CN105919625B - Pulse Doppler wall filtering processing method and processing system - Google Patents

Abstract

The invention provides a pulse Doppler wall filtering processing method and a processing system, wherein the method comprises the following steps: s1, acquiring IQ signals corresponding to the N sampling points on each echo signal to form an IQ signal sequence corresponding to each echo signal; s2, in the slow time direction, respectively carrying out FFT on each IQ signal sequence to obtain N groups of FFT conversion sequences; s3, filtering each group of FFT transform sequences in the fast time direction to obtain a plurality of groups of filtering transform sequences; and S4, respectively obtaining the complex envelopes corresponding to each group of filtering and transforming sequences, and obtaining a total envelope signal according to the complex envelopes corresponding to each group of filtering and transforming sequences for final spectrum display. The pulse Doppler wall filtering method and the processing system can accurately filter the low-speed clutter motion information, improve the convenience and the use efficiency of the ultrasonic imaging equipment and improve the quality of ultrasonic images.

Description

Pulse Doppler wall filtering processing method and processing system

Technical field

The invention belongs to medical ultrasound technical field, a kind of pulse Doppler wall filtering processing method and processing are related generally to System.

Background technique

Ultrasonic imaging becomes clinically because its is non-invasive, real-time, many advantages such as easy to operate, cheap One of means of auxiliary diagnosis being most widely used.Wherein, impulse Doppler imaging can conveniently and efficiently measure the tool of blood flow Body flow velocity becomes the judgment criteria of certain illnesss in clinical diagnosis.

Pulse Doppler is that Doppler frequency shift is detected from ultrasound echo signal according to Doppler effect, to calculate Blood flow velocity out.Ultrasound echo signal is mainly made of three parts: high-intensitive clutter component, blood flow caused by tissue reflection The flow Doppler component that scattering generates, also systematic thermal noise.Wherein the intensity of clutter component is eager to excel than blood flow signal Very much, it so during spectrum analysis, needs effectively to inhibit clutter component with wall filter, so wall filtering It is very important for design.

Wall filtering method is high-pass filtering to be carried out to the I/Q data after quadrature demodulation, to go in slow time orientation at present Remove low frequency Doppler component.Common wall filter has: low order FIR mode filter, IIR mode filter and polynomial regression filter Wave device.In these filters, the performance of projection initialization iir filter and polynomial regression filter has stopband attenuation Greatly, the advantages that intermediate zone is narrow and does not lose data, wherein the stopband cutoff frequency of projection initialization iir filter is more flexible more Become.

According to Doppler effect, scatters and depend on speed in the frequency displacement bandwidth of slow time orientation caused by the speed of son movement Size and signal bandwidth.When pulse Doppler is larger using door, transmitting signal is longer at this time, narrower bandwidth, if tissue and blood When tube wall is static or is moved with slower speed, on slow time orientation, traditional filter can obtain preferable filter effect； But when histokinesis is very fast or when the smaller transmitted signal bandwidth of sampling gate is wider, the frequency displacement bandwidth of clutter component be easy for and The frequency displacement bandwidth of blood flow is overlapped, this results in traditional filter to be difficult to effectively remove noise signal.

Summary of the invention

The purpose of the present invention is to provide a kind of pulse Doppler wall filtering processing method and processing systems.

One of in order to achieve the above-mentioned object of the invention, the pulse Doppler wall filtering processing method of an embodiment of the present invention, It the described method comprises the following steps: S1, the corresponding I/Q signal of N number of sampled point is obtained in every echo-signal, with group At the corresponding I/Q signal sequence of each echo-signal；

S2, on slow time orientation, FFT transform is done to each I/Q signal sequence respectively, to obtain N group FFT transform Sequence；

S3, on fast time orientation, the FFT transform sequence described in every group is filtered respectively, with obtain multiple groups filtering Transform sequence；

S4, the corresponding complex-envelope of every group of filtering transformation sequence is obtained respectively, it is corresponding according to every group of filtering transformation sequence Complex-envelope obtains total envelope signal, to show for final frequency spectrum.

As the further improvement of an embodiment of the present invention, the step S2 is specifically included:

M memory space is preset, each memory space stores one group of I/Q signal sequence, by the way of first in first out successively Storage obtains M group I/Q signal sequence；

Data of the M group I/Q signal sequence on identical column direction are obtained respectively, form the slow time change sequence of N group, and right It does FFT transform, to obtain N group FFT transform sequence.

As the further improvement of an embodiment of the present invention, the step S3 is specifically included:

P1, data of the N group FFT transform sequence on identical column direction, transform sequence before composition M group filters are obtained respectively；

P2, according to preset threshold speed, the repetition scanning frequency of initial transmissions signal, initial transmissions signal center frequency Rate does quadrature demodulation to echo-signal to generate the demodulation bandwidth of the low-pass filter used during I/Q signal, described in acquisition The corresponding frequency displacement cutoff frequency of pre-set velocity threshold value；

P3, it is obtained on fast time orientation according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value to the filtering of M group Preceding transform sequence makees the fast termporal filter being filtered；

Transform sequence is filtered before being filtered respectively to M group using the fast termporal filter, to obtain multiple groups filtering Transform sequence.

As the further improvement of an embodiment of the present invention, the step P3 is specifically included:

Quadrature demodulation is done according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and to echo-signal to generate Numerical relation between the demodulation bandwidth of the low-pass filter used during I/Q signal, the design fast termporal filter are Number,

Transform sequence is filtered by the fast termporal filter respectively before M group is filtered, to obtain M group filtering transformation Sequence.

