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CN-122004933-A - Baseband delay cumulative sum beam synthesis method, system, equipment and medium for ultrasonic imaging

CN122004933ACN 122004933 ACN122004933 ACN 122004933ACN-122004933-A

Abstract

The invention relates to a baseband delay cumulative sum wave beam synthesis method, a system, equipment and a medium for ultrasonic imaging, which comprises the steps of carrying out quadrature demodulation on ultrasonic data and channel signals, and preprocessing to obtain channel signals with delay alignment phase rotation of each emission angle of each voxel in an imaging visual field; and performing baseband delay cumulative summation operation on the channel signals of each voxel after delay alignment phase rotation of each emission angle to obtain a baseband DMAS output signal of an imaging field, and performing ultrasonic imaging based on the baseband DMAS output signal of the imaging field. The invention can be widely applied to the technical field of signal processing, and is particularly suitable for two-dimensional or three-dimensional ultrasonic positioning microscopic imaging, micro-blood flow imaging or other imaging.

Inventors

  • LUO JIANWEN
  • LI ZHIQIANG

Assignees

  • 清华大学

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. A baseband delay-accumulation sum beam-forming method for ultrasound imaging, comprising: the ultrasonic data are acquired and orthogonally demodulated with the channel signals, and the channel signals after the delay alignment phase rotation of each emission angle of each voxel in the imaging visual field are obtained through preprocessing; Performing baseband delay cumulative summation operation on the channel signals of each voxel after delay alignment phase rotation of each emission angle to obtain a baseband DMAS output signal of an imaging field of view; ultrasound imaging is performed based on the baseband DMAS output signal of the imaging field of view.
  2. 2. The method for baseband delay-and-accumulation and beam-forming for ultrasonic imaging according to claim 1, wherein the steps of performing quadrature demodulation on the ultrasonic data and the channel signals, and preprocessing to obtain the channel signals with delay alignment phase rotation of each emission angle of each voxel in the imaging field of view, include: based on the determined ultrasonic beam emission mode, adopting a full-addressing array transducer to acquire ultrasonic data, and obtaining radio frequency channel signals received by each array element; Carrying out quadrature demodulation on radio frequency channel signals received by each array element to obtain complex baseband channel signals; Clutter filtering is carried out on the complex baseband channel signals so as to inhibit tissue echo and keep microbubble scattering signals; For each voxel in the imaging field of view, interpolation and phase rotation are performed on the filtered complex baseband channel signal based on the calculated total propagation delay to obtain a delay-aligned phase-rotated channel signal for each emission angle of each voxel in the imaging field of view.
  3. 3. The method for baseband delay-accumulation and beam synthesis for ultrasound imaging according to claim 2, wherein the acquiring ultrasound data by using a fully addressed array transducer based on the determined ultrasound beam emission mode to obtain radio frequency channel signals received by each array element comprises: Determining an array form of a fully-addressed array transducer, wherein the array form adopts any one or any combination of a linear array, a convex array, a phased array or a fully-addressed two-dimensional matrix array; Defining a coordinate system and symbols of the fully-addressed array transducer; And controlling the fully addressed array transducer to transmit ultrasonic beams based on the determined ultrasonic beam transmitting mode, and obtaining radio frequency channel signals received by each array element.
  4. 4. The method of baseband delay-accumulation and beam-forming for ultrasonic imaging as claimed in claim 2, wherein said quadrature demodulation is performed on the radio frequency channel signals received by each array element to obtain complex baseband channel signals, and the formula is: In the formula, And Respectively represent time frames The lower emission dimension is The array element dimension is Channel signals and complex baseband signals; is a low-pass filtering operator used for reserving a baseband envelope; for demodulating carrier frequencies.
  5. 5. A baseband delay-and-multiply sum beam-forming method for ultrasound imaging as defined in claim 2, wherein said performing interpolation and phase rotation on the complex baseband channel signal based on the calculated total propagation delay for each voxel in the imaging field of view to obtain delay-aligned phase-rotated channel signals for each emission angle of each voxel in the complete imaging field of view comprises: for each voxel in the imaging field of view, calculate the first Ultrasonic wave of each emission angle and the first Total propagation delay of array elements The calculation formula is as follows: In the formula, Representing voxels First, the The transmission delay of ultrasonic waves of different transmission angles; Representing voxels First, the Delay of receiving array elements; and (3) carrying out delay alignment on the calculated total propagation delay by adopting a preset interpolation operator, wherein a calculation formula is as follows: In the formula, Representing the linearly interpolated delay-aligned channel signal; Representing the time delay according to the total propagation An operator for linear interpolation; representing the filtered complex baseband channel signal; Compensating the carrier phase based on the channel signals after delay alignment to obtain the first element of each voxel Delay alignment phase rotated channel signals for multiple transmit angles The calculation formula is as follows: In the formula, For demodulating carrier frequencies.
  6. 6. The method of baseband delay-and-sum beam synthesis for ultrasound imaging of claim 1, wherein said performing a baseband delay-and-sum operation on the delay-aligned phase-rotated channel signal for each of the emission angles of each of the voxels and obtaining a baseband DMAS output signal for the imaging field of view comprises: for each voxel Carrying out amplitude correction on the channel signals after the delay alignment phase rotation of the emission angles; performing conjugate multiplication based on the channel signal pair after amplitude correction, and taking the real part for summation to obtain a baseband DMAS paired summation formula; Equivalent pair summation in the baseband DMAS pair summation formula is calculated as accumulated quantity by using identity to obtain the first pixel of each voxel Baseband DMAS output signals of the emission angles; for each voxel Coherently compounding the baseband DMAS output signals of the emission angles to obtain a baseband DMAS output signal of each voxel; Based on the baseband DMAS output signal of each voxel, a baseband DMAS output signal of the imaging field of view is obtained.
  7. 7. A baseband delay-and-accumulation sum beam forming method for ultrasonic imaging as in claim 1 in which said imaging field-of-view based baseband DMAS output signal is used for ultrasonic imaging including ULM imaging or micro-blood flow imaging based on imaging field-of-view baseband DMAS output signal.
  8. 8. A baseband delay-accumulation sum beam forming system for ultrasound imaging, comprising: The data preprocessing module is used for carrying out quadrature demodulation on ultrasonic data and channel signals, and preprocessing to obtain channel signals after delay alignment phase rotation of each voxel in the complete imaging view; the beam synthesis module is used for executing baseband delay cumulative summation operation on the channel signals after the delay alignment phase rotation of each voxel and obtaining a baseband DMAS output signal of the complete imaging view; And the image generation module is used for carrying out ultrasonic imaging based on the baseband DMAS output signal of the complete imaging view.
  9. 9. A computer readable storage medium storing one or more programs, wherein the one or more programs comprise instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-7.
  10. 10. A computing device comprising one or more processors and memory, the memory having one or more programs stored therein and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods of claims 1-7.

