A chip-level ultrasound probe CMUT system and its usage method

Abstract

This application provides a chip-level ultrasound probe CMUT system and method, applied in the field of medical ultrasound diagnostic technology. By forming a built-in bias voltage in the CMUT array, extracting multi-dimensional imaging reference parameters, and implementing step-by-step dynamic compensation based on capacitance change parameters and imaging residual parameters, the amplitude and phase of the array excitation signal are precisely adjusted. Furthermore, the sound pressure output and spatial resolution of continuous multi-frame imaging are optimized through spectral suppression, inter-element modulation, and consistency constraint processing, thereby improving the continuity, clarity, and Doppler quantitative accuracy of ultrasound images, and ensuring the stability and clinical applicability of the chip-level ultrasound probe in dynamic tissue environments.

Description

Technical Field

[0001] This application relates to the field of medical ultrasound diagnostic technology, and in particular to a chip-level ultrasound probe CMUT system and its usage method. Background Technology

[0002] With the miniaturization, chip-based development, and digitalization of portable ultrasound diagnostic devices, handheld ultrasound, intracardiac ultrasound, and intravascular ultrasound are increasingly being used in medical scenarios such as emergency medicine, cardiology, obstetrics and gynecology, and intensive care.

[0003] In the process of ultrasound imaging, various examination tasks such as cardiac ultrasound, vascular ultrasound, deep abdominal imaging, and real-time intracatheter detection usually need to simultaneously meet multiple requirements such as high resolution, deep penetration, quantitative blood flow analysis (Doppler imaging), and safety. Among these, image quality, blood flow signal intensity, Doppler spectrum clarity, and long-term stability directly affect diagnostic accuracy and clinical decision-making efficiency.

[0004] However, in actual clinical imaging, due to changes in heart rate, blood flow, and tissue acoustic impedance, capacitive micromechanical ultrasound transducer (CMUT) arrays are prone to dynamic capacitance fluctuations and unstable echo responses during imaging. This leads to fluctuations in emitted sound pressure, increased harmonic interference, and more imaging artifacts, affecting the identification of cardiac chamber structures, the judgment of vascular boundaries, and the clarity of deep tissue imaging. Existing CMUT imaging systems typically rely on external high-voltage bias to maintain the transducer's operating state, resulting in high system power consumption and significant challenges in chip-level integration. Although some systems have attempted to use built-in bias voltage to replace external high voltage to reduce power consumption, in practical applications, once the built-in bias voltage is formed, imaging control is still mainly achieved through fixed drive or single-parameter compensation. Typically, only simple gain correction or local harmonic suppression is performed for capacitance drift, making it difficult to simultaneously suppress capacitance changes and imaging interference during continuous scanning. This results in decreased image quality and reduced Doppler quantitative accuracy during long-term continuous scanning, making it difficult to meet the reliability requirements of real-time clinical diagnosis. Summary of the Invention

[0005] This application provides a chip-level ultrasound transducer (CMUT) system and its usage method. The core of the system is as follows: Before imaging a patient, a preset pulse sequence is input into the insulating layer of the capacitive micromechanical ultrasound transducer (CMUT) to form a built-in bias voltage, replacing the external DC high-voltage bias. After establishing a stable bias, preset probe ultrasound waves are emitted to extract imaging reference parameters and capacitance reference parameters. Based on the imaging reference parameters, the initial excitation signal is reverse-compensated to form an initial imaging excitation signal. During imaging, the echo signal of each frame of imaging ultrasound is converted and analyzed to obtain capacitance change parameters and imaging residual parameters. Based on the deviation between the capacitance change parameters and the capacitance reference parameters, the next frame of imaging excitation signal undergoes a first compensation process, and based on the residual deviation between the imaging residual parameters and the imaging reference parameters, a second compensation process is performed. Simultaneously, the imaging mode is dynamically modulated based on the imaging depth range and tissue attenuation. Stable imaging results are output during continuous scanning, thereby achieving stable imaging and real-time diagnosis of the chip-level CMUT driven by the built-in bias.

[0006] To achieve the above objectives, this application adopts the following technical solution: This application provides a method for using a chip-level ultrasonic probe CMUT, the method comprising: Before the patient undergoes imaging examination, a preset pulse sequence is input into the insulating layer of the capacitive micromechanical ultrasonic transducer (CMUT) to form a built-in bias voltage, which is used to replace the external DC high voltage bias. After the built-in bias voltage is formed, a preset detection ultrasonic wave is emitted. When the echo signal of the preset detection ultrasonic wave is received, the corresponding imaging reference parameters and capacitance reference parameters are extracted. When a patient undergoes imaging detection, the initial excitation signal is reverse-compensated based on the imaging reference parameters to obtain an initial imaging excitation signal, and imaging ultrasound is emitted based on the initial imaging excitation signal. During each frame of the patient imaging detection process, the echo signal of the imaging ultrasound is converted and processed to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame. Based on the deviation between the capacitance change parameter and the capacitance reference parameter, the imaging excitation signal of the next frame is subjected to the first compensation processing to obtain the first imaging excitation signal. Based on the residual deviation between the imaging reference parameters and the imaging residual parameters, the first imaging excitation signal is subjected to a second compensation process to obtain the second imaging excitation signal. Based on the second imaging excitation signal, the next frame of imaging ultrasound is emitted, and the echo signal of the next frame of imaging ultrasound is processed to output the corresponding imaging detection result.

[0007] In some possible implementations, the imaging reference parameters include fundamental response parameters, harmonic reference parameters, and crosstalk reference parameters. After forming the built-in bias voltage, a preset detection ultrasonic wave is emitted. Upon receiving the echo signal of the preset detection ultrasonic wave, the corresponding imaging reference parameters and capacitance reference parameters are extracted, including: After the built-in bias voltage is formed, a preset detection ultrasonic wave is emitted; When receiving the echo signal of the preset detection ultrasonic wave, the echo signal of the preset detection ultrasonic wave is converted and processed to obtain the corresponding echo electrical signal. The echo signal is filtered to obtain the corresponding amplitude response sequence and phase response sequence. Feature extraction is performed on the amplitude response sequence and phase response sequence to form the fundamental response parameters. The echo signal is subjected to spectrum analysis to extract harmonic components of a preset order. The harmonic components of the preset order are then analyzed to obtain harmonic reference parameters. Spatial statistical analysis is performed on the echo electrical signal to obtain the corresponding crosstalk reference parameters; When receiving the echo signal of the preset detection ultrasonic wave, the corresponding driving electrical signal is acquired, the capacitance value is calculated based on the driving electrical signal, the capacitance value is statistically analyzed to obtain the average capacitance value and the capacitance fluctuation amplitude, and the average capacitance value and the capacitance fluctuation amplitude are used as the capacitance reference parameters.

[0008] In some possible implementations, the step of performing reverse compensation processing on the initial excitation signal based on the imaging reference parameters to obtain the initial imaging excitation signal includes: Using the fundamental wave response parameter in the imaging reference parameters as the target reference, the corresponding amplitude gain coefficient is calculated. Using the harmonic reference parameters and crosstalk reference parameters in the imaging reference parameters as target references, the corresponding compensation superposition components are calculated. The initial excitation signal is modulated according to the amplitude gain coefficient, and the compensation superposition component is superimposed on the initial excitation signal in reverse to obtain the initial imaging excitation signal.

[0009] In some possible implementations, the first compensation processing of the imaging excitation signal of the next frame based on the deviation between the capacitance change parameter and the capacitance reference parameter to obtain the first imaging excitation signal includes: The capacitance variation parameter is compared with the capacitance reference parameter, and the corresponding deviation parameter is calculated. Based on the deviation parameter, amplitude compensation and phase compensation processing are performed on the imaging excitation signal of the next frame to obtain the first imaging excitation signal.

[0010] In some possible implementations, the step of performing amplitude and phase compensation processing on the imaging excitation signal of the next frame based on the deviation parameter to obtain the first imaging excitation signal includes: Based on the deviation parameter, the corresponding amplitude compensation coefficient is calculated, and the voltage amplitude of the imaging excitation signal of the next frame is modulated according to the amplitude compensation coefficient to obtain the amplitude-compensated imaging excitation signal. Based on the amplitude compensation coefficient and the deviation parameter, the corresponding phase compensation amount is calculated. Based on the phase compensation amount, the amplitude-compensated imaging excitation signal is subjected to phase shift processing to obtain the first imaging excitation signal.

[0011] In some possible implementations, the step of performing a second compensation process on the first imaging excitation signal based on the residual deviation between the imaging reference parameter and the imaging residual parameter to obtain a second imaging excitation signal includes: The imaging reference parameters are compared with the imaging residual parameters to obtain the corresponding residual deviation; Based on the residual deviation, the first imaging excitation signal is subjected to spectral suppression processing, inter-element modulation processing, and consistency constraint processing to obtain the second imaging excitation signal.