As the further improvement of an embodiment of the present invention, the step P3 is specifically included:

Transform sequence does FFT transform and obtains FFT transform sequence before M group filters before filtering respectively to every group of M group；

That bears in FFT transform sequence before reservation M group filters respectively does quadrature demodulation to echo-signal to generate I/Q signal mistake Frequency between the demodulation bandwidth of the low-pass filter used in journey and the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value Component, and other components are set to 0；

FFT transform sequence does inverse FFT transformation before the filtering retained M group, to obtain multiple groups filtering transformation sequence.

One of in order to achieve the above-mentioned object of the invention, an embodiment of the present invention provides a kind of pulse Doppler wall filtering processing System, the system comprises: door sampling module, for obtaining the corresponding IQ of N number of sampled point in every echo-signal Signal, to form the corresponding I/Q signal sequence of each echo-signal；

Slow time-triggered protocol module, for doing FFT transform to each I/Q signal sequence respectively in slow time orientation, To obtain N group FFT transform sequence；

Fast time-triggered protocol module, in fast time orientation, the FFT transform sequence described in every group to be done at filtering respectively Reason, to obtain multiple groups filtering transformation sequence；

Output module, for obtaining the corresponding complex-envelope of every group of filtering transformation sequence respectively, according to every group of filtering transformation The corresponding complex-envelope of sequence obtains total envelope signal, to show for final frequency spectrum.

As the further improvement of an embodiment of the present invention, the slow time-triggered protocol module is also used to:

M memory space is preset, each memory space stores one group of I/Q signal sequence, by the way of first in first out successively Storage obtains M group I/Q signal sequence；

Data of the M group I/Q signal sequence on identical column direction are obtained respectively, form the slow time change sequence of N group, and right It does FFT transform, to obtain N group FFT transform sequence.

As the further improvement of an embodiment of the present invention, the fast time-triggered protocol module is also used to:

Data of the N group FFT transform sequence on identical column direction, transform sequence before composition M group filters are obtained respectively；

According to preset threshold speed, the repetition scanning frequency of initial transmissions signal, the centre frequency of initial transmissions signal, Quadrature demodulation is done to echo-signal to generate the demodulation bandwidth of the low-pass filter used during I/Q signal, is obtained described default The corresponding frequency displacement cutoff frequency of threshold speed；

It is obtained according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and is become before being filtered on fast time orientation to M group It changes sequence and makees the fast termporal filter being filtered；

Transform sequence is filtered before being filtered respectively to M group using the fast termporal filter, to obtain multiple groups filtering Transform sequence.

As the further improvement of an embodiment of the present invention, the fast time-triggered protocol module is specifically used for:

Quadrature demodulation is done according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and to echo-signal to generate Numerical relation between the demodulation bandwidth of the low-pass filter used during I/Q signal, the design fast termporal filter are Number,

Transform sequence is filtered by the fast termporal filter respectively before M group is filtered, to obtain M group filtering transformation Sequence.

As the further improvement of an embodiment of the present invention, the fast time-triggered protocol module is specifically used for:

Transform sequence does FFT transform and obtains FFT transform sequence before M group filters before filtering respectively to every group of M group；

That bears in FFT transform sequence before reservation M group filters respectively does quadrature demodulation to echo-signal to generate I/Q signal mistake Frequency between the demodulation bandwidth of the low-pass filter used in journey and the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value Component, and other components are set to 0；

FFT transform sequence does inverse FFT transformation before the filtering retained M group, to obtain multiple groups filtering transformation sequence.

Compared with prior art, pulse Doppler wall filtering method and processing system of the invention, by existing to I/Q signal Slow time orientation does Fast Fourier Transform (FFT) and obtains its frequency displacement distribution, to obtain for each frequency displacement and the corresponding letter of cut-off speed Number frequency component calculates the cutoff frequency on base band I/Q signal according to the frequency component, thus by fast time orientation into The filtering processing of the row cutoff frequency accurately filters out low speed clutter moition information, pulse Doppler wall filtering processing of the invention Method has not only effectively removed the motion information lower than threshold speed scattering, while effectively maintaining dissipating higher than threshold speed Sub-information is penetrated, the convenience and service efficiency of supersonic imaging apparatus is improved, improves the quality of ultrasound image.

Detailed description of the invention

Fig. 1 is the integral module schematic diagram of traditional imaging system；

Fig. 2 is the module diagram of traditional pulse Doppler wall filtering processing system

Fig. 3 is the flow diagram of pulse Doppler wall filtering processing method in an embodiment of the present invention；

Fig. 4 is the module diagram of pulse Doppler wall filtering processing system in an embodiment of the present invention；

Fig. 5 A, Fig. 5 B be respectively adopted in an of the invention specific example traditional pulse Doppler wall filtering processing method with The contrast schematic diagram for the Two-dimensional FFT distribution map that pulse Doppler wall filtering processing method of the invention obtains；

Fig. 5 C, Fig. 5 D be respectively adopted in an of the invention specific example traditional pulse Doppler wall filtering processing method with The contrast schematic diagram for the speed spectrogram that pulse Doppler wall filtering processing method of the invention obtains.

Specific embodiment

Hereinafter, the present invention will be described in detail with reference to various embodiments shown in the accompanying drawings.But these embodiments are not The limitation present invention, structure that those skilled in the art are made according to these embodiments, method or change functionally It changes and is included within the scope of protection of the present invention.

It should be noted that present invention is mainly applied to ultrasonic device, correspondingly, the determinand can be test serum, It is not described in detail herein.

