阅读说明：本技术 一种基于深度学习的三维电阻抗成像系统 (Three-dimensional electrical impedance imaging system based on deep learning ) 是由 孙世杰 王景浩 王颖 卢旭鹏 张锐 徐立军 于 2021-01-20 设计创作，主要内容包括：本发明公开一种基于深度学习的三维电阻抗成像系统,包括：依次连接的传感器模块、数据采集控制模块及上位机模块；所述传感器模块用于形成被测区域空间的敏感场；所述数据采集控制模块用于对被测区域的表面阻抗进行测量,进行数据的初步处理并传输；所述上位机模块用于根据处理后的阻抗数据进行图像重建。本发明提供基于深度学习的三维电阻抗成像系统,可用于人体乳腺成像,通过一定的激励采集方式,可获得半球测量区域的三维表面阻抗信息,利用乳腺组织和癌症组织的电学特性差异,用于三维半球区域的电导率分布重建,本发明提供的系统可应用于女性乳腺癌早期筛查,且具有造价低、易于携带、对人体的无害的优势。(The invention discloses a three-dimensional electrical impedance imaging system based on deep learning, which comprises: the sensor module, the data acquisition control module and the upper computer module are connected in sequence; the sensor module is used for forming a sensitive field of a measured area space; the data acquisition control module is used for measuring the surface impedance of the measured area, and performing primary processing and transmission of data; and the upper computer module is used for reconstructing an image according to the processed impedance data. The invention provides a three-dimensional electrical impedance imaging system based on deep learning, which can be used for human breast imaging, can obtain three-dimensional surface impedance information of a hemispherical measurement region through a certain excitation acquisition mode, and is used for conductivity distribution reconstruction of a three-dimensional hemispherical region by utilizing the electrical characteristic difference of breast tissues and cancer tissues.)

1. A three-dimensional electrical impedance imaging system based on deep learning is characterized by comprising a sensor module, a data acquisition control module and an upper computer module which are sequentially connected;

the sensor module is used for forming a sensitive field of a measured area space;

the data acquisition control module is used for measuring the surface impedance of the measured area and performing primary processing and transmission of data;

and the upper computer module is used for reconstructing an image according to the processed impedance data.

2. The deep learning based three-dimensional electrical impedance imaging system of claim 1, wherein the sensor module comprises a hemispherical outer wall, an electrode button and a flexible PCB;

a connecting circuit is laid in the flexible PCB; the outer wall of the sensor is provided with a plurality of through holes; the flexible PCB board passes through the electrode is detained with the sensor outer wall links to each other.

3. The deep learning based three-dimensional electrical impedance imaging system according to claim 2, wherein a plurality of via holes and bonding pads are arranged on the flexible PCB;

the through holes are annular, can conduct electricity and are connected with the electrode buckles, and the through holes are symmetrically arranged along the flexible PCB;

the welding pad comprises a welding interface for connecting a shielding wire for transmitting signals, and the welding pad is symmetrically arranged along the flexible PCB;

the via holes and the bonding pads are arranged in pairs on the flexible PCB, and each via hole is connected with the corresponding bonding pad.

4. The deep learning based three-dimensional electrical impedance imaging system according to claim 1, wherein the data acquisition control module comprises a channel switch board and a core control board, and the core control board is connected with the channel switch board;

the channel switching board is used for selecting channels;

the core control board is used for measuring impedance data;

the core control panel is provided with a digital signal control module, and the on-off of chip pins of the channel switching plate is controlled through the digital signal control module.

5. The deep learning-based three-dimensional electrical impedance imaging system according to claim 4, wherein the channel switch board is composed of four 74HC4067 chips, and channels are selected.

6. The deep learning-based three-dimensional electrical impedance imaging system according to claim 1, wherein the upper computer module comprises a Calderon direct image reconstruction algorithm and a deep learning neural network for image reconstruction of the conductivity distribution in the sensitive region formed by the sensor module.

