Ultrasonic image correction method and device for flexible ultrasonic probe and medium

Abstract

The invention provides an ultrasonic image correction method and device for a flexible ultrasonic probe and a medium, and the method comprises the steps: N array elements of the probe serve as transmitting array elements in sequence to transmit pulse sound waves based on a single-transmitting multi-receiving signal transmitting and receiving mode, all array elements receive echo signals at the same time, original radio frequency signals S (m, n, t) are obtained, m is a transmitting event, n is a receiving channel, and t is a receiving channel; t is a fast time point number; calculating correlation between channel signals according to the original radio frequency signal; constructing a loss function according to the correlation, wherein the loss function comprises a channel signal correlation item, an array element spacing constraint item and an image entropy constraint item; estimating the real position of the array element through gradient descent iterative calculation; and performing ultrasonic image reconstruction according to the estimated real positions of the array elements. According to the embodiment of the invention, continuous self-adaptive calibration at low cost can be realized, and manual intervention is avoided.

Description

Technical Field

[0001] This application relates to the field of ultrasonic imaging technology, and particularly relates to an ultrasonic image correction method, device, and medium for a flexible ultrasonic probe. Background Art

[0002] Due to its unique material and structure design, the flexible ultrasonic probe exhibits significant advantages in the field of medical diagnosis, but there are also certain limitations. When the flexible ultrasonic probe is attached to the human skin surface, the geometric shape of the probe changes, and the relative positions of each element on the probe become unfixed, which will cause errors in the calculation of the delay between arrays and ultimately result in the inability to reconstruct a real image. To address this problem, the following are the main solutions in the prior art: 1. After attaching the probe to the skin surface, use a 3D camera to scan the three-dimensional structure of the probe and infer the position of each element. This method has the following problems: First, the accuracy of 3D scanning is not high. For ultrasonic beam synthesis, an element position error exceeding half of the wavelength of the sound wave (tens of micrometers) will have a significant impact. Currently, commonly used 3D scanners on the market cannot achieve this accuracy, or achieving this accuracy requires a high cost; in addition, the time taken for a single 3D scan is relatively long, and the position of the flexible probe will also change after being attached to the human body. If it is not recalibrated, it will also affect the results, and recalibration is time-consuming and laborious.

[0003] 2. Integrate an optical fiber sensor into the flexible probe and estimate the bending degree of the probe based on the attenuation of light in it; or integrate a pressure sensor into the probe and infer the deformation of the probe based on the material of the probe and the strain-stress relationship. However, whether integrating an optical fiber sensor or a pressure sensor into the flexible probe is a costly approach, which will significantly increase the difficulty of the flexible probe manufacturing process. In addition, the integrated sensor itself will also affect the vibration efficiency of the transducer.

[0004] 3. Use the method of deep learning to train an element position prediction model through a large amount of data with real labels. However, no matter how many training samples deep learning has, it cannot fully replicate the real usage scenario because the skin shapes of each person are different, and the prediction model cannot deduce based on unknown data.

[0005] 4. Reduce the operating frequency of the flexible probe. When the wavelength of the sound wave is larger, the distortion of the probe shape has less impact on beam synthesis; however, this method often ignores the impact of element deformation on beam synthesis. Summary of the Invention

[0006] The purpose of this application is to provide an ultrasonic image correction method, device, and medium for a flexible ultrasonic probe, which can achieve continuous adaptive calibration at low cost and avoid manual intervention.

[0007] To solve the above technical problems, on the one hand, an embodiment of the present application provides an ultrasonic image correction method for a flexible ultrasonic probe, including: based on the signal transmission and reception mode of single transmission and multiple receptions, N array elements of the probe are sequentially used as transmitting array elements to transmit pulsed acoustic waves, and all array elements simultaneously receive echo signals to obtain an original radio frequency signal S(m,n,t), where m is the transmission event, n is the reception channel, and t is the fast time point number; calculating the correlation between channel signals according to the original radio frequency signal; constructing a loss function according to the correlation, and the loss function includes a channel signal correlation term, an array element spacing constraint term, and an image entropy constraint term; estimating the true positions of the array elements through gradient descent iterative calculation; and performing ultrasonic image reconstruction according to the estimated true positions of the array elements.