As shown in connection with fig. 1, the module diagram of Doppler Imaging systems；During pulse Doppler wall filtering；

Emit pulse signal into tissue by probe, the pulse signal reflected to form in tissue ultrasonic signal via The different primitives of probe transducers are changed into electric analoging signal, are amplified by preceding amplification module, then are converted by A/D D/A converter module For digital signal；The digital signal of each difference primitive passes through Beam synthesis module, synthesizes radiofrequency signal；Radiofrequency signal is passed through After the quadrature demodulation of fixed frequency, quadrature demodulation result i/q signal is sent into corresponding processing module.

During above-mentioned pulse Doppler wall filtering；Emit scanning repetition rate PRF, the launching centre frequency of pulse signal F0 is that systemic presupposition numerical value needs to do quadrature demodulation, institute by low-pass filter during carrying out Beam synthesis to digital signal Demodulation bandwidth B _ the iq for stating low-pass filter is also systemic presupposition threshold value.

As shown in connection with fig. 2, traditional pulse Doppler (PW) mode imaging need to pass through following process:

In door door sampling module, the signal sampling point in sampling gate is cut, then ask all sampled points are cut It is average, it is sent into subsequent wall filtering module, wall filtering is generally high-pass filter, is mainly used to consider on slow time orientation except letter The tissue signal of low-speed motion in number, conventional method have low order FIR mode filter, IIR mode filter and polynomial regression filtering Device.In these filters, the performance of projection initialization iir filter and polynomial regression filter have stopband attenuation it is big, The advantages that intermediate zone is narrow and does not lose data, wherein the stopband cutoff frequency of projection initialization iir filter is more flexible and changeable. Signal after wall filtering is fed to subsequent FFT energy computation module and two-channel separation module.

FFT energy computation module does Fast Fourier Transform (FFT) (FFT) to the signal after wall filtering, obtains each frequency displacement point The energy size of amount, then log-compressed is carried out by dynamic range compression module, it finally carries out frequency spectrum and shows.

The positive and negative frequency spectrum of signal is mainly carried out left and right acoustic channels separation by two-channel separation module, is converted into using rate and is Sample rate needed for system sound card, finally carries out audio broadcasting.

As shown in connection with fig. 3, Fig. 3 is the flow chart of pulse Doppler wall filtering processing method in an embodiment of the present invention, The described method includes:

S1, the corresponding I/Q signal of N number of sampled point is obtained in every echo-signal, to form each echo-signal Corresponding I/Q signal sequence；

In a specific example of the invention, for the convenience of description, by the corresponding IQ of sampled point N number of in every echo-signal Signal indicates that (x, y) indicates the coordinate of sampled point respectively with IQ (x, y).

Under normal conditions, sampled in corresponding echo-signal according to sampling gate size, the sampling gate size with SV is indicated.

Correspondingly, i is positive integer for i-th of echo-signal, corresponding I/Q signal sequence be may be expressed as:

{IQ(1,i),IQ(2,i),IQ(3,i),….IQ(N,i)}

Wherein, N=2*SV/c*fs, fs are sample frequency.

Further, in an embodiment of the present invention, the method also includes:

S2, on slow time orientation, FFT transform is done to each I/Q signal sequence respectively, to obtain N group FFT transform Sequence.

In a specific example of the invention, M memory space is preset, each memory space is for storing one group of I/Q signal sequence Column, successively storage obtains M group I/Q signal sequence by the way of first in first out；After M memory space whole storing data, under After one I/Q signal sequence needs to wait for the output of the I/Q signal sequence in the memory space of front end or removes, then stored.

In the specific embodiment of the invention, on slow time orientation, chooses M group I/Q signal sequence and does FFT transform,

M group I/Q signal sequence is successively are as follows:

{ IQ(1,i),IQ(2,i),IQ(3,i),…,IQ(N,i)}

{ IQ(1,i+1),IQ(2,i+1),IQ(3,i+1),…,IQ(N,i+1)}

{ IQ(1,i+2),IQ(2,i+2),IQ(3,i+2),…,IQ(N,i+2)}

……

{ IQ(1,i+M-1),IQ(2,i+M-1),IQ(3,i+M-1),…,IQ(N,i+M-1)}

Data of the M group I/Q signal sequence on identical column direction are obtained respectively, form the slow time change sequence of N group, and right It does FFT transform, to obtain N group FFT transform sequence；

Correspondingly, the slow time series of N group of composition is successively are as follows:

{ IQ(1,i),IQ(1,i+1),IQ(1,i+2),…,IQ(1,i+M-1)}

{ IQ(2,i),IQ(2,i+1),IQ(2,i+2),…,IQ(2,i+M-1)}

{ IQ(3,i),IQ(3,i+1),IQ(3,i+2),…,IQ(3,i+M-1)}

……

{ IQ(N,i),IQ(N,i+1),IQ(N,i+2),…,IQ(N,i+M-1)}

After doing FFT transform to the above-mentioned slow time-varying sequence of N group, N group FFT change sequence is obtained successively are as follows:

{ IQ_fft(1,i),IQ_fft(1,i+1),IQ_fft(1,i+2),…,IQ_fft(1,i+M-1)}

{ IQ_fft(2,i),IQ_fft(2,i+1),IQ_fft(2,i+2),…,IQ_fft(2,i+M-1)}

{ IQ_fft(3,i),IQ_fft(3,i+1),IQ_fft(3,i+2),…,IQ_fft(3,i+M-1)}

……

{ IQ_fft(N,i),IQ_fft(N,i+1),IQ_fft(N,i+2),…,IQ_fft(N,i+M-1)}

Further, in an embodiment of the present invention, the method also includes:

S3, on fast time orientation, the FFT transform sequence described in every group is filtered respectively, with obtain multiple groups filter Wave conversion sequence.

