阅读说明：本技术 一种磁声电成像图像重建方法及系统 (Magneto-acoustic-electric imaging image reconstruction method and system ) 是由 陈昕 曾鑫 孙通 郝鹏慧 闫杰杰 于 2020-03-25 设计创作，主要内容包括：本发明涉及一种磁声电成像图像重建方法及系统。所述重建方法包括：以步长阈值为移动距离,沿待测目标的电极连线移动超声换能器,从起始位置进行线性扫描直至移动到终止位置,采集每一帧第一磁声电信号；以旋转角度为移动角度,待测目标为旋转中心,圆周移动超声换能器与电极,进行线性扫描直至完成360度的圆周运动,采集每一帧第一磁声电图像；根据第一磁声电信号进行预处理；对第一磁声电图像进行图像叠加,重建磁声电成像图像,确定叠加后的磁声电成像图像。采用本发明所提供的重建方法及系统能够对每个角度下的磁声电信号进行叠加,反映出实际的电导率差异,消除了声束方向与界面的角度影响。(The invention relates to a magneto-acoustic-electric imaging image reconstruction method and a magneto-acoustic-electric imaging image reconstruction system. The reconstruction method comprises the following steps: taking the step length threshold as a moving distance, moving the ultrasonic transducer along an electrode connecting line of a target to be measured, performing linear scanning from an initial position until the ultrasonic transducer moves to an end position, and collecting a first magnetic-acoustic-electric signal of each frame; taking the rotation angle as a moving angle and the target to be measured as a rotation center, circularly moving the ultrasonic transducer and the electrode, performing linear scanning until the circular motion of 360 degrees is completed, and acquiring a first magneto-acoustic-electric image of each frame; preprocessing according to the first magneto-acoustic electrical signal; and carrying out image superposition on the first magneto-acoustic-electric image, reconstructing the magneto-acoustic-electric imaging image, and determining the superposed magneto-acoustic-electric imaging image. The reconstruction method and the reconstruction system provided by the invention can be used for superposing the magneto-acoustic electric signals under each angle, reflect the actual conductivity difference and eliminate the angle influence of the sound beam direction and the interface.)

1. A magneto-acoustic-electric imaging image reconstruction method is characterized by comprising the following steps:

taking the step length threshold as a moving distance, moving the ultrasonic transducer along an electrode connecting line of a target to be measured, performing linear scanning from an initial position until the ultrasonic transducer moves to an end position, and collecting a first magnetic-acoustic-electric signal of each frame; one frame corresponds to a moving position, and a group of first magneto-acoustic electric signals are obtained after linear scanning;

circularly moving the ultrasonic transducer and the electrode by taking the rotation angle as a moving angle and the target to be detected as a rotation center, and performing linear scanning until the circular motion of 360 degrees is completed; performing linear scanning at an angle, wherein the linear scanning has a plurality of moving positions, one moving position can acquire a frame of first magneto-acoustic electrical signals, and the linear scanning corresponds to a group of first magneto-acoustic electrical signals;

preprocessing the multiple groups of first magneto-acoustic electrical signals to obtain a plurality of images of the region of interest;

image superposition is carried out on the images of the region of interest under each angle, a magnetoacoustic-electric imaging image is reconstructed, and the magnetoacoustic-electric imaging image after superposition is determined; and the superposed magnetoacoustic-electronic imaging image is used for displaying the conductivity of the target to be detected.

2. The magneto-acoustic-electric imaging image reconstruction method according to claim 1, wherein the preprocessing is performed according to a plurality of groups of the first magneto-acoustic electric signals to obtain a plurality of images of a region of interest, specifically comprising:

filtering the first magneto-acoustic electric signal by using a band-pass filter to determine a filtered magneto-acoustic electric signal;

extracting an envelope signal of the filtered magnetoacoustic signal by using Hilbert transform;

filtering the envelope signal by using a wiener filter to determine a preprocessed magneto-acoustic signal; a plurality of first magnetoacoustic electrical signals are generated in one linear scanning process, and the processing processes are repeated to obtain a plurality of preprocessed magnetoacoustic electrical signals;

integrating the same group of preprocessed magneto-acoustic-electric signals into a matrix according to a scanning sequence;

carrying out interpolation processing on the matrix to determine an interpolated image;

and intercepting a target area in the image after interpolation, and determining an image of the region of interest.

