Three-dimensional ultrasonic imaging method and system, terminal and medium

Abstract

The invention relates to the technical field of ultrasonic imaging, and discloses a three-dimensional ultrasonic imaging method and system, a terminal and a medium, and the method comprises the steps: controlling a two-dimensional array probe to sequentially emit a plurality of three-dimensional ultrasonic beams which have incompletely same wavefront curved surface shapes and are in forward and backward reciprocating alternating sequences in the dimension of a wide wave beam; the method comprises the following steps: performing three-dimensional beam forming on collected original channel data to obtain multiple pieces of three-dimensional intermediate imaging data after beam forming, and performing clutter filtering and phase difference correction on the three-dimensional intermediate imaging data to obtain a three-dimensional coherent composite image; the problems that three-dimensional ultrasonic imaging is difficult to choose between time resolution and space resolution and imaging quality is not ideal are solved, phase difference artifacts generated by a moving target can be eliminated, and a three-dimensional ultrasonic image with better resolution and signal-to-noise ratio is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic imaging, and particularly to a three-dimensional ultrasonic imaging method, system, terminal and medium. Background Art

[0002] As an imaging modality with the highest temporal resolution in medical imaging, ultrasound has the advantages of real-time dynamics, low cost, convenient bedside detection, etc., and is often used as a means for imaging the structure and function of various organs in the body, especially the heart. High spatio-temporal resolution ultrasound images are of great significance for the diagnosis of various diseases. However, for an organ like the heart with rapid twisting and pulsating movements, traditional ultrasound imaging methods cannot well characterize its structure or function.

[0003] Traditional medical ultrasound imaging uses a line-by-line focused scanning imaging method. Its low frame rate is difficult to cope with fast-moving target tissues. In this mode, even sacrificing the sound field has limited improvement in the frame rate; multi-line scanning and sector stitching can improve the frame rate, but still cannot cope with the decorrelation noise caused by low-frame line scanning and moving target tissues. In addition, currently successfully applied ultrasound technologies are basically limited to two-dimensional ultrasound, and its imaging of moving target tissues has inherent defects such as lack of a complete image view and out-of-plane movement, which also causes problems of inconsistent subjective operations and limited repeatability in clinical practice. Therefore, it is necessary to develop an ultrasonic imaging technology with high spatio-temporal resolution that can overcome the above deficiencies of traditional methods.

[0004] The ultrafast plane wave proposed in recent years provides a frame rate theoretically reaching several thousand hertz. However, its lack of focus and low sound pressure result in high sidelobes and wide main lobes, and thus low resolution signal-to-noise ratio. Combining multi-angle coherent compounding technology can obtain improved imaging quality, but the large inclination angle of the divergent wave and the movement of the target tissue will cause phase delay interference. In recent years, three-dimensional ultrasonic imaging driven by two-dimensional array probes has gradually developed. It can overcome the deficiencies of two-dimensional ultrasound such as lack of a complete view and out-of-plane movement, and can also overcome problems such as time-consuming reconstruction of three-dimensional images using two-dimensional ultrasound scanning, severe inter-frame artifacts of moving targets, and registration geometric distortion. In three-dimensional ultrasonic imaging using two-dimensional array probes, the extremely low frame rate of line-by-line focused wave imaging is unacceptable, and the above-mentioned image degradation problems faced by simply applying ultrafast plane divergent waves are even more serious than those in two-dimensional imaging, which makes the imaging quality of three-dimensional ultrasound, especially the imaging quality facing moving target tissues, unsatisfactory. How to improve the three-dimensional ultrasonic imaging efficiency and imaging quality, obtain a three-dimensional ultrasonic imaging technology with higher spatio-temporal resolution, and improve the clinical diagnostic utility of three-dimensional ultrasound is an international problem. Summary of the Invention

[0005] To overcome the defects of the above-mentioned existing technologies, the purpose of the present invention is to provide a three-dimensional ultrasonic imaging method, system, terminal and medium, so as to solve the technical problems in the prior art of how to improve the difficult trade-off between time and space resolution in 3D ultrasonic imaging and the unsatisfactory imaging quality.

[0006] The present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides a three-dimensional ultrasonic imaging method, including:

[0008] Construct a plurality of 3D ultrasonic beams with incompletely identical wavefront surface shapes, and set them to be wide beams in at least one dimension, where the emission of the 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in the diverging dimension;

[0009] Transmit a plurality of 3D ultrasonic beams, and in the dimension where they are wide beams, the emitted 3D ultrasonic beam sequence can be divided into a reciprocating alternating sequence of forward and backward branches;

[0010] Receive the 3D imaging channel data of the corresponding 3D ultrasonic beams obtained by a plurality of receiving array elements, perform beam synthesis on the 3D imaging channel data, and obtain 3D intermediate imaging data;

[0011] Calculate the phase shift angle between multiple transmissions and / or the 3D velocity-displacement field based on one to several constraint terms according to the obtained 3D intermediate imaging data, perform volume alignment according to the displacement between the reference 3D volume and other 3D volumes in the imaging sequence, complete 3D phase difference correction, and obtain coherent composite 3D ultrasonic imaging without phase difference artifacts, thereby completing the three-dimensional ultrasonic imaging work.

[0012] Preferably, by designing different transmission delays and / or transmission waveform combinations, beam shaping is performed on the beams emitted by the excited two-dimensional array probe, and a plurality of 3D beam sequences with incompletely identical wavefront surface shapes are constructed, where each 3D beam in the 3D beam sequence is a wide beam in at least one of its dimensions, and this dimension is the first dimension, and the virtual foci of the wide beams are at different positions.

[0013] Preferably, the specific formula for beam synthesis of 3D imaging channel data is as follows:

[0014]

[0015] Among them, w ij is the weight of 3D beam synthesis, set to all 1 or provided by the 3D adaptive beam synthesis algorithm, τ j is the delay required for the two-dimensional array element to receive and synthesize the target point; S ij (t) is the 3D imaging channel data, less than or equal to the number of enabled receiving array elements; R_rawi 3D intermediate imaging data for beam synthesis, i = 1, 2, …, M;

[0016] Among them, the 3D imaging channel data S ij (t) and the echo data RX ik (t) received by the enabled receiving array elements are related by the following formula, which can be called a formula similar to beam synthesis:

[0017]

[0018] Among them, is the weight for synthesizing the 3D imaging channel data from the array element echo data, set to all 1 or given by actual experience; SubMatrix j is the array element group for giving the j-th 3D imaging channel data, and the number of enabled receiving array elements in the group is m = 1, 2, …; Δ k is the difference between the delay of the array elements in the group relative to the reference point and the delay of the center of the array element group relative to the reference point; when m = 1, j = k, S ij (t) = RX ik (t - Δ k ).