The step S3 is specifically included:

P1, data of the N group FFT transform sequence on identical column direction, transform sequence before composition M group filters are obtained respectively；

In the specific embodiment of the invention, the M group of acquisition filters preceding transform sequence successively are as follows:

{ IQ_fft(1,i),IQ_fft(2,i),IQ_fft(3,i),…,IQ_fft(N,i)}

{ IQ_fft(1,i+1),IQ_fft(2,i+1),IQ_fft(3,i+1),…,IQ_fft(N,i+1)}

{ IQ_fft(1,i+2),IQ_fft(2,i+2),IQ_fft(3,i+2),…,IQ_fft(N,i+2)}

……

{ IQ_fft(1,i+M-1),IQ_fft(2,i+M-1),IQ_fft(3,i+M-1),…,IQ_fft(N,i+M-1)}

Further, the step S3 further include:

P2, according to preset threshold speed, the repetition scanning frequency of initial transmissions signal, initial transmissions signal center frequency Rate does quadrature demodulation to echo-signal to generate the demodulation bandwidth of the low-pass filter used during I/Q signal, described in acquisition The corresponding frequency displacement cutoff frequency of pre-set velocity threshold value.

In an of the invention specific example, the corresponding frequency displacement cutoff frequency frej (i) of the pre-set velocity threshold value is indicated,

frej(i) = max( (i –1)/M*PRF*c/(2*abs(Vrej))-f0,-B_iq/2)

Wherein, PRF indicates the repetition scanning frequency of initial transmissions signal, and Vrej indicates pre-set velocity threshold value, and f0 is indicated just Originate the centre frequency for penetrating signal, B_iq/2 indicate to do quadrature demodulation to echo-signal with generate use during I/Q signal it is low Both the demodulation bandwidth of bandpass filter, abs () expression take absolute value, and max () expression takes the larger value.

Further, the step S3 further include:

P3, it is obtained on fast time orientation according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value to the filtering of M group Preceding transform sequence makees the fast termporal filter being filtered；

In one of which embodiment of the invention, on fast time orientation, transform sequence does time-domain filtering before filtering to M group Processing.

Quadrature demodulation is done according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and to echo-signal to generate Numerical relation between the demodulation bandwidth of the low-pass filter used during I/Q signal, the design fast termporal filter are Number.

If frej (i) is not equal to-B_iq/2,

Then the upper cut off frequency B_hp and lower limiting frequency B_lp of fast termporal filter are respectively as follows:

Bp_lp = -B_iq/2;

Bp_hp = frej(i);

If frej (i) is equal to-B_iq/2,

Then the coefficient of the fast termporal filter is 0.

Further, transform sequence is filtered by the fast termporal filter respectively before M group being filtered, to obtain M Group filtering transformation sequence.

The M group filtering transformation sequence is successively are as follows:

{IQ_fft_filterd(1,i),IQ_fft_filterd(2,i),IQ_fft_filterd(3,i),…,IQ_ fft_filterd(N,i)}

{IQ_fft_filterd(1,i+1),IQ_fft_filterd(2,i+1),IQ_fft_filterd(3,i+ 1),…,IQ_fft_filterd(N, i+1)}

{IQ_fft_filterd(1,i+2),IQ_fft_filterd(2,i+2),IQ_fft_filterd(3,i+ 2),…,IQ_fft_filterd(N, i+2)}

……

{IQ_fft_filterd(1,i+M-1),IQ_fft_filterd(2,i+M-1),IQ_fft_filterd(3,i+ M-1),…,IQ_fft_filterd(N,i+M-1)}

In another embodiment of the present invention, on fast time orientation, transform sequence is done at frequency domain filtering before filtering to M group Reason.

Transform sequence does FFT transform and obtains FFT transform sequence before M group filters before filtering respectively to every group of M group；The M group Filter preceding FFT transform sequence successively are as follows:

{IQ_fft_fast_fft(1,i),IQ_fft_fast_fft(2,i),IQ_fft_fast_fft(3,i),…, IQ_fft_fast_fft(N,i)}

{IQ_fft_fast_fft(1,i+1),IQ_fft_fast_fft(2,i+1),IQ_fft_fast_fft(3,i+ 1),…,IQ_fft_fast_fft(N, i+1)}

{IQ_fft_fast_fft(1,i+2),IQ_fft_fast_fft(2,i+2),IQ_fft_fast_fft(3,i+ 2),…,IQ_fft_fast_fft(N, i+2)}

……

{IQ_fft_fast_fft(1,i+M-1),IQ_fft_fast_fft(2,i+M-1),IQ_fft_fast_fft(3, i+M-1),…,IQ_fft_fast_fft(N,i+M-1)}

That bears in FFT transform sequence before reservation M group filters respectively does quadrature demodulation to echo-signal to generate I/Q signal mistake Frequency between the demodulation bandwidth of the low-pass filter used in journey and the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value Component, and other components are set to 0；

FFT transform sequence does inverse FFT transformation before the filtering retained M group, to obtain multiple groups filtering transformation sequence.

