A method and apparatus for full-screen color Doppler blood flow imaging based on sparse delay computation

Abstract

This invention provides a method and apparatus for full-screen color Doppler blood flow imaging based on sparse delay computation. The method includes: transmitting plane wave ultrasound signals of different modes and different deflection angles, and receiving the corresponding echo signals and storing them in a buffer device; performing sparse delay computation on the echo signal data of the effective color blood flow region; performing deviation calibration on the echo signals and demodulating the signals into IQ signals; performing superposition and smoothing processing on the IQ signals of different modes to obtain image data; performing wall filtering on the image data to obtain blood flow signals; calculating Doppler phase shift and blood flow velocity based on the blood flow signals, and generating color blood flow image data according to pseudo-color encoding; and simultaneously displaying the color blood flow image data and B-mode grayscale image in a full-screen display area in real time, and displaying deflection angle indicators and related parameters. This not only eliminates the lack of blood flow information at the image boundaries and presents the complete blood flow distribution, but also simplifies the user operation process.

Description

Technical Field

[0001] This invention relates to the field of ultrasound imaging technology, and in particular to a method and apparatus for full-screen color Doppler blood flow imaging based on sparse delay calculation. Background Technology

[0002] Currently, in medical ultrasound, doctors typically use color Doppler flow imaging (CDFI) to examine a patient's blood flow information and condition. CDFI displays blood flow information to doctors in real time based on a visual representation of pseudo-color blood flow, making it a commonly used examination mode for various organs and parts of the human body. Traditional color Doppler flow imaging (CDFI) typically features a region of interest (ROI) for color blood flow imaging. However, this ROI imposes several limitations on the imaging process. First, because color blood flow is only displayed within the ROI, adjustments to its size, position, and angle can create triangular, trapezoidal, or rectangular non-imaging areas outside the ROI. Within these non-imaging areas, some edge regions may fail to display color blood flow, resulting in missing color blood flow. Second, users actively seek to avoid missing color blood flow, leading to frequent adjustments to parameters such as size, position, and angle, making the CDFI imaging process more cumbersome. Furthermore, widening and deepening the ROI significantly reduces the frame rate of the color blood flow image, even causing stuttering, due to limitations in traditional transmission methods. Therefore, we need a CDFI imaging method and device that offers more comprehensive color blood flow information coverage, is easier to operate, and has fewer frame rate limitations. Therefore, in order to overcome the above-mentioned technical problems, the present invention provides a method and apparatus for full-screen color Doppler blood flow imaging based on sparse delay calculation. Summary of the Invention

[0003] This invention provides a full-screen color Doppler blood flow imaging method and apparatus based on sparse delay computation. By limiting sparse delay computation to the effective color blood flow region and combining it with multi-angle plane wave emission and cross-scanning, the computational complexity is significantly reduced, thereby effectively improving the imaging frame rate while maintaining blood flow detection sensitivity. Through calibration and superposition smoothing of multi-deflection angle echo signals, the uniformity and signal-to-noise ratio of the blood flow signal are improved, resulting in higher quality color blood flow images. Ultimately, the color blood flow image can be displayed synchronously and in real-time across the entire screen, without being limited by the traditional ROI sampling frame. This not only eliminates the loss of blood flow information at image boundaries and fully presents the blood flow distribution but also simplifies the user operation process, eliminating the need for manual adjustment of the sampling frame position and angle. Simultaneously, the deflection angle indicator integrated into the interface further enhances the visualization of the scanning status and the intuitiveness of operation.

[0004] A full-screen color Doppler blood flow imaging method based on sparse delay computation includes: S00: Based on the probe scanning, it emits plane wave ultrasonic signals of different modes and different deflection angles, and receives the corresponding echo signals and stores them in the buffer device; S01: Perform sparse delay calculation on the echo signal data in the effective color blood flow region of the buffer device; S02: Perform deviation calibration on the echo signal after the sparse delay calculation, and demodulate the calibrated signal into an IQ signal; S03: Superimpose and smooth the IQ signals of different modes to obtain image data superimposed with different deflection angles; S04: Perform wall filtering on the image data to obtain the wall-filtered blood flow signal; S05: Calculate the Doppler phase shift and blood flow velocity based on the blood flow signal after wall filtering, and generate color blood flow image data according to pseudo-color encoding; S06: The color blood flow image data and the B-mode grayscale image are simultaneously displayed in real time in the full-screen display area, and the deflection angle indicator and related parameters are displayed.

[0005] Preferably, a full-screen color Doppler blood flow imaging method based on sparse delay computation, wherein step S00 includes: The emitted plane wave ultrasound signal covers the entire scanning area, and cross-scanning of B mode and CDFI mode is performed simultaneously during the scanning process; If the B mode scan ends prematurely, the remaining scan time will be used only for the CDFI mode scan; The deflection angles include -θ, θ, and 0.

[0006] Preferably, a full-screen color Doppler blood flow imaging method based on sparse delay computation includes, in step S01, the method prior to performing sparse delay computation as follows: Acquire a grayscale image obtained by beamforming processing of B-mode data; The grayscale image is subjected to thresholding to obtain a binary mask, wherein the pixel positions that are higher than a preset brightness threshold are marked as the first value, and the remaining pixel positions are marked as the second value; Based on the binary mask, the region composed of the second value pixels is extracted, identified and marked as the effective color imaging region in the grayscale image; The sparse delay calculation is performed within the effective color imaging area.