3. The method for reconstructing a magnetoacoustic-electrical imaging image according to claim 2, wherein the image superposition of the region-of-interest image at each angle is performed to reconstruct a magnetoacoustic-electrical imaging image, and the determination of the magnetoacoustic-electrical imaging image after superposition specifically includes:

one scanning angle corresponds to one first magnetoacoustic-electric image, and the first magnetoacoustic-electric image under each angle is respectively processed as follows:

rotating the image of the region of interest and determining the rotated image;

performing zero filling processing on the rotated image, and determining the image after zero filling;

and carrying out image superposition according to the images after zero padding, reconstructing a magnetoacoustic-electric imaging image, and determining the magnetoacoustic-electric imaging image after superposition.

4. The magneto-acoustic-electric imaging image reconstruction method according to claim 3, wherein the interpolating the matrix to determine the interpolated image specifically includes:

and according to the distance interval of the magneto-acoustic electric signals in the x direction in the interested area image, interpolating the magneto-acoustic electric signals in the y direction in the interested area image by using an interpolation function, and determining an interpolated image.

5. A system for reconstructing a magnetoacoustic-electrical imaging image, comprising:

the first magnetic-acoustic-electric signal acquisition module is used for moving the ultrasonic transducer along an electrode connecting line of a target to be measured by taking the step length threshold value as a moving distance, performing linear scanning from an initial position until the ultrasonic transducer moves to an end position, and acquiring a first magnetic-acoustic-electric signal of each frame; one frame corresponds to a moving position, and a group of first magneto-acoustic electric signals are obtained after linear scanning;

the circular motion acquisition module is used for circularly moving the ultrasonic transducer and the electrode by taking the rotation angle as a moving angle and the target to be detected as a rotation center, and performing linear scanning until the circular motion of 360 degrees is completed; performing linear scanning at an angle, wherein the linear scanning has a plurality of moving positions, one moving position can acquire a frame of first magneto-acoustic electrical signals, and the linear scanning corresponds to a group of first magneto-acoustic electrical signals;

the interested region image determining module is used for preprocessing the plurality of groups of first magneto-acoustic electrical signals to obtain a plurality of interested region images;

the magnetic acoustic electric imaging image reconstruction module is used for carrying out image superposition on the region-of-interest images under all angles, reconstructing a magnetic acoustic electric imaging image and determining the superposed magnetic acoustic electric imaging image; and the superposed magnetoacoustic-electronic imaging image is used for displaying the conductivity of the target to be detected.

6. The system for reconstructing a magnetoacoustic-electroimaging image according to claim 5, wherein the region-of-interest image determining module specifically comprises:

the first filtering unit is used for filtering the first magneto-acoustic electric signal by using a band-pass filter and determining a filtered magneto-acoustic electric signal;

an extraction unit, configured to extract an envelope signal of the filtered magnetoacoustic signal by using hilbert transform;

the second filtering unit is used for filtering the envelope signal by using a wiener filter and determining a preprocessed magneto-acoustic signal; a plurality of first magnetoacoustic electrical signals are generated in one linear scanning process, and the processing processes are repeated to obtain a plurality of preprocessed magnetoacoustic electrical signals;

the magnetoacoustic electrical signal matrix construction unit integrates the same group of preprocessed magnetoacoustic electrical signals into a matrix according to the scanning sequence; the matrix is used for drawing a two-dimensional image;

the interpolation unit is used for carrying out interpolation processing on the matrix and determining an interpolated image;

and the interested region image determining unit is used for intercepting the target region in the interpolated image and determining the interested region image.

7. The system for reconstructing a magnetoacoustic-electrical imaging image according to claim 6, wherein the magnetoacoustic-electrical imaging image reconstructing module specifically comprises:

one scanning angle corresponds to one first magnetoacoustic-electric image, and the first magnetoacoustic-electric image under each angle is respectively processed as follows:

the rotation unit is used for rotating the image of the region of interest and determining the rotated image;

a zero padding unit, configured to perform zero padding processing on the rotated image, and determine a zero padded image;

and the reconstruction unit is used for performing image superposition according to the images after zero padding, reconstructing a magnetoacoustic-electric imaging image and determining the superposed magnetoacoustic-electric imaging image.