The M group filtering transformation sequence is successively are as follows:

{IQ_fft_filterd(1,i),IQ_fft_filterd(2,i),IQ_fft_filterd(3,i),…,IQ_ fft_filterd(N,i)}

{IQ_fft_filterd(1,i+1),IQ_fft_filterd(2,i+1),IQ_fft_filterd(3,i+ 1),…,IQ_fft_filterd(N, i+1)}

{IQ_fft_filterd(1,i+2),IQ_fft_filterd(2,i+2),IQ_fft_filterd(3,i+ 2),…,IQ_fft_filterd(N, i+2)}

……

{IQ_fft_filterd(1,i+M-1),IQ_fft_filterd(2,i+M-1),IQ_fft_filterd(3,i+ M-1),…,IQ_fft_filterd(N,i+M-1)}

Further, in an embodiment of the present invention, the method also includes:

S4, the corresponding complex-envelope of every group of filtering transformation sequence is obtained respectively, it is corresponding according to every group of filtering transformation sequence Complex-envelope obtains total envelope signal, to show for final frequency spectrum.

In a specific embodiment of the invention, total envelope is obtained according to the corresponding complex-envelope of every group of filtering transformation sequence and is believed During number, the average value, weighted average, minimum value, maximum of the corresponding complex-envelope of each group filtering transformation sequence can be removed Value, boundary values and intermediate value are not described in detail herein as total envelope signal.

In following example, take the average value of the corresponding complex-envelope of each group filtering transformation sequence as total envelope signal.

Total envelope signal indicates with Spec_sum (i), then

Spec_sum(i)=fabs(IQ_fft_filterd(1,i))+fabs(IQ_fft_filterd(2,i))+…+ Fabs (IQ_fft_filterd (N, i)),

Wherein i=0,1,2 ... M, fabs () indicate the envelope for seeking every group of filtering transformation sequence plural number respectively.

Specifically, total envelope signal of acquisition is carried out dynamic range compression, finally carry out output and show, does not do herein in detail Carefully repeat.

In conjunction with shown in Fig. 5 A- Fig. 5 D, Fig. 5 A is the two dimension obtained using traditional pulse Doppler wall filtering processing method FFT distribution map;Fig. 5 B is using pulse Doppler wall filtering processing method Two-dimensional FFT distribution map obtained of the invention；Figure 5C is the speed spectrogram obtained using traditional pulse Doppler wall filtering processing method；Fig. 5 D is more using pulse of the invention The general speed spectrogram strangling wall filtering processing method and obtaining.

In Fig. 5 A- Fig. 5 D, sampling gate size SV=0.01m, launching centre frequency is the sine wave of f0=5MHz, scanning weight Complex frequency PRF is 8KHz, and scattering sub- speed is respectively 0.1m/s and 0.13m/s, Sita=0, Vrej=0.115m/s.

By Fig. 5 A- Fig. 5 D: traditional pulse Doppler's wall filtering processing method does not effectively filter out not only lower than speed The motion information for spending scattering of threshold value impairs the information higher than threshold speed scattering, pulse Doppler of the invention Wall filtering processing method has not only effectively removed the motion information lower than threshold speed scattering, while effectively maintaining and being higher than speed Spend the scattering sub-information of threshold value.

As shown in connection with fig. 4, the pulse Doppler wall filtering processing system provided in an embodiment of the present invention, the system It include: a sampling module 100, slow time-triggered protocol module 200, fast time-triggered protocol module 300, output module 400.

Door sampling module 100 in every echo-signal for obtaining the corresponding I/Q signal of N number of sampled point, with group At the corresponding I/Q signal sequence of each echo-signal；

In a specific example of the invention, for the convenience of description, by the corresponding IQ of sampled point N number of in every echo-signal Signal indicates that (x, y) indicates the coordinate of sampled point respectively with IQ (x, y).

Under normal conditions, sampled in corresponding echo-signal according to sampling gate size, the sampling gate size with SV is indicated.

Correspondingly, i is positive integer for i-th of echo-signal, corresponding I/Q signal sequence be may be expressed as:

{IQ(1,i),IQ(2,i),IQ(3,i),….IQ(N,i)}

Wherein, N=2*SV/c*fs, fs are sample frequency.

Further, in an embodiment of the present invention, slow time-triggered protocol module 200 is used for: in slow time orientation, respectively FFT transform is done to each I/Q signal sequence, to obtain N group FFT transform sequence.

In a specific example of the invention, slow time-triggered protocol module 200 presets M memory space, and each memory space is used for One group of I/Q signal sequence is stored, successively storage obtains M group I/Q signal sequence by the way of first in first out；When M memory space After whole storing datas, next I/Q signal sequence needs to wait for the output of the I/Q signal sequence in the memory space of front end or removes Afterwards, it then is stored.

In the specific embodiment of the invention, on slow time orientation, slow time-triggered protocol module 200 is for choosing M group IQ letter Number sequence does FFT transform,

M group I/Q signal sequence is successively are as follows:

{ IQ(1,i),IQ(2,i),IQ(3,i),…,IQ(N,i)}

{ IQ(1,i+1),IQ(2,i+1),IQ(3,i+1),…,IQ(N,i+1)}

{ IQ(1,i+2),IQ(2,i+2),IQ(3,i+2),…,IQ(N,i+2)}

……

{ IQ(1,i+M-1),IQ(2,i+M-1),IQ(3,i+M-1),…,IQ(N,i+M-1)}

Slow time-triggered protocol module 200 is also used to obtain data of the M group I/Q signal sequence on identical column direction respectively, forms The slow time change sequence of N group, and FFT transform is done to it, to obtain N group FFT transform sequence；