[0012] In some possible implementations, the imaging residual parameters include fundamental residual parameters, harmonic residual parameters, and crosstalk residual parameters. Based on the residual deviation, the first imaging excitation signal is subjected to spectral suppression processing, inter-element modulation processing, and consistency constraint processing to obtain the second imaging excitation signal, including: Based on the residual deviation between the harmonic residual parameters and the harmonic reference parameters, the degree of axial resolution degradation during the current imaging process is determined. Based on the degree of axial resolution degradation, the harmonic frequency components in the first imaging excitation signal are subjected to spectral suppression processing to obtain the first imaging excitation signal after spectral compensation. Based on the residual deviation between the crosstalk residual parameter and the crosstalk reference parameter, the lateral artifact distribution characteristics of the inter-element crosstalk are determined. Based on the lateral artifact distribution characteristics, the first imaging excitation signal after spectral compensation is modulated to obtain the first imaging excitation signal after inter-element modulation. Based on the residual deviation between the fundamental residual parameters and the fundamental response parameters, the imaging fluctuation characteristics are determined. According to the imaging fluctuation characteristics, the first imaging excitation signal modulated between array elements is subjected to constraint adjustment processing to obtain the second imaging excitation signal.

[0013] In some possible implementations, the conversion processing of the echo signal of the imaging ultrasound to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame includes: The echo signal of the imaging ultrasound is converted into an electrical signal to obtain the corresponding imaging echo electrical signal; Based on the imaging echo electrical signal, the corresponding capacitance value is calculated to obtain the corresponding capacitance change parameter; The imaging echo signal is filtered to separate the corresponding fundamental echo signal. The fundamental echo signal is then analyzed to obtain the corresponding amplitude response sequence and phase response sequence. The amplitude response sequence and phase response sequence are compared with the fundamental wave response parameters to obtain the fundamental wave residual parameters; Spectral analysis is performed on the imaging echo electrical signal to obtain the corresponding imaging harmonic components, and the imaging harmonic components are compared with the harmonic reference parameters to obtain the harmonic residual parameters. Spatial statistical analysis is performed on the imaging echo electrical signal to obtain the corresponding crosstalk feature information, and the crosstalk feature information is compared with the crosstalk reference parameter to obtain the crosstalk residual parameter.

[0014] Among some possible implementation methods, the following are also included: Based on the echo signal of the imaging ultrasound, the imaging depth range and tissue attenuation degree of the current frame are determined. The corresponding imaging mode is determined based on the imaging depth range and the degree of tissue attenuation. In the imaging mode, the transmission parameters of the second imaging excitation signal are modulated to obtain an adjusted second imaging excitation signal. Based on the adjusted second imaging excitation signal, the next frame of imaging ultrasound is transmitted, and signal processing is performed according to the echo signal of the next frame of imaging ultrasound to output the corresponding imaging detection result.

[0015] A chip-level ultrasonic transducer CMUT system, the system comprising: a capacitive micromechanical ultrasonic transducer CMUT, an electronic integration module, and a digital signal processing module; The electronic integrated module includes a bias generator, a signal generation unit, and a compensation unit; The bias generator is used to input a preset pulse sequence into the insulating layer of the capacitive micromechanical ultrasound transducer (CMUT) before the patient undergoes imaging detection, thereby forming a built-in bias voltage. The signal generation unit is used to perform reverse compensation processing on the initial excitation signal based on imaging reference parameters to obtain the initial imaging excitation signal when the patient is undergoing imaging detection. The compensation unit is used to perform a first compensation process on the imaging excitation signal of the next frame based on the deviation between the capacitance change parameter and the capacitance reference parameter to obtain a first imaging excitation signal, and to perform a second compensation process on the first imaging excitation signal based on the residual deviation between the imaging reference parameter and the imaging residual parameter to obtain a second imaging excitation signal. The CMUT is used to emit a preset detection ultrasonic wave after the built-in bias voltage is formed, emit an imaging ultrasonic wave based on the initial imaging excitation signal, and emit the next frame imaging ultrasonic wave based on the second imaging excitation signal. The digital signal processing module includes a parameter processing unit and an image reconstruction unit; The parameter processing unit is used to extract the corresponding imaging reference parameters and capacitance reference parameters when receiving the echo signal of the preset detection ultrasound. During each frame of the patient imaging detection process, the echo signal of the imaging ultrasound is converted and processed to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame. The image reconstruction unit is used to process the echo signal of the imaging ultrasound in the next frame and output the corresponding imaging detection result.

[0016] As can be seen from the above technical solution, this application has the following beneficial effects: 1. This application uses a preset pulse sequence to form a built-in bias voltage in the CMUT insulation layer, replacing the external DC high voltage bias, so that the chip-level ultrasound probe can work stably without an external high voltage power supply. This reduces system power consumption and circuit size while eliminating the patient contact safety risks caused by high voltage power supplies, and improves the integration and clinical applicability of portable ultrasound equipment.

[0017] 2. This application establishes a multi-dimensional reference template for the CMUT array under ideal linear operating conditions by emitting a preset detection ultrasonic wave after the built-in bias voltage is formed, extracting imaging reference parameters including fundamental response parameters, harmonic reference parameters, and crosstalk reference parameters, as well as capacitance reference parameters. This provides a basis for dynamic compensation in the subsequent imaging process and improves the consistency of sound pressure output and spatial resolution stability of continuous multi-frame imaging.

[0018] 3. This application performs a first compensation process on the imaging excitation signal based on the deviation between the capacitance change parameter and the capacitance reference parameter during continuous imaging, and performs a second compensation process on the first imaging excitation signal based on the residual deviation between the imaging reference parameter and the imaging residual parameter. This forms a two-layer inter-frame compensation mechanism that combines coarse adjustment of the base and fine adjustment of details. This enables the CMUT array to maintain stable sound pressure output and echo reception performance under dynamic environments such as patient movement, temperature changes, or long-term scanning, suppressing harmonic distortion and crosstalk artifacts. As a result, it improves the brightness consistency of two-dimensional grayscale images, the continuity of color blood flow distribution, and the stability and repeatability of Doppler quantitative analysis. Attached Figure Description

[0019] The present application will be further described below with reference to the accompanying drawings.

[0020] Figure 1 A flowchart of a method for using a chip-level ultrasonic probe CMUT provided in this application; Figure 2 A flowchart illustrating another method of using a chip-level ultrasonic probe (CMUT) provided in this application; Figure 3 An example diagram of a chip-level ultrasonic probe CMUT system provided in this application. Detailed Implementation

[0021] The terms "first," "second," and "third," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.

[0022] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0023] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the related technologies is given first: Ultrasonic imaging mainly relies on piezoelectric transducers or capacitive micromechanical ultrasonic transducers (CMUTs) to detect the internal structure of tissues.

[0024] Piezoelectric transducers generate mechanical vibrations by applying voltage to emit ultrasonic waves, and convert the mechanical vibrations into electrical signals when receiving the echoes. Image reconstruction is then completed through beamforming technology and digital signal processing. However, piezoelectric arrays are limited in terms of chip-level integration and miniaturization, making it difficult to meet the size and power consumption requirements of portable medical devices such as handheld ultrasound, intracardiac ultrasound, and intravascular ultrasound.

[0025] CMUT is an ultrasonic transducer based on a microelectromechanical system (MEMS) structure. CMUT generates ultrasonic waves by applying an electric field to a vibrating diaphragm on a cavity structure and converting the acoustic vibration into an electrical signal when receiving the echo signal, thus realizing an integrated working mode of ultrasonic transmission and echo reception.

[0026] In chip-level ultrasound probe systems, through chip integration, the CMUT array and driving, compensation and signal processing functions are completed on the same package or silicon chip. Compared with piezoelectric ultrasound transducers, CMUTs have the advantages of wide bandwidth, easy arraying, easy chip-level integration and integrated design of driving circuit and signal processing circuit. They are suitable for handheld ultrasound devices, intracardiac ultrasound probes, intravascular ultrasound probes and wearable medical ultrasound devices.

[0027] In the actual imaging process of CMUT, the vibrating diaphragm needs to be kept at a stable static operating point by a bias voltage, so as to generate a stable ultrasonic emission sound pressure under the action of the imaging excitation signal. Traditional imaging systems usually use an external high-voltage DC bias power supply to maintain the working state. The external high-voltage bias not only increases the power consumption of the system, but also increases the circuit size and chip packaging complexity, which is not conducive to the miniaturization and integration of chip-level ultrasonic probes. Therefore, some chip-level ultrasonic systems use pulse injection to form a built-in bias voltage inside the insulating layer, so that the capacitive micromechanical ultrasonic transducer CMUT can still maintain a stable working state under the condition of no external high voltage.

[0028] Studies have shown that the quality and accuracy of ultrasound imaging are highly dependent on the transmission stability of the transducer and the reliability of the echo signal. Although CMUT achieves ultrasound transmission by applying an electric field to drive a vibrating diaphragm on a cavity structure and converting acoustic vibrations into electrical signals when receiving echo signals, thus completing the integrated transmission and reception mode, in actual clinical imaging, due to the patient's heartbeat, dynamic changes in blood flow, and spatial differences in tissue acoustic impedance, the CMUT array is prone to dynamic capacitance fluctuations during imaging. These capacitance fluctuations cause the static operating point of the vibrating diaphragm to deviate from the preset value, making the sound pressure output under the imaging excitation signal unstable. This results in phenomena such as transmitted sound pressure fluctuations, enhanced harmonic interference, and increased crosstalk between array elements. These unstable factors directly affect the imaging resolution of cardiac cavity structures, vascular boundaries, and deep tissues, making it difficult for clinicians to obtain accurate anatomical information and quantitative blood flow analysis data when performing cardiac ultrasound, vascular ultrasound, or intracatheter ultrasound.

