Ultrasonic imaging method and system based on ring array and synthetic aperture technology

Abstract

The invention provides an ultrasonic imaging method and system based on a ring array and a synthetic aperture technology, and the method comprises the steps: sequentially controlling all transmitting array elements in a ring array transducer based on a preset sequence, so as to enable each transmitting array element to sequentially transmit an ultrasonic signal to a corresponding imaging region; the method comprises the following steps: when any current transmitting array element transmits a current ultrasonic signal, acquiring a corresponding echo signal matrix through a plurality of receiving array elements corresponding to the current transmitting array element, and generating a region image of a current imaging region corresponding to the current transmitting array element according to the plurality of echo signal matrixes on the basis of a delay superposition mode, the echo signal matrix is composed of echo signals of all preset pixel points in the current imaging area, and the receiving array element itself is also a transmitting array element; and generating a complete ultrasonic imaging result graph according to the regional image corresponding to each transmitting array element, thereby improving the resolution ratio and real-time imaging frame rate of intravascular ultrasonic imaging.

Description

Technical Field

[0001] The present application relates to the fields of synthetic aperture technology and ultrasonic imaging technology, and in particular to an ultrasonic imaging method and system based on a ring array and synthetic aperture technology. Background Art

[0002] As a core imaging guidance technology for percutaneous coronary intervention, intravascular ultrasound imaging (IVUS) has a high resolution and real-time performance that directly impacts the morphological assessment of atherosclerotic plaques and interventional treatment decisions. Current mainstream mechanical rotational systems are limited by the mechanical rotation mode of a single array element, resulting in image tearing and low image frame rates, making it difficult to meet the needs of real-time, rapid imaging, especially in diagnostic scenarios and surgical navigation procedures where real-time performance is critical. However, ring array transducers achieve full-depth dynamic focusing and rapid imaging through a phased array approach, offering broad application prospects.

[0003] Synthetic aperture technology was initially widely used in radar and sonar. Its core concept is to transmit signals at different locations and synthesize the echo signals to achieve an imaging effect equivalent to a larger physical aperture, thereby improving image resolution and imaging depth range. In ultrasound imaging, synthetic aperture technology is often combined with dynamic focusing and beamforming techniques to achieve optimal focusing of the ultrasound beam at different depths, effectively improving both lateral and axial resolution. However, in the field of intravascular ultrasound imaging, most current algorithmic research focuses on linear and convex arrays. Convex array probes, in particular, suffer from low image contrast due to beam spread and sidelobe interference. This is particularly true in deep vascular regions, where heterogeneous plaques are prone to acoustic shadowing artifacts that obscure the true extent of the lesion. Linear array probes, on the other hand, have a narrow scanning range, resulting in incomplete imaging of larger plaques or vessels, requiring "panoramic imaging" software for stitching, which can easily lead to image distortion due to motion errors. Therefore, intravascular ultrasound imaging technologies based on linear and convex arrays still have certain limitations in terms of resolution, frame rate, imaging range, and adaptability to complex environments. Summary of the Invention

[0004] In response to the above technical problems, the present application provides an ultrasound imaging method and system based on ring array and synthetic aperture technology to improve the resolution and real-time imaging frame rate of intravascular ultrasound imaging.

[0005] In a first aspect, an embodiment of the present application provides an ultrasonic imaging method based on a ring array and synthetic aperture technology, comprising:

[0006] Controlling each transmitting element in the ring array transducer in sequence based on a preset order, so that each transmitting element transmits an ultrasonic signal to the corresponding imaging area in sequence;

[0007] When any current transmitting array element transmits a current ultrasonic signal, a corresponding echo signal matrix is ​​obtained through a number of receiving array elements corresponding to the current transmitting array element, and then a regional image of the current imaging area corresponding to the current transmitting array element is generated based on the multiple echo signal matrices in a time-delayed superposition manner, wherein the echo signal matrix is ​​composed of echo signals of each preset pixel point in the current imaging area, and the receiving array element itself is also a transmitting array element;

[0008] A complete ultrasonic imaging result map is generated according to the regional images corresponding to each of the transmitting array elements.

[0009] The present invention provides an ultrasound imaging method based on a ring array and synthetic aperture technology. By controlling each transmitting element to sequentially transmit ultrasonic signals to the corresponding imaging area, and using a number of corresponding receiving elements to receive the echo signal matrix, regional images of each imaging area are sequentially generated based on the respective echo signal matrices, ultimately synthesizing the resulting ultrasound image. The present invention utilizes synthetic aperture technology to achieve dynamic focusing, addressing the depth of focus limitation of traditional ultrasound imaging. The multi-angle transmission and reception coverage of the ring array can synthesize a larger equivalent aperture, avoiding the near-field blind spot problem of linear or convex array probes. Combined with delay-and-addition algorithm optimization, the resolution of intravascular ultrasound imaging is further improved. Furthermore, by fusing regional images from multiple transmitting elements, each transmitting element only requires a single transmission to cover the entire imaging area, avoiding the mechanical scanning delay of traditional mechanical rotation systems, addressing the low imaging rate in single-element mechanical rotation mode, and improving the real-time frame rate of intravascular ultrasound imaging. Furthermore, the receiving elements in the present invention also function as transmitting elements, enabling multiplexing of transmit / receive functions and effectively reducing probe size and hardware redundancy.