8. The system according to claim 7, wherein the interpolation unit comprises:

and the interpolation subunit is used for interpolating the magnetoacoustic electrical signal in the y direction in the image of the region of interest by using an interpolation function according to the distance interval of the magnetoacoustic electrical signal in the x direction in the image of the region of interest, and determining an interpolated image.

Technical Field

The invention relates to the field of electrical impedance imaging, in particular to a magneto-acoustic-electric imaging image reconstruction method and a magneto-acoustic-electric imaging image reconstruction system.

Background

The magnetic acoustic electro-imaging is a multi-physical field coupling imaging method, relates to electromagnetism and ultrasonics, takes the conductivity information of an object to be measured as an imaging target, has the advantages of high contrast of electrical impedance imaging and high resolution of ultrasonic imaging, and is a medical imaging method with great application potential.

Imaging principle: exciting a target to be detected under a static magnetic field by utilizing a beam of ultrasonic signal, exciting ions in the target to be detected by the ultrasonic signal to generate vibration, generating Lorentz force by the moving ions under the action of the static magnetic field, and generating charge separation by the positive ions and the negative ions in opposite directions; when the lorentz force is balanced with the electric field force applied to the ions, a stable potential difference (hall voltage) is generated, and the voltage signal reflects the conductivity information of the target to be measured.

The signal acquired by the electrical parameter image is the floating potential at two sides of the object to be measured, which reflects the conductivity distribution in the object to be measured; in the prior art, a single-array-element probe is used for transmitting an ultrasonic sound beam to excite a target to be measured under a static magnetic field to generate magnetoacoustic electrical signals, a pair of electrodes on two sides of the target to be measured are used for collecting the magnetoacoustic electrical signals, linear scanning is performed at an angle to obtain a group of magnetoacoustic electrical signals, and an electrical parameter image is obtained. However, because the measurement signal is the maximum value when the ultrasonic beam is perpendicular to the interface of the conductivity difference, and when the ultrasonic beam deviates from the perpendicular angle, the acquired magnetic-acoustic-electric signal is smaller, and until the ultrasonic beam is parallel to the interface of the conductivity difference, the magnetic-acoustic-electric signal cannot be acquired, the acquisition method at one angle cannot completely reconstruct the electric parameter image of the target to be measured, that is: for an irregularly shaped object to be measured, an electrical parameter image cannot be reconstructed.

Disclosure of Invention

The invention aims to provide a magneto-acoustic-electric imaging image reconstruction method and a magneto-acoustic-electric imaging image reconstruction system, which aim to solve the problem that an electric parameter image cannot be reconstructed for an irregular-shaped target to be detected by the existing magneto-acoustic-electric imaging method.

In order to achieve the purpose, the invention provides the following scheme:

a method of magneto-acoustic-electric imaging image reconstruction, comprising:

taking the step length threshold as a moving distance, moving the ultrasonic transducer along an electrode connecting line of a target to be measured, performing linear scanning from an initial position until the ultrasonic transducer moves to an end position, and collecting a first magnetic-acoustic-electric signal of each frame; one frame corresponds to a moving position, and a group of first magneto-acoustic electric signals are obtained after linear scanning;

circularly moving the ultrasonic transducer and the electrode by taking the rotation angle as a moving angle and the target to be detected as a rotation center, and performing linear scanning until the circular motion of 360 degrees is completed; performing linear scanning at an angle, wherein the linear scanning has a plurality of moving positions, one moving position can acquire a frame of first magneto-acoustic electrical signals, and the linear scanning corresponds to a group of first magneto-acoustic electrical signals;

preprocessing the multiple groups of first magneto-acoustic electrical signals to obtain a plurality of images of the region of interest;

image superposition is carried out on the images of the region of interest under each angle, a magnetoacoustic-electric imaging image is reconstructed, and the magnetoacoustic-electric imaging image after superposition is determined; and the superposed magnetoacoustic-electronic imaging image is used for displaying the conductivity of the target to be detected.