[0029] Secondly, CMUT imaging systems typically rely on external high-voltage DC bias to maintain the transducer diaphragm's operating state. However, external high-voltage bias not only increases system power consumption but also significantly increases circuit size and chip packaging complexity, limiting the miniaturization and integration of chip-level probes. To address this issue, some systems employ pulse injection technology to create a built-in bias voltage within the insulating layer, enabling the CMUT to maintain basic operation even without external high voltage. While this method offers advantages in reducing power consumption and simplifying hardware design, existing built-in bias schemes typically employ fixed drive or single-parameter compensation methods, such as amplitude gain adjustment or local harmonic suppression. This single-dimensional compensation cannot simultaneously address dynamic capacitance fluctuations and imaging interference changes during continuous scanning or multi-frame imaging, leading to inter-frame inconsistencies, image resolution degradation, and Doppler quantitative errors in the imaging results.

[0030] Therefore, in medical imaging applications, it is impossible to achieve coordinated compensation between dynamic capacitance fluctuations and imaging interference based on the built-in bias voltage. This results in poor image consistency, increased artifacts, and reduced Doppler quantitative accuracy during long-term dynamic imaging processes such as cardiac ultrasound, vascular ultrasound, and real-time intracatheter detection, making it difficult to meet the reliability requirements of real-time clinical diagnosis.

[0031] Example 1: To solve the above problems, this application provides a method for using a chip-level ultrasonic probe (CMUT). Please refer to [link to example]. Figure 1 .

[0032] S101, before the patient undergoes imaging testing, inputs a preset pulse sequence into the insulating layer of the capacitive micromechanical ultrasound transducer (CMUT) to form a built-in bias voltage.

[0033] The technical terms used in this application are described below.

[0034] Preset pulse sequence: This refers to a set of low-voltage pulse signals with specific amplitude gradients, gradually increasing duty cycles, and durations, pre-set and output before imaging begins. Its function is to gradually saturate and capture charge traps in the CMUT insulating layer through electric field driving, thereby forming a stable equivalent electrostatic field within the insulating layer, i.e., a built-in bias voltage. The preset pulse sequence typically includes pulse amplitude parameters, pulse width parameters, pulse interval parameters, and pulse period parameters. By controlling these parameters, directional charge injection and accumulation are achieved, providing a stable working foundation for subsequent imaging without relying on an external high-voltage DC bias power supply.

[0035] Built-in bias voltage: This refers to the equivalent electrostatic field voltage formed between the insulating layer and the vibrating diaphragm after charge is injected and captured into the CMUT insulating layer through a preset pulse sequence. This voltage maintains the vibrating diaphragm at a preset static operating point close to its collapse point, thus stably driving the diaphragm to generate ultrasonic wave emission sound pressure under the superposition of imaging excitation signals. Unlike external high-voltage DC bias, the built-in bias voltage is formed by a fixed charge distribution inside the insulating layer, which can maintain a stable electric field state in the chip-level structure for a long time, reducing system power consumption, circuit size, and patient contact safety risks, and improving the integration and clinical applicability of the chip-level ultrasound probe.

[0036] The array unit refers to the smallest functional structural unit in a CMUT capable of independently performing ultrasonic transmission and echo reception. An array unit typically consists of a vibrating diaphragm, electrode structure, insulating layer, cavity structure, and support structure. Each array unit possesses independent capacitance and acoustic response characteristics. Multiple array units arranged according to a preset spatial distribution rule can achieve spatial direction control and image resolution enhancement through beamforming and signal superposition. Therefore, the array unit is the fundamental structure constituting the imaging capability of a CMUT.

[0037] A CMUT array refers to a capacitive micromechanical ultrasonic transducer structure formed by integrating multiple array units according to two-dimensional or one-dimensional spatial structural rules. The CMUT array achieves directional transmission, focusing control, and spatial acquisition of echo signals by uniformly driving and coordinating the multiple array units. CMUT arrays typically employ matrix or linear array arrangements. Each array unit outputs an imaging excitation signal according to a preset timing sequence, enabling the ultrasonic waves to form a controllable beam in space, while simultaneously receiving echo signals from different spatial locations for image reconstruction.

[0038] The insulating layer is a dielectric isolation structure placed between the CMUT diaphragm and the electrode structure. It is used to create a stable electric field isolation environment between the diaphragm, electrodes, and cavity structure, and to achieve charge storage and electric field establishment under pulse voltage. The insulating layer is usually made of a high dielectric strength material, which can withstand the electric field stress generated during pulse voltage injection while ensuring electrical isolation performance, thereby forming a stable charge distribution state inside the insulating layer.

[0039] During ultrasound imaging, the insulating layer serves two purposes: firstly, it isolates the direct conduction between the vibrating diaphragm and the electrodes, preventing current leakage that could lead to transducer failure; secondly, during the input of a preset pulse sequence, the insulating layer can capture and store charge, creating an equivalent electric field inside the CMUT, thereby constructing a built-in bias voltage. Through the stable distribution of charge inside the insulating layer, the vibrating diaphragm can be maintained at a preset static operating point, generating stable ultrasound waves under the action of the imaging excitation signal, and improving the stability of echo signal conversion.

[0040] In chip-level ultrasonic probe systems, the insulating layer also serves to stabilize the electric field and support the capacitive structure. The thickness, dielectric constant, and charge trapping capability of the insulating layer directly affect the stability of the built-in bias voltage and the capacitance consistency between array units. Therefore, during the injection of the preset pulse sequence, it is necessary to match and control the pulse amplitude and pulse period according to the material properties and structural parameters of the insulating layer to form a uniform and stable electric field distribution inside the insulating layer, thereby ensuring the emission stability and imaging accuracy of the CMUT array during continuous imaging.

[0041] The technical solution of this application will be described below using technical terminology.

[0042] In some possible implementations, before the patient enters the imaging detection process, each array unit in the CMUT array is initialized to obtain the initial capacitance parameters, insulating layer electric field response parameters, and diaphragm static displacement parameters corresponding to each array unit, and the target static operating point range is determined based on the initial capacitance parameters. Target bias electric field parameters are then generated based on the target static operating point range and applied to the target bias electric field parameters.

[0043] A preset pulse sequence is constructed based on the target bias electric field parameters. The preset pulse sequence includes pulse amplitude parameters, pulse width parameters, pulse period parameters, and pulse injection number parameters. The preset pulse sequence is loaded onto the driving electrode corresponding to the CMUT array according to the preset timing sequence, and the pulse voltage is input to the insulating layer structure through the driving interface, so that the charge inside the insulating layer gradually accumulates and forms an electric field distribution.

[0044] During the pulse injection process, the capacitance change curve of the array unit and the response state of the vibrating diaphragm are collected in real time. By analyzing the capacitance change curve, the degree of charge accumulation inside the insulating layer is determined. When the capacitance change tends to stabilize and the static displacement of the vibrating diaphragm reaches the target static operating point range, the preset pulse sequence stops outputting, thereby forming a stable built-in bias voltage inside the insulating layer.

[0045] After the built-in bias voltage is formed, a short-term stability verification test is performed on the CMUT array. By outputting a low-amplitude test excitation signal and collecting echo response parameters, the consistency of sound pressure output and the stability of echo signal of each array unit are judged. When the response deviation of each array unit is within the preset error range, it is determined that the built-in bias voltage has been formed and the subsequent imaging excitation stage is entered.

[0046] In another possible implementation, the preset pulse sequence is based on the charge accumulation characteristics within the CMUT's insulating layer. Multiple pulse voltage injections create a stable equivalent electric field distribution between the insulating layer and the vibrating diaphragm, enabling the diaphragm to maintain a stable static operating point even without external high-voltage DC bias. Because the CMUT's insulating layer exhibits charge trapping and slow release characteristics, when the pulse voltage is periodically applied to the insulating layer, charge gradually accumulates within it, forming a stable potential difference. This potential difference can be equivalent to a continuously existing bias voltage, thus providing a stable electric field basis for the subsequent imaging excitation signal. By controlling the amplitude, width, and duration of the pulse voltage, a uniform and stable charge distribution can be formed within the insulating layer, preventing diaphragm operating point drift due to uneven charge distribution and ensuring the stability of the subsequent ultrasonic emission sound pressure.

[0047] Specifically, the preset pulse sequence can be based on the target bias electric field strength set in advance according to the structural parameters of the CMUT. The corresponding pulse voltage sequence is generated according to the target bias electric field strength and injected into the insulating layer electrode. During the injection process, the charge accumulation state inside the insulating layer is detected. By detecting the capacitance change or echo response change of the vibrating diaphragm, it is determined whether the electric field inside the insulating layer has reached a stable state. When the electric field is stable, the pulse injection is stopped, allowing the CMUT to enter the stable operating point.