[0010] Furthermore, when a corresponding echo signal matrix is ​​obtained through any of the receiving array elements, obtaining the corresponding echo signal matrix through a plurality of receiving array elements corresponding to the current transmitting array element includes:

[0011] Acquiring echo signal data of each preset pixel point in the current imaging area through the receiving array element;

[0012] Performing envelope detection and Hilbert transform processing on each of the echo signal data to generate each corresponding echo signal;

[0013] The echo signal matrix is ​​obtained by combining the respective echo signals.

[0014] In this embodiment of the present application, when acquiring echo signal data for each preset pixel point, the echo signal data is processed using envelope detection and Hilbert transform. Envelope detection effectively extracts the amplitude modulation characteristics of the ultrasonic echo signal, eliminating interference from high-frequency carrier waves on signal analysis and suppressing random noise. Combined with the analytical signal generated by the Hilbert transform, the instantaneous phase and amplitude information of the signal can be accurately extracted, thereby fully preserving key features such as defect boundary reflections and material scattering, thereby improving the resolution of subsequent intravascular ultrasound imaging.

[0015] In one possible implementation, generating a regional image of a current imaging area corresponding to the current transmitting array element based on a delay superposition method according to a plurality of echo signal matrices includes:

[0016] Calculating, based on the current transmitting array element, the corresponding plurality of receiving array elements, and the respective positions of the preset pixel points in the current imaging area, a signal transmission duration of each echo signal in each echo signal matrix, wherein the signal transmission duration of any echo signal is the time interval from the current ultrasonic signal being transmitted to the echo signal being received by the receiving array element;

[0017] Calculating the echo intensity of each of the preset pixel points based on the delay superposition method according to each of the echo signal matrices and each of the signal transmission durations;

[0018] A regional image of the current imaging area is generated according to the echo intensity of each of the preset pixel points.

[0019] The present invention provides a regional imaging method based on echo signals. By calculating the signal transmission time of each echo signal, dynamic focus compensation is achieved for any imaging depth. Compared with the fixed focal zone limitation of traditional focusing modes, this method uses synthetic aperture technology to synthesize a larger equivalent aperture, which maintains the lateral resolution at all depths and avoids the problem of sudden resolution drop outside the focal zone. Signal delays are then superimposed on the same pixel point according to different signal transmission times, and the echo intensity of each pixel point is determined. Finally, the corresponding regional image is generated based on the echo intensity of each pixel point. This process fully integrates the temporal and spatial characteristics of each echo signal, achieving precise imaging of the target area and improving the resolution of subsequent intravascular ultrasound imaging.

[0020] Furthermore, the step of calculating the echo intensity of each preset pixel point based on the delay superposition method according to each echo signal matrix and each signal transmission time includes:

[0021] Traversing each of the preset pixel points, wherein, for any current pixel point, a current echo signal corresponding to the current pixel point is extracted from each of the echo signal matrices, and each of the current echo signals is delayed and superimposed on the current pixel point based on the signal transmission time of each current echo signal to calculate the echo intensity of the current pixel point;

[0022] After the traversal is completed, the echo intensity of each of the preset pixel points is obtained.

[0023] The embodiment of the present application provides a method for calculating the echo intensity of a pixel point, which realizes pixel-level dynamic focusing by traversing each pixel point and independently calculating the echo intensity. Compared with the traditional fixed focus area, the embodiment of the present application can keep the lateral resolution consistent at all depths. In the specific calculation process, the distance difference from the current pixel point to different receiving array elements is reflected by different signal transmission time, and then the difference in contribution of each current echo signal to the imaging of the current pixel point is distinguished. Finally, according to the different contribution differences, each current echo signal is superimposed on the current pixel point, and the echo intensity of the current pixel point is calculated, so that the ultrasonic imaging is more reasonable and accurate, and the accuracy of subsequent intravascular ultrasonic imaging is improved.

[0024] In a possible implementation, after the echo signal matrix is ​​acquired, apodization processing is performed on each echo signal in the echo signal matrix using a preset apodization function.

[0025] In this embodiment, an apodization function is introduced to address artifacts caused by complex intravascular blood flow and transducer element density. Prior to regional imaging, each echo signal in the echo signal matrix is ​​apodized. This apodization process uses spectral shaping to reduce the signal's time-domain oscillation effects, minimizing phase errors and harmonic distortion caused by probe jitter or tissue movement. Therefore, this embodiment effectively reduces artifacts in subsequent intravascular ultrasound imaging through apodization, while also further improving imaging resolution.