[0008] Optionally, the calculation formula for the correlation between channel signals is:

[0009] where is the delay value of each channel signal calculated according to spatial geometry.

[0010] Optionally, the loss function is:

[0011] where is the array element spacing constraint coefficient, is the image entropy constraint coefficient, is the array element position, is the entropy value of the original ultrasonic image constructed according to the original positions of the array elements.

[0012] Optionally, the estimating the true positions of the array elements through gradient descent iterative calculation includes: Using the Adam optimizer for iterative update optimization, and the iterative update formula is:

[0013] where is the array element position parameter, is the learning rate, is the array element position parameter after iterative update.

[0014] Optionally, the performing ultrasonic image reconstruction according to the estimated true positions of the array elements includes: for a point r(X,Z) in the imaging area, calculating the flight time of the acoustic wave from the true position of the transmitting array element to the true position of the receiving array element, and the flight time calculation formula is:

[0015] where is the distance from the true position of the transmitting element to point r, is the distance from point r to the true position of the receiving element, and c is the speed of sound; Based on the time of flight, delay and sum the signals of each channel according to the following formula to obtain the reconstructed image information: .

[0016] Optionally, the method further includes: calculating the transmission delay of the signals of each channel based on the estimated true position of the element; performing focused transmission on the element according to the transmission delay, and collecting Doppler blood flow signals to achieve beam focusing.

[0017] Another aspect of the embodiments of the present application provides an ultrasonic image correction device for a flexible ultrasonic probe, which is applicable to the above ultrasonic image correction method, and includes: an original RF signal acquisition module: based on the signal transmission and reception mode of single transmission and multiple receptions, N elements of the probe are sequentially used as transmitting elements to transmit pulsed sound waves, and all elements receive echo signals simultaneously to obtain the original RF signal S(m,n,t), where m is the transmission event, n is the receiving channel, and t is the number of fast time points; a correlation calculation module: used to calculate the correlation between channel signals according to the original RF signal; a loss function construction module: used to construct a loss function according to the correlation, and the loss function includes a channel signal correlation term, an element spacing constraint term, and an image entropy constraint term; an element true position estimation module: used to estimate the true position of the element by gradient descent iteration; an ultrasonic image reconstruction module: used to reconstruct an ultrasonic image according to the estimated true position of the element.

[0018] Optionally, the ultrasonic image reconstruction module includes: a time of flight calculation module: for a point r(X,Z) in the imaging region, calculate the time of flight of the sound wave from the true position of the transmitting element to the true position of the receiving element, and the time of flight calculation formula is:

[0019] where is the distance from the true position of the transmitting element to point r, is the distance from point r to the true position of the receiving element, and c is the speed of sound; an ultrasonic image reconstruction sub-module: based on the time of flight, delay and sum the signals of each channel according to the following formula to obtain the reconstructed image information: .

[0020] Optionally, the ultrasonic image correction device further includes: a transmission delay calculation module: used to calculate the transmission delay of the signals of each channel based on the estimated true position of the element; a focused transmission module: used to perform focused transmission on the element according to the transmission delay, and collect Doppler blood flow signals to achieve beam focusing.

[0021] Another aspect of the embodiments of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above ultrasonic image correction method are implemented.

[0022] Compared with the prior art, the embodiments of the present application 1. The algorithm for image correction is based on self-calibration of array element positions through echo signal feature extraction. Flexible strategies can be adopted to update the array element position parameters regularly, enabling real-time tracking of array element parameters, and then realizing continuous adaptive calibration to avoid manual intervention.

[0023] 2. The ultrasonic image correction method is implemented based on pure software, without relying on external sensors or devices, with relatively low requirements for the manufacturing process of flexible probes, reducing the correction cost.

[0024] 3. Compared with the deep learning method, this method does not need to establish a large database to train the prediction model, but optimizes according to the current data, can adapt to different individual differences, and has high compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements. Unless otherwise stated, the drawings in the figures do not constitute a proportional limitation.