Correspondingly, the slow time series of N group of composition is successively are as follows:

{ IQ(1,i),IQ(1,i+1),IQ(1,i+2),…,IQ(1,i+M-1)}

{ IQ(2,i),IQ(2,i+1),IQ(2,i+2),…,IQ(2,i+M-1)}

{ IQ(3,i),IQ(3,i+1),IQ(3,i+2),…,IQ(3,i+M-1)}

……

{ IQ(N,i),IQ(N,i+1),IQ(N,i+2),…,IQ(N,i+M-1)}

After slow time-triggered protocol module 200 does FFT transform to the above-mentioned slow time-varying sequence of N group, obtains N group FFT and change sequence Leie are as follows:

{ IQ_fft(1,i),IQ_fft(1,i+1),IQ_fft(1,i+2),…,IQ_fft(1,i+M-1)}

{ IQ_fft(2,i),IQ_fft(2,i+1),IQ_fft(2,i+2),…,IQ_fft(2,i+M-1)}

{ IQ_fft(3,i),IQ_fft(3,i+1),IQ_fft(3,i+2),…,IQ_fft(3,i+M-1)}

……

{ IQ_fft(N,i),IQ_fft(N,i+1),IQ_fft(N,i+2),…,IQ_fft(N,i+M-1)}

Further, in an embodiment of the present invention, fast time-triggered protocol module 300 is used for: in fast time orientation, respectively The FFT transform sequence described in every group is filtered, to obtain multiple groups filtering transformation sequence.

Fast time-triggered protocol module 300 is specifically used for: data of the N group FFT transform sequence on identical column direction are obtained respectively, Form transform sequence before M group filters；

In the specific embodiment of the invention, the M group of acquisition filters preceding transform sequence successively are as follows:

{ IQ_fft(1,i),IQ_fft(2,i),IQ_fft(3,i),…,IQ_fft(N,i)}

{ IQ_fft(1,i+1),IQ_fft(2,i+1),IQ_fft(3,i+1),…,IQ_fft(N,i+1)}

{ IQ_fft(1,i+2),IQ_fft(2,i+2),IQ_fft(3,i+2),…,IQ_fft(N,i+2)}

……

{ IQ_fft(1,i+M-1),IQ_fft(2,i+M-1),IQ_fft(3,i+M-1),…,IQ_fft(N,i+M-1)}

Further, fast time-triggered protocol module 300 is also used to: according to preset threshold speed, the weight of initial transmissions signal Multiple scanning frequency, the centre frequency of initial transmissions signal do quadrature demodulation to echo-signal to generate use during I/Q signal Low-pass filter demodulation bandwidth, obtain the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value.

In an of the invention specific example, the corresponding frequency displacement cutoff frequency frej (i) of the pre-set velocity threshold value is indicated,

frej(i) = max( (i –1)/M*PRF*c/(2*abs(Vrej))-f0,-B_iq/2)

Wherein, PRF indicates the repetition scanning frequency of initial transmissions signal, and Vrej indicates pre-set velocity threshold value, and f0 is indicated just Originate the centre frequency for penetrating signal, B_iq/2 indicate to do quadrature demodulation to echo-signal with generate use during I/Q signal it is low Both the demodulation bandwidth of bandpass filter, abs () expression take absolute value, and max () expression takes the larger value.

Further, fast time-triggered protocol module 300 is also used to: according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value Rate, which is obtained, makees the fast termporal filter being filtered to transform sequence before the filtering of M group on fast time orientation；

In one of which embodiment of the invention, on fast time orientation, fast time-triggered protocol module 300 is used to filter M group Wavefront transform sequence does time-domain filtering processing.

Quadrature demodulation is done according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and to echo-signal to generate Numerical relation between the demodulation bandwidth of the low-pass filter used during I/Q signal, the design fast termporal filter are Number.

If frej (i) is not equal to-B_iq/2,

Then the upper cut off frequency B_hp and lower limiting frequency B_lp of fast termporal filter are respectively as follows:

Bp_lp = -B_iq/2;

Bp_hp = frej(i);

If frej (i) is equal to-B_iq/2,

Then the coefficient of the fast termporal filter is 0.

Further, transform sequence is filtered by the fast time respectively before fast time-triggered protocol module 300 is used to filter M group Wave device is filtered, to obtain M group filtering transformation sequence.

The M group filtering transformation sequence is successively are as follows:

{IQ_fft_filterd(1,i),IQ_fft_filterd(2,i),IQ_fft_filterd(3,i),…,IQ_ fft_filterd(N,i)}

{IQ_fft_filterd(1,i+1),IQ_fft_filterd(2,i+1),IQ_fft_filterd(3,i+ 1),…,IQ_fft_filterd(N, i+1)}

{IQ_fft_filterd(1,i+2),IQ_fft_filterd(2,i+2),IQ_fft_filterd(3,i+ 2),…,IQ_fft_filterd(N, i+2)}

……

{IQ_fft_filterd(1,i+M-1),IQ_fft_filterd(2,i+M-1),IQ_fft_filterd(3,i+ M-1),…,IQ_fft_filterd(N,i+M-1)}

In another embodiment of the present invention, on fast time orientation, fast time-triggered protocol module 300 is used to filter M group Preceding transform sequence does frequency domain filtering processing.