[0026] In a second aspect, an embodiment of the present application provides an ultrasound imaging system based on a ring array and synthetic aperture technology, comprising a transmitting module, a regional imaging module, and a synthesizing module;

[0027] The transmitting module is used to sequentially control each transmitting element in the ring array transducer based on a preset order, so that each transmitting element sequentially transmits an ultrasonic signal to the corresponding imaging area;

[0028] The regional imaging module is configured to, when any current transmitting array element transmits a current ultrasonic signal, obtain a corresponding echo signal matrix through a plurality of receiving array elements corresponding to the current transmitting array element, and then generate a regional image of the current imaging area corresponding to the current transmitting array element based on the plurality of echo signal matrices in a time-delayed superposition manner, wherein the echo signal matrix is ​​composed of echo signals of each preset pixel point in the current imaging area, and the receiving array element itself is also a transmitting array element;

[0029] The synthesis module is used to generate a complete ultrasonic imaging result image according to the regional images corresponding to each of the transmitting array elements.

[0030] Furthermore, when a corresponding echo signal matrix is ​​acquired through any of the receiving array elements, the regional imaging module acquires the corresponding echo signal matrix through a number of receiving array elements corresponding to the current transmitting array element, including:

[0031] Acquiring echo signal data of each preset pixel point in the current imaging area through the receiving array element;

[0032] Performing envelope detection and Hilbert transform processing on each of the echo signal data to generate each corresponding echo signal;

[0033] The echo signal matrix is ​​obtained by combining the respective echo signals.

[0034] In one possible implementation, the regional imaging module generates a regional image of a current imaging area corresponding to the current transmitting array element based on a delay superposition method according to a plurality of echo signal matrices, including:

[0035] Calculating, based on the current transmitting array element, the corresponding plurality of receiving array elements, and the respective positions of the preset pixel points in the current imaging area, a signal transmission duration of each echo signal in each echo signal matrix, wherein the signal transmission duration of any echo signal is the time interval from the current ultrasonic signal being transmitted to the echo signal being received by the receiving array element;

[0036] Calculating the echo intensity of each of the preset pixel points based on the delay superposition method according to each of the echo signal matrices and each of the signal transmission durations;

[0037] A regional image of the current imaging area is generated according to the echo intensity of each of the preset pixel points.

[0038] Furthermore, the step of calculating the echo intensity of each preset pixel point based on the delay superposition method according to each echo signal matrix and each signal transmission time includes:

[0039] Traversing each of the preset pixel points, wherein, for any current pixel point, a current echo signal corresponding to the current pixel point is extracted from each of the echo signal matrices, and each of the current echo signals is delayed and superimposed on the current pixel point based on the signal transmission time of each current echo signal to calculate the echo intensity of the current pixel point;

[0040] After the traversal is completed, the echo intensity of each of the preset pixel points is obtained.

[0041] In a possible implementation, after the echo signal matrix is ​​acquired, apodization processing is performed on each echo signal in the echo signal matrix using a preset apodization function. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a flow chart of an ultrasonic imaging method based on a ring array and synthetic aperture technology provided in an embodiment of the present application;

[0043] Figure 2 A detailed flowchart of an ultrasonic imaging method based on a ring array and synthetic aperture technology provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of the technical principle of time-delay superposition imaging in an ultrasound imaging method based on a ring array and synthetic aperture technology provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of defect locations in a simulation experiment conducted based on the ultrasonic imaging method provided in an embodiment of the present application;

[0046] Figure 5 A schematic diagram of imaging results in a simulation experiment based on the ultrasound imaging method provided in an embodiment of the present application;

[0047] Figure 6 A schematic diagram of a curve showing a change in the number of receiving array elements and a -6dB resolution value in another simulation experiment based on the ultrasonic imaging method provided in an embodiment of the present application;

[0048] Figure 7 A schematic structural diagram of an ultrasonic imaging system based on a ring array and synthetic aperture technology provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] It should be noted that the step numbers herein are for convenience of explanation of the specific embodiments and do not serve to define the order in which the steps are to be performed. In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature designated "first" or "second" may explicitly or implicitly include one or more of such features.

[0051] Example 1:

[0052] like Figure 1 As shown, embodiment 1 provides an ultrasonic imaging method based on a ring array and synthetic aperture technology, including steps S1-S3:

[0053] Step S1: controlling each transmitting element in the ring array transducer in sequence based on a preset order, so that each transmitting element transmits an ultrasonic signal to a corresponding imaging area in sequence;

[0054] Step S2: When any current transmitting array element transmits a current ultrasonic signal, a corresponding echo signal matrix is ​​obtained through a plurality of receiving array elements corresponding to the current transmitting array element, and then a regional image of the current imaging area corresponding to the current transmitting array element is generated based on the plurality of echo signal matrices in a time-delayed superposition manner, wherein the echo signal matrix is ​​composed of echo signals of each preset pixel point in the current imaging area, and the receiving array element itself is also a transmitting array element;

[0055] Step S3: Generate a complete ultrasonic imaging result map based on the regional images corresponding to the respective transmitting array elements.