7. The three-dimensional electrical impedance imaging system based on deep learning of claim 6, wherein the process of the upper computer module three-dimensional image reconstruction is as follows: performing initial reconstruction of the conductivity on a group of surface impedance measurement data by using a Calderon algorithm to obtain an initial conductivity distribution image; inputting the preliminary conductivity distribution image as a training sample of the neural network, and performing supervision training on the neural network by using an expected conductivity distribution binary image as a label to obtain a trained neural network; inputting the measured impedance data and the preliminary conductivity distribution image into the trained neural network to obtain a conductivity distribution reconstructed image, and quantitatively analyzing the reconstructed image result according to the position and size information of the abnormal block of the reconstructed image to obtain the conductivity distribution reconstructed image.

Technical Field

The invention relates to the field of three-dimensional electrical impedance imaging, in particular to a three-dimensional electrical impedance imaging system based on deep learning.

Background

An Electrical Impedance Tomography (EIT) technique developed on the basis of an Electrical Impedance measurement technique is a technique aiming at reconstructing Electrical property distribution inside a human body. The EIT technology has the unique advantages of no radiation, no special environment, low cost, high cost performance, no wound, high speed and the like, is gradually developed into an important supplementary means for early screening and diagnosis of breast cancer, is expected to become a portable medical instrument used in community-level hospitals and even personal daily care, has great significance for reducing the occurrence of breast diseases and improving the survival rate of patients, and has wide application prospect.

Research shows that the biological impedance is determined by the shape, size, structure, physiology and pathology of the tissue, and when the excitation frequency is below 100MHz, the electrical conductivity and dielectric constant of malignant tumor tissue and normal tissue are obviously different. The bioimpedance characteristics of breast tissue can therefore be used to distinguish between tumor tissue and normal breast tissue. The breast tumor in the early stage of development has no obvious morphological change, and is not easy to be detected by using a general imaging detection means, but the electrical characteristics of the breast tumor are changed at the moment. I.e., functional changes in breast tissue often precede organic lesions and various symptoms. Therefore, compared with other imaging methods, the EIT technology has unique advantages for early detection of canceration, and the medical value and the application prospect of the EIT technology are reflected.

The EIT technology has been used as an auxiliary screening device for breast cancer screening, but it faces the following problems: firstly, the computation process of the inverse problem in the EIT technique is not adaptive, i.e. small perturbations of the boundary measurements may cause large changes in the solution (electrical parameter distribution); next, although the amount of information to be measured is small and the amount of measurement data can be increased by increasing the number of electrodes, the amount of calculation increases rapidly due to the increase in the amount of data. The above difficulties cause the poor system resolution of the EIT technique.

The deep learning is a branch of artificial intelligence, is a nonlinear deep network structure provided by the shallow learning, has strong self-adaptive learning capability compared with the hidden layer with less shallow learning and the characteristic of poor characteristic extraction capability, and can intelligently learn data characteristics and process various information. The deep learning is applied to the EIT inverse problem, and due to the excellent self-adaptive learning capability of the deep learning, the defect of solving the EIT inverse problem can be well improved, and the deep learning method has great significance to the field of EIT breast cancer detection.

Disclosure of Invention

The invention discloses a three-dimensional electrical impedance imaging system based on deep learning, which realizes image reconstruction of EIT through a deep learning image reconstruction algorithm, thereby improving the problems of nonlinearity and the like of the traditional reconstruction method of EIT and obtaining higher imaging quality.

In order to achieve the purpose, the invention provides the following scheme: the invention provides a three-dimensional electrical impedance imaging system based on deep learning, which comprises a sensor module, a data acquisition control module and an upper computer module which are sequentially connected;

the sensor module is used for forming a sensitive field of a measured area space;

the data acquisition control module is used for measuring the surface impedance of the measured area and performing primary processing and transmission of data;

and the upper computer module is used for reconstructing an image according to the processed impedance data.

Preferably, the sensor module comprises a hemispherical outer wall, an electrode button and a flexible PCB;

a connecting circuit is laid in the flexible PCB; the outer wall of the sensor is provided with a plurality of through holes; the flexible PCB board passes through the electrode is detained with the sensor outer wall links to each other.