[0026] Figure 1 is a flowchart of the ultrasonic image correction method according to an embodiment of the present application; Figure 2 is a flowchart of the ultrasonic image correction method according to another embodiment of the present application; Figure 3 is a schematic structural diagram of the ultrasonic image correction device according to an embodiment of the present application; Figure 4 is a schematic structural diagram of the ultrasonic image correction device according to another embodiment of the present application; Figure 5 is a schematic structural diagram of the ultrasonic image correction device according to still another embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following describes the implementation manners of the present application through specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0028] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects described herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects described herein.

[0029] It should also be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application schematically. The diagrams only show the components related to the present application, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0030] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the examples can be practiced without these specific details.

[0031] In the current medical ultrasonic detection technology, the principle is that an ultrasonic probe emits pulsed ultrasonic waves to biological tissues. After the sound waves are scattered at tissue interfaces, echo signals are formed. These echo signals are received by the probe and converted into electrical signals for subsequent processing. The ultrasonic probe adopts an array transducer design, consisting of dozens of transducer array elements arranged in a precise array. Each element is equipped with an independent drive circuit. By precisely controlling the phase delay of the excitation timing of each element, electronic focusing of the transmit / receive beam is achieved, and the energy of the acoustic wave signal is increased through signal superposition. This process is called beamforming of the array.

[0032] In beamforming, the delay control accuracy directly determines the quality of the signal, and the calculation of the delay relies on the relative positions between array elements as parameters. Therefore, when the positions of the array elements change, if the corresponding calculation parameters are not changed, the calculated delay amount will be incorrect, and then the sound wave cannot be focused. When a flexible probe is attached to the human body surface, the array elements will undergo dynamic deformation when the probe is attached to the human body surface, and the state of each person's skin is different. At this time, the positions of the array elements will become unknowns. If the array element position parameters in the normal state are still used for beam synthesis, it is difficult to obtain an ideal effect. Therefore, it is necessary to optimize the array element position parameters so that the optimized array element position parameters are infinitely close to the true positions of the array elements, thereby improving the accuracy of image reconstruction.

[0033] Based on this, on the one hand, an embodiment of the present application provides an ultrasonic image correction method for a flexible ultrasonic probe, as Figure 1 shown, including the following steps: In step 101, based on the signal transmission and reception mode of single transmission and multiple receptions, N array elements of the probe are sequentially used as transmitting array elements to transmit pulsed sound waves, and all array elements simultaneously receive echo signals to obtain the original radio frequency signal S(m, n, t), where m is the transmission event, n is the reception channel, and t is the fast time point number.

[0034] In the embodiment of the present application, the signal transmission and reception mode of single transmission and multiple receptions is: assuming that the probe has a total of N array elements, then each array element will generate a transmission event, and there will be a total of N transmission events for N array elements. In the first transmission event, array element 1 transmits a beam of pulsed sound waves, and then all N array elements simultaneously participate in receiving the echo signal. Similarly, in the second transmission event, it is the turn of array element 2 to transmit the sound wave, and still all N array elements participate in receiving the echo signal. And so on. After N transmission events are completed, it returns to the first transmission event and repeats in a loop. The advantage of using a single array element to transmit sequentially is that there is no need for physical focusing in transmission, but only post-focusing in the reception stage. In this step, N array elements sequentially transmit pulsed sound waves, and all array elements simultaneously receive echo signals. This echo signal is amplified, filtered, and then sampled by an analog-to-digital converter into a radio frequency signal, thereby obtaining the original radio frequency signal S(m, n, t), where m is the transmission event, n is the reception channel, and t is the fast time point number.

[0035] In step 102, the correlation between channel signals is calculated according to the original radio frequency signal to evaluate the accuracy of the original positions of the array elements. Specifically, assume that the initial position of each array element is . For a certain point in the imaging area, it is necessary to calculate the flight time of the sound wave. The flight time can be calculated by dividing the flight distance by the speed of sound. The flight distance includes two parts. The first part is the distance from the transmitting array element to the point , denoted by Denote that the second part is the distance from the point after reflection back to the receiving array element, denoted by , and the calculation formulas for both are as follows: Denote that the calculation formulas for both are as follows:

[0036]

[0037] Where is the original position of the transmitting array element, and is the original position of the receiving array element. Assume that in the nth transmission event, the nth array element is used for transmission, and all N array elements participate in reception in each event. The flight time can be calculated from the flight distance, and the flight time is the delay applied to the channel signal : (1) For the point , in each transmission event, a delay can be obtained on each channel.