[0007] Preferably, a full-screen color Doppler blood flow imaging method based on sparse delay calculation, wherein in step S01, sparse delay calculation is performed on the echo signal data in the effective color blood flow region of the buffer device, including: Based on the geometric relationship between the primary and secondary computational scan lines, a delay difference function T(t) is established relative to the delay of the primary computational scan line. Calculate the first and second partial derivatives of the delay difference function T(t); Wherein, the first-order partial derivative is equal to or greater than 0 and the second-order partial derivative is less than 0. At the same time, when the difference of T(t) between two adjacent sampling points is less than the minimum sampling point interval, the delay calculation of the delay of adjacent sampling points is omitted based on the delay difference function T(t). Based on the aforementioned main calculation, the time delay t of the scan line at sampling point n is calculated. n The time delay t of sampling point n+m is determined by the time delay difference function T(t). n+m .

[0008] Preferably, in a full-screen color Doppler blood flow imaging method based on sparse delay computation, step S02 involves deviation calibration of the echo signal after sparse delay computation, including: The echo signal data at different deflection angles is divided into multiple data blocks; Calculate the target deviation of each data block relative to the reference deflection angle data; The data blocks are proportionally calibrated according to the target deviation to ensure that all deflection angle data are located in the same coordinate system.

[0009] Preferably, in a full-screen color Doppler blood flow imaging method based on sparse delay computation, step S03 involves superimposing and smoothing the IQ signals from different modes, including: The IQ data is divided into B-mode IQ signal data and CDFI-mode IQ signal data according to the imaging mode. Acquire IQ signal data with different deflection angles stored in sequence according to the scanning time order; Correct the IQ signal data corresponding to different deflection angles to the same coordinate system; The corrected IQ signal data is subjected to superposition smoothing processing to obtain superposition smoothed target data, wherein the superposition smoothing processing includes: spatial multi-angle composite superposition or weighted superposition. For B-mode IQ signal data, after the above-mentioned superposition smoothing process, grayscale image post-processing is performed to generate a B-mode image. For CDFI mode IQ signal data, the aforementioned superposition and smoothing process is performed.

[0010] Preferably, in a full-screen color Doppler blood flow imaging method based on sparse delay computation, step S04 involves wall filtering of the image data, including: Acquire image data containing blood flow signals; The image data includes tissue noise signals, effective blood flow signals, and other clutter noise signals. The amplitude of the tissue noise signal is greater than the amplitude of the effective blood flow signal; The image data is subjected to wall filtering to remove the tissue noise signal and other clutter noise signals, and the effective blood flow signal is extracted based on the filtering result; Among them, the wall filtering method includes at least one of the following filtering methods: infinite impulse response filtering, finite impulse response filtering, polynomial regression filtering, or singular value decomposition filtering; Based on the wall filtering process, blood flow signal data after filtering out clutter is obtained.

[0011] Preferably, a full-screen color Doppler blood flow imaging method based on sparse delay computation includes, in step S05: The formula for calculating the Doppler phase shift of the blood flow signal after wall filtering is as follows: ; in, The Doppler phase shift represents the blood flow signal; N represents the total number of frames of continuous blood flow signal data. The sequence number value represents the frame number corresponding to the blood flow signal; This represents the in-phase component of the demodulated and filtered IQ signal data corresponding to the nth frame of the blood flow signal. This represents the quadrature component of the demodulated and filtered IQ signal data corresponding to the nth frame of the blood flow signal; This represents the in-phase component of the demodulated and filtered IQ signal data corresponding to the (n-1)th frame of the blood flow signal. This represents the quadrature component of the demodulated and filtered IQ signal data corresponding to the (n-1)th frame of the blood flow signal; Represents the arctangent function; According to the Doppler phase shift Calculate the blood flow velocity at different locations within the scanning range; ; in, Indicates blood flow velocity; This indicates the speed at which ultrasound travels through human tissues, and prrf represents the pulse repetition frequency. Indicates the center frequency; It represents pi (π).

[0012] Preferably, in a full-screen color Doppler blood flow imaging method based on sparse delay computation, in S06, the color blood flow image data and the B-mode grayscale image are simultaneously displayed in real time in the full-screen display area, and the deflection angle indicator and related parameters are displayed, including: Set the image display area and other parameter display areas on the display interface; The image display area is used to simultaneously display B-mode images and CDFI-mode color blood flow images in full screen. The displayed CDFI mode color blood flow image is a full-screen image that is not limited by the boundaries of the ROI sampling frame; An angle indicator is set within the image display area, and the deflection state of the current scan is indicated according to the angle indicator; When the angle indicator is rectangular, it indicates that the scan is in a no-deflection state; When the angle indicator presents a parallelogram shape, it indicates that the scan is in a deflection state; The left and right sides of the parallelogram are used to indicate the direction of deflection, and the degree of inclination of the sides is used to indicate the magnitude of the deflection angle.