[0056] The present invention provides an ultrasound imaging method based on a ring array and synthetic aperture technology. By controlling each transmitting element to sequentially transmit ultrasonic signals to the corresponding imaging area, and using a number of corresponding receiving elements to receive the echo signal matrix, regional images of each imaging area are sequentially generated based on the respective echo signal matrices, ultimately synthesizing the resulting ultrasound image. The present invention utilizes synthetic aperture technology to achieve dynamic focusing, addressing the depth of focus limitation of traditional ultrasound imaging. The multi-angle transmission and reception coverage of the ring array can synthesize a larger equivalent aperture, avoiding the near-field blind spot problem of linear or convex array probes. Combined with delay-and-addition algorithm optimization, the resolution of intravascular ultrasound imaging is further improved. Furthermore, by fusing regional images from multiple transmitting elements, each transmitting element only requires a single transmission to cover the entire imaging area, avoiding the mechanical scanning delay of traditional mechanical rotation systems, addressing the low imaging rate in single-element mechanical rotation mode, and improving the real-time frame rate of intravascular ultrasound imaging. Furthermore, the receiving elements in the present invention also function as transmitting elements, enabling multiplexing of transmit / receive functions and effectively reducing probe size and hardware redundancy.

[0057] In a preferred embodiment, the total number of ring array elements is set to N, which means that the number of transmitting elements is N, corresponding to the existence of N imaging areas, and each element is set to n receiving elements. During an ultrasonic imaging process, elements 1 to N are controlled in sequence based on a preset order to transmit ultrasonic signals to the corresponding imaging areas, and regional images of each imaging area are generated according to the matrix of echo signals received by the receiving elements, and finally synthesized into a complete ultrasonic imaging result image. The specific ultrasonic imaging process is as follows Figure 2 As shown, the following steps are included:

[0058] 1. Set the number of array elements n for signal reception, that is, a total of n array elements on the left and right of the transmitting array element are used for reception.

[0059] The number of receiving elements is set to n. This means that each time an ultrasonic signal is transmitted, n elements, centered around the transmitting element, participate in the reception. For a 64-element ring array transducer, the number of receiving elements, n, is limited to a value between 1 and 31. This is because when the number of receiving elements exceeds 31, elements located perpendicular to or to the other side of the transmitting element will not be able to detect valid signals.

[0060] 2. Divide the circular imaging area into N equal parts according to the total number of array elements N in the ring array.

[0061] The center of the circular imaging area is used as the reference point, and the 360° central angle of the ring is divided into N equal parts based on the total number of ring array elements N. In this way, the central angle of the sector area corresponding to each part is 360° / N, laying the foundation for subsequent imaging operations.

[0062] 3. Excite the first array element to emit an ultrasonic signal.

[0063] A Gaussian pulse is used to excite the first array element, prompting it to transmit an ultrasonic signal to the imaging area. With its excellent time and frequency domain characteristics, the Gaussian pulse effectively ensures the quality and stability of the transmitted signal, providing a strong foundation for subsequent processing of the received signal.

[0064] 4. The receiving array element detects the echo signal matrix as RF(i,n), which is n groups. The data is subjected to signal processing such as envelope detection and Hilbert transform.

[0065] The echo signal matrix detected by the receiving element is represented by RF(i,n), where i represents the transmitting element number and n represents the receiving element number. Since each transmitting element corresponds to n receiving elements, a single transmission operation will receive M×n sets of data (M is the number of pixels). After all elements have completed their transmissions, the cumulative number of data sets is M×n×N. After acquiring the raw data, a series of signal processing steps, such as envelope detection and Hilbert transform, are performed to extract useful information and improve signal quality in preparation for subsequent imaging.

[0066] 5. Perform apodization on the received echo signal matrix, that is, multiply the original signal by the apodization function, and perform apodization on the area I that the transmitting array element i faces. i Perform data delay superposition to obtain the image S of the area i .

[0067] Apply apodization to the received signal, that is, multiply the original signal by the apodization function to reduce the signal sidelobe effect and improve the imaging quality. i , according to the preset delay rules, the data is delayed and superimposed, thereby generating an image S of the corresponding area i This process fully integrates the temporal and spatial characteristics of the signals from each receiving element to achieve precise imaging of the target area.

[0068] 6. Set i to i=i+1, that is, rotate to the next array element to transmit ultrasonic waves.

[0069] The array element number i is updated to i=i+1 to achieve smooth switching from the current array element to the next array element, and then prepare for the next round of ultrasonic transmission and reception tasks, continuously expanding the imaging area.