[0038] Since the echo signals from the same scattering point arrive at different array elements at different times, if the correct delays are applied to the channel signals (i.e., the delays corresponding to the true array element positions and the scattering point positions), then the signals after these delays are aligned should have a high degree of phase consistency (coherence), manifested as a high cross-correlation value between each other. Conversely, if the delays are incorrect (due to inaccurate position estimation), the correlation between the signals decreases. Therefore, the accuracy of the original positions of the array elements can be evaluated by the level of correlation between the signals, and the calculation formula for the correlation between the channel signals is: (2) Where is the received original RF signal, m is the transmission event, n is the receiving channel, t is the number of fast time points, and τ is the delay value of each channel signal calculated according to the spatial geometry. The larger C is, the higher the correlation between the channel signals, which means the more accurate the array element positions. Vice versa. Therefore, the embodiments of the present application can optimize the array element position parameters by maximizing the correlation C between the channels.

[0039] In step 103, a loss function is constructed according to the correlation, and the loss function includes a channel signal correlation term, an array element spacing constraint term, and an image entropy constraint term. Specifically, when constructing the loss function, the correlation C between the channels can be inverted. Assume that there are a total of M transmission events, so the total correlation coefficient is the sum of the correlation coefficients of all transmission events, that is:

[0040] To prevent the optimization process from converging to a non-physical parameter solution and to keep the array elements at reasonable intervals and in order, a constraint term for the element spacing needs to be introduced into the loss function. Among them, the first term aims to impose a minimum spacing constraint between array elements. This constraint term calculates the sum of the Manhattan distances between all pairs of array elements, multiplies it by a regularization coefficient, and then adds it to the loss function. The main consideration for using the Manhattan distance is its piecewise linear characteristic, which simplifies the gradient calculation process of the loss function with respect to the optimization parameters: The constraint term for the element spacing can be expressed as:

[0041] where is the constraint coefficient for the element spacing, is the probe position. It should be noted that in order to impose a constraint on the lateral geometric order of the array elements and make the array elements arranged strictly in order, the absolute value is used for the distance in the z direction and not for the x direction in the above formula.

[0042] In addition, in order to maximize the richness of the image information and avoid the optimization from falling into a local optimum, an image entropy constraint term is also introduced into the loss function in the embodiments of the present application. The image entropy constraint term can be expressed as:

[0043] where is the constraint coefficient for the image entropy, is the initial ultrasound image obtained according to formula (1), and X and Z are points on the image. This initial ultrasound image can be obtained according to the following formula:

[0044] Therefore, the total loss function can be expressed as: (3) where is the element position, is the entropy value of the original ultrasound image constructed according to the original positions of the array elements, 、 The specific values of can be determined according to experimental data. For example, by presetting different parameter combinations and using the image quality as an evaluation index, the optimal parameter combination is selected.

[0045] In step 104, the true positions of the array elements are estimated by iterative calculation using gradient descent. Specifically, the Adam optimizer can be used for iterative update and optimization. The iterative update formula is: (4) where, is the array element position parameter (its initial parameter is set to the original position of the array elements when the probe is in the planar state), is the array element position parameter after iterative update, is the learning rate, which can be adaptively adjusted. For example, a larger step size is adopted at the initial stage of optimization to accelerate convergence, and the step size is automatically reduced in the later stage to achieve fine adjustment. The key in the above process is to calculate the loss function with respect to the array element position . First, the calculation formula (3) of is defined as a function, and the forward calculation graph of with respect to the parameter is saved during the definition. When the partial derivative needs to be calculated, the partial derivative value corresponding to the specific parameter value is obtained through backpropagation, and then applied to the iterative update formula (4).

[0046] In this embodiment, is the array element position parameter obtained after iterative update calculation, and this parameter is applied in the next iterative update calculation. In this way, the loop continues until the preset number of iterations is reached, and the array element position parameter obtained from the last iterative update calculation is used as the estimated true position of the array element.

