Pulse excitation signal generation method and system of multi-frequency transducer, equipment and medium

Abstract

The invention provides a pulse excitation signal generation method and system of a multi-frequency transducer, equipment and a medium. The method comprises the following steps: acquiring a working center frequency and an excitation signal type of the multi-frequency transducer; calculating the pulse width through the center frequency and the excitation signal type; generating a pulse excitation signal according to the excitation signal type, the pulse width, the pulse excitation voltage and the repetition frequency; and processing the collected original analog echo signal to obtain corresponding high and low frequency echo data. The pulse excitation waveform generated by adopting the scheme of the invention can efficiently excite the transducer to perform multi-band ultrasonic emission, so that high-frequency ultrasound and low-frequency ultrasound are simultaneously emitted, and the imaging depth and the imaging resolution are improved, thereby obtaining better imaging quality. In the invention, a pulse generation mode is simple and can be realized, a hardware module circuit can be compatible with excitation and imaging of traditional single-frequency ultrasound without changing or slightly changing, and the method has good economic value and practicability.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic transducer excitation systems, and in particular to a method and system, equipment and medium for generating pulse excitation signals of a multi-frequency transducer. Background Art

[0002] Ultrasonic transducers play a vital role in biomedical imaging systems. Among them, high-frequency transducers can provide higher resolution, but their penetration depth is shallow; low-frequency transducers have a larger penetration depth, but their resolution is lower. Most current ultrasound transducers only work in a single frequency band, and when more information is needed, the ultrasound probe usually needs to be replaced. In interventional ultrasound (such as intravascular ultrasound IVUS and endobronchial ultrasound EBUS), replacing the ultrasound probe may prolong the operation time and increase the risk, while also causing additional pain to the patient. Therefore, the inherent contradiction between the imaging depth and resolution of traditional single-frequency ultrasound transducers limits the further improvement of ultrasound image quality. To this end, researchers have developed multi-frequency ultrasound transducers, which combine the high resolution of high-frequency ultrasound with the deep penetration ability of low-frequency ultrasound, thereby achieving higher imaging quality. At present, multi-frequency transducers are mainly divided into two categories:

[0003] 1. Spatial combination type: This type of multi-frequency transducer is realized by combining two or more single-frequency transducers in space. For example, K. Kirk Shung's team used two single-frequency transducers of 30MHz and 90MHz in a back-to-back manner to achieve intravascular multi-frequency ultrasound imaging and provide more comprehensive vascular structure information. Although the spatial combination transducer has a mature process and a simple design, it is large in size and has high requirements on the relative position of the transducers, otherwise it may cause deviation and distortion of image fusion.

[0004] 2. Single-element type: This type of transducer develops different resonant frequencies on a single element to achieve dual-frequency or multi-frequency capabilities. For example, Jong Seob Jeong's team achieved dual-frequency ultrasound through the fundamental and harmonic modes of the transducer. Single-element transducers are small in size and there is no position deviation during imaging, so they are particularly suitable for applications with strict size requirements, such as interventional ultrasound imaging. However, since a single transducer integrates multiple operating frequencies, its impedance and excitation method are different from traditional transducers, so further research and development of its driving method is needed.

[0005] In terms of transducer excitation, two main types of high-voltage pulse waveforms are currently used: sharp pulses and square wave pulses. Sharp pulses have a wide spectrum coverage range and can effectively excite transducers of different frequencies. They are suitable for single-frequency and multi-frequency transducers. However, since the pulse energy of the sharp pulse is dispersed and cannot be tuned to the resonance point, its power utilization rate is low, which reduces the sensitivity of the transducer and the image signal-to-noise ratio. The square wave pulse achieves tuning by adjusting the pulse width to ensure that the excitation signal frequency matches the resonant frequency of the transducer, thereby more effectively transferring the transmission energy to the transducer. Compared with the sharp pulse, the square wave pulse excitation can significantly improve the sensitivity of the transducer, thereby improving the image quality. Therefore, the square wave pulse is widely used in medical and industrial ultrasound equipment.

[0006] At present, for pulse excitation of single-element dual-frequency transducers, the existing technology uses sharp pulse excitation, and does not use other pulses such as square wave pulses with higher efficiency. This is mainly because traditional square wave pulses and other pulses are adjusted for a single resonance point, which limits their application in dual-frequency transducers. Therefore, the present invention further studies and designs the excitation pulses of multi-frequency transducers to improve the sensitivity and imaging quality of multi-frequency transducers. Summary of the invention

[0007] In order to achieve the above-mentioned purpose and other advantages of the present invention, the first purpose of the present invention is to provide a method for generating a pulse excitation signal of a multi-frequency transducer, comprising the following steps:

[0008] Obtain the working center frequency and excitation signal type of the multi-frequency transducer;

[0009] Calculate the pulse width by the center frequency and the excitation signal type;

[0010] Generate a pulse excitation signal by using the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency;

[0011] The collected original analog echo signal is processed to obtain the corresponding high and low frequency echo data.

[0012] Further, obtaining the working center frequency of the multi-frequency transducer includes:

[0013] Acquiring impedance characteristic data of the multi-frequency transducer;

[0014] Finding a series resonance point and a parallel resonance point from the impedance characteristic data;

[0015] The frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer are calculated through the series resonance point and the parallel resonance point.

