specifically, it is expressed as:

[0063] (4)

[0064] Among them, B i The magnetic field value generated by the multi-channel coil at the target field point; the smaller the maximum asymmetry value v of the magnetic field, the higher the symmetry of the magnetic field distribution, thereby improving the symmetry of the magnetic field generated by the coil.

[0065] The interaction between coil units is represented by the mutual inductance coupling coefficient k, which is the ratio between the mutual inductance between coil units and the self-inductance of the coil unit. Specifically, it is expressed as:

[0066] (5)

[0067] Among them, M 12 For the mutual inductance between any two coil units, L self1 L self2 The self-inductance is for two coil units.

[0068] The power loss p of a multi-channel coil is the sum of the power consumed by all coil units, specifically expressed as:

[0069] (6)

[0070] Among them, I i and R i Let be the current and resistance of the i-th coil unit, respectively, and L be the number of coil units.

[0071] In another embodiment, when the target magnetic field is a multi-target field, the target optimization equation specifically includes:

[0072] (7)

[0073] Where N is the number of target fields, I N = Let N be the vector of currents corresponding to the N target fields. = λ1-λ4 is represented as the magnetic field intensity vector composed of N target fields, where λ1-λ4 are weighting coefficients. This represents the maximum asymmetry value of the magnetic field of the Nth target field. This represents the power loss of the Nth target field. The unit magnetic field strength matrix is ​​specifically represented as:

[0074] (8)

[0075] It should be noted that the multi-channel coil structure is fixed in each optimization process; therefore, the mutual inductance between coil units and the surface coverage of the coil unit carrier are fixed. Furthermore, since different target fields correspond to different power and magnetic field distributions, N weighting coefficients need to be set for each of the power and magnetic field asymmetries, and these N weighting coefficients must be different for each power or magnetic field asymmetry. Preferably, to reduce the number of optimization parameters, the weighting coefficients for power and magnetic field asymmetries can be set to the same weighting coefficient.

[0076] When determining whether the solution results of the target optimization equation meet the design requirements, it is stipulated that the accuracy of each target magnetic field must meet the design requirements, as specifically stated below:

[0077] (9)

[0078] in, This represents the maximum magnetic field error corresponding to the Nth target field. It should be noted that the multi-channel coil optimization method for multiple target fields differs from that for single target fields in terms of the target optimization equation and the determination of whether the result meets the design requirements. Other steps can refer to the optimization process proposed in this invention.

[0079] In summary, the multi-channel coil collaborative optimization method proposed in this invention, by introducing a multi-layer structural layout and utilizing the Tikhonov regularization method, collaboratively optimizes magnetic field accuracy, coil power loss, magnetic field asymmetry, inter-unit mutual inductance coupling, and carrier surface coverage. While ensuring magnetic field quality, it effectively improves the surface coverage of coil units, enhances the freedom and flexibility of magnetic field control, reduces power loss and magnetic field non-uniformity, improves working efficiency, and significantly enhances the overall performance of the coil. This invention provides a feasible technical solution for the design of coils in magnetic resonance imaging systems. Furthermore, based on the ability of multi-channel coils to flexibly generate various magnetic field shapes, it can simultaneously adapt to the functional requirements of gradient coils and shimming coils, possessing advantages of high system integration and compact structure. The optimization method of this invention has good flexibility in both structural design and current control, providing reliable coil hardware support for the miniaturization and clinical application of magnetic resonance imaging systems.

[0080] To further illustrate the present invention, specific embodiments are described below. This embodiment optimizes only the structural parameters and dimensions of the coil units. The target field is selected as a single target field, and the multi-channel coil to be optimized is a double-layer complementary rectangular structure. Its overall effect is shown in Figure 2(a), and its top view is shown in Figure 2(b). In the figures, there are certain gaps 202 between the coil units 102 of the inner coil 201. The magnetic field effect missing in these gaps 202 can be compensated by the coil units 102 of the outer coil 203 covering the surface of these gaps; while the gaps 204 between the coil units 102 of the outer coil 203 are covered by the coil units 102 of the inner coil 201. The surface unfolding effect of the double-layer complementary rectangular multi-channel coil in this embodiment is shown in the figure. Figure 3 As shown, Figure 3 In this embodiment, the inner coil 201 has a 4-row, 3-column structure. The height of each coil unit in each row is 301-304 (denoted as d1-d4), and the arc length of each coil unit in each column is 305-307 (denoted as l1-l3). The outer coil 203 also has a 4-row, 3-column structure. The height of each coil unit in each row is 308-311 (denoted as d5-d8), and the arc length of each coil unit in each column is 312-314 (denoted as l4-l6). The specific coil unit optimization process in this embodiment is as follows:

[0081] Step S401: Initialize the structural parameters d1-d8, l1-l6, and λ1-λ4.