[0019] Furthermore, clutter filtering is performed on the data after 3D beam synthesis to obtain M clutter-filtered beam synthesis 3D intermediate imaging data R i , i = 1, 2, …, M, and the specific process is as follows:

[0020] First, perform SVD decomposition on the beam synthesis data, specifically as follows:

[0021] R_raw i (t) = UΔV T

[0022] Among them, U is the spatial singular vector, V is the temporal singular vector, and Δ is the singular value matrix; the filtered 3D intermediate imaging data is:

[0023] R i (t) = U f Δ f V f T

[0024] Among them, U f is the spatial singular vector after threshold screening, Δ f is the temporal singular vector after threshold screening, Δ f is the singular value matrix after threshold screening, and the threshold is judged according to the inflection point position in the singular value curve and experience.

[0025] Preferably, calculate the phase shift angle between multiple transmissions according to the obtained 3D intermediate imaging data;

[0026] Among them, according to the 3D intermediate imaging data sequence Rf after beam synthesis and clutter filtering of the 3D ultrasonic beam located in the forward branch i perform autocorrelation calculation, i = 1, 2, …, K, 4 ≤ 2K ≤ M; obtain the 3D intermediate imaging data autocorrelation coefficient К of the forward branch f ;

[0027] According to the 3D intermediate imaging data sequence Rb after beam synthesis of the 3D ultrasonic beam located in the backward branch i perform autocorrelation calculation, i = K + 1, K + 2, …, K + P, 4 ≤ K + P ≤ M, and obtain the 3D intermediate imaging data autocorrelation coefficient К of the forward branch b .

[0028] Furthermore, the phase shift angle θ is provided by the product of the 3D intermediate imaging data autocorrelation angles, and the phase rotation and / or the displacement between multi-beam transmissions are adjusted;

[0029] The phase shift angle calculated by the autocorrelation angle product is calculated by the following equation:

[0030]

[0031] The adjustment of the phase rotation is performed in the 3D coherence compounding step, as shown in the following equation:

[0032]

[0033] The adjustment of the displacement between multi-beam transmissions is performed in the 3D coherence compounding step, as shown in the following equation:

[0034]

[0035] where, w k is the weight of coherence compounding; ξ is the phase rotation indication factor, and its value is 1 or 1 / e ikθ ; ε is the displacement compensation indication factor, and its value is 0 or 1.

[0036] Preferably, calculate the 3D velocity-displacement field based on one to several constraint terms according to the obtained 3D intermediate imaging data, construct a cost function J(v) for globally optimizing the 3D velocity-displacement field, and be constrained by one to several constraint terms. The specific equation is as follows:

[0037] J(v) = λ1·J o (v) + λ2·J d (v) + μ1·J div (v) + μ2·J smooth (v)

[0038] where λ1 + λ2 = 0 or 1. When its value is 0, μ1 and μ2 are also 0, which is equivalent to not performing this step; J o (v) is a local displacement constraint term, J d (v) is a global displacement constraint term, J div (v) is a divergence-free regularization term, J smooth (v) is a smoothness regularization term.

[0039] In a second aspect, the present invention also provides a three-dimensional ultrasonic imaging system, comprising:

[0040] A beam construction module (1) for constructing a plurality of 3D ultrasonic beams with incompletely identical wavefront surface shapes and setting them to be wide beams in at least one dimension, wherein the emission of the 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in the diverging dimension;

[0041] A beam emission module (2) for emitting a plurality of 3D ultrasonic beams and reciprocally alternating the emitted 3D ultrasonic beam sequence that can be divided into a forward branch and a backward branch in the dimension where it is a wide beam;

[0042] A beam processing module (3) for receiving 3D imaging channel data of the corresponding 3D ultrasonic beams obtained by a plurality of receiving elements, performing beam synthesis on the 3D imaging channel data, and obtaining 3D intermediate imaging data;

[0043] An imaging module (4) for calculating the phase shift angle between multiple emissions and / or the 3D velocity-displacement field based on one to several constraint terms according to the obtained 3D intermediate imaging data, performing volume alignment according to the displacement between the reference 3D volume and other 3D volumes in the imaging sequence, completing 3D phase difference correction, obtaining coherent composite 3D ultrasonic imaging without phase difference artifacts, and completing three-dimensional ultrasonic imaging work.

[0044] In a third aspect, the present invention also provides a mobile terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the three-dimensional ultrasonic imaging as described above are implemented.

[0045] In a fourth aspect, the present invention also provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the steps of the three-dimensional ultrasonic imaging as described above are implemented.

[0046] Compared with the prior art, the present invention has the following beneficial technical effects:

[0047] The present invention provides a three-dimensional ultrasonic imaging method, system, terminal and medium, which controls a two-dimensional array probe to sequentially emit a plurality of three-dimensional ultrasonic beams with incompletely identical wavefront surface shapes and in a forward and backward reciprocating alternating sequence in the dimension where the wide beam is located, performs three-dimensional beam synthesis on the collected original channel data to obtain a plurality of three-dimensional intermediate imaging data after beam synthesis, and then performs clutter filtering and phase difference correction on the three-dimensional intermediate imaging data to obtain a three-dimensional coherent composite image, improving the problem of difficult trade-off between time and space resolution and unsatisfactory imaging quality in three-dimensional ultrasonic imaging, capable of eliminating the phase difference artifacts generated by moving targets, and obtaining a three-dimensional ultrasonic image with better resolution and signal-to-noise ratio.

[0048] Furthermore, the present invention extends the imaging advantage of multi-angle coherent compounding in traditional 2D ultrasonic imaging to 3D imaging, achieves a good compromise between imaging efficiency and imaging quality by simultaneously emitting 3D ultrasonic beams with different morphologies, and eliminates the phase difference artifacts generated by moving targets through 3D phase difference correction. By using multi-3D multi-beam coherent superposition, it is possible to suppress side lobes and highlight the main lobe, improve the problem of difficult trade-off between time and space resolution and unsatisfactory imaging quality in 3D ultrasonic imaging, and obtain a 3D ultrasonic image with better resolution and signal-to-noise ratio.

[0049] Even further, the imaging method of multi-angle coherent compounding in traditional 2D ultrasonic imaging is extended to 3D imaging in different application ways, and the advantage of synchronous improvement of time and space resolution is obtained.

[0050] Even further, a good compromise between imaging efficiency and imaging quality is achieved by emitting 3D ultrasonic beams with different morphologies, and different schemes are selected under different imaging tasks to improve the image quality of three-dimensional ultrasonic imaging.