[0016] Further, obtaining the working center frequency of the multi-frequency transducer includes:

[0017] Acquiring sound field data of the multi-frequency transducer;

[0018] Processing the sound field data to obtain frequency spectrum information;

[0019] The frequency corresponding to the highest point of the frequency spectrum is processed to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

[0020] Further, obtaining the working center frequency of the multi-frequency transducer includes:

[0021] Acquiring original echo data reflected by the multi-frequency transducer stimulated by a sharp pulse;

[0022] Processing the original echo data to obtain echo spectrum information;

[0023] The frequency corresponding to the highest point of the frequency spectrum is processed to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

[0024] Furthermore, the excitation signal types include half-cycle square wave signal, half-cycle sine wave signal, full-cycle square wave signal, and full-cycle sine wave signal.

[0025] Further, the step of generating a pulse excitation signal by using the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency includes:

[0026] Input the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency into a driving generator to generate a logic level of a specific timing;

[0027] The logic level is input into the MOS driver to drive the MOS pair tube to achieve the generation of high-speed high-voltage pulses.

[0028] Furthermore, the step of processing the collected original analog echo signal to obtain corresponding high-frequency and low-frequency echo data includes:

[0029] Amplifying and converting the collected original analog echo signal into digital form to obtain echo data;

[0030] High and low frequency echo signals are separated from the echo data.

[0031] Furthermore, the high and low frequency echo signals are imaged separately to form a low frequency image and a high frequency image; or, the high and low frequency echo signals are processed by a fusion algorithm to form a fused image.

[0032] The second object of the present invention is to provide a pulse excitation signal generating system for a multi-frequency transducer, which implements the above method and includes a host computer, a multi-frequency excitation circuit module, an echo receiving circuit, and a data processing module; wherein,

[0033] The host computer is used to obtain the working center frequency and excitation signal type of the multi-frequency transducer, calculate the pulse width according to the center frequency and the excitation signal type, and transmit the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency to the multi-frequency excitation circuit module;

[0034] The multi-frequency excitation circuit module is used to generate a pulse excitation signal according to the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency;

[0035] The echo receiving circuit is used to collect the original analog echo signal, and process the original analog echo signal to obtain echo data and transmit it to the data processing module;

[0036] The data processing module is used to process the echo data to obtain corresponding high-frequency and low-frequency echo data.

[0037] Furthermore, the multi-frequency excitation circuit module includes a drive generator, a MOS driver, and a MOS pair of transistors; wherein,

[0038] The host computer inputs the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency into the drive generator to generate a logic level of a specific timing and output it to the MOS driver;

[0039] The MOS driver drives the MOS pair tube according to the logic level to achieve the generation of high-speed high-voltage pulses.

[0040] Furthermore, the echo receiving circuit includes a low noise amplifier, an analog-to-digital converter, and a data transmission module; wherein,

[0041] The low noise amplifier is used to amplify the original analog echo signal;

[0042] The analog-to-digital converter is used to perform analog-to-digital conversion on the amplified echo signal to obtain echo data;

[0043] The data transmission module is used to transmit the echo data to the data processing module.

[0044] Furthermore, the data processing module includes a first digital filter and a second digital filter, the first digital filter is used to filter the echo data to obtain low-frequency echo data, and the second digital filter is used to filter the echo data to obtain high-frequency echo data.

[0045] The third object of the present invention is to provide an electronic device, comprising: a memory on which a program code is stored; a processor, which is connected to the memory and implements the above method when the program code is executed by the processor.

[0046] A fourth object of the present invention is to provide a computer-readable storage medium having program instructions stored thereon, wherein the program instructions implement the above method when executed.

[0047] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0048] The present invention provides a pulse excitation signal generation method and system, device, and medium for a multi-frequency transducer. The pulse excitation waveform generated by the scheme of the present invention can efficiently excite the transducer to transmit multi-band ultrasound, achieve simultaneous emission of high-frequency ultrasound and low-frequency ultrasound, and simultaneously improve imaging depth and imaging resolution, thereby obtaining better imaging quality. In the present invention, the pulse generation method is simple and achievable, and the hardware module circuit can be compatible with the excitation and imaging of traditional single-frequency ultrasound without change or with a small amount of change, and has good economic value and practicality.

[0049] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0051] Figure 1 A flow chart of a method for generating a pulse excitation signal for a multi-frequency transducer;

[0052] Figure 2 Process for obtaining the center frequency of a multi-frequency transducer Figure 1 ;

[0053] Figure 3 Process for obtaining the center frequency of a multi-frequency transducer Figure 2 ;

[0054] Figure 4 Generate a flow chart for a pulse excitation signal;

[0055] Figure 5 is the original analog echo signal processing flow chart;

[0056] Figure 6 It is a schematic diagram of the impedance characteristic data of the transducer;

[0057] Figure 7 is a flow chart of transducer sound field data processing;

[0058] Figure 8 It is a schematic diagram of a half-period square wave pulse signal;

[0059] Fig. 9 It is a schematic diagram of a full-cycle square wave pulse signal;

[0060] Fig.10 It is a schematic diagram of a pulse excitation signal generation system for a multi-frequency transducer;

[0061] Fig.11 Output timing for multiple drive generator pins Figure 1 ;

[0062] Fig.12 Output timing for multiple drive generator pins Figure 2 ;

[0063] Fig.13 It is a schematic diagram of echo data;

[0064] Fig.14 is a schematic diagram of an electronic device;

[0065] Fig.15 Schematic diagram of an electronic device. DETAILED DESCRIPTION

[0066] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. It should be noted that, under the premise of no conflict, the embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0067] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0068] The figure numbers in this application are only used to distinguish the various steps in the scheme, and are not used to limit the execution order of the various steps. The specific execution order is subject to the description in the specification.