[0082] Step S402: Calculate the unit magnetic field strength B generated by the coil structure in the imaging region 105 under the action of a unit current. MC ,

[0083] (10)

[0084] In the formula, the unit magnetic field strength matrix B MC This represents the magnetic field generated at the i-th target field point when the l-th coil unit is supplied with a unit current (1A). There are a total of M target field points and L coil units. The target field points are set within the imaging area.

[0085] Step S403: Optimize the current of each coil unit using a preset iterative optimization algorithm based on the optimization objective equation. The specific optimization objective equation is as follows:

[0086] (2)

[0087] Where |||2 is the second-order norm, representing the error between the actual magnetic field strength at the target field point in the imaging region and the target magnetic field strength, and I is the coil element current vector, denoted as [I1, I2, ..., I... L ]T B MC B is the unit magnetic field strength matrix. tg Let [B] be the target field magnetic field intensity vector, denoted as [B] tg1 B tg2 B tgM ] T , which is the target field value set at M target field points, λ1-λ4 are weighting coefficients used to adjust the proportion of the regularization term in the optimization equation, min represents the minimum value, η represents the surface coverage of the coil unit carrier, v represents the maximum asymmetric value of the magnetic field, k represents the mutual inductance coupling coefficient, and p represents the power loss.

[0088] Step S404: Determine whether the solution result of the target optimization equation in step S403 meets the design requirements of magnetic field accuracy δ. The calculation method is shown in formula (1):

[0089] (1)

[0090] Step S405: If step S404 meets the design requirements, then accept the coil structure as the result of this multi-channel coil structure design, and the design ends.

[0091] Step S406: If the conditions in step S404 are not met, the coil unit height d1-d7, arc length l1-l6 and weight coefficient λ1-λ4 need to be iteratively updated using the preset iterative optimization algorithm. Then the iterated parameters are brought into step S402, and then through steps S403, S404 and S405 until the design ends.

[0092] This application also provides an electronic device, which includes a processor and a memory. The memory stores at least one instruction or at least one program, which is loaded by the processor and executed using the multi-channel coil collaborative optimization method provided in the above-described method embodiments.

[0093] Furthermore, an electronic device is provided for implementing the method provided in the embodiments of this application. This device can participate in constituting or including the apparatus or system provided in the embodiments of this application. The electronic device may include one or more processors (processors may include, but are not limited to, processing devices such as microprocessors (MCUs) or programmable logic devices (FPGAs), a memory for storing data, and a transmission device for communication functions. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a power supply, and / or a camera.

[0094] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits can be implemented wholly or partially as software, hardware, firmware, or any other combination. Furthermore, the data processing circuits can be a single, independent processing module, or wholly or partially integrated into any other element within a device (or mobile device). As involved in the embodiments of this application, the data processing circuit serves as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0095] The memory can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the method described in the embodiments of this application. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, thereby realizing the above-mentioned data processing method. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to electronic devices via a network. Examples of the above-mentioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0096] The transmission device is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the device's communication provider. In one example, the transmission device includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device may be a Radio Frequency (RF) module, used for wireless communication with the Internet.

[0097] The display can be, for example, a touchscreen liquid crystal display (LCD), which allows users to interact with the user interface of an electronic device (or mobile device).

[0098] This application also provides a computer storage medium storing at least one instruction or at least one program, which is loaded and executed by a processor to implement the multi-channel coil collaborative optimization method provided in the above method embodiments.

[0099] Optionally, in this embodiment, the aforementioned computer storage medium may be located at at least one of the multiple network servers in a computer network. Optionally, in this embodiment, the aforementioned storage medium may include, but is not limited to, various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0100] This application also provides a computer program product or computer program that includes computer instructions stored in a computer storage medium. The processor of an electronic device reads the computer instructions from the computer storage medium and executes the computer instructions, causing the electronic device to perform the multi-channel coil collaborative optimization method provided in the above-described method embodiments.

[0101] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0102] It should be understood that the above description of the preferred embodiments is quite detailed, but it should not be considered as a limitation on the scope of protection of this invention. Those skilled in the art, under the guidance of this invention, can make substitutions or modifications without departing from the scope of protection of the claims of this invention, and all such substitutions or modifications fall within the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims.