Optionally, the preprocessing is performed according to a plurality of groups of the first magneto-acoustic-electric signals to obtain a plurality of images of the region of interest, and the preprocessing specifically includes:

filtering the first magneto-acoustic electric signal by using a band-pass filter to determine a filtered magneto-acoustic electric signal;

extracting an envelope signal of the filtered magnetoacoustic signal by using Hilbert transform;

filtering the envelope signal by using a wiener filter to determine a preprocessed magneto-acoustic signal; a plurality of first magnetoacoustic electrical signals are generated in one linear scanning process, and the processing processes are repeated to obtain a plurality of preprocessed magnetoacoustic electrical signals;

integrating the same group of preprocessed magneto-acoustic-electric signals into a matrix according to a scanning sequence;

carrying out interpolation processing on the matrix to determine an interpolated image;

and intercepting a target area in the image after interpolation, and determining an image of the region of interest.

Optionally, the image superposition of the region-of-interest image at each angle, reconstructing a magnetoacoustic-electric imaging image, and determining the superposed magnetoacoustic-electric imaging image specifically include:

one scanning angle corresponds to one first magnetoacoustic-electric image, and the first magnetoacoustic-electric image under each angle is respectively processed as follows:

rotating the image of the region of interest and determining the rotated image;

performing zero filling processing on the rotated image, and determining the image after zero filling;

and carrying out image superposition according to the images after zero padding, reconstructing a magnetoacoustic-electric imaging image, and determining the magnetoacoustic-electric imaging image after superposition.

Optionally, the interpolating the matrix to determine the interpolated image specifically includes:

and according to the distance interval of the magneto-acoustic electric signals in the x direction in the interested area image, interpolating the magneto-acoustic electric signals in the y direction in the interested area image by using an interpolation function, and determining an interpolated image.

A magneto-acoustic-electric imaging image reconstruction system, comprising:

the first magnetic-acoustic-electric signal acquisition module is used for moving the ultrasonic transducer along an electrode connecting line of a target to be measured by taking the step length threshold value as a moving distance, performing linear scanning from an initial position until the ultrasonic transducer moves to an end position, and acquiring a first magnetic-acoustic-electric signal of each frame; one frame corresponds to a moving position, and a group of first magneto-acoustic electric signals are obtained after linear scanning;

the circular motion acquisition module is used for circularly moving the ultrasonic transducer and the electrode by taking the rotation angle as a moving angle and the target to be detected as a rotation center, and performing linear scanning until the circular motion of 360 degrees is completed; performing linear scanning at an angle, wherein the linear scanning has a plurality of moving positions, one moving position can acquire a frame of first magneto-acoustic electrical signals, and the linear scanning corresponds to a group of first magneto-acoustic electrical signals;

the interested region image determining module is used for preprocessing the plurality of groups of first magneto-acoustic electrical signals to obtain a plurality of interested region images;

the magnetic acoustic electric imaging image reconstruction module is used for carrying out image superposition on the region-of-interest images under all angles, reconstructing a magnetic acoustic electric imaging image and determining the superposed magnetic acoustic electric imaging image; and the superposed magnetoacoustic-electronic imaging image is used for displaying the conductivity of the target to be detected.

Optionally, the region-of-interest image determining module specifically includes:

the first filtering unit is used for filtering the first magneto-acoustic electric signal by using a band-pass filter and determining a filtered magneto-acoustic electric signal;

an extraction unit, configured to extract an envelope signal of the filtered magnetoacoustic signal by using hilbert transform;

the second filtering unit is used for filtering the envelope signal by using a wiener filter and determining a preprocessed magneto-acoustic signal; a plurality of first magnetoacoustic electrical signals are generated in one linear scanning process, and the processing processes are repeated to obtain a plurality of preprocessed magnetoacoustic electrical signals;

the magnetoacoustic electrical signal matrix construction unit integrates the same group of preprocessed magnetoacoustic electrical signals into a matrix according to the scanning sequence;

the interpolation unit is used for carrying out interpolation processing on the matrix and determining an interpolated image;

and the interested region image determining unit is used for intercepting the target region in the interpolated image and determining the interested region image.

Optionally, the magnetic acoustic electric imaging image reconstruction module specifically includes:

one scanning angle corresponds to one first magnetoacoustic-electric image, and the first magnetoacoustic-electric image under each angle is respectively processed as follows:

the rotation unit is used for rotating the image of the region of interest and determining the rotated image;

a zero padding unit, configured to perform zero padding processing on the rotated image, and determine a zero padded image;

and the reconstruction unit is used for performing image superposition according to the images after zero padding, reconstructing a magnetoacoustic-electric imaging image and determining the superposed magnetoacoustic-electric imaging image.