[0069] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0070] Example 1

[0071] A method for generating a pulse excitation signal for a multi-frequency transducer, such as Figure 1 As shown, the following steps are included:

[0072] S1. Obtain the working center frequency and excitation signal type of the multi-frequency transducer;

[0073] Taking a dual-frequency ultrasonic transducer as an example, the dual-frequency ultrasonic transducer should have two working center frequency points, namely Fc1 and Fc2, wherein Fc1 is a low frequency and Fc2 is a high frequency.

[0074] In some embodiments, the center frequency of the multi-frequency transducer is provided by the transducer manufacturer.

[0075] In other embodiments, the working center frequency of the multi-frequency transducer can be obtained by using the impedance characteristic data of the multi-frequency transducer. Figure 2 As shown, obtaining the working center frequency of the multi-frequency transducer includes:

[0076] S100, obtaining impedance characteristic data of the multi-frequency transducer;

[0077] Optionally, an impedance analyzer may be used to measure impedance characteristic data of the multi-frequency transducer to obtain the operating center frequency of the multi-frequency transducer.

[0078] S101, searching for a series resonance point and a parallel resonance point from the impedance characteristic data;

[0079] S102: Calculate the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer through the series resonance point and the parallel resonance point.

[0080] like Figure 6 As shown, the first series resonance point Fs1 and the first parallel resonance point Fp1 of the multi-frequency transducer are found from the impedance characteristic data, and the low frequency frequency Fc1 = (Fs1 + Fp1) / 2; similarly, the second series resonance point Fs2 and the second parallel resonance point Fp2 are found, and the high frequency frequency Fc2 = (Fs2 + Fp2) / 2, thereby determining the frequency center points of the low and high frequency bands of the transducer.

[0081] In some other embodiments, the operating center frequency of the multi-frequency transducer can be obtained by measuring the sound field of the dual-frequency transducer. Figure 3 As shown, obtaining the working center frequency of the multi-frequency transducer includes:

[0082] S110, acquiring sound field data of the multi-frequency transducer;

[0083] S111, processing the sound field data to obtain spectrum information;

[0084] S112, processing the frequency corresponding to the highest point of the frequency spectrum to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

[0085] Optionally, a hydrophone can be used to measure the sound field of the dual-frequency transducer. Specifically, the hydrophone is moved to the strongest point of the sound field, the waveform received by the hydrophone is collected, and then processed. The processing method is as follows: Figure 7 As shown, the collected waveform data is subjected to fast Fourier transform (FFT) to obtain the spectrum information of the waveform, and the two points with the highest frequency in the spectrum corresponding to frequencies F1 and F2 are found. F1 is moved down by 6dB to obtain f1 and f2. The first frequency center point Fc1 = (f1 + f2) / 2. Similarly, the spectrum point F2 is moved down by 6dB to obtain f3 and f4. The second frequency center point Fc2 = (f3 + f4) / 2, thereby determining the frequency center points of the low and high frequency bands of the transducer.

[0086] In some optional embodiments, an ultrasonic pulse reflection method may be used to obtain echoes to obtain the working center frequency of the multi-frequency transducer. Specifically, obtaining the working center frequency of the multi-frequency transducer includes:

[0087] Acquiring original echo data reflected by the multi-frequency transducer stimulated by a sharp pulse;

[0088] Processing the original echo data to obtain echo spectrum information;

[0089] The frequency corresponding to the highest point of the frequency spectrum is processed to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

[0090] Optionally, use a sharp pulse excitation device to excite the dual-frequency transducer, obtain the original echo reflected back, process the echo data, obtain the echo spectrum information, and find the two points Fh1 and Fh2 with the highest spectrum. Move Fh1 down by 6dB to obtain f1 and f2, and the first frequency center point Fc1 = (f1 + f2) / 2. Similarly, move the spectrum point Fh2 down by 6dB to obtain f3 and f4, and the second frequency center point Fc2 = (f3 + f4) / 2, thereby determining the frequency center points of the low and high frequency bands of the transducer.

[0091] S2, calculating the pulse width according to the center frequency and the excitation signal type;

[0092] Optionally, the excitation signal types include a half-cycle square wave signal, a half-cycle sine wave signal, a full-cycle square wave signal, and a full-cycle sine wave signal.

[0093] The pulse width calculation is performed after determining whether the excitation pulse P uses a half-cycle square wave or a full-cycle square wave.

[0094] Specifically, the pulse width T is calculated as follows: T=1 / 2*Fc.

[0095] If a half-cycle square wave pulse is used, the following can be used: Figure 8 The two pulses shown in (a) and (b) are as follows: Tc1 = 1 / 2*Fc1, Tc2 = 1 / 2*Fc2.