[0070] 7. Determine whether i is greater than N. This means determining whether all array elements have completed transmission, effectively obtaining a 360° image. If the result is NO, the next array element is transmitted and imaging is performed. If the result is YES, the process ends, completing imaging of all areas. Finally, by scientifically overlaying and fusing the imaging results from all sector-shaped areas, a complete and clear ultrasound image is constructed.

[0071] Furthermore, in step S2, when a corresponding echo signal matrix is ​​obtained through any of the receiving array elements, obtaining the corresponding echo signal matrix through a plurality of receiving array elements corresponding to the current transmitting array element includes:

[0072] Acquiring echo signal data of each preset pixel point in the current imaging area through the receiving array element;

[0073] Performing envelope detection and Hilbert transform processing on each of the echo signal data to generate each corresponding echo signal;

[0074] The echo signal matrix is ​​obtained by combining the respective echo signals.

[0075] In this embodiment of the present application, when acquiring echo signal data for each preset pixel point, the echo signal data is processed using envelope detection and Hilbert transform. Envelope detection effectively extracts the amplitude modulation characteristics of the ultrasonic echo signal, eliminating interference from high-frequency carrier waves on signal analysis and suppressing random noise. Combined with the analytical signal generated by the Hilbert transform, the instantaneous phase and amplitude information of the signal can be accurately extracted, thereby fully preserving key features such as defect boundary reflections and material scattering, thereby improving the resolution of subsequent intravascular ultrasound imaging.

[0076] In one possible implementation, in step S2, generating a regional image of a current imaging area corresponding to the current transmitting array element based on a delay superposition method according to a plurality of echo signal matrices includes:

[0077] Calculating, based on the current transmitting array element, the corresponding plurality of receiving array elements, and the respective positions of the preset pixel points in the current imaging area, a signal transmission duration of each echo signal in each echo signal matrix, wherein the signal transmission duration of any echo signal is the time interval from the current ultrasonic signal being transmitted to the echo signal being received by the receiving array element;

[0078] Calculating the echo intensity of each of the preset pixel points based on the delay superposition method according to each of the echo signal matrices and each of the signal transmission durations;

[0079] A regional image of the current imaging area is generated according to the echo intensity of each of the preset pixel points.

[0080] The present invention provides a regional imaging method based on echo signals. By calculating the signal transmission time of each echo signal, dynamic focus compensation is achieved for any imaging depth. Compared with the fixed focal zone limitation of traditional focusing modes, this method uses synthetic aperture technology to synthesize a larger equivalent aperture, which maintains the lateral resolution at all depths and avoids the problem of sudden resolution drop outside the focal zone. Signal delays are then superimposed on the same pixel point according to different signal transmission times, and the echo intensity of each pixel point is determined. Finally, the corresponding regional image is generated based on the echo intensity of each pixel point. This process fully integrates the temporal and spatial characteristics of each echo signal, achieving precise imaging of the target area and improving the resolution of subsequent intravascular ultrasound imaging.

[0081] Furthermore, the step of calculating the echo intensity of each preset pixel point based on the delay superposition method according to each echo signal matrix and each signal transmission time includes:

[0082] Traversing each of the preset pixel points, wherein, for any current pixel point, a current echo signal corresponding to the current pixel point is extracted from each of the echo signal matrices, and each of the current echo signals is delayed and superimposed on the current pixel point based on the signal transmission time of each current echo signal to calculate the echo intensity of the current pixel point;

[0083] After the traversal is completed, the echo intensity of each of the preset pixel points is obtained.

[0084] The embodiment of the present application provides a method for calculating the echo intensity of a pixel point, which realizes pixel-level dynamic focusing by traversing each pixel point and independently calculating the echo intensity. Compared with the traditional fixed focus area, the embodiment of the present application can keep the lateral resolution consistent at all depths. In the specific calculation process, the distance difference from the current pixel point to different receiving array elements is reflected by different signal transmission time, and then the difference in contribution of each current echo signal to the imaging of the current pixel point is distinguished. Finally, according to the different contribution differences, each current echo signal is superimposed on the current pixel point, and the echo intensity of the current pixel point is calculated, so that the ultrasonic imaging is more reasonable and accurate, and the accuracy of subsequent intravascular ultrasonic imaging is improved.

[0085] In a preferred embodiment, the imaging principle of the specific time-delay superposition method of this embodiment is as follows: Figure 3 As shown, in any imaging area, the ultrasound signal is generated by the i-th array element e i (x i ,y i) is transmitted and propagated to point (a, b) and then reflected back to array element e j (x j ,y j ) The time taken to receive is:

[0086]

[0087] Where c is the propagation speed of ultrasound in the medium, i is the number of the transmitting array element, and j is the number of the receiving array element. The jth array element receives the echo signal, performs appropriate envelope detection and toe-cutting function processing, and can superimpose the calculated time t at point (a, b) to obtain the echo intensity there. Similarly, traverse I i All the pixels in the area are superimposed, and the imaging S in the area is obtained. i The imaging of the next area is carried out in this way until all array elements have completed the superposition of the transmitted signals and the pixels of the corresponding area, and the final imaging image is obtained. The formula is as follows:

[0088]

[0089] Where F(n) is the apodization function, and the array element sequence j1,j2...,j n Represents the array element sequence of the received signal, array element sequence i1,i2,...,i N represents the array element sequence of the transmitting signal, t(p,k,a,b) represents the propagation time from the sound wave transmitted by the p-th array element to the sound wave received by the k-th array element, and RF[k,t(p,k,a,b)] represents the echo signal received by the receiving array element k.