[0047] In step 105, ultrasonic image reconstruction is performed according to the estimated true position of the array element. Specifically, for a point r in the imaging region, the flight time of the sound wave from the true position of the transmitting array element to the true position of the receiving array element is calculated, and the flight time calculation formula is:

[0048] where is the distance from the true position of the transmitting array element to the point r, is the distance from the point r to the true position of the receiving array element, and c is the speed of sound; Based on the flight time, the signals of each channel are delayed and superimposed according to the following formula to obtain the reconstructed image information.

[0049]

[0050] It should be noted that the method of ultrasonic image reconstruction according to the estimated true position of the array element in this step is the same as the method of constructing the original ultrasonic image, except that the position parameters of the array elements used are different. The original position of the array element is used when constructing the original ultrasonic image, while the estimated true position of the array element is used in the ultrasonic image reconstruction in this step.

[0051] In the embodiments of the present application, a real ultrasonic image is reconstructed according to the estimated true position of the array element. Then, after operations such as envelope extraction, downsampling, scan conversion, and logarithmic compression on the image intensity, the calibrated B-mode image can be obtained.

[0052] Compared with the prior art, the embodiments of the present application can correct the delay calculation error caused by probe deformation by evaluating the true positions of the array elements, avoid image blurring or distortion, and thus reconstruct an accurate ultrasonic image. Moreover, the ultrasonic image correction method is implemented based on pure software, without relying on external sensors or devices, has relatively low requirements for the manufacturing process of flexible probes, and reduces the correction cost. The image correction algorithm realizes self-calibration of the array element positions through echo signal feature extraction, can adopt a flexible strategy to update the array element position parameters regularly, can realize real-time tracking of the array element parameters, achieve continuous adaptive calibration, and avoid manual intervention. Compared with the deep learning method, this method does not need to establish a large database to train the estimation model, but optimizes according to the current data, can adapt to different human tissues, and has high compatibility.

[0053] In another embodiment, as Figure 2 shown, this embodiment is optimized on the basis of the embodiment shown in Figure 1 . The optimization lies in that after estimating the true positions of the array elements in this embodiment, correct phase delays are applied between the array elements to maximize the acoustic wave energy at the focus and improve the Doppler signal intensity. The specific process is as follows: Steps 201 - 205 are similar to steps 101 - 105 in the Figure 1 shown embodiment, and will not be elaborated here.

[0054] In step 206, based on the estimated true positions of the array elements, the transmission delays of the signals of each channel are calculated. Specifically, the transmission delay calculation of the signals of each channel is:

[0055]

[0056] where is the estimated true array element position, is the focus position; is the flight time of the acoustic wave from the true array element position to the focus; is the relative delay (subtracting the minimum delay to ensure that all ≥0 to avoid negative delays).

[0057] In step 207, the array elements are focused and emitted according to the transmission delays, and Doppler blood flow signals are collected to achieve beam focusing. Specifically, the focus position can be set at the center of the blood vessel (which can be pre-positioned through B-mode images or blood flow detection), and then each array element is triggered according to the calculated delay during transmission, so that all acoustic waves reach the focus simultaneously and achieve in-phase superposition. In this way, the sound pressure at the focus is enhanced and the energy is concentrated, while the sound energy in the non-focus area is dispersed, reducing interference.

[0058] In this embodiment, the time delay is calculated based on the optimized element positions and blood vessel coordinates. By applying the correct phase delay between the elements, the acoustic wave energy at the focus can be maximized, the Doppler signal intensity can be enhanced, and thus a high-resolution ultrasonic imaging result can be obtained.

[0059] Based on the same inventive concept, the present application also provides an ultrasonic image correction device for a flexible ultrasonic probe. It should be noted that the device exemplified below is an example of the device corresponding to the above method embodiment, and in other device embodiments, the function of the unit modules and the setting of the number of modules can be set accordingly according to the foregoing method embodiments.