[0051] Even further, by using multi-3D beam coherent superposition and corresponding 3D phase difference correction, suppressing the side lobes of the sound beam and highlighting the main lobe in three-dimensional imaging, the problem of phase difference artifacts generated by fast-moving imaging targets can be solved, and a 3D ultrasonic image with better resolution and signal-to-noise ratio can be obtained. Description of the Drawings

[0052] Figure 1 It is a flowchart of the three-dimensional ultrasonic imaging method in the embodiment of the present invention;

[0053] Figure 2 It is a schematic structural diagram of the three-dimensional ultrasonic imaging system in the embodiment of the present invention;

[0054] Figure 3 It is a schematic diagram of the 3D multi-beam sequence imaging method in the embodiment of the present invention;

[0055] Figure 4 It is a schematic diagram of the 3D multi-beam sequence imaging method in the embodiment of the present invention;

[0056] Figure 5 This is a schematic diagram of the 3D beam sequence in the embodiments of the present invention and the beam sequence imaging method that can be regarded as decomposed into the first dimension and the second dimension;

[0057] Figure 6 This is a schematic diagram of the 3D beam sequence in another embodiment of the present invention and the beam sequence imaging method that can be regarded as decomposed into the first dimension and the second dimension;

[0058] Figure 7 This is a schematic diagram of the structure of a three-dimensional ultrasonic imaging terminal in the embodiments of the present invention;

[0059] In the figure: 1 - beam construction module; 2 - beam transmission module; 3 - beam processing module; 4 - imaging module; 100 - mobile terminal; 101 - two-dimensional array ultrasonic probe; 120 - transmit / receive control module; 130 - processor; 140 - beam synthesis module; 150 - display; 160 - memory; 170 - input module. Detailed implementation manners

[0060] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0061] The present invention will be further described in detail below with reference to the accompanying drawings:

[0062] The purpose of the present invention is to provide a three-dimensional ultrasonic imaging method, system, terminal and medium to solve the technical problems in the prior art of how to improve the difficult trade-off between time and space resolution in 3D ultrasonic imaging and the unsatisfactory imaging quality.

[0063] See Figure 1 , the present invention provides a three-dimensional ultrasonic imaging method, including the following steps:

[0064] Step 1, construct multiple 3D ultrasonic beams with incompletely identical wavefront surface shapes, and set them to be wide beams in at least one dimension, where the emission of the 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in the divergent dimension;

[0065] Specifically, by designing different transmission delays and / or transmission waveform combinations, beamforming is performed on the beams emitted by the excited two-dimensional array probe, and multiple 3D beam sequences with wavefront surface shapes that are not exactly the same are constructed. Each 3D beam in the 3D beam sequence appears as a wide beam in at least one of its dimensions, which is the first dimension, and the virtual foci of the wide beams are at different positions.

[0066] Step 2: Transmit multiple 3D ultrasonic beams, and in the dimension where the 3D ultrasonic beam sequence appears as a wide beam, divide the transmitted 3D ultrasonic beam sequence into a reciprocating alternating sequence of forward and backward beams that can be divided into a forward branch and a backward branch;

[0067] Specifically, when transmitting the beam sequence in the dimension where the wide beam appears in the reciprocating alternating order of the forward and backward beams, determine whether the wide beam has an inclination angle. When it is determined that the wide beam has an inclination angle, the inclination angle of the midline of its wavefront is to changing (θ1, β1, θ2, β2 ≥ 0), where the inclination angle of the wavefront midline of the subsequence of beams 1 to K (4 ≤ 2K ≤ M) in the forward branch is increasing from to in non-uniform or uniform steps, and the inclination angle of the wavefront midline of the subsequence of beams K + 1 to K + P (K and P are equal or nearly equal, 4 ≤ K + P ≤ M) in the backward branch is decreasing from to

[0068] When it is determined that the wide beam has no inclination angle, the wide beam has no inclination angle, and the virtual focus position is determined according to the size of the transmitting sub-aperture, the center position of the sub-aperture, and the beam fan angle; among them, the virtual foci of the subsequence of beams 1 to K in the forward branch move from the first on the left to the second from the right; the virtual foci of the subsequence of beams K + 1 to K + P in the backward branch move from the first on the right to the second from the left.

[0069] In the present invention, the second dimension of each 3D beam can be expressed as: a non-focused beam, a focused beam, and a multi-line focused beam;

[0070] Among them, the non-focused beam includes a plane wave and a divergent wave; the non-focused beam and the first dimension are both set by determining whether the wide beam has an inclination angle;

[0071] Focused beam: Traverse the imaging area of this dimension with multiple focus lines in the second dimension. Combining with the divergent wave form in the first dimension, the 3D beam appears as a sequence of focus planes, traversing the entire 3D imaging area.

[0072] Multi-line focused beam: Based on the focused beam, L (L≥2) focused lines are combined in a single transmitted beam to obtain a frame rate that is up to L times that of the focused beam.

[0073] In the second dimension, a focused beam or a multi-line focused beam is adopted. In addition to 1, the number of scan lines synthesized or participated in the synthesis by each focused line can also be set to, preferably, 2, or 3, or 4, so as to multiply reduce the number of times of transmitting focused lines required to synthesize the same number of scan lines, that is, the total number of 3D ultrasonic beam transmissions M, and then increase the frame rate to 2 to 4 times. When synthesizing a certain scan line, the weighting value of each focused line participating in the synthesis is adjustable.

[0074] In the present invention, multiple 3D ultrasonic beams with wavefront surface shapes that are not exactly the same are two-dimensional delay matrices having both the first dimension and the second dimension characteristics, and are obtained by exciting a two-dimensional array probe to transmit ultrasonic beams.

[0075] Step 3: Receive the 3D imaging channel data of the corresponding 3D ultrasonic beams obtained by multiple receiving elements, and perform beam synthesis on the 3D imaging channel data to obtain 3D intermediate imaging data;

[0076] Specifically, the 3D beam synthesis method synthesizes the obtained channel data, and the weighting value assigned to the channel data during synthesis is adjustable; at the same time, when the second dimension is the transmitted beam of the focused beam or the multi-line focused beam, according to each focused line in this dimension, the number of scan lines n synthesized or participated in the synthesis is greater than or equal to 1.

[0077] Specifically, the specific formula for performing beam synthesis on the 3D imaging channel data is as follows:

[0078]

[0079] where, w ij is the weight of 3D beam synthesis, set to all 1 or provided by the 3D adaptive beam synthesis algorithm, τ j is the delay required for the two-dimensional array element to receive and synthesize the target point; S ij (t) is the 3D imaging channel data, less than or equal to the number of enabled receiving elements; R_raw i is the 3D intermediate imaging data of beam synthesis, i = 1, 2,..., M;

[0080] where, the 3D imaging channel data S ij (t) and the received echo data RX ik (t) received by the enabled receiving elements are related as follows, which can be called a formula similar to beam synthesis:

[0081]

[0082] where, is the weight for synthesizing the channel data of the 3D imaging from the echo data of the array elements, set to all 1s or given by actual experience; SubMatrix j is the array element group for the j-th 3D imaging channel data, and the number of enabled receiving array elements m in the group is 1, 2, …; Δ k is the difference between the delay of the array elements in the group relative to the reference point and the delay of the center of the array element group relative to the reference point; when m = 1, j = k, S ij (t) = RX ik (t - Δ k ).

[0083] Step 4: Calculate the phase shift angle between multiple transmissions and / or the 3D velocity-displacement field based on one or several constraint terms according to the obtained 3D intermediate imaging data, perform volume alignment according to the displacement between the reference 3D volume and other 3D volumes in the imaging sequence, complete 3D phase difference correction, obtain coherent composite 3D ultrasonic imaging without phase difference artifacts, and complete the three-dimensional ultrasonic imaging work.