[0090] In a possible implementation, after the echo signal matrix is ​​acquired, apodization processing is performed on each echo signal in the echo signal matrix using a preset apodization function.

[0091] In this embodiment, an apodization function is introduced to address artifacts caused by complex intravascular blood flow and transducer element density. Prior to regional imaging, each echo signal in the echo signal matrix is ​​apodized. This apodization process uses spectral shaping to reduce the signal's time-domain oscillation effects, minimizing phase errors and harmonic distortion caused by probe jitter or tissue movement. Therefore, this embodiment effectively reduces artifacts in subsequent intravascular ultrasound imaging through apodization, while also further improving imaging resolution.

[0092] In a preferred embodiment, a Gaussian apodization function is used to perform apodization processing on each echo signal. The Gaussian apodization function is shown as follows:

[0093]

[0094] Where A is the amplitude coefficient, B is the mean (expected value), and C is the standard deviation (or Gaussian width).

[0095] In a preferred embodiment, a ring array with 32 elements is selected as the research object, with a center frequency of 55 MHz and a ring array diameter of 1.5 mm. The ring array is precisely placed at the center of the imaging area, and two metal needles are placed in the imaging area to act as defect reflectors, such as Figure 4 As shown in the figure, the two defects are located approximately 1.2mm and 1.8mm from the center of the ring array, respectively. According to the algorithm flow, the 32 array elements are excited in sequence, and the echo signal is received simultaneously. After the signal is collected, the filtering, envelope detection, Hilbert transform and other processing steps are carried out in sequence to eliminate noise interference and highlight the effective signal characteristics. Next, the delayed superposition post-focusing synthetic aperture algorithm is used for deep processing of each sector area, and the image data of the area facing each array element is generated one by one (S1...S N ). Finally, these scattered image data are accurately superimposed to present a complete imaging image. The ultrasound imaging result image generated in this embodiment is as follows Figure 5 As shown in the figure, detailed information of the defects can be clearly observed from the imaging result diagram. At the same time, compared with the traditional method, the artifact phenomenon in the imaging is significantly reduced, and the imaging resolution is significantly improved, which fully demonstrates the excellent performance and practical value of the algorithm of the present invention in the field of intravascular ultrasound imaging.

[0096] Furthermore, based on the ultrasound imaging method provided by the present application, the embodiment of the present application uses the FOCUS ultrasound simulator to carry out simulation research on the intravascular ring array synthetic aperture imaging algorithm. In the simulation scenario, the number of arrays of the ring array transducer is set to 64, the center frequency is 50MHz, and the diameter of the ring array is maintained at 1.5mm. A scattering point is set at a position 1.5mm away from the center of the ring array, which is specifically used to conduct a detailed analysis of the transducer performance and the resolution of the algorithm of the present invention. According to the algorithm flow, the 64 array elements are excited in turn, and the number n of receiving array elements is cleverly changed. For each different value of n, the -6dB resolution of the corresponding scattering point is calculated. The simulation results are as follows. Figure 6 As shown in Figure 2, with the gradual increase in the number of receiving array elements n, the -6dB resolution of the scattering point shows a trend of steady improvement. Figure 6 The smaller the -6dB resolution value is, the smaller the minimum size that can be distinguished is, which means the image resolution is higher. Figure 6 The simulation results shown intuitively and quantitatively confirm the significant advantages of the algorithm of the present invention in improving resolution, and strongly confirm the reliability and effectiveness of the algorithm.

[0097] Example 2:

[0098] like Figure 7 As shown, embodiment 2 provides an ultrasonic imaging system based on a ring array and synthetic aperture technology, comprising a transmitting module 10, a regional imaging module 20, and a synthesizing module 30;

[0099] The transmitting module 10 is used to sequentially control each transmitting element in the ring array transducer based on a preset order, so that each transmitting element sequentially transmits an ultrasonic signal to the corresponding imaging area;

[0100] The regional imaging module 20 is configured to, when any current transmitting array element transmits a current ultrasonic signal, obtain a corresponding echo signal matrix through a number of receiving array elements corresponding to the current transmitting array element, and then generate a regional image of the current imaging area corresponding to the current transmitting array element based on the multiple echo signal matrices in a time-delayed superposition manner, wherein the echo signal matrix is ​​composed of echo signals of each preset pixel point in the current imaging area, and the receiving array element itself is also a transmitting array element;

[0101] The synthesis module 30 is used to generate a complete ultrasonic imaging result image according to the regional images corresponding to each of the transmitting array elements.