Preferably, the flexible PCB board is provided with a plurality of through holes and bonding pads;

the through holes are annular, can conduct electricity and are connected with the electrode buckles, and the through holes are symmetrically arranged along the flexible PCB;

the welding pad comprises a welding interface for connecting a shielding wire for transmitting signals, and the welding pad is symmetrically arranged along the flexible PCB;

the via holes and the bonding pads are arranged in pairs on the flexible PCB, and each via hole is connected with the corresponding bonding pad.

Preferably, the data acquisition control module comprises a channel switching board and a core control board, and the core control board is connected with the channel switching board;

the channel switching board is used for selecting channels;

the core control board is used for measuring impedance data;

the core control panel is provided with a digital signal control module, and the on-off of chip pins of the channel switching plate is controlled through the digital signal control module.

Preferably, the channel switching board is composed of four 74HC4067 chips, and selects a channel.

Preferably, the upper computer module comprises a Calderon direct image reconstruction algorithm and a deep learning neural network, and is used for performing image reconstruction on the conductivity distribution in the sensitive area formed by the sensor module.

Preferably, the process of reconstructing the three-dimensional image of the upper computer module is as follows: performing initial reconstruction of the conductivity on a group of surface impedance measurement data by using a Calderon algorithm to obtain an initial conductivity distribution image; inputting the preliminary conductivity distribution image as a training sample of the neural network, and performing supervision training on the neural network by using an expected conductivity distribution binary image as a label to obtain a trained neural network; inputting the measured impedance data and the preliminary conductivity distribution image into the trained neural network to obtain a conductivity distribution reconstructed image, and quantitatively analyzing the reconstructed image result according to the position and size information of the abnormal block of the reconstructed image to obtain the conductivity distribution reconstructed image.

The invention discloses the following technical effects:

the system provided by the invention uses the core control board and the control channel switching board to apply excitation to the sensor electrode and collect field boundary voltage, so that three-dimensional surface voltage information of a hemispherical measurement area can be obtained and used for conductivity distribution reconstruction of the three-dimensional hemispherical area; by utilizing the difference of the electrical characteristics of the breast tissue and the cancer tissue, the sensor provided by the invention can be applied to the early screening of female breast cancer, and has the advantages of low manufacturing cost, easy carrying and no harm to human body; meanwhile, the invention has no radioactivity, avoids the damage to the body caused by the detection of breast cancer in the traditional medical industry, can realize a three-dimensional image reconstruction algorithm based on deep learning, and improves the quality and speed of image reconstruction by combining the traditional reconstruction algorithm and the deep learning technology.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic structural diagram of a three-dimensional electrical impedance imaging system based on deep learning according to the present invention;

FIG. 2 is a schematic diagram of the data acquisition module of the deep learning-based three-dimensional electrical impedance imaging system of the present invention;

FIG. 3 is a schematic diagram of a channel switching board of a data acquisition module of a deep learning-based three-dimensional electrical impedance imaging system according to the present invention;

FIG. 4 is a schematic diagram of the realization of the reconstruction algorithm of the upper computer module of the three-dimensional electrical impedance imaging system based on deep learning;

fig. 5 is a schematic diagram of a biological impedance equivalent circuit model.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in figure 1, the invention provides a three-dimensional electrical impedance imaging system based on deep learning, and a hardware system comprises a sensor module, a data acquisition control module and an upper computer module which are sequentially connected.

The sensor module is used for forming a sensitive field of a measured area space;

the data acquisition control module is used for measuring the surface impedance of the measured area, processing and transmitting data;

and the upper computer module is used for reconstructing an image according to the processed impedance data.

The sensor module includes hemisphere outer wall, electrode knot and flexible PCB board, supports the outside at the hemisphere sensor and adheres to flexible PCB circuit board, and in this embodiment, the hemisphere sensor is used for supporting electrode knot, flexible PCB and external signal radio frequency line to adopt the hemisphere shape can laminate women's breast, improve the data acquisition accuracy. And a connecting circuit is laid in the flexible PCB and used for connecting the electrodes and an external signal wire.