[0048] The preset pulse sequence can be adjusted based on the structural characteristics of the CMUT array. During the initialization phase, the capacitance distribution characteristics of the array elements are obtained, and the pulse amplitude and pulse period are configured hierarchically according to the capacitance differences between array elements, so that a uniform electric field distribution is formed inside the insulation layer of each element. For array elements with larger capacitance, the number of pulse injections can be increased or the pulse width can be extended; for array elements with smaller capacitance, the pulse amplitude can be reduced or the injection time can be shortened. This ensures that the entire CMUT array maintains a consistent static operating point after the built-in bias voltage is formed, improving the consistency and stability of the array's emitted sound pressure.

[0049] The preset pulse sequence can also be set using a staged injection method. In the initial stage, a high-amplitude pulse is used to quickly establish the initial charge distribution inside the insulating layer; in the stabilization stage, a low-amplitude high-frequency pulse is used to fine-tune the charge distribution, gradually stabilizing the electric field; in the final stage, pulse injection is stopped and the imaging detection stage begins. By setting the preset pulse sequence in stages, a stable built-in bias voltage can be formed in a shorter time, while reducing the impact on the insulating layer structure, thus improving the lifespan and stability of the chip-level ultrasonic probe. It should be noted that the above-described method for setting the preset pulse sequence can be adapted by those skilled in the art according to actual conditions, and no specific limitations are imposed here.

[0050] S102, after forming the built-in bias voltage, emits a preset detection ultrasonic wave, and when receiving the echo signal of the preset detection ultrasonic wave, extracts the corresponding imaging reference parameters and capacitance reference parameters.

[0051] To ensure clarity and conciseness in the description of the following embodiments, a brief introduction to the relevant terms is given first.

[0052] Imaging reference parameters: These refer to the reference characteristic parameters extracted under ideal linear operating conditions by emitting a preset low-power ultrasonic wave and receiving the echo signal after the built-in bias voltage is formed. These parameters include the fundamental frequency response parameters, harmonic reference parameters, and crosstalk reference parameters.

[0053] Capacitor reference parameter: refers to the capacitor reference value calculated under stable operating conditions by synchronously acquiring the drive electrical signal after the built-in bias voltage is formed.

[0054] In some possible implementations, the extraction of imaging reference parameters and capacitance reference parameters is achieved by acquiring reference states through low-power probe ultrasound after the built-in bias voltage is formed and stabilized. The core of this approach is to establish a linear acoustic response reference and capacitance stability reference for the CMUT array without introducing tissue disturbance or array overdrive.

[0055] Specifically, the CMUT array is controlled to emit preset probe ultrasound waves. These waves are driven by short pulses, causing the diaphragm to vibrate linearly under a built-in bias voltage. In this state, the emitted ultrasound waves enter the tissue and generate echo signals. Upon receiving the echo signals, the CMUT array converts the acoustic vibrations into current changes via the diaphragm. These current changes are then processed by a front-end amplification circuit and an analog-to-digital converter to form an echo electrical signal. Within the linear operating range, the echo electrical signal accurately reflects the acoustic response characteristics and electric field stability of the array units, thus serving as a reference for subsequent imaging.

[0056] In the extraction of fundamental response parameters, bandpass filtering is performed on the echo electrical signal to remove environmental noise and signals outside the operating frequency band, resulting in stable amplitude and phase response sequences. Envelope detection is performed on the amplitude response sequence to extract fundamental amplitude features, while phase unfolding is performed on the phase response sequence to extract phase change features. Fundamental response parameters are then established based on amplitude stability and phase consistency. In medical ultrasound detection, the echo intensity and propagation path of stable tissue regions exhibit relatively stable characteristics. When the CMUT array is in a stable built-in bias voltage state, the transmitted sound pressure and the receiving sensitivity remain consistent, thus the echo amplitude and phase changes follow a stable pattern. When the static operating point of the vibrating diaphragm shifts, the sound pressure output and receiving sensitivity change synchronously, causing fluctuations in amplitude and phase. Therefore, the fundamental response parameters can directly reflect the current sound pressure output capability and echo reception capability, and can serve as a basic criterion for judging imaging stability.

[0057] In the process of extracting harmonic reference parameters, the echo electrical signal is processed by Fast Fourier Transform (FFT) to convert the time-domain echo signal into a frequency-domain spectral signal. The fundamental frequency and its integer multiples are located within the frequency-domain spectral signal to extract harmonic components of a preset order. These preset-order harmonic components can include second, third, and fourth harmonic components. Statistical analysis is performed on the energy distribution, frequency offset, and harmonic proportion of the harmonic components to form harmonic reference parameters. In clinical imaging, tissue echoes are mainly concentrated in the fundamental frequency band. When the CMUT array operates in the linear region, the displacement of the vibrating diaphragm maintains a linear relationship with the driving signal, resulting in low harmonic components. When fluctuations in the insulating layer's electric field or changes in capacitance cause the diaphragm to enter the nonlinear vibration range, higher-order harmonic components are generated, resulting in energy enhancement in the spectrum. Therefore, changes in harmonic energy can reflect the degree of nonlinear vibration of the vibrating diaphragm and the stability of the electric field, making the harmonic reference parameters a key basis for judging imaging distortion and sound pressure stability.

[0058] In the process of extracting crosstalk reference parameters, spatial statistical analysis is performed on the echo electrical signals corresponding to different array units. By calculating the signal correlation between adjacent array units, the degree of spatial interference between array units is obtained, and crosstalk reference parameters are formed. In medical imaging detection, different array units are responsible for spatial detection in different directions. Ideally, the echo signals of each array unit should have significant spatial differences. When mutual interference or superposition occurs between array units due to electric field, structural, or acoustic factors, adjacent array units will receive similar echo signals, leading to a decrease in beam focusing capability and blurring of image boundaries. Therefore, by statistically analyzing the signal correlation between array units, the array crosstalk level can be accurately assessed, allowing the crosstalk reference parameters to serve as a basis for judging the stability of spatial resolution.

[0059] During the extraction of capacitance reference parameters, the drive electrical signal is acquired simultaneously with the received echo signal, and the real-time capacitance value of the array unit is calculated based on the relationship between the drive voltage and drive current. Subsequently, statistical analysis is performed on the capacitance values ​​of multiple array units to obtain the average capacitance value and capacitance fluctuation amplitude, which are then used as capacitance reference parameters. The capacitance value of the CMUT array directly reflects the change in distance between the vibrating diaphragm and the electrode, as well as the stable state of the electric field inside the insulating layer. Under stable operating conditions, capacitance variation should remain within a small range; therefore, a stable capacitance reference for the array can be established through capacitance statistical analysis.

[0060] In some possible implementations, the imaging and capacitance reference parameters can be updated. During continuous multi-frame imaging, echo signals and capacitance change data are acquired in real time. The reference parameters are updated by moving average or weighted averaging based on the statistical characteristics of historical frames to reflect minor drifts of the array under long-term use, temperature changes, or tissue contact conditions. The updated reference parameters can serve as a reference for the first and second compensations, ensuring that the compensation process is always adjusted based on the current actual operating state of the array, thereby further improving the linear stability, sound pressure level consistency, and spatial resolution stability of continuous multi-frame imaging.

[0061] In continuous dynamic imaging scenarios such as medical ultrasound detection, this application extracts fundamental response parameters, harmonic reference parameters, crosstalk reference parameters, and capacitance reference parameters after the built-in bias voltage is formed, forming a joint imaging reference of acoustic response and capacitance stability. This enables the CMUT array to establish a linear working reference before entering the formal scanning process, thereby accurately distinguishing tissue echo changes and CMUT working point offsets under patient tissue movement or blood flow disturbances. This avoids erroneous triggering of gain compensation or beam adjustment, ensures consistency of sound pressure output and spatial resolution stability during continuous multi-frame imaging, and improves the imaging reliability of chip-level ultrasound probes in dynamic medical imaging environments.

[0062] S103, during patient imaging, the initial excitation signal is reverse-compensated based on imaging reference parameters to obtain the initial imaging excitation signal, and imaging ultrasound is emitted based on the initial imaging excitation signal. Please refer to [link to relevant documentation]. Figure 2 .

[0063] To ensure clarity and conciseness in the description of the following embodiments, a detailed introduction of the relevant terms is given first.

[0064] Initial excitation signal: This refers to the transmission drive signal preset according to the CMUT array design parameters and imaging mode before the patient undergoes ultrasound imaging. This signal typically includes information such as amplitude, frequency, pulse width, and pulse repetition period, and is used to drive the CMUT array to emit ultrasound waves in the tissue. The initial excitation signal has not undergone compensation processing for imaging reference parameters and reflects the default driving state of the CMUT array under ideal or standard conditions. It is mainly used to generate the baseline of the ultrasound transmission signal to be compensated.

[0065] Initial imaging excitation signal: This refers to the transmit drive signal obtained after inverse compensation processing of the initial excitation signal following the acquisition of imaging reference parameters. Inverse compensation processing involves correcting the amplitude, phase, frequency, and time characteristics of the initial excitation signal based on fundamental response parameters, harmonic reference parameters, crosstalk reference parameters, and capacitance reference parameters, thereby compensating for the dynamic offset of the CMUT array under actual operating conditions. The initial imaging excitation signal enables the CMUT array to maintain linear and stable acoustic pressure output and echo reception performance in the dynamic environment of patient tissue, providing a consistent driving basis for continuous multi-frame imaging.