[0084] Specifically, perform clutter filtering on the data after 3D beam synthesis to obtain M beam synthesis 3D intermediate imaging data R i (i = 1, 2, …, M), and the specific process is as follows:

[0085] First, perform SVD decomposition on the beam synthesis data, specifically as follows:

[0086] R_raw i (t) = UΔV T

[0087] where U is the spatial singular vector, V is the temporal singular vector, and Δ is the singular value matrix; the filtered 3D intermediate imaging data is:

[0088] R i (t) = U f Δ f V f T

[0089] where U f is the spatial singular vector after threshold screening, Δ f is the temporal singular vector after threshold screening, Δ f is the singular value matrix after threshold screening, and the threshold is determined according to the image inflection point position and experience in the singular value curve.

[0090] Specifically, calculate the phase shift angle between multiple transmissions according to the obtained 3D intermediate imaging data. Among them, according to the 3D intermediate imaging data sequence Rf after beam synthesis and clutter filtering of the 3D ultrasonic beam located in the forward branch iPerform autocorrelation calculations for (i = 1, 2, …, K, 4 ≤ 2K ≤ M) to obtain the autocorrelation coefficient К of the 3D intermediate imaging data of the forward branch f ;

[0091] According to the 3D intermediate imaging data sequence Rb after beam synthesis of the 3D ultrasonic beam located in the backward branch i (i = K + 1, K + 2, …, K + P, 4 ≤ K + P ≤ M) perform autocorrelation calculations to obtain the autocorrelation coefficient К of the 3D intermediate imaging data of the forward branch b .

[0092] The phase shift angle θ is provided by the autocorrelation angle product of the 3D intermediate imaging data, and adjusts the phase rotation and / or the displacement between multi-beam transmissions;

[0093] The phase shift angle calculated by the autocorrelation angle product is calculated by the following equation:

[0094]

[0095] The adjustment of the phase rotation is performed in the 3D coherence compounding step, as shown in the following equation:

[0096]

[0097] The adjustment of the displacement between multi-beam transmissions is performed in the 3D coherence compounding step, as shown in the following equation:

[0098]

[0099] where, w k is the weight of the coherence compounding; ξ is the phase rotation indication factor, and its value is 1 or 1 / e ikθ ; ε is the displacement compensation indication factor, and its value is 0 or 1.

[0100] Specifically, calculate the 3D velocity-displacement field based on one to several constraint terms according to the obtained 3D intermediate imaging data, construct a cost function J(v) for globally optimizing the 3D velocity-displacement field, and be constrained by one to several constraint terms. The specific equation is as follows:

[0101] J(v) = λ1·J o (v) + λ2·J d (v) + μ1·J div (v) + μ2·J smooth (v)

[0102] where, λ1 + λ2 = 0 or 1. When its value is 0, μ1 and μ2 are also 0, which is equivalent to not performing this step; J o (v) is the local displacement constraint term, J d (v) is the global displacement constraint term, Jdiv (v) is a divergence - free regularization term, J smooth (v) is a smoothness regularization term.

[0103] Among them, the formula of the local displacement constraint term is as follows:

[0104]

[0105] Among them, is the image gradient at the i - th virtual source position, u i is the corresponding estimated velocity field of the local displacement.

[0106] The formula of the global displacement constraint term is as follows:

[0107]

[0108] Among them, d j is the unit vector in the direction of the beam synthesis line, v d,j is the estimated phase velocity at the position of the j - th line.

[0109] The formulas of the divergence - free regularization term and the smoothness regularization term are as follows:

[0110]

[0111] J div (v) ensures that the velocity field satisfies the divergence - free condition, which is in line with the incompressible assumption of the tissue. J smooth (v) increases the smoothness of the velocity field by minimizing the spatial variation of the velocity field, reducing noise and artifacts.

[0112] Embodiment 1

[0113] The three - dimensional ultrasonic imaging method according to an embodiment of the present invention includes the following steps:

[0114] Step S1, constructing a plurality of 3D ultrasonic beams, such that they have wavefront surface shapes that are not exactly the same and are wide - shaped beams (including plane waves, divergent waves) in at least one dimension.

[0115] Specifically, multiple 3D ultrasonic beams are constructed to have non-identical wavefront surface shapes and exhibit a wide beam shape (including plane waves, divergent waves) in at least one dimension. Among them, the non-identical wavefront surface shapes are generally realized by a set of delay parameters of the activated array elements located at different spatial positions, and the delay parameters are calculated from the relative spatial positions of the array elements. The 3D ultrasonic beams all exhibit a wide beam shape in at least one dimension (which can be called the first dimension), mainly including plane waves, divergent waves, etc. The array elements to be activated in the dimension where the plane wave is located are synchronously activated, and the wavefront exhibited in this dimension is parallel to the array. While the array elements to be activated in the dimension where the divergent wave is located are first activated in the middle and then activated on both sides, and the wavefront exhibited in this dimension is an arc-shaped wavefront facing forward. Typically, there is a virtual focus, or a virtual point, behind the two-dimensional array probe for the divergent wave. Different virtual points can define divergent waves with different sub-apertures or with inclination angles in the embodiments described below. Different from the first dimension, the second dimension can exhibit a wide beam shape, or a focused beam or a multi-line focused beam. When the second dimension exhibits a wide beam shape, it has the same characteristics as the first dimension; when the second dimension exhibits a focused beam, the array elements to be activated in this dimension are first activated on both sides and then activated in the middle, and then converge at a target in front of the two-dimensional array probe to form a focus point, forming a focus line; when the second dimension exhibits a multi-line focused beam, based on the above-mentioned second dimension focused beam rule, the activation instructions of multiple focus lines are superimposed to achieve focusing multiple scan lines at one time. The first dimension and the second dimension are only any two dimensions split when constructing or analyzing the 3D ultrasonic beam, and do not have to be orthogonal. The beam characteristics exhibited by the first dimension and the second dimension mean that the 3D ultrasonic beam has the characteristics when observed from a certain first dimension and a certain second dimension, and does not mean that the 3D beam is uniquely constructed by simply superimposing the beam delays of these two dimensions, even though this method can be implemented as a preferred example.

[0116] Step S2, drive the two-dimensional array probe to emit a 3D ultrasonic beam sequence, and emit the beam sequence in a forward-backward reciprocating alternating order in the dimension that exhibits a wide beam shape.

[0117] Specifically, drive the two-dimensional array probe to emit a sequence of 3D ultrasonic beams, and emit the beam sequence in the dimension presenting as a wide beam in a forward-backward reciprocating alternating order. Among them, the two-dimensional array probe can be selected in the form of a rigid probe or a flexible patch with various element arrangements as described above. Its element arrangement and spatial relative position determine the calculation of the delay of the 3D ultrasonic beam in the previous step, and in this step, multiple 3D ultrasonic beams are emitted according to the designed delay. The emitted beam sequence is emitted in the dimension where the wide beam is located (when the second dimension presents as a wide beam, the dimension is the first dimension + the second dimension; when the second dimension presents as a focused beam or a multi-line focused beam, the dimension is the first dimension) in a forward-backward reciprocating alternating order. Typically, taking the movement path of the virtual point as the standard, the virtual point movement sequence moving in one direction is called forward, and the virtual point movement sequence moving in the opposite direction of this direction is called backward. Or, the movement sequence from the starting virtual point to the terminal virtual point is called forward, and the movement sequence from the terminal virtual point back to the starting virtual point in the reverse order is called backward.