[0102] Furthermore, when a corresponding echo signal matrix is ​​acquired through any of the receiving array elements, the regional imaging module 20 acquires the corresponding echo signal matrix through several receiving array elements corresponding to the current transmitting array element, including:

[0103] Acquiring echo signal data of each preset pixel point in the current imaging area through the receiving array element;

[0104] Performing envelope detection and Hilbert transform processing on each of the echo signal data to generate each corresponding echo signal;

[0105] The echo signal matrix is ​​obtained by combining the respective echo signals.

[0106] In one possible implementation, the regional imaging module 20 generates a regional image of a current imaging area corresponding to the current transmitting array element based on a delay superposition method according to a plurality of echo signal matrices, including:

[0107] Calculating, based on the current transmitting array element, the corresponding plurality of receiving array elements, and the respective positions of the preset pixel points in the current imaging area, a signal transmission duration of each echo signal in each echo signal matrix, wherein the signal transmission duration of any echo signal is the time interval from the current ultrasonic signal being transmitted to the echo signal being received by the receiving array element;

[0108] Calculating the echo intensity of each of the preset pixel points based on the delay superposition method according to each of the echo signal matrices and each of the signal transmission durations;

[0109] A regional image of the current imaging area is generated according to the echo intensity of each of the preset pixel points.

[0110] Furthermore, the step of calculating the echo intensity of each preset pixel point based on the delay superposition method according to each echo signal matrix and each signal transmission time includes:

[0111] Traversing each of the preset pixel points, wherein, for any current pixel point, a current echo signal corresponding to the current pixel point is extracted from each of the echo signal matrices, and each of the current echo signals is delayed and superimposed on the current pixel point based on the signal transmission time of each current echo signal to calculate the echo intensity of the current pixel point;

[0112] After the traversal is completed, the echo intensity of each of the preset pixel points is obtained.

[0113] In a possible implementation, after the echo signal matrix is ​​acquired, apodization processing is performed on each echo signal in the echo signal matrix using a preset apodization function.

[0114] The present invention provides an ultrasound imaging system based on a ring array and synthetic aperture technology. By controlling each transmitting element to sequentially transmit ultrasonic signals to the corresponding imaging area, and using a number of corresponding receiving elements to receive the echo signal matrix, regional images of each imaging area are sequentially generated based on the respective echo signal matrices, ultimately synthesizing the resulting ultrasound image. The present invention utilizes synthetic aperture technology to achieve dynamic focusing, addressing the depth of focus limitation of traditional ultrasound imaging. The multi-angle transmission and reception coverage of the ring array can synthesize a larger equivalent aperture, avoiding the near-field blind spots of linear or convex array probes. Combined with delay-and-addition algorithm optimization, the resolution of intravascular ultrasound imaging is further improved. Furthermore, by fusing the regional images of multiple transmitting elements, each transmitting element only requires a single transmission to cover the entire imaging area, avoiding the mechanical scanning delay of traditional mechanical rotation systems, addressing the low imaging rate of single-element mechanical rotation mode, and improving the real-time frame rate of intravascular ultrasound imaging. Furthermore, the receiving elements in the present invention also function as transmitting elements, enabling multiplexing of transmit / receive functions and effectively reducing probe size and hardware redundancy.

[0115] The more detailed working principle and process flow of this embodiment can be referred to, but not limited to, the relevant records of the first embodiment.

[0116] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application by those skilled in the art should be included within the scope of protection of this application.

Claims

1. An ultrasonic imaging method based on ring array and synthetic aperture technology, characterized in that: include: Controlling each transmitting element in the ring array transducer in sequence based on a preset order, so that each transmitting element transmits an ultrasonic signal to the corresponding imaging area in sequence; When any current transmitting array element transmits a current ultrasonic signal, a corresponding echo signal matrix is ​​obtained through a number of receiving array elements corresponding to the current transmitting array element, and then a regional image of the current imaging area corresponding to the current transmitting array element is generated based on the multiple echo signal matrices in a time-delayed superposition manner, wherein the echo signal matrix is ​​composed of echo signals of each preset pixel point in the current imaging area, and the receiving array element itself is also a transmitting array element; A complete ultrasonic imaging result map is generated according to the regional images corresponding to each of the transmitting array elements.

2. The ultrasonic imaging method based on ring array and synthetic aperture technology according to claim 1, characterized in that: When the corresponding echo signal matrix is ​​acquired through any of the receiving array elements, the acquiring the corresponding echo signal matrix through a plurality of receiving array elements corresponding to the current transmitting array element includes: Acquiring echo signal data of each preset pixel point in the current imaging area through the receiving array element; Performing envelope detection and Hilbert transform processing on each of the echo signal data to generate each corresponding echo signal; The echo signal matrix is ​​obtained by combining the respective echo signals.