[0066] During patient imaging, the actual operating state of the CMUT array may be affected by factors such as the static operating point offset of the vibrating diaphragm, dynamic fluctuations in capacitance, inter-array crosstalk, and nonlinear vibration, directly causing the amplitude, phase, and spectral characteristics of the echo signal to deviate from the ideal linear state. To ensure the consistency of ultrasound emission and the stability of image resolution during continuous multi-frame imaging, the initial excitation signal is subjected to inverse compensation processing to generate an initial imaging excitation signal, thereby compensating for the offset and interference of the CMUT array in the actual dynamic environment.

[0067] In some possible implementations, the fundamental response parameter in the imaging reference parameters is used as the target reference to calculate the corresponding amplitude gain coefficient; the harmonic reference parameter and crosstalk reference parameter in the imaging reference parameters are used as the target reference to calculate the corresponding compensation superposition component; the initial excitation signal is modulated according to the amplitude gain coefficient, and the compensation superposition component is superimposed on the initial excitation signal to obtain the initial imaging excitation signal.

[0068] Specifically, the first step is amplitude compensation. Using the fundamental response parameter in the imaging reference parameters as the primary target reference, the amplitude of the current initial excitation signal is compared with the reference amplitude response sequence at each depth or element position to obtain the overall amplitude deviation. Based on the magnitude and direction of this overall amplitude deviation, the amplitude gain coefficient is determined. When the deviation is small, no adjustment is made; when the deviation increases, the amplitude gain coefficient increases or decreases gradually according to the direction of the overall amplitude deviation, thereby amplifying or reducing the overall voltage amplitude of the initial excitation signal, making the transmitted sound pressure as close as possible to the reference level, resulting in an amplitude-compensated intermediate signal. This coefficient is used to correct transmitted sound pressure deviations caused by small fluctuations in the built-in bias voltage or differences in array consistency. This amplitude gain coefficient is then applied to the voltage amplitude of the initial excitation signal for linear modulation processing, making the transmitted sound pressure as close as possible to the reference level, resulting in an amplitude-compensated intermediate signal.

[0069] The second step involves compensation superposition. Further referencing the harmonic and crosstalk reference parameters in the imaging reference parameters, a spectral pre-analysis is performed on the initial excitation signal to predict the proportion of second and third harmonic energy that may be generated under the current bias state. This prediction is then compared with the harmonic energy proportions in the harmonic reference parameters to obtain the harmonic deviation. Simultaneously, an inter-element correlation pre-analysis is performed on the initial excitation signal to predict the possible crosstalk energy distribution between elements. This prediction is then compared with the crosstalk distribution in the crosstalk reference parameters to obtain the crosstalk deviation. Based on these harmonic and crosstalk deviations, a compensation superposition component is generated. This component consists of two parts: first, an anti-phase harmonic superposition component opposite to the predicted harmonic deviation direction, whose amplitude is proportionally determined according to the magnitude of the harmonic deviation; and second, a reverse phase offset component for elements with high crosstalk risk, whose offset is finely adjusted according to the magnitude of the crosstalk deviation. The compensation superposition component obtained in this way can preemptively offset potential nonlinear distortion and spatial interference.

[0070] The calculated amplitude gain coefficient and the compensation superposition component are jointly applied to the initial excitation signal: the voltage amplitude of the initial excitation signal is multiplied by the amplitude gain coefficient to complete amplitude modulation and obtain the amplitude-compensated signal; then the compensation superposition component is superimposed on the amplitude-compensated signal in reverse, and the anti-phase harmonic component and crosstalk suppression component are incorporated into it through linear superposition to obtain the initial imaging excitation signal.

[0071] The reverse compensation processing in this application is not simply a single parameter adjustment of the initial excitation signal, but rather a combined processing method that uses imaging reference parameters as a multi-dimensional reference template and combines amplitude compensation with compensation superposition components. This method fully utilizes the stable static operating point provided by the built-in bias voltage. Without introducing external high voltage, it effectively suppresses harmonic interference and crosstalk artifacts that may occur in subsequent imaging processes by pre-correcting the amplitude and superimposing the reverse component. This provides a clean and stable emission starting point for the first and second compensation processes in subsequent imaging, thereby achieving higher image consistency and Doppler quantitative accuracy in medical scenarios.

[0072] S104: During each frame of the patient imaging detection process, the echo signal of the imaging ultrasound is converted and processed to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame.

[0073] To clearly describe the following embodiments, relevant terms will first be explained in detail and technically expanded.

[0074] Capacitance variation parameter: This refers to a quantitative indicator obtained by real-time detection of the dynamic capacitance changes of the CMUT array during each frame of imaging. This parameter reflects the stability of the built-in bias voltage under actual operating conditions, mainly including the average instantaneous capacitance value and capacitance fluctuation amplitude of the current frame. The average instantaneous capacitance value is a statistical average calculated based on the voltage-current correspondence by synchronously acquiring the current signal and drive voltage signal of the CMUT sensing electrode over multiple sampling periods; the capacitance fluctuation amplitude is the standard deviation or peak range of these instantaneous capacitance values. The capacitance variation parameter is used to assess in real-time whether the built-in bias voltage has drifted. In clinical continuous scanning scenarios, the capacitance value may fluctuate slightly due to increased patient body temperature, changes in probe contact pressure, or slow charge leakage caused by prolonged operation. The capacitance variation parameter can capture these changes in a timely manner, providing a quantitative basis for bias stability.

[0075] Imaging residual parameters refer to the actual deviation characteristics relative to the imaging reference parameters extracted from the echo signal during each frame of imaging. These mainly include fundamental residual parameters, harmonic residual parameters, and crosstalk residual parameters. These parameters collectively reflect the difference between the current frame's imaging signal and the reference state.

[0076] During each frame of the patient's imaging detection, the imaging ultrasound echo signal received by the CMUT array is converted into a digital electrical signal through a front-end amplification circuit and an analog-to-digital conversion circuit, forming the imaging echo electrical signal of the current frame.

[0077] In some possible implementations, during the extraction of imaging residual parameters, the imaging echo electrical signal is bandpass filtered to separate the fundamental echo signal. The deviation and phase difference between the current amplitude and the fundamental response parameters are calculated through amplitude response sequence and phase response sequence analysis to obtain the fundamental residual parameters. The echo electrical signal is then subjected to spectral analysis to extract higher-order harmonic components at integer multiples of the fundamental frequency, and these components are compared with harmonic reference parameters to obtain harmonic residual parameters. Furthermore, the signal correlation between adjacent array units is calculated through spatial statistical analysis and compared with crosstalk reference parameters to obtain crosstalk residual parameters.

[0078] In some possible implementations, during the extraction of capacitance variation parameters, the driving voltage and current signals of the array units are simultaneously acquired. The real-time capacitance value of each array unit is calculated, and statistical analysis is performed on the capacitance values ​​of multiple array units to obtain the average capacitance value and capacitance fluctuation amplitude. This average capacitance value and capacitance fluctuation amplitude are then compared with the average capacitance value and capacitance fluctuation amplitude of the capacitance reference parameters to form the capacitance variation parameters for each frame. This parameter can reflect the change in the static operating point of the vibrating diaphragm and the stability of the electric field inside the insulation layer, providing a basis for array status monitoring under dynamic organizational environments.

[0079] This application dynamically identifies array operating state shifts, nonlinear harmonic enhancement, and inter-element crosstalk trends by real-time calculation of capacitance variation parameters and imaging residual parameters in each frame, providing a precise basis for excitation signal compensation and beam optimization in subsequent frames. This method ensures that the CMUT array maintains a linear operating state and stable sound pressure output, guaranteeing amplitude consistency, phase stability, and spatial resolution in continuous multi-frame imaging, thereby improving the reliability and quantitative analysis accuracy of chip-level ultrasound probes in clinical dynamic imaging scenarios.

[0080] S105, based on the deviation between the capacitance change parameter and the capacitance reference parameter, and the residual deviation between the imaging reference parameter and the imaging residual parameter, performs a first compensation process and a second compensation process on the imaging excitation signal of the next frame to obtain the second imaging excitation signal. Please refer to [link to relevant documentation]. Figure 2 .

[0081] During continuous multi-frame imaging of a patient, the actual operating state of the CMUT array in each frame may deviate from the ideal linear state due to drift of the static operating point of the vibrating diaphragm, slight changes in capacitance, crosstalk between arrays, or nonlinear vibration. To ensure the consistency of sound pressure output and image resolution stability in each frame, this application adopts a step-by-step, continuous inter-frame fine-tuning compensation strategy, including a first compensation and a second compensation, to make subtle corrections to the imaging excitation signal of each frame after the first frame. The first compensation performs a fast coarse adjustment for capacitance drift and overall amplitude deviation, with a response speed synchronized with the imaging cycle of each frame to ensure that the emission starting point returns to the reference level in a timely manner. The second compensation performs a slow fine adjustment for fundamental residual, harmonic residual, and crosstalk between array elements. Historical deviations are processed through multi-frame moving average or low-pass filtering, and the excitation signal is gradually adjusted to avoid response conflicts between the two compensation loops, thereby improving the overall stability and image consistency of continuous multi-frame imaging.