[0118] Step S3: Receive 3D imaging channel data through the two-dimensional array probe, perform beam synthesis on the 3D imaging channel data, and obtain 3D intermediate imaging data.

[0119] Specifically, obtain the original channel data through the receiving elements, and use the 3D beam synthesis algorithm to calculate the imaging data for the 3D imaging volume or the imaging plane of one to several scanning sections. Preferably, when the second dimension presents as a wide beam, the 3D imaging volume is calculated every time a reception is made; when the second dimension presents as a focused beam or a multi-line focused beam, the scanning line fitting the second dimension, the imaging plane where the wide beam in the first dimension is located, and / or several imaging planes nearby are calculated every time a reception is made. When the focused scanning line traverses the entire scanning area of the second dimension, the entire 3D imaging volume is calculated. After 3D beam synthesis, 3D intermediate imaging data is obtained, and clutter filtering is performed on the data after beam synthesis to obtain the filtered 3D intermediate imaging data.

[0120] Step S4: Calculate the phase shift and / or displacement based on the forward and backward 3D intermediate imaging data, and perform 3D coherent compound ultrasonic imaging with 3D phase difference correction.

[0121] Specifically, determine the forward and backward 3D intermediate imaging data according to the forward-backward reciprocating alternating emission order of the 3D ultrasonic beam sequence, and calculate the phase shift and / or displacement. Exemplarily, calculate the product of the autocorrelation angles of the forward and backward branches to obtain the phase shift angle between emissions, which is used for phase difference correction between the forward and backward branch emissions.

[0122] It should be noted and understood that any combination of different 3D ultrasonic beam shapes, forward-backward emission sequences, phase difference correction methods, etc. in the above steps belongs to the technical framework of the present invention and thus falls entirely within the protection scope of the present invention. However, the adaptability and comprehensive effectiveness of different combination strategies should be considered and selected for different imaging tasks. The present invention does not limit, for example, whether the transmitting array elements and receiving array elements are sparse, the pulse waveforms transmitted, etc.

[0123] Embodiment 2

[0124] According to Figure 3 As shown, an embodiment of the 3D imaging method of the present invention provides a preferred 3D multi-angle wide beam diagonal reciprocating emission sequence and its phase difference compensation 3D ultrasonic imaging method in combination with the following steps. The specific steps include:

[0125] Step L1, construct a group of M (M≥2) 3D wide beams. Preferably, M = 5×5. The virtual points of the 25 3D wide beams in this group are distributed in a 5×5 square matrix behind the two-dimensional array probe. For non-divergent spherical waves, it can be considered that their virtual points are located on an arbitrary spherical surface centered at a certain point on the normal line of the array center behind the probe; for divergent spherical waves, their virtual points are located on a certain spherical surface centered at a certain point on the normal line of the array center behind the probe, and the height of this spherical surface obviously determines the fan angle size of the divergent wave.

[0126] Obviously, in this preferred embodiment, the 3D wide beam has an inclination angle, and the wavefront normal vector of the wide beam can be found on the straight line connecting the virtual point and the array center. The wavefront unit normal vector can be defined by the side angle θ and the elevation angle as The virtual foci of the 3D multi-angle wide beam sequence can be expressed as {[α i ,β i |α i =m·Δα,β i =n·Δβ, i = 1, 2, 3, 4, 5, m, n = -2, -1, 0, 1, 2}, and the delay matrix of the two-dimensional array is calculated therefrom.

[0127] Step L2, apply the calculated two-dimensional array delay matrix to the array elements to be activated. Preferably, a single pulse is emitted by the full-aperture elements of a 32×32 rectangular planar two-dimensional array, thereby driving the probe to emit a 3D multi-angle wide beam sequence. The beam sequence is emitted in a forward-backward reciprocating folding order in the diagonal direction of the 5×5 virtual point square matrix. As Figure 3 shown, starting from the starting point in the lower left corner of the square matrix and sequentially emitting along the diagonal path to the end point in the upper right corner is called forward, and returning from the end point in the upper right corner to the starting point in the lower left corner along this path is called backward.

[0128] Step L3: Receive the echo data generated by each 3D wide beam emission. Preferably, perform a 32×32 full-aperture single reception to obtain 3D imaging channel data S of 1024 array elements in 50 groups (5×5 virtual points × 2 reciprocations). ij (i = 1, 2, …, 50; j = 1, 2, …, 1024), and then perform 50 times of intermediate imaging data R for reconstructing the entire 3D volume in sequence. i (i = 1, 2, …, 50) for 3D beam synthesis:

[0129]

[0130] where, w ij is the weight of 3D beam synthesis. Typically, all are set to 1 with the delay-and-sum algorithm, and τ j is the delay required for the two-dimensional array elements to receive and synthesize the target point.

[0131] Perform clutter filtering on the data after 3D beam synthesis to obtain M clutter-filtered beam synthesis 3D intermediate imaging data R i (i = 1, 2, …, M). Preferably, the clutter filtering algorithm includes the following steps: First, perform SVD decomposition on the beam synthesis data, specifically as follows:

[0132] R_raw i (t) = UΔV T

[0133] where, U is the spatial singular vector, V is the temporal singular vector, and Δ is the singular value matrix. The filtered 3D intermediate imaging data is:

[0134] R i (t) = U f Δ f V f T

[0135] where, U f is the spatial singular vector after threshold screening, Δ f is the temporal singular vector after threshold screening, and Δ f is the singular value matrix after threshold screening. The threshold is judged according to the inflection point position and experience in the singular value curve.

[0136] Step L4: Perform 3D phase difference correction. Preferably, in this embodiment, the global displacement motion displacement compensation method is adopted. Calculate the 3D intermediate imaging data autocorrelation coefficients К i (i = 1, 2, …, 25) of the forward branch Rf i (i = 26, 27, …, 50) and the backward branch Rb f and Кb , and calculate the product of the autocorrelation angles between the two. The calculation formula is as follows:

[0137]

[0138] After obtaining the phase shift angle θ, adjust the displacement between phase rotation and multi-beam transmission, and perform coherent compounding:

[0139]

[0140] where w k is the weight of coherent compounding. Typically, all are 1.

[0141] After Figure 3 the above steps in a preferred embodiment in

[0142] Example 3

[0143] According to Figure 4 as shown, another embodiment of the 3D imaging method of the present invention provides a preferred 3D multi-subaperture wide beam looped reciprocating transmission sequence and its phase difference compensation 3D ultrasonic imaging method. The specific steps include:

[0144] Step K1, construct a set of M (M≥2) 3D wide beams. Preferably, M = 37. The virtual points of this set of 37 3D wide beams are concentrically distributed behind the two-dimensional array probe and are parallel to it. In this preferred embodiment, sub-aperture emission is used to emit non-inclined divergent spherical waves, and the virtual focus of the divergent spherical wave is at a certain height behind the center of the sub-aperture. Obviously, this height determines the fan angle size of the divergent spherical wave.