[0060] As Figure 3 shown, the ultrasonic image correction device includes: an original RF signal acquisition module 1: based on the signal transceiver mode of single transmit and multiple receive, N elements of the probe are sequentially used as transmitting elements to transmit pulsed acoustic waves, and all elements simultaneously receive echo signals to obtain the original RF signal S(m,n,t), where m is the transmission event, n is the receiving channel, and t is the number of fast time points; a correlation calculation module 2: used to calculate the correlation between channel signals according to the original RF signal; a loss function construction module 3: used to construct a loss function according to the correlation, and the loss function includes a channel signal correlation term, an element spacing constraint term, and an image entropy constraint term; an element true position estimation module 4: used to estimate the true position of the element by gradient descent iteration calculation; an ultrasonic image reconstruction module 5: used to reconstruct an ultrasonic image according to the estimated true position of the element.

[0061] Compared with the prior art in the embodiments of the present application, the element true position estimation module 4 can make the element position infinitely close to the true position of the element by evaluating the element position, can correct the time delay calculation error caused by the deformation of the probe, and avoid image blurring or distortion, so that the ultrasonic image reconstruction module 5 can reconstruct an accurate ultrasonic image according to the estimated true position of the element. Each functional module is implemented based on pure software, without relying on external sensors or devices, has low requirements for the manufacturing process of the flexible probe, and reduces the correction cost. The element true position estimation module can realize the self-calibration of the element position based on the extraction of echo signal features, can adopt a flexible strategy to update the element position parameters regularly, can realize the real-time tracking of the element parameters, realize continuous adaptive calibration, and avoid manual intervention. This device does not need to establish a large database to train the prediction model, but optimizes according to the current data, can cope with different human tissues, adapt to different individual differences, and has high compatibility.

[0062] In an alternative embodiment, as Figure 4 shown, the ultrasonic image reconstruction module 5 includes: The time-of-flight calculation module 51 is configured to calculate the time of flight of sound waves from the actual position of the transmitting element to the actual position of the receiving element for a point r(X,Z) in the imaging region. The formula for calculating the time of flight is as follows:

[0063] Where is the distance from the actual position of the transmitting element to the point r, is the distance from the point r to the actual position of the receiving element, and c is the speed of sound; The ultrasonic image reconstruction sub-module 52 is configured to perform delay superposition on the signals of each channel based on the time of flight according to the following formula to obtain the reconstructed image information: .

[0064] The embodiment of the present application provides a specific implementation manner of ultrasonic image reconstruction. The ultrasonic image reconstruction module 5 performs ultrasonic image reconstruction based on the estimated actual position of the element, effectively correcting the delay calculation error caused by the deformation of the element position, thereby reconstructing an accurate ultrasonic image.

[0065] In another optional embodiment, as Figure 5 shown, the ultrasonic image correction device further includes: The transmit delay calculation module 6: configured to calculate the transmit delay of the signals of each channel based on the estimated actual position of the element; The focused transmit module 7: configured to perform focused transmission on the elements according to the transmit delay and collect Doppler blood flow signals to achieve beam focusing.

[0066] In this embodiment, the transmit delay calculation module 6 calculates the delay based on the optimized element position and blood vessel coordinates. By applying the correct phase delay between the elements through the focused transmit module 7, the acoustic energy at the focus can be maximized, the Doppler signal intensity can be enhanced, and thus a high-resolution ultrasonic imaging result can be obtained.

[0067] The embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the ultrasonic image correction method described in any one of the embodiments of the present application are implemented.

[0068] It should be noted that the computer storage medium may include, but is not limited to: portable disks, hard disks, random access memories, read-only memories, erasable programmable read-only memories, optical storage devices, magnetic storage devices, or any suitable combination of the above. In a possible implementation manner, the present invention may also provide a form of implementing data processing as a program product, which includes program code. When the program product runs on a terminal device, the program code is used to cause the terminal device to execute several steps in the method described in any one of the foregoing embodiments. The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0069] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

[0070] Those of ordinary skill in the art can understand that the above-described embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made in form and details without departing from the spirit and scope of the present invention.