Optionally, the interpolation unit specifically includes:

and the interpolation subunit is used for interpolating the magnetoacoustic electrical signal in the y direction in the image of the region of interest by using an interpolation function according to the distance interval of the magnetoacoustic electrical signal in the x direction in the image of the region of interest, and determining an interpolated image.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects: the invention provides a magneto-acoustic-electric imaging image reconstruction method and a magneto-acoustic-electric imaging image reconstruction system, wherein an interface with a certain conductivity difference in a target to be detected is observed, after 360-degree scanning, a magneto-acoustic electric signal is generated at each angle, the magneto-acoustic electric signals at each angle are superposed to reflect the actual conductivity difference, the angle influence of the direction of an acoustic beam and the interface is eliminated, the magneto-acoustic-electric imaging image can be reconstructed for the target to be detected with an irregular shape, and the superposed magneto-acoustic-electric imaging image, namely an electric parameter image, is determined.

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 diagram of magnetoacoustic-electrical imaging provided by the present invention;

FIG. 2 is a flowchart of a magneto-acoustic-electric imaging image reconstruction method provided by the present invention;

FIG. 3 is a top view of a linear scan provided by the present invention;

FIG. 4 is a schematic view of a 360 degree scan provided by the present invention;

FIG. 5 is a schematic diagram of a rotational-linear scan of a transducer provided by the present invention;

FIG. 6 is a schematic view of a linear scan under y-direction movement provided by the present invention;

FIG. 7 is a flow chart of signal preprocessing provided by the present invention;

FIG. 8 is a block diagram of a magnetic acoustic electronic imaging image reconstruction system provided by the present invention.

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.

The invention aims to provide a magneto-acoustic-electric imaging image reconstruction method and a magneto-acoustic-electric imaging image reconstruction system, which can be used for superposing magneto-acoustic electric signals under each angle, reflecting the actual conductivity difference, eliminating the angle influence of the direction of an acoustic beam and an interface, reconstructing a magneto-acoustic-electric imaging image for an irregularly-shaped target to be detected and determining the superposed magneto-acoustic-electric imaging image.

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.

FIG. 1 is a schematic diagram of the magnetoacoustic-electrical imaging provided by the present invention, as shown in FIG. 1, an object to be measured is placed in a static magnetic field, the direction of the magnetic field is parallel to the z direction, an ultrasonic signal is sent out by a signal generator, amplified by a power amplifier, and excites an ultrasonic transducer to generate an ultrasonic beam, the direction of the beam is parallel to the x direction (assuming that the ultrasonic beam is perpendicular to the connection line between two electrodes when the ultrasonic beam is in the x direction, the beam is rotated, and the collecting electrode is also rotated), the object to be measured generates magnetoacoustic electrical signals under the action of the ultrasonic beam and the static magnetic field, the signals are collected by arc electrodes attached to both sides of the object to be measured, amplified by a differential amplifier, voltage signals are collected and stored by an oscilloscope, and then the stored data are led to a computer, and are subjected to signal processing by MAT L AB.

Fig. 2 is a flowchart of a magnetoacoustic-electrical imaging image reconstruction method provided by the present invention, and as shown in fig. 2, a magnetoacoustic-electrical imaging image reconstruction method includes:

step 201: taking the step length threshold as a moving distance, moving the ultrasonic transducer along an electrode connecting line of a target to be measured, performing linear scanning from an initial position until the ultrasonic transducer moves to an end position, and collecting a first magnetic-acoustic-electric signal of each frame; one frame corresponds to a moving position, and a group of first magneto-acoustic electric signals are obtained after linear scanning.

The platform shown in fig. 1 is built, and the ultrasonic transducer of the platform can move in two ways, namely linear movement along the y-axis direction and circular movement with the z-axis as the rotation center. The collecting electrode moves along with the circular motion of the ultrasonic transducer, but does not move along the y axis, and each moving position can collect a frame of magneto-acoustic electric signals.

And the magneto-acoustic signal is linearly moved along the y axis, and a frame of magneto-acoustic signal is acquired every time the position moves by one step length. Until the ultrasonic transducer moves linearly from one end to the end of the other, i.e., a linear scan, as shown in fig. 3.