[0145] Obviously, in this preferred embodiment, since the sequence virtual points are translated and the sub-aperture size is the same for each transmission, the delay matrix applied to the two-dimensional sub-aperture for each transmission is similar. The virtual focus sequence of the divergent spherical waves of the 3D multi-subaperture wide beam sequence can be expressed as {(α n , β n ) ∣ α n = Δr·p·cosθ0[p] + Δθ[p]·q, βn = Δr·p·sinθ0p + Δθp·q, n = 1, 2,..., N, p = 0, 1,..., P - 1, q = 0, 1,..., Q[p] - 1}, where Δr is the radial interval between concentric circles, P - 1 is the number of concentric circles, Q[p] is the number of virtual points on the p-th concentric circle (Q[0] = 1 when p = 0), and ∑Q[p] = M. θ0[p] is the angle between the first virtual point on the p-th concentric circle and the α axis, and Δθ[p] is the angular interval between adjacent virtual points on the p-th concentric circle. From this, the delay matrix of the two-dimensional array sub-aperture is calculated.

[0146] Step K2: Apply the calculated two-dimensional array sub-aperture delay matrix to the sub-aperture array elements of the probe to be activated. Preferably, use the 16×16 sub-aperture array elements of a two-dimensional 32×32 rectangular planar array to transmit a single pulse, thereby driving the probe to emit a 3D multi-sub-aperture divergent spherical wave sequence. Transmit the beam sequence in an alternating forward-backward loop sequence on concentric circles. As shown in Figure 4 the figure, start from an initial point on the outer side of the concentric circles and transmit sequentially along the circle. After traversing one circle, start from the innermost adjacent point on the inner side and continue to transmit back and forth sequentially along its concentric circle in the opposite direction, repeating until the virtual end point at the center of the circle, which is called forward, and returning from this path from the center end point to the outer starting point is called backward.

[0147] Step K3: Receive the echo data generated by each 3D wide beam emission, and perform 3D beam synthesis and clutter filtering, which is the same as that in a previous embodiment specifically.

[0148] Step K4: Perform 3D phase difference correction. Preferably, in this embodiment, a compensation method for multi-constraint 3D velocity field estimation is adopted to construct a cost function J(v) for globally optimizing the 3D velocity-displacement field, which is constrained by one to several constraint terms. Preferably, as described by the following equation:

[0149] J(v) = λ1·J o (v) + λ2·J d (v) + μ1·J div (v) + μ2·J smooth (v)

[0150] where λ1 + λ2 = 1; J o (v) is preferably a local displacement constraint term, J d (v) is preferably a global displacement constraint term, J div (v) is preferably a divergence-free regularization term, J smooth (v) is preferably a smoothness regularization term, as shown in the following equation:

[0151]

[0152] where, is the image gradient at the i-th virtual source position, and u i is the corresponding local displacement velocity field.

[0153]

[0154] where d j is the unit vector in the direction of the beam synthesis line, and v d,j is the global displacement velocity estimate at the position of the j-th line.

[0155]

[0156] J div (v) Ensure that the velocity field satisfies the divergence - free condition, which is in line with the incompressible assumption of the tissue. J smooth (v) Increase the smoothness of the velocity field by minimizing the spatial variation of the velocity field, reducing noise and artifacts.

[0157] Adopt a numerical optimization method. Typically, use the gradient - descent method to iteratively solve the optimization problem to obtain the 3D velocity field estimate, multiply it by the frame interval to obtain the 3D displacement field, and perform volume alignment according to the displacement between the reference 3D volume and other 3D volumes within the imaging sequence to complete 3D phase - contrast correction, and obtain multi - beam coherent compound 3D ultrasound imaging without phase - contrast artifacts.

[0158] Example 4

[0159] According to Figure 5 As shown, another embodiment of the 3D imaging method of the present invention provides a preferred 3D diverging - focusing compound focusing - plane scanning transmission sequence and its phase - contrast - compensated 3D ultrasound imaging method. The specific steps include:

[0160] Step Z1: Construct a set of M×N (M, N≥2) 3D beams. Preferably, M = 9 and N = 90. These 810 3D beams show diverging waves with 9 sub - aperture translations in the first dimension and 90 line - by - line scanned focusing waves in the second dimension. One transmission can be regarded as scanning a diverging section within the imaging target volume. Calculate the delay vectors in the first dimension and the second dimension respectively according to the element delay calculation rules of the diverging wave and the focusing wave, and superimpose them in each row and each column to obtain the two - dimensional delay matrix of this 3D diverging - focusing compound beam sequence.

[0161] Step Z2: Apply the calculated two - dimensional array delay matrix to the probe elements to be activated. Preferably, use the full - aperture elements of a 32×32 two - dimensional rectangular planar array to transmit a single pulse. First, in the first focusing line of the second dimension, transmit the 9×2 sub - aperture diverging waves of this focusing plane in a forward - backward reciprocating order. Preferably, the number of sub - aperture elements is 16, and then transmit the 2nd, 3rd, …, 90th focusing lines of the second dimension with the same rule to complete the entire volume scan.

[0162] Step Z3: Receive the echo data generated by each 3D wide - beam transmission. Preferably, use 32×32 full - aperture single - time reception to obtain 3D imaging channel data S of 1024 elements in 1620 groups (9 virtual points in the first dimension × 2 reciprocations × 90 focal points in the second dimension) ij(i = 1, 2, …, 1620; j = 1, 2, …, 1024), and then successively use the channel data S within the n-th focusing line in the second dimension ij (i = [1, 2, …, 18] + 18×(n - 1); j = 1, 2, …, 1024; n = 1, 2, …, N), perform beamforming on one plane and / or several adjacent planes corresponding thereto to obtain the intermediate data R of the imaging plane i (i = 1, 2, …, 1620), and the synthesis formula is the same as that in the foregoing embodiment.

[0163] In some embodiments, one focusing line only performs beamforming on the scanning plane where it is located; in other embodiments, one focusing line can participate in the synthesis of multiple planes, or each synthesized plane can be synthesized from the echo data generated by multiple focusing lines, and the weights of each focusing line participating in the synthesis are adjustable. Any optional method for reconstructing the planes within the volume can be adopted, and the present invention is not limited thereto.

[0164] Step Z4, perform 3D phase difference correction. Preferably, in this embodiment, first calculate the global displacement phase shift within the n-th synthesized plane, based on the forward branch Rf n,i (i = [1, 2, …, 9] + 18×(n - 1); n = 1, 2, …, N) and the backward branch Rb n,i (i = [10, 11, …, 18] + 18×(n - 1); n = 1, 2, …, N) of the 3D intermediate imaging data of the autocorrelation coefficient К fn and К bn , generally, calculating a set of К fn and К bn applied to each set of synthesized planes is sufficient, and then calculate the phase shift and the global displacement velocity. The formula is as follows:

[0165]

[0166] Step Z5, perform phase difference compensation and coherent compounding on the first-dimension imaging intermediate data included in the n-th synthesized plane in the second dimension to obtain the N imaging compounded plane intermediate data R of the second dimension Compounding_Plane :

[0167]

[0168] wherein, w k is the weight of coherent compounding, typically all 1.