[0096] If a full-cycle square wave pulse is used, the following can be used: Fig. 9 The two pulses shown in (a) and (b) are shown in FIG. 1 , where Tc2 = 1 / 2*Fc2 and Tc1 = 1 / 2*Fc1.

[0097] The voltage of the pulse excitation includes positive and negative voltages, the maximum value of the positive voltage V1 ranges from 10 to 400 V, preferably 60 to 100 V, and the maximum value of the negative voltage V2 ranges from -10 to -400 V, preferably -60 to -100 V. The maximum values ​​of the positive and negative voltages preferably have the same amplitude, and the amplitudes may also be different, depending on the requirements.

[0098] The pulse repetition frequency (PRF) of the excitation depends on the imaging depth and frame rate and is set according to requirements.

[0099] S3, generating a pulse excitation signal according to the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency;

[0100] In some embodiments, Figure 4 As shown, the step of generating a pulse excitation signal by using the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency includes:

[0101] S31, inputting the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency into a driving generator to generate a logic level of a specific timing;

[0102] Alternatively, if Fig.10 As shown, the host computer inputs the excitation signal P, pulse width Tc1, Tc2, pulse excitation voltage V1, V2 and repetition frequency PRF parameters into the lower computer through the protocol, and the lower computer drives the generator to generate a specific I / O pin logic level. The lower computer drive generator can be implemented using FPGA, DSP, single-chip microcomputer and other programming. Due to the strict timing requirements between pins, FPGA is preferably used as the lower computer drive generator.

[0103] S32, inputting the logic level into the MOS driver to drive the MOS pair tube to achieve the generation of high-speed high-voltage pulses.

[0104] Specifically, the drive generator I / O outputs a specific timing logic level to the MOSFET gate driver. The drive generator pin output timing is as follows Fig.11 and Fig.12 shown. Fig.11 The logical sequence of (a) corresponds to Figure 8 The pulse in (a) is Fig.11 The logical sequence of (b) corresponds to Figure 8 The pulse in (b); Fig.12 The logical sequence of (a) corresponds to Fig. 9 The pulse in (a) is Fig.12 (b) Logical timing correspondence Fig. 9 The logic voltage is usually 1.8V, 2.5V or 3.3V. The MOSFET driver output is used to drive high-voltage P-channel and N-channel MOSFET transistors, and its output voltage is usually 5V, 10V, 12V. The MOSFET transistor uses an N / P-channel enhancement mode dual MOSFET pair to achieve high-speed high-voltage pulse generation.

[0105] S4. Process the collected original analog echo signal to obtain corresponding high-frequency and low-frequency echo data.

[0106] In some embodiments, Figure 5 , Fig.10 As shown, the steps of processing the collected original analog echo signal to obtain corresponding high and low frequency echo data include:

[0107] S41, amplifying and converting the collected original analog echo signal into analog-to-digital signals to obtain echo data;

[0108] S42, separating high-frequency and low-frequency echo signals from the echo data.

[0109] Specifically, the echo data needs to be processed to separate the low-frequency and high-frequency signals. First, the high and low-frequency echo signals are separated by two digital filters Fi l t1 and Fi l t2. The filter Fi l t1 can be a low-pass filter or a band-pass filter, and its high cut-off frequency cannot be greater than Fc2; the filter Fi l t2 can be a high-pass filter or a band-pass filter, and its low cut-off frequency cannot be less than Fc1. Since the transducer bandwidth is limited and generally does not exceed 100%, a band-pass filter can usually be used. When Fi lt1 uses a band-pass filter, the passband frequency is usually 1 / 2Fc1-3 / 2Fc1, and when Fi lt2 uses a band-pass filter, the passband frequency is usually 1 / 2Fc2-3 / 2Fc2. If the transducer bandwidth is wide, the range of the frequency band passing can also be adjusted according to demand. The data after filtering by Fi l t1 is a low-frequency echo, and the data after filtering by Fi l t2 is a high-frequency echo. The echo data can be imaged separately, that is, forming a low-frequency image and a high-frequency image, or it can be processed by a fusion algorithm to form a fused image. This method can achieve simultaneous acquisition of high- and low-frequency images with a single excitation without reducing the image frame rate.

[0110] In one embodiment, the above method is implemented by taking a dual-frequency micro-transducer as an example, and the waveform generated by the method of the present invention is compared with the relative sensitivity of the transducer under other pulse excitations to verify the advantages of the waveform generated by the method of the present invention:

[0111] Transducer relative sensitivity calculation formula: Srel = 20log 10 (Vc / Vp).

[0112] Where Vc is the peak-to-peak value of the received echo, and Vp is the peak voltage of the excitation pulse.

[0113] Specifically, the pulse excitation signal generation process of the dual-frequency micro-transducer is as follows:

[0114] The impedance characteristic data of the transducer was measured using an impedance analyzer, and after calculation, Fc1 and Fc2 were found to be 2.5MHz and 10MH respectively.

[0115] Calculate the pulse width based on the determined center frequency. Select a full-cycle square wave pulse for excitation, and select Fig. 9 In (a), the waveform used as the excitation is used, the pulse width is calculated to be Tc1=200ns, Tc2=50ns, and PRF=1kHz is set.

[0116] Substitute this value into the host computer and set the pulse shape to achieve the generation of ultrasonic excitation waveform.