Transform sequence does FFT transform and obtains FFT transform sequence before M group filters before filtering respectively to every group of M group；The M group Filter preceding FFT transform sequence successively are as follows:

{IQ_fft_fast_fft(1,i),IQ_fft_fast_fft(2,i),IQ_fft_fast_fft(3,i),…, IQ_fft_fast_fft(N,i)}

{IQ_fft_fast_fft(1,i+1),IQ_fft_fast_fft(2,i+1),IQ_fft_fast_fft(3,i+ 1),…,IQ_fft_fast_fft(N, i+1)}

{IQ_fft_fast_fft(1,i+2),IQ_fft_fast_fft(2,i+2),IQ_fft_fast_fft(3,i+ 2),…,IQ_fft_fast_fft(N, i+2)}

……

{IQ_fft_fast_fft(1,i+M-1),IQ_fft_fast_fft(2,i+M-1),IQ_fft_fast_fft(3, i+M-1),…,IQ_fft_fast_fft(N,i+M-1)}

Fast time-triggered protocol module 300, which is also used to retain respectively, negative in FFT transform sequence before M group filters to be done echo-signal Quadrature demodulation with generate the low-pass filter used during I/Q signal demodulation bandwidth and the pre-set velocity threshold value it is corresponding Frequency component between frequency displacement cutoff frequency, and other components are set to 0；

FFT transform sequence does inverse FFT transformation before the filtering retained M group, to obtain multiple groups filtering transformation sequence.

The M group filtering transformation sequence is successively are as follows:

{IQ_fft_filterd(1,i),IQ_fft_filterd(2,i),IQ_fft_filterd(3,i),…,IQ_ fft_filterd(N,i)}

{IQ_fft_filterd(1,i+1),IQ_fft_filterd(2,i+1),IQ_fft_filterd(3,i+ 1),…,IQ_fft_filterd(N, i+1)}

{IQ_fft_filterd(1,i+2),IQ_fft_filterd(2,i+2),IQ_fft_filterd(3,i+ 2),…,IQ_fft_filterd(N, i+2)}

……

{IQ_fft_filterd(1,i+M-1),IQ_fft_filterd(2,i+M-1),IQ_fft_filterd(3,i+ M-1),…,IQ_fft_filterd(N,i+M-1)}

Further, in an embodiment of the present invention, output module 400 is used for: obtaining every group of filtering transformation sequence respectively Corresponding complex-envelope obtains total envelope signal according to the corresponding complex-envelope of every group of filtering transformation sequence, for final Frequency spectrum is shown.

In a specific embodiment of the invention, total envelope is obtained according to the corresponding complex-envelope of every group of filtering transformation sequence and is believed During number, the average value, weighted average, minimum value, maximum of the corresponding complex-envelope of each group filtering transformation sequence can be removed Value, boundary values and intermediate value are not described in detail herein as total envelope signal.

In following example, take the average value of the corresponding complex-envelope of each group filtering transformation sequence as total envelope signal.

Total envelope signal indicates with Spec_sum (i), then

Spec_sum(i)=fabs(IQ_fft_filterd(1,i))+fabs(IQ_fft_filterd(2,i))+…+ Fabs (IQ_fft_filterd (N, i)),

Wherein i=0,1,2 ... M, fabs () indicate the envelope for seeking every group of filtering transformation sequence plural number respectively.

Specifically, the dynamic compression module will obtain the system also includes dynamic compression module and display module Total envelope signal carry out dynamic range compression, the display module be used for the data result Jing Guo dynamic compression resume module Output display, is not described in detail herein.

It is apparent to those skilled in the art that for convenience and simplicity of description, the system of foregoing description The specific work process of middle module, can be with reference to the corresponding process in preceding method embodiment, and details are not described herein.

In conclusion pulse Doppler wall filtering method of the invention and processing system, by I/Q signal in the slow time Direction does Fast Fourier Transform (FFT) and obtains its frequency displacement distribution, to obtain for each frequency displacement and the corresponding signal frequency of cut-off speed Component calculates the cutoff frequency on base band I/Q signal according to the frequency component, thus by carrying out this section in fast time orientation The only filtering processing of frequency accurately filters out low speed clutter moition information, and pulse Doppler wall filtering processing method of the invention is not The motion information lower than threshold speed scattering is only effectively eliminated, while effectively maintaining the scattering letter higher than threshold speed Breath；The convenience and service efficiency for improving supersonic imaging apparatus, improve the quality of ultrasound image.

For convenience of description, it is divided into various modules when description apparatus above with function to describe respectively.Certainly, implementing this The function of each module can be realized in the same or multiple software and or hardware when application.

As seen through the above description of the embodiments, those skilled in the art can be understood that the application can It realizes by means of software and necessary general hardware platform.Based on this understanding, the technical solution essence of the application On in other words the part that contributes to existing technology can be embodied in the form of software products, which can protect In the presence of saving in medium, such as ROM/RAM, magnetic disk, CD, including some instructions are used so that computer equipment (can be with It is personal computer, Information Push Server or the network equipment etc.) execute each embodiment of the application or embodiment Certain parts described in method.

Device embodiments described above are only schematical, wherein the module as illustrated by the separation member It may or may not be physically separated, the component shown as module may or may not be physics mould Block, it can it is in one place, or may be distributed on multiple network modules.It can be selected according to the actual needs In some or all of the modules realize the purpose of present embodiment scheme.Those of ordinary skill in the art are not paying creation Property labour in the case where, it can understand and implement.

The application can describe in the general context of computer-executable instructions executed by a computer, such as program Module.Generally, program module includes routines performing specific tasks or implementing specific abstract data types, programs, objects, group Part, data structure etc..The application can also be practiced in a distributed computing environment, in these distributed computing environments, by Task is executed by the connected remote processing devices of communication network.In a distributed computing environment, program module can be with It is saved in medium positioned at the local and remote computer including saving equipment.