[0013] A full-screen color Doppler blood flow imaging device based on sparse delay computation includes: The plane wave signal transmission, reception and buffering module is used to transmit plane wave ultrasonic signals of different modes and different deflection angles based on probe scanning, and to receive the corresponding echo signals and store them in the buffer device. A sparse delay calculation module is used to perform sparse delay calculation on echo signal data in the effective color blood flow region of the buffer device; The signal demodulation module is used to perform deviation calibration on the echo signal after sparse delay calculation, and demodulate the calibrated signal into an IQ signal; The signal superposition and smoothing module is used to superimpose and smooth the IQ signals of different modes to obtain image data superimposed at different deflection angles; A wall filtering module is used to perform wall filtering on the image data to obtain the blood flow signal after wall filtering. The blood flow parameter calculation module is used to calculate the Doppler phase shift and blood flow velocity based on the blood flow signal after wall filtering, and to generate color blood flow image data according to pseudo-color encoding. The full-screen image and parameter display module is used to simultaneously display the color blood flow image data and the B-mode grayscale image in the full-screen display area in real time, and to display the deflection angle indicator and related parameters.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: By limiting sparse delay calculation to the effective color blood flow region and combining multi-angle plane wave emission and cross-scanning, the computational complexity is significantly reduced, thereby effectively improving the imaging frame rate while maintaining blood flow detection sensitivity. Calibration and superposition smoothing of multi-deflection angle echo signals improves the uniformity and signal-to-noise ratio of the blood flow signal, resulting in higher quality color blood flow images. Ultimately, the color blood flow image can be displayed synchronously and in real-time across the entire screen, without being limited by the traditional ROI sampling frame. This not only eliminates the loss of blood flow information at image boundaries and fully presents the blood flow distribution but also simplifies the user operation process, eliminating the need for manual adjustment of the sampling frame position and angle. Furthermore, the deflection angle indicator integrated into the interface further enhances the visualization of the scanning status and the intuitiveness of operation.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in this application.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of a full-screen color Doppler blood flow imaging method based on sparse delay computation in an embodiment of the present invention; Figure 2 This is a schematic diagram of image plane wave emission and scanning in CDFI mode in a full-screen color Doppler blood flow imaging method based on sparse delay calculation in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the sparse delay calculation of the effective color blood flow region in a full-screen color Doppler blood flow imaging method based on sparse delay calculation in an embodiment of the present invention. Figure 4 This is a schematic diagram of data calibration in a full-screen color Doppler blood flow imaging method based on sparse delay computation in an embodiment of the present invention; Figure 5 This is a schematic diagram of the superimposed smoothing in a full-screen color Doppler blood flow imaging method based on sparse delay calculation in an embodiment of the present invention; Figure 6 This is a schematic diagram of the signal spectrum before wall filtering in a full-screen color Doppler blood flow imaging method based on sparse delay computation in an embodiment of the present invention. Figure 7 This is a schematic diagram of the calculation module for Doppler signal phase shift and blood flow velocity in a full-screen color Doppler blood flow imaging method based on sparse delay computation in an embodiment of the present invention. Figure 8 This is a schematic diagram of the final image and parameters in a full-screen color Doppler blood flow imaging method based on sparse delay computation in an embodiment of the present invention; Figure 9 This is a structural diagram of a full-screen color Doppler blood flow imaging device based on sparse delay computation in an embodiment of the present invention. Detailed Implementation

[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0019] Example 1: This example provides a full-screen color Doppler blood flow imaging method based on sparse delay computation, such as... Figure 1 As shown, it includes: S00: Based on the probe scanning, it emits plane wave ultrasonic signals of different modes and different deflection angles, and receives the corresponding echo signals and stores them in the buffer device; S01: Perform sparse delay calculation on the echo signal data in the effective color blood flow region of the buffer device; S02: Perform deviation calibration on the echo signal after the sparse delay calculation, and demodulate the calibrated signal into an IQ signal; S03: Superimpose and smooth the IQ signals of different modes to obtain image data superimposed with different deflection angles; S04: Perform wall filtering on the image data to obtain the wall-filtered blood flow signal; S05: Calculate the Doppler phase shift and blood flow velocity based on the blood flow signal after wall filtering, and generate color blood flow image data according to pseudo-color encoding; S06: The color blood flow image data and the B-mode grayscale image are simultaneously displayed in real time in the full-screen display area, and the deflection angle indicator and related parameters are displayed.

[0020] In this embodiment, B-mode image: ultrasound grayscale image; C-mode (CDFI mode) image: ultrasound color Doppler blood flow imaging; demodulation: a signal processing method; IQ data: a data format obtained after signal processing; wall filtering: a filter used to highlight blood flow signals; plane wave ultrasound: a form of ultrasound propagation used for ultrasound scanning; deflection angle: an angle that causes the ultrasound scan line to deviate from the probe normal direction; phase shift: Doppler phase shift, a data variable used for blood flow velocity calculation; sparse delay: a calculation method that reduces the number of delay calculations along the depth direction based on the change in delay calculation, thereby improving imaging efficiency.

[0021] The working principle and beneficial effects of the above technical solution are as follows: By limiting sparse delay calculation to the effective color blood flow region and combining multi-angle plane wave emission and cross-scanning, the computational complexity is significantly reduced, thereby effectively improving the imaging frame rate while ensuring blood flow detection sensitivity. By calibrating and superimposing smoothing the multi-deflection angle echo signals, the uniformity and signal-to-noise ratio of the blood flow signal are improved, resulting in better quality color blood flow images. Finally, the color blood flow image can be displayed synchronously and in real-time across the entire screen, without being limited by the traditional ROI sampling frame. This not only eliminates the loss of blood flow information at image boundaries and fully presents the blood flow distribution, but also simplifies the user operation process, eliminating the need to manually adjust the sampling frame position and angle. Simultaneously, the deflection angle indicator integrated into the interface further enhances the visualization of the scanning status and the intuitiveness of operation.

[0022] Example 2: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay computation. S00 includes: The emitted plane wave ultrasound signal covers the entire scanning area, and cross-scanning of B mode and CDFI mode is performed simultaneously during the scanning process; If the B mode scan ends prematurely, the remaining scan time will be used only for the CDFI mode scan; The deflection angles include -θ, θ, and 0.