[0082] Specifically, in the first compensation process, the capacitance change parameters of the current frame are obtained and compared with the initially formed capacitance reference parameters to calculate the capacitance deviation of each array unit. This deviation reflects the capacitance change of the array unit caused by factors such as diaphragm position offset, electric field fluctuations in the insulating layer, or temperature effects. Based on this deviation, the corresponding amplitude compensation coefficient is calculated, consistent with the amplitude gain coefficient calculation logic in S103, which will not be described in detail here. This allows for targeted amplification or reduction of the voltage amplitude of the original imaging excitation signal in the next frame, making the emitted sound pressure as close as possible to the reference level, resulting in the amplitude-compensated imaging excitation signal. The purpose of this amplitude compensation is to correct the overall sensitivity change caused by capacitance drift and ensure the stability of the emitted sound pressure.

[0083] Based on the aforementioned amplitude gain coefficient and deviation value, the corresponding phase compensation amount is calculated. The calculation logic is as follows: when the amplitude is amplified, the nonlinear vibration of the diaphragm will cause the phase to advance slightly, therefore the phase compensation amount is negative (phase shifted backward); when the amplitude is reduced, the phase compensation amount is positive (phase advanced). The amplitude of the phase compensation amount is controlled within a small range to avoid over-adjustment leading to waveform distortion. The amplitude-compensated imaging excitation signal is then subjected to phase shift processing. By using time-series resampling or a digital phase shifter, the signal sequence is shifted on the time axis by the corresponding phase compensation amount to obtain the first imaging excitation signal.

[0084] The capacitance change directly reflects the stability of the built-in bias voltage, while the static operating point shift of the diaphragm simultaneously affects the amplitude and phase of the emitted sound pressure. By first performing amplitude compensation for the overall energy, and then using the amplitude compensation result as a reference for phase fine-tuning, low-frequency floor errors caused by bias drift can be effectively suppressed. This compensation is a pre-compensation method with a small amplitude and phase adjustment range, mainly serving as a coarse floor adjustment to avoid oscillations or slow convergence in subsequent compensation due to baseline instability. In medical scenarios, this compensation can effectively reduce inter-frame image fluctuations caused by patient movement or changes in probe contact pressure, improving imaging consistency.

[0085] The first compensation can only correct the overall amplitude and phase deviation caused by capacitance changes. However, in actual continuous imaging, there may still be small residual errors such as fundamental amplitude fluctuations, harmonic enhancement, and inter-array crosstalk. The second compensation performs more precise inter-frame fine-tuning to address these residual errors.

[0086] Specifically, in the second compensation process, the first imaging excitation signal is further dynamically corrected by incorporating imaging residual parameters. The fundamental residual parameters, harmonic residual parameters, and crosstalk residual parameters extracted from the current frame echo signal are compared with the corresponding reference parameters to obtain residual deviations. These residual deviations reflect the nonlinear vibrations, harmonic enhancements, and inter-element interference still present in the current frame. Based on these residual deviations, three types of processing are applied to the first imaging excitation signal.

[0087] Spectral suppression processing determines the degree of axial resolution degradation during the current imaging process based on the residual deviation between the harmonic residual parameters and the harmonic reference parameters. Spectral suppression is then applied to the higher-order harmonic frequency components in the first imaging excitation signal. This is done by digitally expanding the first imaging excitation signal in the frequency domain and then applying a selective attenuation window to the higher-order frequency region according to a frequency segmentation suppression table. The selective attenuation window does not simply suppress the entire signal; instead, it performs flexible attenuation band by band according to the distribution of the harmonic residual deviation, maintaining stable energy output in the dominant frequency region while gradually reducing the energy proportion in the higher-order harmonic region. The processed frequency domain signal is then converted back into a time-domain driving waveform to obtain the spectrally compensated first imaging excitation signal.

[0088] Inter-element modulation processing is performed by determining the lateral artifact distribution characteristics caused by inter-element crosstalk based on the residual deviation between the crosstalk residual parameters and the crosstalk reference parameters, and then applying inter-element modulation processing to the first imaging excitation signal after spectral compensation. By establishing an inter-element interference distribution map, the crosstalk residual parameters reflect the spatial coupling strength between different elements and the location of lateral artifacts. Based on this interference distribution map, the array elements are divided into multiple local modulation units according to their spatial adjacency. When generating the next frame excitation signal, the excitation amplitude and phase of each element are differentially modulated: for elements with large crosstalk deviations, the driving amplitude is appropriately reduced and a small phase misalignment is performed to make its output waveform weakly correlated with neighboring elements; for elements with small crosstalk, a stable driving amplitude is maintained to ensure the overall sound pressure output. To avoid excessive suppression affecting the imaging intensity, the overall beam energy distribution of the array is monitored in real time during the element modulation process. When the beam energy drops to the target range, further attenuation is stopped, resulting in the first imaging excitation signal after inter-element modulation.

[0089] It should be noted that crosstalk in CMUT arrays can be divided into two categories: electrical crosstalk and acoustic crosstalk.

[0090] Electrical crosstalk mainly originates from parasitic capacitive coupling between electrodes of array elements. By performing inter-element modulation processing as described in this application, that is, differentially modulating the amplitude and phase of the imaging excitation signal, the correlation between the driving signals of adjacent array elements is reduced, thereby suppressing the influence of electrical crosstalk on the echo signal.

[0091] Consistency constraint processing is used to determine imaging fluctuation characteristics based on the residual deviation between the fundamental wave residual parameters and the fundamental wave response parameters. Constraint adjustment processing is then applied to the first imaging excitation signal modulated between array elements. By analyzing the trend of the fundamental wave residual parameters over multiple consecutive frames, imaging fluctuation characteristics are extracted, including amplitude fluctuation direction, phase drift trend, and inter-frame variation amplitude. The current frame excitation signal is compared with the excitation signals of several previous frames to generate a stable reference interval. When generating the next frame drive signal, amplitude and phase variations are restricted to remain within the stable reference interval, and abrupt changes are avoided through gentle smoothing adjustments. A gradual adjustment strategy is introduced during the drive signal update process, meaning that the amplitude and phase adjustment amplitude of each frame does not exceed a set threshold. Simultaneously, abnormally fluctuating array elements are locally backed up to maintain continuous and stable overall array output, resulting in the second imaging excitation signal.

[0092] This application first compensates for the base deviation caused by capacitor drift, providing a relatively stable transmission starting point. The second compensation targets the dynamic residual deviations (fundamental residual, harmonic residual, crosstalk residual) extracted in real-time for the current frame, performing local compensation in three dimensions: frequency domain (spectral suppression), spatial domain (inter-element modulation), and time domain (consistency constraints). This multi-dimensional serial fine-tuning method fully utilizes the stable baseline after the first compensation, avoiding large-scale repeated adjustments to global amplitude or phase, thereby suppressing residual artifacts caused by tissue dynamics and array nonlinearity. In long-term dynamic imaging scenarios, this compensation can improve image consistency, axial and lateral resolution, and Doppler quantitative accuracy, while maintaining low system power consumption and security.

[0093] S106: Based on the second imaging excitation signal, transmit the next frame imaging ultrasound, process the echo signal of the next frame imaging ultrasound, and output the corresponding imaging detection result.

[0094] During each frame of patient imaging, a second imaging excitation signal is loaded into the CMUT array drive channel. Drive voltages are applied to each array unit sequentially, causing the CMUT array diaphragm to generate stable mechanical vibrations under the influence of a built-in equivalent bias voltage, thereby transmitting the next frame of imaging ultrasound to the patient tissue. Because the second imaging excitation signal has undergone multi-dimensional compensation processing in the frequency, spatial, and temporal domains, the emitted ultrasound pulses are close to the baseline state in terms of sound pressure amplitude, phase consistency, and spectral structure. This results in higher stability and directionality of ultrasound propagation in human tissue, enabling the formation of a clear and stable sound beam structure.

[0095] After transmitting the next frame of imaging ultrasound, the CMUT array continues to collect the echo signals reflected back from the tissue as a receiving array. The echo signals are amplified by a front-end low-noise amplifier circuit to improve the signal-to-noise ratio of weak echo signals, and then converted into digital imaging echo signals by an analog-to-digital converter. To ensure the accuracy of subsequent imaging processing, the digital echo signals undergo preliminary preprocessing, including bandpass filtering to remove low-frequency drift and high-frequency noise, and timing alignment to ensure the consistency of echo signals from each array element on the time axis. The preprocessed echo signals are then delayed and superimposed to align the phase of echo signals from different array elements at the target location, thereby enhancing the echo intensity of the target tissue and suppressing background noise, resulting in a stable beam focusing effect.

[0096] After time-delay overlay, the echo signal undergoes envelope extraction processing, converting high-frequency carrier information into amplitude envelope information to facilitate the construction of a grayscale image. Simultaneously, dynamic range compression processing is applied to the envelope signal, ensuring that strong and weak echoes are clearly displayed within the same grayscale range, preventing tissue details from being obscured. Based on the array scanning sequence and time depth information, the echo amplitudes at different depth positions are mapped to two-dimensional imaging coordinates to form the ultrasound image data of the current frame. In scenarios requiring blood flow detection or tissue motion analysis, multi-frame correlation analysis can be performed on consecutive echo signals to extract Doppler frequency shift information or tissue motion information, thereby generating blood flow velocity maps or tissue motion maps, improving the accuracy of clinical diagnosis.