Claims

1. An ultrasonic image correction method for a flexible ultrasonic probe, characterized in that, Comprising: Based on the signal transceiver mode of single transmit and multiple receive, N array elements of the probe are sequentially used as transmit array elements to transmit pulsed acoustic waves, and all array elements simultaneously receive echo signals to obtain the original radio frequency signal S(m, n, t), where m is the transmit event, n is the receive channel, and t is the number of fast time points; Calculating the correlation between channel signals according to the original radio frequency signal; Constructing a loss function according to the correlation, the loss function including a channel signal correlation term, an array element spacing constraint term, and an image entropy constraint term; Estimating the true positions of the array elements by gradient descent iteration calculation; Performing ultrasonic image reconstruction according to the estimated true positions of the array elements.

2. The ultrasonic image correction method according to claim 1, characterized in that, The calculation formula for the correlation between the channel signals is: Among them, S(*) is the received original RF signal, is the delay value of each channel signal calculated according to the spatial geometry.

3. The ultrasonic image correction method according to claim 2, wherein The loss function is: wherein is the array element spacing constraint coefficient, is the image entropy constraint coefficient, is the array element position, is the entropy value of the original ultrasonic image constructed according to the original positions of the array elements.

4. The ultrasonic image correction method according to claim 3, characterized in that The estimating the true positions of the array elements by gradient descent iteration calculation includes: Using an Adam optimizer for iterative update optimization, and the iterative update formula is: wherein is the array element position parameter, is the learning rate, is the array element position parameter after iterative update.

5. The ultrasonic image correction method according to claim 1, characterized in that, The performing ultrasonic image reconstruction according to the estimated true positions of the array elements includes: For a point r(X, Z) in the imaging region, calculating the flight time of the acoustic wave from the true position of the transmit array element to the true position of the receive array element, and the flight time calculation formula is: wherein is the distance from the actual position of the transmitting array element to point r, is the distance from point r to the actual position of the receiving array element, and c is the speed of sound; Based on the time of flight, according to the formula delay and superimpose the signals of each channel to obtain the reconstructed image information.

6. The ultrasonic image correction method according to claim 1, wherein The method further includes: Based on the estimated true positions of the array elements, calculating the transmit delays of each channel signal; Performing focused transmission on the array elements according to the transmit delays, and collecting Doppler blood flow signals to achieve beam focusing.

7. An ultrasonic image correction device for a flexible ultrasonic probe, which is applied to the ultrasonic image correction method described in any one of claims 1-6, characterized in that, Comprising: An original radio frequency signal acquisition module: Based on the signal transceiver mode of single transmit and multiple receive, N array elements of the probe are sequentially used as transmit array elements to transmit pulsed acoustic waves, and all array elements simultaneously receive echo signals to obtain the original radio frequency signal S(m, n, t), where m is the transmit event, n is the receive channel, and t is the number of fast time points; A correlation calculation module: Used for calculating the correlation between channel signals according to the original radio frequency signal; A loss function construction module: Used for constructing a loss function according to the correlation, the loss function including a channel signal correlation term, an array element spacing constraint term, and an image entropy constraint term; An array element true position estimation module: Used for estimating the true positions of the array elements by gradient descent iteration calculation; An ultrasonic image reconstruction module: Used for performing ultrasonic image reconstruction according to the estimated true positions of the array elements.

8. The ultrasonic image correction device according to claim 7, characterized in that, The ultrasonic image reconstruction module includes: A flight time calculation module: For a point r(X, Z) in the imaging region, calculating the flight time of the acoustic wave from the true position of the transmit array element to the true position of the receive array element, and the flight time calculation formula is: where is the distance from the true position of the transmitting array element to point r, is the distance from point r to the true position of the receiving array element, and c is the speed of sound; An ultrasonic image reconstruction sub-module: Based on the flight time according to the formula: Performing delay superposition on each channel signal to obtain the reconstructed image information.

9. The ultrasonic image correction device according to claim 7, wherein The ultrasonic image correction device further includes: A transmit delay calculation module: Used for calculating the transmit delays of each channel signal based on the estimated true positions of the array elements; A focused transmission module: Used for performing focused transmission on the array elements according to the transmit delays, and collecting Doppler blood flow signals to achieve beam focusing.

10. A computer-readable storage medium, on which a computer program is stored, characterized in that When the computer program is executed by a processor, it implements the steps of the ultrasonic image correction method according to any one of claims 1 to 6.

Images