[0169] Step Z6, after each synthesized plane is corrected, the time interval between two adjacent synthesized planes is Multiply it by the global displacement speed to sequentially correct the inter-plane phase difference displacement motion of the intermediate data in the middle of the second-dimension imaging composite plane, obtain the 3D imaging data after phase difference compensation, and obtain the final 3D image data through image post-processing.

[0170] Embodiment 5

[0171] According to Figure 6 As shown, another embodiment of the 3D imaging method of the present invention provides a preferred 3D divergent-multi-focus composite multi-focus plane scanning emission sequence and its phase difference compensation 3D ultrasonic imaging method. The specific steps are basically the same as those of the previous embodiment, except that:

[0172] Construct a group of M×N (M, N≥2) 3D beams. Preferably, M = 5 and N = 30. The first dimension of the 3D beam is a multi-angle divergent wave emitted with full aperture in this dimension, and the second dimension is a multi-focus wave emitted with multiple lines. The number of multi-line focus lines L≥2, and L is preferably 3.

[0173] Each group of 3D imaging channel data S ij Simultaneously synthesize the L planes where the focus lines are located and / or several adjacent planes to obtain the intermediate data R of the imaging multi-plane. i / 3 .

[0174] After each synthesized plane is corrected, the time interval between adjacent two plane groups is Multiply it by the global displacement speed to sequentially correct the phase difference displacement motion of the L corresponding planes between the plane groups of the multi-plane intermediate data after the second-dimension imaging composite, obtain the 3D imaging data after phase difference compensation, and obtain the final 3D image data through image post-processing.

[0175] Embodiment 6

[0176] According to Figure 2 As shown, this embodiment also provides a three-dimensional ultrasonic imaging system, including a beam construction module 1, a beam emission module 2, a beam processing module 3, and an imaging module 4;

[0177] The beam construction module 1 is used to construct multiple 3D ultrasonic beams with incompletely identical wavefront surface shapes, and is set to be a wide beam in at least one dimension, where the emission of the 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in the dimension where divergence belongs;

[0178] The beam emission module 2 is used to emit multiple 3D ultrasonic beams, and in the dimension where it is a wide beam, the emitted 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in an alternating reciprocating order of beams;

[0179] The beam processing module 3 is configured to receive the 3D imaging channel data of the corresponding 3D ultrasonic beams obtained by multiple receiving array elements, perform beam synthesis on the 3D imaging channel data, and obtain 3D intermediate imaging data;

[0180] The imaging module 4 is configured to calculate the phase shift angle between multiple transmissions and / or the 3D velocity-displacement field based on one or several constraint terms according to the obtained 3D intermediate imaging data, perform volume alignment according to the displacement between the reference 3D volume and other 3D volumes within the imaging sequence, complete 3D phase difference correction, and obtain coherent compound 3D ultrasonic imaging without phase difference artifacts, thereby completing the three-dimensional ultrasonic imaging work.

[0181] Embodiment 7

[0182] The present invention further provides a mobile terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor, such as a three-dimensional ultrasonic imaging program.

[0183] Specifically, the mobile terminal 100 includes a two-dimensional array ultrasonic probe 110, a transmit / receive control module 120, a processor 130, a beam synthesis module 140, a display 150, a memory 160, and an input module 170.

[0184] The two-dimensional array ultrasonic probe 110 is configured to transmit ultrasonic beams and receive echoes. The two-dimensional array ultrasonic probe 110 can be designed in the form of a rigid probe or a flexible patch including, but not limited to, a two-dimensional matrix array, a two-dimensional spiral array, or a two-dimensional irregularly distributed array; the parameters of the transducer array elements in the array, such as size, center frequency, etc., do not have to be exactly the same based on the imaging task to be performed.

[0185] The transmit / receive control module 120 may include multiple groups of circuits. In transmit control, the transmit / receive control module 120 is configured to generate a transmit beam sequence based on the transmit parameters of the processor 130, and control some or all of the array elements in the two-dimensional array ultrasonic probe 110 to transmit ultrasonic waves towards the imaging target; the transmit parameters include the activated transducer array elements, transmit amplitude, frequency, delay, etc. In receive control, the transmit / receive control module 120 is configured to receive the ultrasonic echo signal, amplify the signal after appropriate gain compensation, perform analog-to-digital conversion on the signal, and send the ultrasonic echo signal and the transmit parameters that determine the reconstruction method to the beam synthesis module 140 for processing.

[0186] The beam synthesis module 140 determines the reconstruction method according to the transmit mode of the transmit / receive control module 120, and then performs appropriate beam synthesis processing such as delay alignment, weighting, and channel summation on the ultrasonic echo signal, and then sends it to the processor 130 for further processing.

[0187] The processor 130 is used to perform signal detection, signal enhancement, logarithmic compression, coordinate transformation, etc. on the ultrasonic echo signal to form a three-dimensional ultrasonic image, and can be used to further edit the obtained three-dimensional ultrasonic image. The data generated by the processor 130 can be sent to the display 150 for display or sent to the memory 160 for storage. The processor 130 can be implemented as software, hardware, firmware, or any combination thereof, and can use one or more application-specific integrated circuits, one or more general-purpose integrated circuits, one or more microprocessors, one or more programmable logic devices, or any combination of the foregoing circuits and / or devices, or other suitable circuits or devices. Moreover, the processor 130 can control other components in the mobile terminal 100 to execute the corresponding steps of the methods in the various embodiments of this specification.

[0188] The display 150 is used to display the three-dimensional ultrasonic image obtained by the processor 130. It can also provide an interactive graphical interface to the user, enabling the user to control the controlled objects set in the graphical interface. For example, based on the three-dimensional ultrasonic image obtained by the processor 130, a three-dimensional rendered volume image and slice images of any section are displayed, and the section can be selected and transformed in the graphical interface using the input module 170, and regions of interest can also be drawn, etc.

[0189] The memory 160 is used to store the instructions executed by the processor, store the received ultrasonic echoes, store ultrasonic images, etc. The memory can be a flash card, solid-state memory, hard disk, etc. It can be volatile memory and / or non-volatile memory, removable memory and / or non-removable memory, etc.

[0190] The input module 170 can include, but is not limited to, one or a combination of a mouse, keyboard, roller, knob, graphics tablet, touch screen, microphone, camera, etc. The corresponding input methods include, but are not limited to, one or a combination of mechanical interaction, voice commands, gesture recognition, etc. It is connected to the processor 130 through an external input / output interface, and the external input / output interface includes wireless and / or wired communication modules, etc., and can also be implemented based on bus protocols such as USB and / or network protocols.

[0191] It should be understood that Figure 7 The components included in the illustrated mobile terminal 100 are only illustrative, and it can include more or fewer components. Under the implementation of the characteristic technologies in the claims of the present invention, the present invention is not limited thereto.

[0192] Embodiment 8

[0193] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the three-dimensional ultrasonic imaging method are implemented.

[0194] If the modules / units integrated in the mobile terminal are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0195] Based on such understanding, all or part of the processes in the above method of the present invention can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above method for preventing the incomplete randomness phase attack can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc.