[0097] After the aforementioned signal processing, the corresponding imaging detection results are output, including a two-dimensional grayscale image, a color Doppler image, a spectral Doppler curve, and relevant quantitative indicators (such as peak blood flow velocity and estimated valve regurgitation area). It should be noted that the output imaging detection results are only for auxiliary analysis and judgment. The technical solution of this application is mainly used to improve the stability and quality of imaging signals, providing those skilled in the art with clearer, more stable, and quantitatively valuable ultrasound imaging results. By providing stable and reliable two-dimensional grayscale images, color Doppler images, spectral Doppler curves, and quantitative indicators, this application enables those skilled in the art to conduct comprehensive analysis and judgment based on their professional experience, thereby improving the accuracy and reliability of clinical imaging detection.

[0098] By using a stable driving signal after two-stage compensation as the basis for transmission, the CMUT array maintains linear sound pressure output and stable echo reception capability during continuous dynamic imaging. High-quality imaging detection results are generated through real-time echo processing, thereby achieving high-resolution, low-artifact, stable and continuous ultrasound imaging in medical scenarios.

[0099] In some possible implementations, after completing the signal processing of the ultrasonic echo signal of the current frame, a depth distribution statistical analysis is further performed on the imaging echo electrical signal. By segmenting and statistically analyzing the propagation delay of the echo signal on the time axis, the distribution of echo energy in different depth regions is determined, thereby obtaining the imaging depth range of the current frame.

[0100] Specifically, the echo signal is divided into multiple depth intervals according to propagation time. The echo amplitude intensity, echo energy attenuation rate, and effective echo percentage within each depth interval are statistically analyzed. When the echo energy in a certain depth interval remains below a preset threshold, that depth region is determined to be outside the effective imaging boundary, thus defining the effective imaging depth range of the current frame. Simultaneously, by analyzing the echo energy attenuation trend across different depth intervals, the echo attenuation curve along the depth direction is calculated. Combined with changes in tissue echo intensity, the degree of tissue attenuation is determined. The degree of tissue attenuation reflects the energy loss of ultrasound waves during propagation within tissues. For example, the echo attenuation rate differs in adipose tissue, muscle tissue, or deep organ regions. The attenuation trend can be used to determine the tissue propagation characteristics of the current imaging environment.

[0101] After determining the imaging depth range and tissue attenuation level, the corresponding imaging mode is automatically selected according to the preset imaging mode mapping rules. Imaging modes may include high-resolution mode for superficial tissues, penetrating enhancement mode for deep tissues, blood flow Doppler mode, or dynamic structure detection mode, etc.

[0102] Specifically, when the imaging depth is small and tissue attenuation is low, a high-resolution imaging mode is selected. This enhances axial resolution by increasing the center frequency and shortening the excitation pulse width, making superficial tissue structures clearer. When the imaging depth is large or tissue attenuation is high, a deep penetration mode is selected. This reduces the center frequency and appropriately increases the excitation energy, allowing ultrasound waves to propagate to deeper tissue regions, thereby improving the imaging stability of deep organs. When there are obvious periodic velocity changes in the echo signal, a blood flow Doppler mode can be selected. This optimizes the excitation repetition frequency and array scanning rhythm, making blood flow detection more stable. This method of automatically matching imaging modes based on echo characteristics allows imaging parameters to be dynamically adjusted according to changes in the tissue environment, avoiding frequent manual mode switching.

[0103] Under the determined imaging mode, the transmission parameters of the second imaging excitation signal are modulated to generate an adjusted second imaging excitation signal. The modulation of the transmission parameters mainly includes excitation amplitude, excitation pulse width, array transmission frequency, array element excitation rhythm, and transmission period control. For example, in deep penetration mode, the excitation amplitude is appropriately increased and the excitation pulse duration is extended to enhance ultrasound propagation energy, while the array transmission frequency is reduced to give the ultrasound stronger penetration capability. In high-resolution mode, the excitation pulse duration is shortened and the array center frequency is increased to improve axial resolution, and the array element transmission rhythm is refined to make the imaging more detailed. In blood flow detection mode, the transmission period and array scanning interval are adjusted so that continuous multi-frame echoes can form a stable Doppler signal sequence. Through the above modulation methods, the second imaging excitation signal has different transmission characteristics in different imaging modes, thereby adapting to the imaging needs of different tissue environments.

[0104] After generating the adjusted second imaging excitation signal, the CMUT array is driven to transmit the next frame of imaging ultrasound based on the adjusted second imaging excitation signal. The echo signal of the next frame of imaging ultrasound is then processed by signal acquisition, filtering, delay superposition, envelope extraction, and Doppler analysis to output the corresponding imaging detection results. By introducing an adaptive modulation mechanism for imaging modes based on the imaging depth range and tissue attenuation during continuous imaging, the array transmission parameters can be dynamically adjusted according to the tissue propagation environment. This ensures stable imaging quality in different medical scenarios such as superficial tissue detection, deep organ imaging, and blood flow detection, improving the environmental adaptability and continuous detection stability of ultrasound imaging.

[0105] This application addresses the scenario of continuous multi-frame imaging detection in medical ultrasound. By constructing an embedded equivalent bias voltage before imaging to stabilize the static operating point of the CMUT array, and by performing stepwise dynamic compensation on the imaging excitation signal of each frame based on capacitance change parameters and imaging residual parameters during continuous imaging, the array's emitted sound pressure, fundamental response, harmonic components, and inter-element crosstalk are always maintained within a reference stable range. This application can maintain stable brightness of two-dimensional grayscale images, continuous and consistent color blood flow distribution, and smooth and reliable spectral Doppler curves in continuous detection scenarios. This improves the stability and repeatability of quantitative indicators such as peak blood flow velocity, valve regurgitation range, and tissue motion state. It enables those skilled in the art to obtain continuous and consistent imaging results without frequent probe recalibration during long-term dynamic detection, thereby improving the reliability of clinical imaging judgment and detection efficiency.

[0106] Example 2, based on Example 1, this application provides a chip-level ultrasonic transducer CMUT system. The module functions of this system correspond to the specific implementation steps in Example 1, including a capacitive micromechanical ultrasonic transducer CMUT, an electronic integration module, and a digital signal processing module. Please refer to [link / reference needed]. Figure 3 .

[0107] The signal generation unit is used to perform reverse compensation processing on the initial excitation signal based on the imaging reference parameters to obtain the initial imaging excitation signal when the patient is undergoing imaging detection. The compensation unit is used to perform a first compensation process on the imaging excitation signal of the next frame based on the deviation between the capacitance change parameter and the capacitance reference parameter to obtain a first imaging excitation signal, and to perform a second compensation process on the first imaging excitation signal based on the residual deviation between the imaging reference parameter and the imaging residual parameter to obtain a second imaging excitation signal. CMUT is used to emit a preset probe ultrasonic wave after forming a built-in bias voltage, emit an imaging ultrasonic wave based on an initial imaging excitation signal, and emit the next frame imaging ultrasonic wave based on a second imaging excitation signal. The digital signal processing module includes a parameter processing unit and an image reconstruction unit; The parameter processing unit is used to extract the corresponding imaging reference parameters and capacitance reference parameters when receiving the echo signal of the preset detection ultrasound. During each frame of the patient imaging detection process, the echo signal of the imaging ultrasound is converted and processed to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame. The image reconstruction unit is used to process the echo signal of the imaging ultrasound in the next frame and output the corresponding imaging detection result.

[0108] This application achieves stable driving, consistent echo, and high image quality during continuous imaging by integrating CMUT driver and digital signal processing modules at the chip level and combining them with a two-stage excitation signal compensation mechanism. Compared with existing discrete systems, it reduces the impact of bias fluctuations and noise coupling on array response, improves multi-frame imaging stability and resolution, and is suitable for portable and bedside ultrasound testing scenarios.