[0023] In this embodiment, S00 transmits plane wave ultrasonic signals in different modes and performs cross-scanning at different deflection angles, as follows: Figure 2 The diagram shows the image transmission and scanning when entering CDFI mode. S10 is the direction of ultrasound signal scanning in CDFI mode in chronological order. S11 is the B mode transmission scan line (black) and the CDFI mode transmission scan line (gray). S12 is a set of B mode scan lines (black) and a set of CDFI mode scan lines (gray). Figure 2In S12, the number and duration of each scan line group are determined by the parameters of both B and CDFI modes, such as line density and scan duration. During emission scanning, a plane wave needs to be emitted to cover the entire screen of the image scan. When initially entering CDFI mode, since both B and CDFI mode images are being formed, B mode scan lines and CDFI scan lines need to be scanned alternately. Once the B mode scan lines have been emitted and scanned in advance, the remaining time is used only for CDFI mode emission scanning.

[0024] Then data at different deflection angles under each mode is received, such as Figure 2 The diagram illustrates cross-scanning at different deflection angles. S13 represents the direction of ultrasound signal scanning in chronological order in CDFI mode, and S14 represents the transmission deflection angle at the first ultrasound signal transmission. The plane wave, the deflection angle of the second ultrasonic signal transmission is "". The plane wave, the deflection angle of the emitted ultrasonic signal during the third emission is " The plane wave, S15, indicates that during one cycle of transmitting ultrasonic signals, the waves are sequentially emitted with deflection angles of "". A plane wave. In one cycle, three plane waves need to be emitted, and the angle needs to be "". The plane wave echo signals received in each cycle are sequentially stored in a buffer. In subsequent calculation steps, a GPU can be added to the ultrasonic machine hardware to accelerate data processing. In one embodiment, the image processing system uses an NVIDIA RTX 4090 GPU with 24GB of video memory and 82 TFLOPS of computing power.

[0025] The beneficial effects of the above technical solution are: by combining full-screen plane wave coverage, dual-mode cross scanning and multi-angle deflection sequence, the frame rate and temporal resolution of imaging are significantly improved while ensuring image quality; at the same time, combined with GPU acceleration processing, real-time and efficient full-screen color Doppler blood flow imaging is realized, which is suitable for dynamic blood flow detection scenarios such as heart and blood vessels.

[0026] Example 3: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay calculation. In step S01, before performing the sparse delay calculation, the following steps are included: Acquire a grayscale image obtained by beamforming processing of B-mode data; The grayscale image is subjected to thresholding to obtain a binary mask, wherein the pixel positions that are higher than a preset brightness threshold are marked as the first value, and the remaining pixel positions are marked as the second value; Based on the binary mask, the region composed of the second value pixels is extracted, identified and marked as the effective color imaging region in the grayscale image; The sparse delay calculation is performed within the effective color imaging area.

[0027] In this embodiment, before performing sparse delay calculation on CDFI data, beamforming processing is first performed on the B-mode data to obtain the corresponding grayscale image, denoted as B_gray.

[0028] Next, a thresholding process is applied to B_gray by setting a preset brightness threshold: pixels with grayscale values ​​higher than the threshold are identified as non-blood flow regions (usually corresponding to high-brightness structures such as tissue), while the remaining locations are considered potential blood flow regions. A binary mask is generated based on the judgment result, where the positions of valid color imaging points (i.e., blood flow regions) are marked as 1 (second value), and the positions of invalid points (such as highly reflective tissue) are marked as 0 (first value).

[0029] Based on this binary mask, the system identifies and marks the effective color imaging region in the grayscale image, denoted as region Ω. In subsequent sparse time-delay calculations, the corresponding blood flow estimation and imaging processing are performed only within this region Ω. This avoids redundant calculations on the entire frame image, significantly saving computation time and resources.

[0030] The beneficial effects of the above technical solution are: by determining the effective color imaging area, redundant calculations on the entire frame image are avoided, significantly saving calculation time and resources, thereby effectively improving the calculation efficiency while ensuring the quality of blood flow imaging.

[0031] Example 4: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay calculation. In step S01, sparse delay calculation is performed on the echo signal data in the effective color blood flow region of the buffer device, including: Based on the geometric relationship between the primary and secondary computational scan lines, a delay difference function T(t) is established relative to the delay of the primary computational scan line. Calculate the first and second partial derivatives of the delay difference function T(t); Wherein, the first-order partial derivative is equal to or greater than 0 and the second-order partial derivative is less than 0. At the same time, when the difference of T(t) between two adjacent sampling points is less than the minimum sampling point interval, the delay calculation of the delay of adjacent sampling points is omitted based on the delay difference function T(t). Based on the aforementioned main calculation, the time delay t of the scan line at sampling point n is calculated. n The time delay t of sampling point n+m is determined by the time delay difference function T(t). n+m。

[0032] In this embodiment, as shown in Figure 3 , the schematic diagram of sparse delay calculation for the effective color blood flow area of the received data is shown. S20 represents the imaging area in the ultrasonic CDFI mode, where the x - direction represents the direction of the probe element sorting, and the y - direction represents the imaging depth direction. S21 and S22 respectively represent the secondary calculation scan lines Line n and Line n+1 at two different transmission time delays tn and tn + 1 at the same transmission position. S23 represents the primary calculation scan line that provides the time delay points and data points for the secondary calculation scan lines. Here, the time delay is t i . S24 represents the interval distance K between the starting positions of the primary and secondary calculation scan lines, and S25 represents the angle φ formed by the primary calculation scan line and the distance K in the triangle formed by the primary and secondary calculation scan lines.