Claims

1. A multi-channel coil collaborative optimization method, characterized in that, A multi-channel coil consists of several coil units distributed on the surface of a coil carrier. The method includes: Obtain a first preset parameter combination of the multi-channel coil to be optimized, wherein the multi-channel coil to be optimized is set according to the first preset parameter combination, and the first preset parameter combination includes at least one structural parameter and at least one weighting parameter; Obtain the unit magnetic field strength of the target magnetic field constructed by the multi-channel coil to be optimized, and obtain the first current value of each coil unit according to the target optimization equation; Based on the first current value of each coil unit and the unit magnetic field strength, it is determined whether the multi-channel coil to be optimized meets the preset constraint conditions. If it does, the first preset parameter combination is used as the optimization parameters of the multi-channel coil to be optimized.

2. The method according to claim 1, characterized in that, The method further includes: If the multi-channel coil to be optimized does not meet the preset constraint conditions based on the first current value of each coil unit and the unit magnetic field strength, then the second preset parameter combination is obtained according to the first preset iterative optimization algorithm, wherein the first preset parameter combination is different from the second preset parameter combination. The multi-channel coil to be optimized is reset according to the second preset parameter combination; Obtain the second unit magnetic field strength of the target magnetic field constructed by the reconfigured multi-channel coil to be optimized, and obtain the second current value of each coil unit according to the target optimization equation; Based on the second current value of each coil unit and the second unit magnetic field strength, it is determined whether the multi-channel coil to be optimized meets the preset constraint conditions. If it does, the second preset parameter combination is used as the optimization parameters of the multi-channel coil to be optimized. If not satisfied, the next preset parameter combination is obtained according to the first preset iterative optimization algorithm, and the determination step of whether the preset constraints are satisfied is performed.

3. The method according to claim 1, characterized in that, The process of obtaining the first current value of each coil unit according to the target optimization equation includes: According to the second preset iterative optimization algorithm, the current value combination corresponding to multiple coil units is obtained. The current value combination corresponding to the coil unit that makes the target optimization equation reach the minimum value is used as the first current value of each coil unit. Each coil unit corresponds to a current value, and the current values ​​corresponding to different coil units are the same or different.

4. The method according to claim 1, characterized in that, The step of determining whether the multi-channel coil to be optimized meets the preset conditions based on the first current value of each coil unit and the unit magnetic field strength includes: The target value δ is determined based on the first current value of each coil unit and the unit magnetic field strength. The target value δ is used to represent the maximum magnetic field error of the multi-channel coil to be optimized. If the target value δ is less than the preset value, then the preset constraint condition is considered to be satisfied.

5. The method according to claim 1, characterized in that, The method includes: The first preset parameter combination includes at least a first weight parameter corresponding to the surface coverage of the coil unit carrier and a second weight parameter corresponding to the maximum asymmetry value of the magnetic field, which are used to constrain the flexibility and magnetic field symmetry of the multi-channel coil to be optimized.

6. The method according to claim 1, characterized in that, The target magnetic field is a single-target field, and the target optimization equation specifically includes: （2）； Where |||2 is the second-order norm, representing the error between the actual magnetic field strength at the target field point in the imaging region and the target magnetic field strength, and I is the coil element current vector, denoted as [I1, I2, ..., I... L ] T B MC B is the unit magnetic field strength matrix. tg Let [B] be the target field magnetic field intensity vector, denoted as [B] tg1 B tg2 B tgM ] T λ1-λ4 are weighting coefficients used to adjust the proportion of the regularization term in the optimization equation, min represents the minimum value, η represents the surface coverage of the coil unit carrier, v represents the maximum asymmetry value of the magnetic field, k represents the mutual inductance coupling coefficient, and p represents the power loss.

7. The method according to claim 1, characterized in that, The method includes: the target magnetic field is a multi-target field, and the target optimization equation specifically includes: （7）； Where N is the number of target fields, I N = Let N be the vector of currents corresponding to the N target fields. = , represented as the magnetic field strength vector composed of N target fields. Here, λ1-λ4 is the unit magnetic field strength matrix, η is the weighting coefficient, and η represents the surface coverage of the coil unit carrier. Let represent the maximum asymmetric value of the magnetic field of the Nth target field, and k represent the mutual inductance coupling coefficient. This represents the power loss of the Nth target field.

8. A computer device, characterized in that, The computer device includes a processor and a memory, the memory storing a computer program that is loaded and executed by the processor to implement the method as claimed in any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which is loaded and executed by a processor to implement the method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that, The computer program product includes a computer program stored in a computer-readable storage medium, which a processor reads from and executes to implement the method as described in any one of claims 1 to 7.

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