[0117] The pulse echo method was used to measure the relative sensitivity of the transducer. The collected echo signals were respectively subjected to two band-pass filters. The Filter 1 filter was set to a band-pass filter of 0.5-5 MHZ, and the Filter 2 filter was set to a band-pass filter of 6-14 MHZ to obtain the corresponding high and low frequency echo data.

[0118] In order to verify the advantages of the square wave pulse excitation signal generated by the method provided by the present invention, a comparison test was conducted between it and the traditional sharp pulse. The pulse echo method was used for testing. The original echo was collected and filtered to obtain the corresponding low-frequency echo data and high-frequency echo data. Fig.13 The echo amplitude and relative sensitivity results are shown in Table 1. The test results show that the generated square wave pulse can effectively improve the sensitivity of the two frequency bands of the dual-frequency transducer, and also verify its potential as an effective excitation method for the dual-frequency transducer, providing a good signal-to-noise ratio for subsequent dual-frequency images and fused images.

[0119] Table 1 Comparison of transducer dual-band sensitivity and echo amplitude under different pulses

[0120]

[0121] The above embodiment uses a dual-frequency ultrasonic transducer as an example to illustrate the scheme for generating a transducer pulse excitation signal. This method can also conveniently introduce a single-element three-frequency or higher transducer pulse excitation signal generation scheme, thereby achieving three-frequency or higher simultaneous imaging and image fusion.

[0122] This embodiment further studies and designs the square wave excitation pulse of the multi-frequency transducer to improve the sensitivity and imaging quality of the multi-frequency transducer. This embodiment can make changes and add functions to the traditional single-frequency imaging system. On the basis of not changing or making little changes to the existing hardware, the designed waveform generation is achieved mainly by changing the driving mode in the software, which has good economy and practicality.

[0123] Example 2

[0124] A pulse excitation signal generating system for a multi-frequency transducer implements the above method. For a detailed description of the method, please refer to the corresponding description in the above method embodiment, which will not be repeated here. Fig.10 As shown, the system includes a host computer, a multi-frequency excitation circuit module, an echo receiving circuit, and a data processing module; wherein,

[0125] The host computer is used to obtain the working center frequency and excitation signal type of the multi-frequency transducer, calculate the pulse width according to the center frequency and the excitation signal type, and transmit the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency to the multi-frequency excitation circuit module;

[0126] Taking a dual-frequency ultrasonic transducer as an example, the dual-frequency ultrasonic transducer should have two working center frequency points, namely Fc1 and Fc2, wherein Fc1 is a low frequency and Fc2 is a high frequency.

[0127] In some embodiments, the center frequency of the multi-frequency transducer is provided by the transducer manufacturer.

[0128] In other embodiments, the working center frequency of the multi-frequency transducer can be obtained by using the impedance characteristic data of the multi-frequency transducer. Figure 2 As shown, obtaining the working center frequency of the multi-frequency transducer includes:

[0129] S100, obtaining impedance characteristic data of the multi-frequency transducer;

[0130] Optionally, an impedance analyzer may be used to measure impedance characteristic data of the multi-frequency transducer to obtain the operating center frequency of the multi-frequency transducer.

[0131] S101, searching for a series resonance point and a parallel resonance point from the impedance characteristic data;

[0132] S102: Calculate the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer through the series resonance point and the parallel resonance point.

[0133] like Figure 6 As shown, the first series resonance point Fs1 and the first parallel resonance point Fp1 of the multi-frequency transducer are found from the impedance characteristic data, and the low frequency frequency Fc1 = (Fs1 + Fp1) / 2; similarly, the second series resonance point Fs2 and the second parallel resonance point Fp2 are found, and the high frequency frequency Fc2 = (Fs2 + Fp2) / 2, thereby determining the frequency center points of the low and high frequency bands of the transducer.

[0134] In some other embodiments, the operating center frequency of the multi-frequency transducer can be obtained by measuring the sound field of the dual-frequency transducer. Figure 3 As shown, obtaining the working center frequency of the multi-frequency transducer includes:

[0135] S110, acquiring sound field data of the multi-frequency transducer;

[0136] S111, processing the sound field data to obtain spectrum information;

[0137] S112, processing the frequency corresponding to the highest point of the frequency spectrum to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

[0138] Optionally, a hydrophone can be used to measure the sound field of the dual-frequency transducer. Specifically, the hydrophone is moved to the strongest point of the sound field, the waveform received by the hydrophone is collected, and then processed. The processing method is as follows: Figure 7 As shown, the collected waveform data is subjected to fast Fourier transform (FFT) to obtain the spectrum information of the waveform, and the two points with the highest frequency in the spectrum corresponding to frequencies F1 and F2 are found. F1 is moved down by 6dB to obtain f1 and f2. The first frequency center point Fc1 = (f1 + f2) / 2. Similarly, the spectrum point F2 is moved down by 6dB to obtain f3 and f4. The second frequency center point Fc2 = (f3 + f4) / 2, thereby determining the frequency center points of the low and high frequency bands of the transducer.