3. The ultrasonic imaging method based on ring array and synthetic aperture technology according to claim 1, characterized in that: The generating, based on a delay superposition method according to a plurality of echo signal matrices, a regional image of a current imaging region corresponding to the current transmitting array element includes: Calculating, based on the current transmitting array element, the corresponding plurality of receiving array elements, and the respective positions of the preset pixel points in the current imaging area, a signal transmission duration of each echo signal in each echo signal matrix, wherein the signal transmission duration of any echo signal is the time interval from the current ultrasonic signal being transmitted to the echo signal being received by the receiving array element; Calculating the echo intensity of each of the preset pixel points based on the delay superposition method according to each of the echo signal matrices and each of the signal transmission durations; A regional image of the current imaging area is generated according to the echo intensity of each of the preset pixel points.

4. The ultrasonic imaging method based on ring array and synthetic aperture technology according to claim 3, characterized in that: The step of calculating the echo intensity of each preset pixel point based on the delay superposition method according to each echo signal matrix and each signal transmission time includes: Traversing each of the preset pixel points, wherein, for any current pixel point, a current echo signal corresponding to the current pixel point is extracted from each of the echo signal matrices, and each of the current echo signals is delayed and superimposed on the current pixel point based on the signal transmission time of each current echo signal to calculate the echo intensity of the current pixel point; After the traversal is completed, the echo intensity of each of the preset pixel points is obtained.

5. The ultrasonic imaging method based on ring array and synthetic aperture technology according to any one of claims 1 to 4, characterized in that: After the echo signal matrix is ​​acquired, apodization processing is performed on each echo signal in the echo signal matrix using a preset apodization function.

6. An ultrasonic imaging system based on ring array and synthetic aperture technology, characterized in that: It includes a transmitting module, a regional imaging module and a synthesis module; The transmitting module is used to sequentially control each transmitting element in the ring array transducer based on a preset order, so that each transmitting element sequentially transmits an ultrasonic signal to the corresponding imaging area; The regional imaging module is configured to, when any current transmitting array element transmits a current ultrasonic signal, obtain a corresponding echo signal matrix through a number of receiving array elements corresponding to the current transmitting array element, and then generate a regional image of the current imaging area corresponding to the current transmitting array element based on the multiple echo signal matrices in a time-delayed superposition manner, wherein the echo signal matrix is ​​composed of echo signals of each preset pixel point in the current imaging area, and the receiving array element itself is also a transmitting array element; The synthesis module is used to generate a complete ultrasonic imaging result image according to the regional images corresponding to each of the transmitting array elements.

7. The ultrasonic imaging system based on ring array and synthetic aperture technology according to claim 6, characterized in that: When the corresponding echo signal matrix is ​​acquired through any of the receiving array elements, the regional imaging module acquires the corresponding echo signal matrix through a number of receiving array elements corresponding to the current transmitting array element, including: Acquiring echo signal data of each preset pixel point in the current imaging area through the receiving array element; Performing envelope detection and Hilbert transform processing on each of the echo signal data to generate each corresponding echo signal; The echo signal matrix is ​​obtained by combining the respective echo signals.

8. The ultrasonic imaging system based on ring array and synthetic aperture technology according to claim 6, characterized in that: The regional imaging module generates a regional image of the current imaging area corresponding to the current transmitting array element based on a delay superposition method according to a plurality of echo signal matrices, including: Calculating, based on the current transmitting array element, the corresponding plurality of receiving array elements, and the respective positions of the preset pixel points in the current imaging area, a signal transmission duration of each echo signal in each echo signal matrix, wherein the signal transmission duration of any echo signal is the time interval from the current ultrasonic signal being transmitted to the echo signal being received by the receiving array element; Calculating the echo intensity of each of the preset pixel points based on the delay superposition method according to each of the echo signal matrices and each of the signal transmission durations; A regional image of the current imaging area is generated according to the echo intensity of each of the preset pixel points.

9. The ultrasonic imaging system based on ring array and synthetic aperture technology according to claim 8, characterized in that: The step of calculating the echo intensity of each preset pixel point based on the delay superposition method according to each echo signal matrix and each signal transmission time includes: Traversing each of the preset pixel points, wherein, for any current pixel point, a current echo signal corresponding to the current pixel point is extracted from each of the echo signal matrices, and each of the current echo signals is delayed and superimposed on the current pixel point based on the signal transmission time of each current echo signal to calculate the echo intensity of the current pixel point; After the traversal is completed, the echo intensity of each of the preset pixel points is obtained.

10. The ultrasonic imaging system based on ring array and synthetic aperture technology according to any one of claims 6 to 9, characterized in that: After the echo signal matrix is ​​acquired, apodization processing is performed on each echo signal in the echo signal matrix using a preset apodization function.

Images