[0109] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for using a chip-level ultrasonic probe CMUT, characterized in that, The method includes: Before the patient undergoes imaging examination, a preset pulse sequence is input into the insulating layer of the capacitive micromechanical ultrasonic transducer (CMUT) to form a built-in bias voltage, which is used to replace the external DC high voltage bias. After the built-in bias voltage is formed, a preset detection ultrasonic wave is emitted. When the echo signal of the preset detection ultrasonic wave is received, the corresponding imaging reference parameters and capacitance reference parameters are extracted. The imaging reference parameters include fundamental response parameters, harmonic reference parameters and crosstalk reference parameters. After the built-in bias voltage is formed, a preset detection ultrasonic wave is emitted; When receiving the echo signal of the preset detection ultrasonic wave, the echo signal of the preset detection ultrasonic wave is converted and processed to obtain the corresponding echo electrical signal. The echo signal is filtered to obtain the corresponding amplitude response sequence and phase response sequence. Feature extraction is performed on the amplitude response sequence and phase response sequence to form the fundamental response parameters. The echo signal is subjected to spectrum analysis to extract harmonic components of a preset order. The harmonic components of the preset order are then analyzed to obtain harmonic reference parameters. Spatial statistical analysis is performed on the echo electrical signal to obtain the corresponding crosstalk reference parameters; When receiving the echo signal of the preset detection ultrasonic wave, the corresponding driving electrical signal is obtained, the capacitance value is calculated based on the driving electrical signal, the capacitance value is statistically analyzed to obtain the average capacitance value and the capacitance fluctuation amplitude, and the average capacitance value and the capacitance fluctuation amplitude are used as the capacitance reference parameters. When a patient undergoes imaging detection, the fundamental wave response parameter in the imaging reference parameters is used as the target reference to calculate the corresponding amplitude gain coefficient. Using the harmonic reference parameters and crosstalk reference parameters in the imaging reference parameters as target references, the corresponding compensation superposition components are calculated. The initial excitation signal is modulated according to the amplitude gain coefficient, and the compensation superposition component is superimposed on the initial excitation signal in reverse to obtain the initial imaging excitation signal. Based on the initial imaging excitation signal, imaging ultrasound is emitted. During each frame of the patient imaging detection process, the echo signal of the imaging ultrasound is converted and processed to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame. The imaging residual parameters include fundamental residual parameters, harmonic residual parameters and crosstalk residual parameters. Based on the deviation between the capacitance change parameter and the capacitance reference parameter, the imaging excitation signal of the next frame is subjected to the first compensation processing to obtain the first imaging excitation signal. Based on the residual deviation between the imaging reference parameters and the imaging residual parameters, the first imaging excitation signal is subjected to a second compensation process to obtain the second imaging excitation signal. Based on the second imaging excitation signal, the next frame of imaging ultrasound is emitted, and the echo signal of the next frame of imaging ultrasound is processed to output the corresponding imaging detection result.

2. The method according to claim 1, characterized in that, The first compensation processing of the imaging excitation signal of the next frame based on the deviation between the capacitance change parameter and the capacitance reference parameter to obtain the first imaging excitation signal includes: The capacitance variation parameter is compared with the capacitance reference parameter, and the corresponding deviation parameter is calculated. Based on the deviation parameter, amplitude compensation and phase compensation processing are performed on the imaging excitation signal of the next frame to obtain the first imaging excitation signal.

3. The method according to claim 2, characterized in that, The step of performing amplitude compensation and phase compensation processing on the imaging excitation signal of the next frame according to the deviation parameter to obtain the first imaging excitation signal includes: Based on the deviation parameter, the corresponding amplitude compensation coefficient is calculated, and the voltage amplitude of the imaging excitation signal of the next frame is modulated according to the amplitude compensation coefficient to obtain the amplitude-compensated imaging excitation signal. Based on the amplitude compensation coefficient and the deviation parameter, the corresponding phase compensation amount is calculated. Based on the phase compensation amount, the amplitude-compensated imaging excitation signal is subjected to phase shift processing to obtain the first imaging excitation signal.

4. The method according to claim 3, characterized in that, The step of performing a second compensation process on the first imaging excitation signal based on the residual deviation between the imaging reference parameters and the imaging residual parameters to obtain a second imaging excitation signal includes: The imaging reference parameters are compared with the imaging residual parameters to obtain the corresponding residual deviation; Based on the residual deviation, the first imaging excitation signal is subjected to spectral suppression processing, inter-element modulation processing, and consistency constraint processing to obtain the second imaging excitation signal.

5. The method according to claim 4, characterized in that, The imaging residual parameters include fundamental residual parameters, harmonic residual parameters, and crosstalk residual parameters. Based on the residual deviation, the first imaging excitation signal is subjected to spectral suppression processing, inter-element modulation processing, and consistency constraint processing to obtain the second imaging excitation signal, including: Based on the residual deviation between the harmonic residual parameters and the harmonic reference parameters, the degree of axial resolution degradation during the current imaging process is determined. Based on the degree of axial resolution degradation, the harmonic frequency components in the first imaging excitation signal are subjected to spectral suppression processing to obtain the first imaging excitation signal after spectral compensation. Based on the residual deviation between the crosstalk residual parameter and the crosstalk reference parameter, the lateral artifact distribution characteristics of the inter-element crosstalk are determined. Based on the lateral artifact distribution characteristics, the first imaging excitation signal after spectral compensation is modulated to obtain the first imaging excitation signal after inter-element modulation. Based on the residual deviation between the fundamental residual parameters and the fundamental response parameters, the imaging fluctuation characteristics are determined. According to the imaging fluctuation characteristics, the first imaging excitation signal modulated between array elements is subjected to constraint adjustment processing to obtain the second imaging excitation signal.

6. The method according to claim 5, characterized in that, The process of converting the echo signal of the imaging ultrasound to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame includes: The echo signal of the imaging ultrasound is converted into an electrical signal to obtain the corresponding imaging echo electrical signal; Based on the imaging echo electrical signal, the corresponding capacitance value is calculated to obtain the corresponding capacitance change parameter; The imaging echo signal is filtered to separate the corresponding fundamental echo signal. The fundamental echo signal is then analyzed to obtain the corresponding amplitude response sequence and phase response sequence. The amplitude response sequence and phase response sequence are compared with the fundamental wave response parameters to obtain the fundamental wave residual parameters; Spectral analysis is performed on the imaging echo electrical signal to obtain the corresponding imaging harmonic components, and the imaging harmonic components are compared with the harmonic reference parameters to obtain the harmonic residual parameters. Spatial statistical analysis is performed on the imaging echo electrical signal to obtain the corresponding crosstalk feature information, and the crosstalk feature information is compared with the crosstalk reference parameter to obtain the crosstalk residual parameter.

7. The method according to claim 1, characterized in that, Also includes: Based on the echo signal of the imaging ultrasound, the imaging depth range and tissue attenuation degree of the current frame are determined. The corresponding imaging mode is determined based on the imaging depth range and the degree of tissue attenuation. In the imaging mode, the transmission parameters of the second imaging excitation signal are modulated to obtain an adjusted second imaging excitation signal. Based on the adjusted second imaging excitation signal, the next frame of imaging ultrasound is transmitted, and signal processing is performed according to the echo signal of the next frame of imaging ultrasound to output the corresponding imaging detection result.

8. A chip-level ultrasonic probe CMUT system, characterized in that, The system includes: a capacitive micromechanical ultrasonic transducer (CMUT), an electronic integration module, and a digital signal processing module; The electronic integrated module includes a bias generator, a signal generation unit, and a compensation unit; The bias generator is used to input a preset pulse sequence into the insulating layer of the capacitive micromechanical ultrasound transducer (CMUT) before the patient undergoes imaging detection, thereby forming a built-in bias voltage. The signal generation unit is used to calculate the corresponding amplitude gain coefficient by taking the fundamental wave response parameter in the imaging reference parameters as the target reference when the patient is undergoing imaging detection. Using the harmonic reference parameters and crosstalk reference parameters in the imaging reference parameters as target references, the corresponding compensation superposition components are calculated. The initial excitation signal is modulated according to the amplitude gain coefficient, and the compensation superposition component is superimposed on the initial excitation signal in reverse to obtain the initial imaging excitation signal. The compensation unit is used to perform a first compensation process on the imaging excitation signal of the next frame based on the deviation between the capacitance change parameter and the capacitance reference parameter to obtain a first imaging excitation signal, and to perform a second compensation process on the first imaging excitation signal based on the residual deviation between the imaging reference parameter and the imaging residual parameter to obtain a second imaging excitation signal. The CMUT is used to emit a preset detection ultrasonic wave after the built-in bias voltage is formed, emit an imaging ultrasonic wave based on the initial imaging excitation signal, and emit the next frame imaging ultrasonic wave based on the second imaging excitation signal. The digital signal processing module includes a parameter processing unit and an image reconstruction unit; The parameter processing unit is used to extract the corresponding imaging reference parameters and capacitance reference parameters when receiving the echo signal of the preset detection ultrasonic wave. The imaging reference parameters include fundamental response parameters, harmonic reference parameters and crosstalk reference parameters. After the built-in bias voltage is formed, a preset detection ultrasonic wave is emitted; When receiving the echo signal of the preset detection ultrasonic wave, the echo signal of the preset detection ultrasonic wave is converted and processed to obtain the corresponding echo electrical signal. The echo signal is filtered to obtain the corresponding amplitude response sequence and phase response sequence. Feature extraction is performed on the amplitude response sequence and phase response sequence to form the fundamental response parameters. The echo signal is subjected to spectrum analysis to extract harmonic components of a preset order. The harmonic components of the preset order are then analyzed to obtain harmonic reference parameters. Spatial statistical analysis is performed on the echo electrical signal to obtain the corresponding crosstalk reference parameters; When receiving the echo signal of the preset detection ultrasonic wave, the corresponding driving electrical signal is obtained, the capacitance value is calculated based on the driving electrical signal, the capacitance value is statistically analyzed to obtain the average capacitance value and the capacitance fluctuation amplitude, and the average capacitance value and the capacitance fluctuation amplitude are used as the capacitance reference parameters. During each frame of the patient imaging detection process, the echo signal of the imaging ultrasound is converted and processed to obtain the capacitance change parameters and imaging residual parameters corresponding to the current frame. The imaging residual parameters include fundamental residual parameters, harmonic residual parameters and crosstalk residual parameters. The image reconstruction unit is used to process the echo signal of the imaging ultrasound in the next frame and output the corresponding imaging detection result.

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