[0139] In some optional embodiments, an ultrasonic pulse reflection method may be used to obtain echoes to obtain the working center frequency of the multi-frequency transducer. Specifically, obtaining the working center frequency of the multi-frequency transducer includes:

[0140] Acquiring original echo data reflected by the multi-frequency transducer stimulated by a sharp pulse;

[0141] Processing the original echo data to obtain echo spectrum information;

[0142] The frequency corresponding to the highest point of the frequency spectrum is processed to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

[0143] Optionally, use a sharp pulse excitation device to excite the dual-frequency transducer, obtain the original echo reflected back, process the echo data, obtain the echo spectrum information, and find the two points Fh1 and Fh2 with the highest spectrum. Move Fh1 down by 6dB to obtain f1 and f2, and the first frequency center point Fc1 = (f1 + f2) / 2. Similarly, move the spectrum point Fh2 down by 6dB to obtain f3 and f4, and the second frequency center point Fc2 = (f3 + f4) / 2, thereby determining the frequency center points of the low and high frequency bands of the transducer.

[0144] S2, calculating the pulse width according to the center frequency and the excitation signal type;

[0145] Optionally, the excitation signal types include a half-cycle square wave signal, a half-cycle sine wave signal, a full-cycle square wave signal, and a full-cycle sine wave signal.

[0146] The pulse width calculation is performed after determining whether the excitation pulse P uses a half-cycle square wave or a full-cycle square wave.

[0147] Specifically, the pulse width T is calculated as follows: T=1 / 2*Fc.

[0148] If a half-cycle square wave pulse is used, the following can be used: Figure 8 The two pulses shown in (a) and (b) are as follows: Tc1 = 1 / 2*Fc1, Tc2 = 1 / 2*Fc2.

[0149] If a full-cycle square wave pulse is used, the following can be used: Fig. 9 The two pulses shown in (a) and (b) are shown in FIG. 1 , where Tc2 = 1 / 2*Fc2 and Tc1 = 1 / 2*Fc1.

[0150] The voltage of the pulse excitation includes positive and negative voltages, the maximum value of the positive voltage V1 ranges from 10 to 400 V, preferably 60 to 100 V, and the maximum value of the negative voltage V2 ranges from -10 to -400 V, preferably -60 to -100 V. The maximum values ​​of the positive and negative voltages preferably have the same amplitude, and the amplitudes may also be different, depending on the requirements.

[0151] The pulse repetition frequency (PRF) of the excitation depends on the imaging depth and frame rate and is set according to requirements.

[0152] The multi-frequency excitation circuit module is used to generate a pulse excitation signal according to the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency;

[0153] In some embodiments, the multi-frequency excitation circuit module includes a drive generator, a MOS driver, and a MOS pair of transistors; wherein,

[0154] The host computer inputs the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency into the drive generator to generate a logic level of a specific timing and output it to the MOS driver;

[0155] like Fig.10 As shown, the host computer inputs the excitation signal P, pulse width Tc1, Tc2, pulse excitation voltage V1, V2 and repetition frequency PRF parameters into the lower computer through the protocol, and the lower computer drives the generator to generate a specific I / O pin logic level. The lower computer drive generator can be implemented using FPGA, DSP, single-chip microcomputer and other programming. Due to the strict timing requirements between pins, FPGA is preferably used as the lower computer drive generator.

[0156] The MOS driver drives the MOS pair tube according to the logic level to achieve the generation of high-speed high-voltage pulses.

[0157] Specifically, the drive generator I / O outputs a specific timing logic level to the MOSFET gate driver. The drive generator pin output timing is as follows Fig.11 and Fig.12 shown. Fig.11 The logical sequence of (a) corresponds to Figure 8 The pulse in (a) is Fig.11 The logical sequence of (b) corresponds to Figure 8 The pulse in (b); Fig.12 The logical sequence of (a) corresponds to Fig. 9 The pulse in (a) is Fig.12 (b) Logical timing correspondence Fig. 9 The logic voltage is usually 1.8V, 2.5V or 3.3V. The MOSFET driver output is used to drive high-voltage P-channel and N-channel MOSFET transistors, and its output voltage is usually 5V, 10V, 12V. The MOSFET transistor uses an N / P-channel enhancement mode dual MOSFET pair to achieve high-speed high-voltage pulse generation.

[0158] The echo receiving circuit is used to collect the original analog echo signal, and process the original analog echo signal to obtain echo data and transmit it to the data processing module;

[0159] In some embodiments, the echo receiving circuit includes a low noise amplifier, an analog-to-digital converter, and a data transmission module; wherein,

[0160] The low noise amplifier is used to amplify the original analog echo signal;

[0161] The analog-to-digital converter is used to perform analog-to-digital conversion on the amplified echo signal to obtain echo data;

[0162] The data transmission module is used to transmit the echo data to the data processing module.

[0163] The data processing module is used to process the echo data to obtain corresponding high-frequency and low-frequency echo data.

[0164] In some embodiments, the data processing module includes a first digital filter and a second digital filter, the first digital filter is used to filter the echo data to obtain low-frequency echo data, and the second digital filter is used to filter the echo data to obtain high-frequency echo data.