And moving the ultrasonic transducer along the electrode connecting line to enable the ultrasonic beam to be positioned at the edge of the region to be detected, exciting the ultrasonic transducer and collecting the magnetic-acoustic-electric signal. And moving the ultrasonic transducer along the y direction according to the set step length, repeatedly exciting the ultrasonic transducer, and acquiring the magneto-acoustic electrical signals until the ultrasonic beam moves to the other side edge of the region to be measured.

Step 202: circularly moving the ultrasonic transducer and the electrode by taking the rotation angle as a moving angle and the target to be detected as a rotation center, and performing linear scanning until the circular motion of 360 degrees is completed; the linear scanning is carried out at an angle, a plurality of moving positions are arranged in one linear scanning, one moving position can acquire a frame of first magneto-acoustic electric signals, and one linear scanning corresponds to one group of first magneto-acoustic electric signals.

The size of the collected magnetic-acoustic-electric signal is related to the ultrasonic beam direction and the included angle of the conductivity difference interface, and a 360-degree scanning method is provided for accurately reconstructing conductivity information of the target to be detected. The measurement signal is the maximum value under the condition that the ultrasonic sound beam is perpendicular to the interface of the conductivity difference, and when the ultrasonic sound beam deviates from the perpendicular angle, the collected magnetic sound electric signal is smaller until the ultrasonic sound beam is parallel to the interface of the conductivity difference, and the magnetic sound electric signal cannot be collected. Therefore, when the target to be measured is scanned by 360 degrees, the situation is greatly improved, as shown in fig. 4, when an interface with a certain conductivity difference in the target to be measured is observed, and after the 360-degree scanning, a magnetoacoustic signal is generated at each angle. The magneto-acoustic electric signals under each angle are superposed, so that the actual conductivity difference can be reflected, the angle influence of the sound beam direction and the interface is eliminated, and the smaller the step length of the rotation angle is, the better the effect is.

Rotating the transducer, as shown in fig. 5, in an xy plane, rotating the ultrasonic transducer and the collecting electrode according to a set angle i step length by taking the center of the target to be measured as a rotation center; after the ultrasonic transducer moves a straight line (finishes a linear scanning), the ultrasonic transducer returns to the initial position to perform circular motion, the motion angle is a rotation step length, and after the rotation, the step 202 is repeated to perform the linear scanning at a new rotation angle; a linear scan of the next angle is performed until a 360 degree circular motion is completed.

Step 203: and preprocessing the plurality of groups of first magneto-acoustic electrical signals to obtain a plurality of groups of interested area images.

The body processing method comprises the following steps:

filtering the magnetoacoustic signals by using a band-pass filter, then obtaining envelopes by using Hilbert transform, filtering the envelope signals by using a wiener filter, reducing noise, obtaining signals required by image reconstruction, integrating a group of first magnetoacoustic signals obtained by linear scanning as a matrix, performing interpolation normalization on the matrix to obtain a first magnetoacoustic-electric image, and intercepting the first magnetoacoustic-electric image to obtain an image of a region of interest. A signal processing method flowchart is shown in fig. 7.

In addition, the signal preprocessing method may be different. Algorithms such as kalman filtering, matched filtering, deconvolution, other envelope extraction methods, etc., implement signal preprocessing.

And integrating the two-dimensional images, namely processing each group of first magneto-acoustic-electric signals by using an imagesc function in MAT L AB to obtain first magneto-acoustic-electric images under various angles.

And (3) interpolation processing, namely performing interpolation on each interested magnetoacoustic-electric image by using an interp1 function in MAT L AB to ensure that the resolution of rows and columns among all pixel points is consistent, so as to obtain an interpolated magnetoacoustic-electric image.

Intercepting a target area: and intercepting the first magneto-acoustic-electric image according to the region of interest to obtain the magneto-acoustic-electric image of interest.

Step 204: rotating the images of the region of interest at all angles, overlapping the rotated images, reconstructing a magnetoacoustic-electric imaging image, and determining the overlapped magnetoacoustic-electric imaging image; and the superposed magnetoacoustic-electronic imaging image is used for displaying the conductivity of the target to be detected.

The image reconstruction method utilizes linear scanning data under the same angle to form a linear scanning image after signal preprocessing. Each rotation angle will have a corresponding linear scan image. Each linear scan image is rotated in a direction opposite to the direction of rotation of the corresponding transducer by the same angle as the direction of rotation of the corresponding transducer. And (simply, turning back) overlapping the rotated images to obtain a final electrical parameter image.