[0033] In this embodiment, the primary scan line is the central element scan line, and the secondary scan line is the scan line of other elements. By converting and marking the time delay distances of the primary and secondary calculation scan lines as t and tc respectively, the relationship formula between the two can be obtained: From this, the first - order and second - order partial derivatives of t are respectively: When the calculation results t n and t n+1 of Line n and Line n+1 already exist, it is found that there are and , and the between adjacent sampling points is less than the minimum sampling point interval. Omitting the direct calculation steps of , the delay time is directly related to t. In one embodiment, is directly used as the calculation result of the deeper sampling point in the depth direction; thus, the time spent on directly calculating the delay is greatly saved.

[0034] The beneficial effects of the above - mentioned technical solution are as follows: By introducing a sparse delay calculation method based on geometric relationships, the computational complexity and resource occupancy are significantly reduced while ensuring the accuracy of blood flow imaging. By establishing a delay difference function and judging the conditions of its first - order and second - order partial derivatives, the independent delay calculation of adjacent sampling points can be intelligently omitted, thereby greatly improving the processing efficiency without affecting the imaging quality.

[0035] Embodiment 5: On the basis of Embodiment 1, this embodiment provides a full-screen color Doppler flow imaging method based on sparse delay calculation. In S02, deviation calibration is performed on the echo signal after sparse delay calculation, including: Dividing the echo signal data with different deflection angles into multiple data blocks; Calculating the target deviation of each data block relative to the reference deflection angle data; Performing proportional calibration on each data block according to the target deviation so that all deflection angle data are located in the same coordinate system.

[0036] In this embodiment, as Figure 4 shown, in the data calibration schematic diagram, S30 represents the timing direction of ultrasonic scanning in the CDFI mode, S31 represents the echo data with different deflection angles received in the buffer, S32 represents the coordinate calibration process, and S33 represents the result data data_norm obtained after calibration. In one embodiment, when calculating the calibration result for each scan cycle, the echo data with deflection angles of " " and " " are calibrated according to the deviation from the echo data with a deflection angle of " ". The main process is as follows: The data with a deflection angle of " " are respectively marked as , , . First, the horizontal and vertical dimensions of the three types of data are respectively extracted as , , ; then the three types of data are respectively divided into small data blocks of size , , . The minimum values of the variables , , shall not be less than 1. Then, calculate the deviation between the , in each , small data block and the corresponding in small data block, and calibrate each small data block according to the deviation in proportion, that is, finally complete the calibration of , , .

[0037] After calibration, each echo data with a deflection angle will correspond to a data_norm result. It is necessary to perform quadrature demodulation on the B-mode data and CDFI-mode data respectively to obtain the IQ signal.

[0038] The beneficial effects of the above technical solution are as follows: by adopting a data block division and deviation calibration mechanism, the problem of coordinate system inconsistency between echo signals with multiple deflection angles is effectively solved, and the spatial consistency and geometric accuracy of blood flow imaging are improved; by calculating the deviation of each data block relative to the reference data and performing proportional calibration, image distortion and artifacts caused by scanning angle differences can be eliminated, thereby enhancing the authenticity and comparability of color Doppler images.

[0039] Example 6: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay computation. In step S03, the IQ signals of different modes are superimposed and smoothed, including: The IQ data is divided into B-mode IQ signal data and CDFI-mode IQ signal data according to the imaging mode. Acquire IQ signal data with different deflection angles stored in sequence according to the scanning time order; Correct the IQ signal data corresponding to different deflection angles to the same coordinate system; The corrected IQ signal data is subjected to superposition smoothing processing to obtain superposition smoothed target data, wherein the superposition smoothing processing includes: spatial multi-angle composite superposition or weighted superposition. For B-mode IQ signal data, after the above-mentioned superposition smoothing process, grayscale image post-processing is performed to generate a B-mode image. For CDFI mode IQ signal data, the aforementioned superposition and smoothing process is performed.

[0040] In this embodiment, such as Figure 5 As shown in the superimposed smoothing diagram, S40 represents the temporal direction of ultrasound scanning in CDFI mode, and S41, S42, and S43 represent the IQ data stored in the buffer in chronological order after demodulation. In one embodiment, S41, S42, and S43 respectively represent " "", "", "The data corresponding to the deflection angle, S44 is the data after superposition and smoothing, data_smooth. S44 is obtained after superposition and smoothing of S41, S42, and S43. After demodulating the IQ data, the data is divided into B-mode and CDFI-mode IQ data according to different modes. The B-mode data is superimposed and then post-processed to obtain the grayscale image; the CDFI-mode data is only superimposed. During superposition, the IQ data with different deflection angles need to be pre-corrected to the same coordinate system; here, superposition usually refers to spatial multi-angle composite superposition, weighted superposition, etc., to achieve the purpose of superposition smoothing."

[0041] The beneficial effects of the above technical solution are: by correcting and superimposing multi-angle IQ signal data in different modes, the image signal-to-noise ratio and spatial consistency are significantly improved, and artifacts are effectively suppressed.

[0042] Example 7: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay computation. In step S04, wall filtering is performed on the image data, including: Acquire image data containing blood flow signals; The image data includes tissue noise signals, effective blood flow signals, and other clutter noise signals. The amplitude of the tissue noise signal is greater than the amplitude of the effective blood flow signal; The image data is subjected to wall filtering to remove the tissue noise signal and other clutter noise signals, and the effective blood flow signal is extracted based on the filtering result; Among them, the wall filtering method includes at least one of the following filtering methods: infinite impulse response filtering, finite impulse response filtering, polynomial regression filtering, or singular value decomposition filtering; Based on the wall filtering process, blood flow signal data after filtering out clutter is obtained.