The arrangement mode of the electrodes is as follows: the horizontal direction is uniformly divided by taking the vertex supported by the hemispherical sensor module as a center, namely the horizontal direction is divided along the meridian direction by taking the vertex supported by the hemispherical sensor module as a starting point, in the embodiment, the horizontal direction is divided along 17 meridians, and the arc lengths between the midpoints of the adjacent meridians are the same; and the cutting is carried out in the weft direction which forms angles of 25 degrees, 50 degrees and 75 degrees with the connecting line of the spherical center and the bottom surface respectively in the longitudinal direction, the crossed point of each warp and weft is the position of the electrode, the electrode is used for buckling the outer wall and the flexible PCB, and the PCB is provided with a bonding pad packaged by SMB and used for connecting an external radio frequency signal line.

As shown in fig. 2, the data acquisition control module integrates a multifunctional core control board as an excitation, acquisition and expansion digital signal control module of the system, the core of the channel switch board is composed of four 74HC4067 chips, and the four chips select channels, and the digital signal control module of the core control board controls the on-off of the chip pins of the channel switch board. The sensor module is connected with the data acquisition module, a channel is selected to excite the sensor electrode and acquire voltage, the result is transmitted to an upper computer through a core control panel, the upper computer carries out image reconstruction on conductivity distribution in a sensor sensitive area, and the channel switching plate structure of the data acquisition control module is shown in fig. 3.

As shown in fig. 4, the upper computer module primarily reconstructs an image by using a conventional reconstruction algorithm Calderon according to the limitations of the conventional reconstruction algorithm and the sensor, and inputs the image into the neural network to optimize the algorithm, wherein the specific optimization process is as follows:

(1) designing a model and parameters in the Comsol, setting conductivity distribution by an external matlab function, wherein the conductivity distribution is designed in the matlab in advance to obtain a group of conductivity distribution samples corresponding to a certain amount of voltage;

(2) performing initial reconstruction of the conductivity on a group of surface impedance measurement data by using a Calderon algorithm to obtain an initial conductivity distribution image; inputting the reconstructed EIT image as a training sample of a neural network, and performing supervision training on the EIT image by using an expected conductivity distribution binary image as a label;

(3) after the neural network is trained, inputting the voltage data obtained by measurement and the preliminarily reconstructed image into the trained neural network to obtain a conductivity distribution reconstructed image, and quantitatively analyzing a reconstructed result according to the position and size information of an abnormal block of the reconstructed image.

The working principle is as follows: human breast is composed of various cells and extracellular substances, and its physiological and pathological states are closely related to its electromagnetic effects. Since most biological tissues exhibit diamagnetic reactions, the study of electrical properties is of great interest. The electrical properties of breast tissue are represented by the biological impedance, which reflects the conductive and dielectric properties of tissue under the action of small currents and can be used to distinguish between tumor and normal breast tissue. Fig. 5 is a bioimpedance equivalent circuit model, wherein C represents an insulation film equivalent capacitance, and R1 and R2 are equivalent resistances of intracellular fluid and extracellular fluid, respectively.

When the injected alternating current is at a low frequency, the cell membrane will act as an isolator, allowing the electrical signal to pass only through the extracellular fluid. As the excitation frequency increases, the cell membrane will act as a capacitor and the fluid within the cell will gradually participate in conducting the current. The actual measured conductivity includes both the capacitive and resistive portions, i.e. a composite conductivity, with the real portion being primarily affected by the conductivity distribution and the imaginary portion being primarily affected by the dielectric constant, and the resistance value measured by the electrode button (from which the conductivity distribution can be calculated) corresponding to the resistive portion in fig. 1.

The measuring mode of the three-dimensional electrical impedance imaging system adopts an adjacent excitation method and an S-shaped measuring sequence; the resistance matrix measuring mode for conductivity distribution reconstruction adopts an adjacent excitation method and an S-shaped measuring sequence, and the scheme can provide a lower measuring dynamic range, is beneficial to the design of a measuring system, obtains better image quality and can reflect the shape and the position of the cancer tissue more accurately.

According to the invention, a Calderon algorithm and a deep learning reconstruction algorithm are combined, a preliminarily reconstructed conductivity distribution image is obtained through Calderon, and then the preliminarily reconstructed conductivity distribution image and measured voltage data are input into a deep learning neural network model together, so that the mapping degree can be enhanced, the crossing of simulation and experiment boundaries can be completed, and higher imaging quality can be obtained.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.