Image superimposition program flow: rotating the image; zero filling processing is carried out, so that the number of points of each image is the same; and (5) image superposition.

And (3) rotation processing, namely processing each interpolation magneto-acoustic-electric image by using an ecrate function in MAT L AB, wherein the rotation angle is the rotation angle of the first magneto-acoustic-electric image corresponding to each interpolation magneto-acoustic-electric image, and the rotation angle of each interpolation magneto-acoustic-electric image is 0 degree after rotation to obtain a rotation magneto-acoustic-electric image.

And (4) zero filling, namely filling zero around each rotating magneto-acoustic-electric image by using an MAT L AB program to ensure that the dimensionality of each image is consistent.

Image superposition: and linearly scanning the two-dimensional image after the j zero padding. And (4) superposing to obtain a final electrical parameter image.

Fig. 8 is a structural diagram of a magneto-acoustic-electric imaging image reconstruction system provided by the present invention, and as shown in fig. 8, a magneto-acoustic-electric imaging image reconstruction system includes:

a first magnetoacoustic electrical signal acquisition module 801, configured to take the step threshold as a moving distance, move the ultrasonic transducer along an electrode connection line of the target to be measured, perform linear scanning from an initial position until the ultrasonic transducer moves to an end position, and acquire a first magnetoacoustic electrical signal of each frame; one frame corresponds to a moving position, and a group of first magneto-acoustic electric signals are obtained after linear scanning.

A circular motion acquisition module 802, configured to circumferentially move the ultrasonic transducer and the electrode with the rotation angle as a movement angle and the target to be detected as a rotation center, and perform linear scanning until a circular motion of 360 degrees is completed; the linear scanning is carried out at an angle, a plurality of moving positions are arranged in one linear scanning, one moving position can acquire a frame of first magneto-acoustic electric signals, and one linear scanning corresponds to one group of first magneto-acoustic electric signals.

And the region-of-interest image determining module 803 is configured to perform preprocessing according to the multiple groups of first magneto-acoustic electrical signals to obtain multiple groups of first magneto-acoustic electrical images.

The region-of-interest image determining module 803 specifically includes: the first filtering unit is used for filtering the first magneto-acoustic electric signal by using a band-pass filter and determining a filtered magneto-acoustic electric signal; an extraction unit, configured to extract an envelope signal of the filtered magnetoacoustic signal by using hilbert transform; the second filtering unit is used for filtering the envelope signal by using a wiener filter and determining a preprocessed magneto-acoustic signal; the magnetoacoustic electrical signal matrix construction unit integrates the same group of preprocessed magnetoacoustic electrical signals into a matrix according to the scanning sequence; the interpolation unit is used for carrying out interpolation processing on the matrix and determining an interpolated image; the interested region image determining unit is used for intercepting a target region in the interpolated image and determining an interested region image;

the magnetoacoustic-electric imaging image reconstruction module 804 is used for performing image superposition on the region-of-interest images at all angles, reconstructing a magnetoacoustic-electric imaging image and determining a superposed magnetoacoustic-electric imaging image; and the superposed magnetoacoustic-electronic imaging image is used for displaying the conductivity of the target to be detected.

The magnetic acoustic electric imaging image reconstruction module 804 specifically includes:

the rotation unit is used for rotating the image of the region of interest and determining the rotated image; a zero padding unit, configured to perform zero padding processing on the rotated image, and determine a zero padded image; and the reconstruction unit is used for performing image superposition according to the images after zero padding, reconstructing a magnetoacoustic-electric imaging image and determining the superposed magnetoacoustic-electric imaging image.

The interpolation unit specifically includes: and the interpolation subunit is used for interpolating the magnetoacoustic electrical signal in the y direction in the image of the region of interest by using an interpolation function according to the distance interval of the magnetoacoustic electrical signal in the x direction in the image of the region of interest, and determining an interpolated image.

The invention observes an interface with certain conductivity difference in a target to be measured, and generates a magnetoacoustic-electric signal under each angle after 360-degree scanning. The magneto-acoustic electric signals under each angle are superposed, so that the actual conductivity difference can be reflected, and the angle influence of the direction of the acoustic beam and the interface is eliminated; and the smaller the rotation angle step, the better the effect.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.