[0043] In this embodiment, the wall filtering method is not limited to one or more, but is intended to filter out tissue noise and clutter signals; the wall filtering method does not exclude the use of artificial intelligence to achieve automatic filtering.

[0044] In this embodiment, such as Figure 6 As shown in the diagram, in the spectrum diagram of the signal before wall filtering, S50 represents the amplitude of the tissue noise signal, S51 represents the schematic spectrum of the tissue noise signal, S52 represents the amplitude of the effective blood flow signal, S53 represents the schematic bandwidth of the effective blood flow signal, S54 represents the schematic spectrum of the effective blood flow signal, S55 represents the schematic spectrum of other clutter noise signals, and S56 represents the amplitude of other clutter noise signals. In normally acquired CDFI signals, the amplitude of the tissue noise signal is generally much higher than that of the effective blood flow signal. If it is not filtered out, the effective blood flow signal cannot be extracted and analyzed; in addition, the presence of other clutter signals will also affect the quality of the CDFI image. Common wall filtering methods include initial infinite impulse response (IIR) filtering, finite impulse response (FIR) filtering, polynomial regression filtering, and singular value decomposition filtering. After wall filtering, the blood flow signal data data_IQ_filt with clutter signals filtered out is obtained.

[0045] The beneficial effects of the above technical solution are as follows: By introducing a wall filtering process, the key problem of tissue motion noise masking low-velocity and weak blood flow signals in color Doppler imaging is effectively solved; by identifying and separating high-amplitude tissue noise, clutter, and effective blood flow signals, and using one or more methods such as infinite impulse response filtering, finite impulse response filtering, polynomial regression filtering, or singular value decomposition filtering for targeted filtering, the system's detection sensitivity and signal purity for low-velocity blood flow are significantly improved. This step, while preserving hemodynamic information, greatly suppresses interference caused by vessel wall pulsation and tissue movement, thereby obtaining clearer and more reliable blood flow signal data.

[0046] Example 8: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay computation. Step S05 includes: The formula for calculating the Doppler phase shift of the blood flow signal after wall filtering is as follows: ; in, The Doppler phase shift represents the blood flow signal; N represents the total number of frames of continuous blood flow signal data. The sequence number value represents the frame number corresponding to the blood flow signal; This represents the in-phase component of the demodulated and filtered IQ signal data corresponding to the nth frame of the blood flow signal. This represents the quadrature component of the demodulated and filtered IQ signal data corresponding to the nth frame of the blood flow signal; This represents the in-phase component of the demodulated and filtered IQ signal data corresponding to the (n-1)th frame of the blood flow signal. This represents the quadrature component of the demodulated and filtered IQ signal data corresponding to the (n-1)th frame of the blood flow signal; Represents the arctangent function; According to the Doppler phase shift Calculate the blood flow velocity at different locations within the scanning range; ; in, Indicates blood flow velocity; This indicates the speed at which ultrasound travels through human tissues, and prrf represents the pulse repetition frequency. Indicates the center frequency; It represents pi (π).

[0047] In this embodiment, the pulse repetition frequency generally refers to the frame rate after the superposition calculation is completed.

[0048] In this embodiment, such as Figure 7In the schematic diagram of the Doppler signal phase shift and blood flow information calculation modules shown, S60 is the input data, which represents the blood flow signal data data_IQ_filt after wall filtering; S61 is to perform phase shift calculation on the input data; S62 is to calculate blood flow information based on the phase shift; and S63 is to generate a blood flow Doppler image by mapping the blood flow information results. When calculating blood flow intensity images, the time-delayed calculation of blood flow velocity needs to be changed to a time-free calculation. After calculation, the obtained Doppler blood flow data is Img. Then, S63 sets the image threshold according to the calculation and displays a color Doppler blood flow image with color encoding based on the blood flow velocity results.

[0049] The beneficial effects of the above technical solution are as follows: by using the Doppler phase shift calculation formula based on the arctangent operation of IQ signal data, a high-precision and stable conversion from the wall-filtered signal to the quantitative blood flow velocity is achieved; the formula makes full use of the phase relationship of continuous frame IQ signal data, effectively suppresses the influence of noise interference on velocity estimation, and significantly improves the accuracy and repeatability of blood flow velocity measurement.

[0050] Example 9: Based on Example 1, this example provides a full-screen color Doppler blood flow imaging method based on sparse delay computation. In S06, the color blood flow image data and the B-mode grayscale image are simultaneously displayed in real time in the full-screen display area, and the deflection angle indicator and related parameters are displayed, including: Set the image display area and other parameter display areas on the display interface; The image display area is used to simultaneously display B-mode images and CDFI-mode color blood flow images in full screen. The displayed CDFI mode color blood flow image is a full-screen image that is not limited by the boundaries of the ROI sampling frame; An angle indicator is set within the image display area, and the deflection state of the current scan is indicated according to the angle indicator; When the angle indicator is rectangular, it indicates that the scan is in a no-deflection state; When the angle indicator presents a parallelogram shape, it indicates that the scan is in a deflection state; The left and right sides of the parallelogram are used to indicate the direction of deflection, and the degree of inclination of the sides is used to indicate the magnitude of the deflection angle.