Description

Baseband delay cumulative sum beam synthesis method, system, equipment and medium for ultrasonic imaging Technical Field The present invention relates to the field of signal processing technologies, and in particular, to a baseband delay and accumulation sum (DMAS) beam forming method, system, device, and medium for ultrasonic imaging. Background The abnormality of the structure and the function of the cerebral microvasculature is closely related to various cerebrovascular diseases and neurodegenerative diseases, and the accurate assessment of the shape and the blood flow of the microvasculature has important significance for disease diagnosis, monitoring and mechanism research. The existing imaging means have different limits that CT vascular imaging (CTA)/magnetic resonance vascular imaging (MRA) and the like can cover the whole brain but have high cost, ionizing radiation is possibly involved, the resolution is at millimeter level, optical means such as Optical Coherence Tomography (OCT) and two-photon imaging have high resolution but limited penetration depth, and the traditional transcranial Doppler and other ultrasonic technologies are sensitive to large blood vessels, but difficult to present the resolution and sensitivity required by a microvascular network. Ultrasonic Localization Microscopy (ULM) can achieve micron-scale super-resolution imaging at centimeter-scale penetration depths by combining frame-by-frame localization and frame-by-frame tracking by considering microbubble contrast agents as intravascular isolated scatterers, and has shown potential for application in organs such as brain, heart, kidneys, and the like. However, the existing ULM applications are mostly focused on two dimensions, and two dimensions ULM have the limitations of out-of-plane blood vessel and velocity component loss, projection errors, and operator dependence, etc., which drive the development of three-dimensional ULM to be necessary. Three-dimensional ULM requires three-dimensional channel data acquisition and volumetric reconstruction. Compared with a layer-by-layer acquisition mode of a mechanical scanning one-dimensional array, the fully-addressed two-dimensional matrix array can cover the whole volume at a higher volume frame rate, but the matrix array is often limited by factors such as reduced sensitivity of effective aperture and array element, relatively low center frequency and the like, so that the Point Spread Function (PSF) is degraded and the signal to noise ratio is reduced, thereby reducing the microbubble detection, positioning and tracking performance. After the channel data is acquired, the ULM typical procedure includes beam forming, clutter filtering, microbubble localization and tracking. The beam synthesis method has obvious influence on the positioning and separating capability of the microbubbles, namely, the adjacent microbubbles are difficult to separate due to wider main lobes, and the side lobes are misjudged as the microbubbles due to stronger side lobes. The traditional delay and sum (DAS) has the problems of wider main lobe and higher side lobe, and the coherence weighting methods such as Coherence Factor (CF), spatial Angle Coherence Factor (SACF) and the like can improve PSF indexes, but can inhibit or discard effective microbubble signals under the condition of low signal-to-noise ratio or microbubble weak echo so as to influence subsequent positioning and tracking. Delay-and-accumulation (DMAS) is a nonlinear beam-forming method that enhances spatial mutual coherence by multiplicatively coupling between pairs of delay channel signals, thereby suppressing side lobes and enhancing target echoes. However, existing DMAS are often implemented in the radio frequency domain, often requiring oversampling and additional filtering to recover the nonlinear multiplied spectral components, and forEach array element needs to be aboutSub-pairwise operation with a computational complexity ofIt is difficult to directly use three-dimensional ULM real-time or near real-time processing of large channel number fully addressed arrays. Disclosure of Invention The invention aims to provide a baseband delay cumulative sum beam forming method, a system, equipment and a medium for ultrasonic imaging, which are used for solving at least one of the following technical problems: (1) Aiming at the problem that the weak echoes of microbubbles are difficult to detect due to relatively low signal-to-noise ratio and sensitivity of the fully-addressed two-dimensional matrix array, a beam forming method capable of enhancing the detectability of the microbubbles is provided; (2) Oversampling and additional bandpass filtering are required for conventional radio frequency domain DMAS with computational complexity of To provide a method for realizing DMAS in a complex baseband domain and having an equivalent reduced calculation form, so as to reduce the calculation amount. In order to achieve the above purpose, the pres