[0165] Specifically, the echo data needs to be processed to separate the low-frequency and high-frequency signals. First, the high and low-frequency echo signals are separated by two digital filters Fi l t1 and Fi l t2. The filter Fi l t1 can be a low-pass filter or a band-pass filter, and its high cut-off frequency cannot be greater than Fc2; the filter Fi l t2 can be a high filter or a band-pass filter, and its low cut-off frequency cannot be less than Fc1. Since the transducer bandwidth is limited and generally does not exceed 100%, a band-pass filter can usually be used. When Fi l t1 uses a band-pass filter, the passband frequency is usually 1 / 2Fc1-3 / 2Fc1, and when Fi l t2 uses a band-pass filter, the passband frequency is usually 1 / 2Fc2-3 / 2Fc2. If the transducer bandwidth is wide, the range of the frequency band passing can also be adjusted according to demand. The data after filtering by Fi l t1 is a low-frequency echo, and the data after filtering by Fi l t2 is a high-frequency echo. The echo data can be imaged separately, that is, forming a low-frequency image and a high-frequency image, or it can be processed by a fusion algorithm to form a fused image. This method can achieve simultaneous acquisition of high- and low-frequency images with a single excitation without reducing the image frame rate.

[0166] In one embodiment, the above solution is implemented by taking a dual-frequency micro-transducer as an example, and the waveform generated by the solution of the present invention is compared with the relative sensitivity of the transducer under other pulse excitations to verify the advantages of the waveform generated by the solution of the present invention:

[0167] The calculation formula for transducer relative sensitivity is: Sre l=20log10(Vc / Vp).

[0168] Where Vc is the peak-to-peak value of the received echo, and Vp is the peak voltage of the excitation pulse.

[0169] Specifically, the pulse excitation signal generation process of the dual-frequency micro-transducer is as follows:

[0170] The impedance characteristic data of the transducer was measured using an impedance analyzer, and after calculation, Fc1 and Fc2 were found to be 2.5MHz and 10MH respectively.

[0171] Calculate the pulse width based on the determined center frequency. Select a full-cycle square wave pulse for excitation, and select Fig. 9 In (a), the waveform used as the excitation is used, the pulse width is calculated to be Tc1=200ns, Tc2=50ns, and PRF=1kHz is set.

[0172] Substitute this value into the host computer and set the pulse shape to achieve the generation of ultrasonic excitation waveform.

[0173] The pulse echo method was used to measure the relative sensitivity of the transducer. The collected echo signals were respectively subjected to two band-pass filters. The Filter 1 filter was set to a band-pass filter of 0.5-5 MHZ, and the Filter 2 filter was set to a band-pass filter of 6-14 MHZ to obtain the corresponding high and low frequency echo data.

[0174] In order to verify the advantages of the square wave pulse excitation signal generated by the solution provided by the present invention, a comparison test was conducted with the traditional sharp pulse. The pulse echo method was used for testing. The original echo was collected and filtered to obtain the corresponding low-frequency echo data and high-frequency echo data. Fig.13 The echo amplitude and relative sensitivity results are shown in Table 1. The test results show that the generated square wave pulse can effectively improve the sensitivity of the two frequency bands of the dual-frequency transducer, and also verify its potential as an effective excitation method for the dual-frequency transducer, providing a good signal-to-noise ratio for subsequent dual-frequency images and fused images.

[0175] Table 1 Comparison of transducer dual-band sensitivity and echo amplitude under different pulses

[0176]

[0177] The above embodiment uses a dual-frequency ultrasonic transducer as an example to illustrate the scheme for generating a transducer pulse excitation signal. This method can also conveniently introduce a single-element three-frequency or higher transducer pulse excitation signal generation scheme, thereby achieving three-frequency or higher simultaneous imaging and image fusion.

[0178] This embodiment further studies and designs the square wave excitation pulse of the multi-frequency transducer to improve the sensitivity and imaging quality of the multi-frequency transducer. This embodiment can make changes and add functions to the traditional single-frequency imaging system. On the basis of not changing or making little changes to the existing hardware, the designed waveform generation is achieved mainly by changing the driving mode in the software, which has good economy and practicality.

[0179] Example 3

[0180] An electronic device, such as Fig.14 As shown, it includes: a memory on which program codes are stored; a processor connected to the memory, and when the program codes are executed by the processor, a method for generating a pulse excitation signal for a multi-frequency transducer is implemented. For a detailed description of the method, reference may be made to the corresponding description in the above method embodiment, which will not be repeated here.

[0181] Example 4

[0182] A computer readable storage medium such as Fig.15 As shown, program instructions are stored thereon, and when the program instructions are executed, a method for generating a pulse excitation signal for a multi-frequency transducer is implemented. For a detailed description of the method, reference may be made to the corresponding description in the above method embodiment, and no further description is given here.

[0183] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0184] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

[0185] The apparatus, electronic device, non-volatile computer storage medium and method provided in the embodiments of this specification correspond to each other, and therefore, the apparatus, electronic device and non-volatile computer storage medium also have beneficial technical effects similar to those of the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the corresponding apparatus, electronic device and non-volatile computer storage medium will not be repeated here.

[0186] Those skilled in the art also know that, in addition to implementing the controller in a purely computer-readable program code, the controller can be made to implement the same function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, such a controller can be considered as a hardware component, and the devices for implementing various functions included therein can also be considered as structures within the hardware component. Or even, the devices for implementing various functions can be considered as both software units for implementing the method and structures within the hardware component.

[0187] The systems, devices or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described separately by functions in various units. Of course, when implementing one or more embodiments of this specification, the functions of each unit can be implemented in the same or more software and / or hardware.