[0051] In this embodiment, such as Figure 8As shown, in the display of the final image and parameters, S70 is the chart interface area for the current mode, S71 is the image display area, S72 is the CDFI mode color blood flow image displayed in the image, S73 is a parallelogram / rectangular angle indicator indicating the current angle deflection, and S74 is the display area for other parameters and buttons. The S71 display area occupies the main display portion of the screen and can simultaneously display both B mode and CDFI mode images in full screen. In one embodiment, the CDFI mode image displayed in S72 no longer exhibits incomplete display or missing corners due to the boundary limitations of the ROI sampling frame, and can be displayed in full screen in the image area like the B mode. In one embodiment, the S73 angle indicator is displayed in the lower right corner of the image. When the indicator displays a rectangle, the scan is not deflected; when it displays a parallelogram, it indicates that a deflection scan is currently in progress. If the direction of the two sides of the parallelogram is "upper left to lower right," the scan is deflected to the right; if the direction is "upper right to lower left," the scan is deflected to the left. The greater the tilt of the sides, the larger the deflection angle. A numerical display can be used near the indicator to make the deflection angle indication more accurate. The S74 display area is mainly used to display other parameters, buttons, icons, charts, etc.

[0052] The beneficial effects of the above technical solution are as follows: By using a full-screen fusion display scheme and intuitive visual indicators of deflection angle, the observation efficiency and operational intuitiveness of color Doppler imaging are significantly improved; by simultaneously displaying B-mode structural images and complete CDFI blood flow images without ROI limitations across the entire screen, information omissions caused by traditional local sampling frames are avoided, and panoramic observation of blood flow and anatomical structures is realized; at the same time, by designing a graphical angle indicator that can dynamically change according to the deflection state, the operator can grasp the deflection direction and angle of the scanning beam in real time and intuitively, enhancing the visualization and interactive feedback of the system status, which is conducive to the optimization and adjustment of scanning parameters and the assurance of image quality.

[0053] A full-screen color Doppler blood flow imaging device based on sparse delay computation, such as Figure 9 As shown, it includes: The plane wave signal transmission, reception and buffering module is used to transmit plane wave ultrasonic signals of different modes and different deflection angles based on probe scanning, and to receive the corresponding echo signals and store them in the buffer device. A sparse delay calculation module is used to perform sparse delay calculation on echo signal data in the effective color blood flow region of the buffer device; The signal demodulation module is used to perform deviation calibration on the echo signal after sparse delay calculation, and demodulate the calibrated signal into an IQ signal; The signal superposition and smoothing module is used to superimpose and smooth the IQ signals of different modes to obtain image data superimposed at different deflection angles; A wall filtering module is used to perform wall filtering on the image data to obtain the blood flow signal after wall filtering. The blood flow parameter calculation module is used to calculate the Doppler phase shift and blood flow velocity based on the blood flow signal after wall filtering, and to generate color blood flow image data according to pseudo-color encoding. The full-screen image and parameter display module is used to simultaneously display the color blood flow image data and the B-mode grayscale image in the full-screen display area in real time, and to display the deflection angle indicator and related parameters.

[0054] The working principle and beneficial effects of the above technical solution are as follows: By limiting sparse delay calculation to the effective color blood flow region and combining multi-angle plane wave emission and cross-scanning, the computational complexity is significantly reduced, thereby effectively improving the imaging frame rate while ensuring blood flow detection sensitivity. By calibrating and superimposing smoothing the multi-deflection angle echo signals, the uniformity and signal-to-noise ratio of the blood flow signal are improved, resulting in better quality color blood flow images. Finally, the color blood flow image can be displayed synchronously and in real-time across the entire screen, without being limited by the traditional ROI sampling frame. This not only eliminates the loss of blood flow information at image boundaries and fully presents the blood flow distribution, but also simplifies the user operation process, eliminating the need to manually adjust the sampling frame position and angle. Simultaneously, the deflection angle indicator integrated into the interface further enhances the visualization of the scanning status and the intuitiveness of operation.

[0055] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A full-screen color Doppler blood flow imaging method based on sparse delay computation, characterized in that, include: S00: Based on the probe scanning, it emits plane wave ultrasonic signals of different modes and different deflection angles, and receives the corresponding echo signals and stores them in the buffer device; S01: Perform sparse delay calculation on the echo signal data in the effective color blood flow region of the buffer device; S02: Perform deviation calibration on the echo signal after the sparse delay calculation, and demodulate the calibrated signal into an IQ signal; S03: Superimpose and smooth the IQ signals of different modes to obtain image data superimposed with different deflection angles; S04: Perform wall filtering on the image data to obtain the wall-filtered blood flow signal; S05: Calculate the Doppler phase shift and blood flow velocity based on the blood flow signal after wall filtering, and generate color blood flow image data according to pseudo-color encoding; S06: The color blood flow image data and the B-mode grayscale image are simultaneously displayed in real time in the full-screen display area, and the deflection angle indicator and related parameters are displayed.

2. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, The S00 includes: The emitted plane wave ultrasound signal covers the entire scanning area, and cross-scanning of B mode and CDFI mode is performed simultaneously during the scanning process; If the B mode scan ends prematurely, the remaining scan time will be used only for the CDFI mode scan; The deflection angles include -θ, θ, and 0.

3. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, In step S01, before performing sparse delay calculation, the following is included: Acquire a grayscale image obtained by beamforming processing of B-mode data; The grayscale image is subjected to thresholding to obtain a binary mask, wherein the pixel positions that are higher than a preset brightness threshold are marked as the first value, and the remaining pixel positions are marked as the second value; Based on the binary mask, the region composed of the second value pixels is extracted, identified and marked as the effective color imaging region in the grayscale image; The sparse delay calculation is performed within the effective color imaging area.

4. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, In step S01, sparse delay calculation is performed on the echo signal data in the effective color blood flow region of the buffer device, including: Based on the geometric relationship between the primary and secondary computational scan lines, a delay difference function T(t) is established relative to the delay of the primary computational scan line. Calculate the first and second partial derivatives of the delay difference function T(t); Wherein, the first-order partial derivative is equal to or greater than 0 and the second-order partial derivative is less than 0. At the same time, when the difference of T(t) between two adjacent sampling points is less than the minimum sampling point interval, the delay calculation of the delay of adjacent sampling points is omitted based on the delay difference function T(t). Based on the aforementioned main calculation, the time delay t of the scan line at sampling point n is calculated. n The time delay t of sampling point n+m is determined by the time delay difference function T(t). n+m .

5. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, In step S02, deviation calibration is performed on the echo signal after the sparse delay calculation, including: The echo signal data at different deflection angles is divided into multiple data blocks; Calculate the target deviation of each data block relative to the reference deflection angle data; The data blocks are proportionally calibrated according to the target deviation to ensure that all deflection angle data are located in the same coordinate system.

6. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, In step S03, the IQ signals of different modes are superimposed and smoothed, including: The IQ data is divided into B-mode IQ signal data and CDFI-mode IQ signal data according to the imaging mode. Acquire IQ signal data with different deflection angles stored in sequence according to the scanning time order; Correct the IQ signal data corresponding to different deflection angles to the same coordinate system; The corrected IQ signal data is subjected to superposition smoothing processing to obtain superposition smoothed target data, wherein the superposition smoothing processing includes: spatial multi-angle composite superposition or weighted superposition. For B-mode IQ signal data, after the above-mentioned superposition smoothing process, grayscale image post-processing is performed to generate a B-mode image. For CDFI mode IQ signal data, the aforementioned superposition and smoothing process is performed.

7. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, In step S04, wall filtering is performed on the image data, including: Acquire image data containing blood flow signals; The image data includes tissue noise signals, effective blood flow signals, and other clutter noise signals. The amplitude of the tissue noise signal is greater than the amplitude of the effective blood flow signal; The image data is subjected to wall filtering to remove the tissue noise signal and other clutter noise signals, and the effective blood flow signal is extracted based on the filtering result; Among them, the wall filtering method includes at least one of the following filtering methods: infinite impulse response filtering, finite impulse response filtering, polynomial regression filtering, or singular value decomposition filtering; Based on the wall filtering process, blood flow signal data after filtering out clutter is obtained.

8. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, S05 includes: The formula for calculating the Doppler phase shift of the blood flow signal after wall filtering is as follows: ； in, The Doppler phase shift represents the blood flow signal; N represents the total number of frames of continuous blood flow signal data. This indicates the sequence number of the blood flow signal corresponding to the frame. This represents the in-phase component of the demodulated and filtered IQ signal data corresponding to the nth frame of the blood flow signal. This represents the quadrature component of the demodulated and filtered IQ signal data corresponding to the nth frame of the blood flow signal; This represents the in-phase component of the demodulated and filtered IQ signal data corresponding to the (n-1)th frame of the blood flow signal. This represents the quadrature component of the demodulated and filtered IQ signal data corresponding to the (n-1)th frame of the blood flow signal; Represents the arctangent function; According to the Doppler phase shift Calculate the blood flow velocity at different locations within the scanning range; ； in, Indicates blood flow velocity; This indicates the speed at which ultrasound travels through human tissues, and prrf represents the pulse repetition frequency. Indicates the center frequency; It represents pi (π).

9. The full-screen color Doppler blood flow imaging method based on sparse delay computation according to claim 1, characterized in that, In S06, the color blood flow image data and the B-mode grayscale image are simultaneously displayed in real time in the full-screen display area, and the deflection angle indicator and related parameters are displayed, including: Set the image display area and other parameter display areas on the display interface; The image display area is used to simultaneously display B-mode images and CDFI-mode color blood flow images in full screen. The displayed CDFI mode color blood flow image is a full-screen image that is not limited by the boundaries of the ROI sampling frame; An angle indicator is set within the image display area, and the deflection state of the current scan is indicated according to the angle indicator; When the angle indicator is rectangular, it indicates that the scan is in a no-deflection state; When the angle indicator presents a parallelogram shape, it indicates that the scan is in a deflection state; The left and right sides of the parallelogram are used to indicate the direction of deflection, and the degree of inclination of the sides is used to indicate the magnitude of the deflection angle.

10. A full-screen color Doppler blood flow imaging device based on sparse delay computation, characterized in that, include: The plane wave signal transmission, reception and buffering module is used to transmit plane wave ultrasonic signals of different modes and different deflection angles based on probe scanning, and to receive the corresponding echo signals and store them in the buffer device. The sparse delay calculation module is used to perform sparse delay calculation on the echo signal data in the effective color blood flow region of the buffer device. The signal demodulation module is used to perform deviation calibration on the echo signal after sparse delay calculation, and demodulate the calibrated signal into an IQ signal; The signal superposition and smoothing module is used to superimpose and smooth the IQ signals of different modes to obtain image data superimposed at different deflection angles; A wall filtering module is used to perform wall filtering on the image data to obtain the blood flow signal after wall filtering. The blood flow parameter calculation module is used to calculate the Doppler phase shift and blood flow velocity based on the blood flow signal after wall filtering, and to generate color blood flow image data according to pseudo-color encoding. The full-screen image and parameter display module is used to simultaneously display the color blood flow image data and the B-mode grayscale image in the full-screen display area in real time, and to display the deflection angle indicator and related parameters.

Images