[0196] The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0197] It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0198] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A three-dimensional ultrasonic imaging method, characterized in that, Comprising: Constructing a plurality of 3D ultrasonic beams with non-identical wavefront surface shapes, and setting them to be wide beams in at least one dimension, wherein the emission of the 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in the diverging dimension; Emitting a plurality of 3D ultrasonic beams, and in the dimension where the emitted 3D ultrasonic beam sequence is a wide beam, emitting reciprocating alternating sequential beams that can be divided into a forward branch and a backward branch; Receiving 3D imaging channel data of the corresponding 3D ultrasonic beams obtained by a plurality of receiving elements, performing beam synthesis on the 3D imaging channel data, and obtaining 3D intermediate imaging data; Calculating the phase shift angle between multiple emissions and / or the 3D velocity-displacement field based on one to several constraint terms according to the obtained 3D intermediate imaging data, performing volume alignment according to the displacement between the reference 3D volume and other 3D volumes in the imaging sequence, completing 3D phase difference correction, and obtaining coherent compound 3D ultrasonic imaging without phase difference artifacts to complete 3D ultrasonic imaging work.

2. The three-dimensional ultrasonic imaging method according to claim 1, characterized in that By designing different transmission delays and / or transmission waveform combinations, beam shaping is performed on the beams emitted by the excited two-dimensional array probe, and a plurality of 3D beam sequences with non-identical wavefront surface shapes are constructed. Each 3D beam in the 3D beam sequence is a wide beam in at least one of its dimensions, where this dimension is the first dimension, and the virtual foci of the wide beams are at different positions.

3. The three-dimensional ultrasonic imaging method according to claim 1, wherein The specific formula for performing beam synthesis on the 3D imaging channel data is as follows: where, w ij is the weight of 3D beamforming, set to all 1s or provided by a 3D adaptive beamforming algorithm, and τ j is the delay required for the two-dimensional array elements to receive and synthesize the target point; S ij (t) is the 3D imaging channel data, less than or equal to the number of enabled receiving array elements; R_raw i is the 3D intermediate imaging data of beamforming, i = 1, 2, …, M; Among them, the 3D imaging channel data S ij (t) and the echo data RX received by the enabled receiving array elements ik (t) are related by the following formula, which can be called beamforming-like: Among them, is the weight for synthesizing the 3D imaging channel data from the array element echo data, set to all 1s or given by actual experience; SubMatrix j is the array element group for the j-th 3D imaging channel data, and the number of enabled receiving array elements m in the group is 1, 2, …; Δ k is the difference between the delay of the array element relative to the reference point in the group and the delay of the center of the array element group relative to the reference point; when m = 1, j = k, S ij (t) = RX ik (t - Δ k ).

4. A three-dimensional ultrasonic imaging method according to claim 3, characterized in that Perform clutter filtering on the data after 3D beamforming to obtain M clutter-filtered beamformed 3D intermediate imaging data R i , where i = 1, 2, …, M. The specific process is as follows: First, perform SVD decomposition on the beam synthesis data, specifically as follows: R_raw i (t) = UΔV T Wherein, U is the spatial singular vector, V is the temporal singular vector, and Δ is the singular value matrix; the filtered 3D intermediate imaging data is: R i (t) = U f Δ f V f T Among them, U f is the spatial singular vector after threshold screening, and Δ f is the temporal singular vector after threshold screening, and Δ f is the singular value matrix after threshold screening. The threshold is determined based on the inflection point position of the image in the singular value curve and experience.

5. A three-dimensional ultrasonic imaging method according to claim 1, characterized in that, Calculating the phase shift angle between multiple emissions according to the obtained 3D intermediate imaging data; Among them, according to the 3D intermediate imaging data sequence Rf after beam synthesis and clutter filtering of the 3D ultrasonic beam located in the forward branch i perform autocorrelation calculation, i = 1, 2, …, K, 4 ≤ 2K ≤ M; obtain the 3D intermediate imaging data autocorrelation coefficient К of the forward branch f ; Based on the 3D intermediate imaging data sequence Rb after beam synthesis of the 3D ultrasonic beam located in the backward branch i Perform autocorrelation calculation, where i = K + 1, K + 2, …, K + P, 4 ≤ K + P ≤ M, to obtain the autocorrelation coefficient К of the 3D intermediate imaging data of the forward branch b .

6. A three-dimensional ultrasonic imaging method according to claim 5, characterized in that The phase shift angle θ is provided by the autocorrelation angle product of the 3D intermediate imaging data, and the phase rotation and / or the displacement between multiple beam emissions are adjusted; The phase shift angle calculated by the autocorrelation angle product is calculated by the following equation: The adjustment of the phase rotation is performed in the 3D coherent compounding step, as shown in the following equation: The adjustment of the displacement between multiple beam emissions is performed in the 3D coherent compounding step, as shown in the following equation: where, w k is the weight of coherent combination; ξ is the phase rotation indication factor, and its value is 1 or 1 / e ikθ ; ε is the displacement compensation indication factor, and its value is 0 or 1.

7. A three-dimensional ultrasonic imaging method according to claim 1, characterized in that, Calculating the 3D velocity-displacement field based on one to several constraint terms according to the obtained 3D intermediate imaging data, constructing a cost function J(v) for globally optimizing the 3D velocity-displacement field, and being constrained by one to several constraint terms, with the specific equation as follows: J(v) = λ1·J o (v) + λ2·J d (v) + μ1·J div (v) + μ2·J smooth (v) Among them, λ1 + λ2 = 0 or 1. When its value is 0, μ1 and μ2 are also 0, which is equivalent to not performing this step; J o (v) is a local displacement constraint term, J d (v) is a global displacement constraint term, J div (v) is a divergence-free regularization term, J smooth (v) is a smoothness regularization term.

8. A three-dimensional ultrasonic imaging system, characterized in that, Including A beam construction module (1) for constructing a plurality of 3D ultrasonic beams with non-identical wavefront surface shapes, and setting them to be wide beams in at least one dimension, wherein the emission of the 3D ultrasonic beam sequence can be divided into a forward branch and a backward branch in the diverging dimension; A beam emission module (2) for emitting a plurality of 3D ultrasonic beams, and in the dimension where the emitted 3D ultrasonic beam sequence is a wide beam, emitting reciprocating alternating sequential beams that can be divided into a forward branch and a backward branch; A beam processing module (3) for receiving 3D imaging channel data of the corresponding 3D ultrasonic beams obtained by a plurality of receiving elements, performing beam synthesis on the 3D imaging channel data, and obtaining 3D intermediate imaging data; An imaging module (4) is configured to calculate a phase shift angle between multiple transmissions and / or a 3D velocity-displacement field based on one to several constraint terms according to the acquired 3D intermediate imaging data, perform volume alignment according to the displacement between a reference 3D volume and other 3D volumes within an imaging sequence, complete 3D phase difference correction, obtain coherent compound 3D ultrasonic imaging without phase difference artifacts, and complete three-dimensional ultrasonic imaging work.

9. A mobile terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, the steps of three-dimensional ultrasonic imaging as described in any one of claims 1-7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the steps of three-dimensional ultrasonic imaging as described in any one of claims 1-7 are implemented.

Images