[0188] Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification may be in the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the embodiments of this specification may be in the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0189] This specification is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of this specification. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0190] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0191] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0192] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0193] The specification may be described in the general context of computer-executable instructions executed by a computer, such as program units. Generally, program units include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communications network. In a distributed computing environment, program units may be located in local and remote computer storage media, including storage devices.

[0194] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0195] The above description is only an embodiment of this specification and is not intended to limit one or more embodiments of this specification. For those skilled in the art, one or more embodiments of this specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of this specification shall be included in the scope of the claims of one or more embodiments of this specification.

Claims

1. A method for generating a pulse excitation signal for a multi-frequency transducer, It is characterized in that The following steps are involved: Obtain the working center frequency and excitation signal type of the multi-frequency transducer; Calculate the pulse width by the center frequency and the excitation signal type; Generate a pulse excitation signal by using the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency; The collected original analog echo signal is processed to obtain the corresponding high and low frequency echo data.

2. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 1, It is characterized in that The obtaining of the working center frequency of the multi-frequency transducer comprises: Acquiring impedance characteristic data of the multi-frequency transducer; Finding a series resonance point and a parallel resonance point from the impedance characteristic data; The frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer are calculated through the series resonance point and the parallel resonance point.

3. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 1, It is characterized in that The obtaining of the working center frequency of the multi-frequency transducer comprises: Acquiring sound field data of the multi-frequency transducer; Processing the sound field data to obtain frequency spectrum information; The frequency corresponding to the highest point of the frequency spectrum is processed to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

4. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 1, It is characterized in that The obtaining of the working center frequency of the multi-frequency transducer comprises: Acquiring original echo data reflected by the multi-frequency transducer stimulated by a sharp pulse; Processing the original echo data to obtain echo spectrum information; The frequency corresponding to the highest point of the frequency spectrum is processed to determine the frequency center points of the low frequency band and the high frequency band of the multi-frequency transducer.

5. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 1, Features: The excitation signal types include half-cycle square wave signal, half-cycle sine wave signal, full-cycle square wave signal, and full-cycle sine wave signal.

6. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 1, It is characterized in that The step of generating a pulse excitation signal by using the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency comprises: Input the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency into a driving generator to generate a logic level of a specific timing; The logic level is input into the MOS driver to drive the MOS pair tube to achieve the generation of high-speed high-voltage pulses.

7. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 1, It is characterized in that The step of processing the collected original analog echo signal to obtain corresponding high-frequency and low-frequency echo data includes: Amplifying and converting the collected original analog echo signal into digital form to obtain echo data; High and low frequency echo signals are separated from the echo data.

8. A method for generating a pulse excitation signal for a multi-frequency transducer as claimed in claim 7, Features: The high and low frequency echo signals are imaged separately to form a low frequency image and a high frequency image; or, the high and low frequency echo signals are processed by a fusion algorithm to form a fused image.

9. A pulse excitation signal generating system for a multi-frequency transducer, implementing the method according to any one of claims 1 to 8, Features: It includes a host computer, a multi-frequency excitation circuit module, an echo receiving circuit, and a data processing module; wherein, The host computer is used to obtain the working center frequency and excitation signal type of the multi-frequency transducer, calculate the pulse width according to the center frequency and the excitation signal type, and transmit the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency to the multi-frequency excitation circuit module; The multi-frequency excitation circuit module is used to generate a pulse excitation signal according to the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency; The echo receiving circuit is used to collect the original analog echo signal, and process the original analog echo signal to obtain echo data and transmit it to the data processing module; The data processing module is used to process the echo data to obtain corresponding high-frequency and low-frequency echo data.

10. A pulse excitation signal generating system for a multi-frequency transducer as claimed in claim 9, Features: The multi-frequency excitation circuit module includes a drive generator, a MOS driver, and a MOS pair of transistors; wherein, The host computer inputs the excitation signal type, the pulse width, the voltage of the pulse excitation and the repetition frequency into the drive generator to generate a logic level of a specific timing and output it to the MOS driver; The MOS driver drives the MOS pair tube according to the logic level to achieve the generation of high-speed high-voltage pulses.

11. A pulse excitation signal generating system for a multi-frequency transducer as claimed in claim 9, Features: The echo receiving circuit includes a low noise amplifier, an analog-to-digital converter, and a data transmission module; wherein, The low noise amplifier is used to amplify the original analog echo signal; The analog-to-digital converter is used to perform analog-to-digital conversion on the amplified echo signal to obtain echo data; The data transmission module is used to transmit the echo data to the data processing module.

12. A pulse excitation signal generating system for a multi-frequency transducer as claimed in claim 9, Features: The data processing module includes a first digital filter and a second digital filter. The first digital filter is used to filter the echo data to obtain low-frequency echo data, and the second digital filter is used to filter the echo data to obtain high-frequency echo data.

13. An electronic device, It is characterized in that include: A memory having program code stored therein; A processor is connected to the memory, and when the program code is executed by the processor, the method according to any one of claims 1 to 8 is implemented.

14. A computer-readable storage medium, It is characterized in that Program instructions are stored thereon, and when the program instructions are executed, the method according to any one of claims 1 to 8 is implemented.

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