It should be appreciated that although this specification is described in terms of embodiments, but not each embodiment only includes one A independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art should will say As a whole, the technical solution in each embodiment may also be suitably combined to form those skilled in the art can for bright book With the other embodiments of understanding.

The series of detailed descriptions listed above only for feasible embodiment of the invention specifically Protection scope bright, that they are not intended to limit the invention, it is all without departing from equivalent implementations made by technical spirit of the present invention Or change should all be included in the protection scope of the present invention.

Claims (6)

1. a kind of pulse Doppler wall filtering processing method, which is characterized in that the described method comprises the following steps:

S1, the corresponding I/Q signal of N number of sampled point is obtained in every echo-signal, it is corresponding to form each echo-signal I/Q signal sequence；

S2, on slow time orientation, FFT transform is done to each I/Q signal sequence respectively, to obtain N group FFT transform sequence；

S3, on fast time orientation, the FFT transform sequence described in every group is filtered respectively, to obtain multiple groups filtering transformation Sequence；

S4, the corresponding complex-envelope of every group of filtering transformation sequence is obtained respectively, according to the corresponding plural number of every group of filtering transformation sequence Envelope obtains total envelope signal, to show for final frequency spectrum；

Wherein, the step S2 is specifically included:

M memory space is preset, each memory space is stored one group of I/Q signal sequence, successively stored by the way of first in first out Obtain M group I/Q signal sequence；

Data of the M group I/Q signal sequence on identical column direction are obtained respectively, form the slow time change sequence of N group, and do to it FFT transform, to obtain N group FFT transform sequence；

The step S3 is specifically included:

P1, data of the N group FFT transform sequence on identical column direction, transform sequence before composition M group filters are obtained respectively；

P2, according to preset threshold speed, the repetition scanning frequency of initial transmissions signal, the centre frequency of initial transmissions signal, Quadrature demodulation is done to echo-signal to generate the demodulation bandwidth of the low-pass filter used during I/Q signal, is obtained described default The corresponding frequency displacement cutoff frequency of threshold speed；

P3, it is obtained on fast time orientation according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value to change before the filtering of M group It changes sequence and makees the fast termporal filter being filtered；

Transform sequence is filtered before being filtered respectively to M group using the fast termporal filter, to obtain multiple groups filtering transformation Sequence.

2. pulse Doppler wall filtering processing method according to claim 1, which is characterized in that the step P3 is specifically wrapped It includes:

According to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and quadrature demodulation is done to echo-signal to generate IQ letter Numerical relation between the demodulation bandwidth of the low-pass filter used during number designs the coefficient of the fast termporal filter,

Transform sequence is filtered by the fast termporal filter respectively before M group is filtered, to obtain M group filtering transformation sequence Column.

3. pulse Doppler wall filtering processing method according to claim 2, which is characterized in that the step P3 is specifically wrapped It includes:

Transform sequence does FFT transform and obtains FFT transform sequence before M group filters before filtering respectively to every group of M group；

Retain before M group filters respectively in FFT transform sequence it is negative quadrature demodulation is done to echo-signal to generate I/Q signal during Frequency component between the demodulation bandwidth of the low-pass filter of use and the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value, And other components are set to 0；

FFT transform sequence does inverse FFT transformation before the filtering retained M group, to obtain multiple groups filtering transformation sequence.

4. a kind of pulse Doppler wall filtering processing system, which is characterized in that the system comprises:

Door sampling module, it is each to form for obtaining the corresponding I/Q signal of N number of sampled point in every echo-signal The corresponding I/Q signal sequence of echo-signal；

Slow time-triggered protocol module, for FFT transform being done to each I/Q signal sequence respectively, to obtain in slow time orientation Obtain N group FFT transform sequence；

Fast time-triggered protocol module, is used in fast time orientation, and the FFT transform sequence described in every group is filtered respectively, with Obtain multiple groups filtering transformation sequence；

Output module, for obtaining the corresponding complex-envelope of every group of filtering transformation sequence respectively, according to every group of filtering transformation sequence Corresponding complex-envelope obtains total envelope signal, to show for final frequency spectrum；

Wherein, the slow time-triggered protocol module is also used to:

M memory space is preset, each memory space is stored one group of I/Q signal sequence, successively stored by the way of first in first out Obtain M group I/Q signal sequence；

Data of the M group I/Q signal sequence on identical column direction are obtained respectively, form the slow time change sequence of N group, and do to it FFT transform, to obtain N group FFT transform sequence；

The fast time-triggered protocol module is also used to:

Data of the N group FFT transform sequence on identical column direction, transform sequence before composition M group filters are obtained respectively；

According to preset threshold speed, the repetition scanning frequency of initial transmissions signal, the centre frequency of initial transmissions signal, to return Wave signal does quadrature demodulation to generate the demodulation bandwidth of the low-pass filter used during I/Q signal, obtains the pre-set velocity The corresponding frequency displacement cutoff frequency of threshold value；

It is obtained according to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and wavefront transform sequence is filtered to M group on fast time orientation Column make the fast termporal filter being filtered；

Transform sequence is filtered before being filtered respectively to M group using the fast termporal filter, to obtain multiple groups filtering transformation Sequence.

5. pulse Doppler wall filtering processing system according to claim 4, which is characterized in that the fast time-triggered protocol mould Block is specifically used for:

According to the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value and quadrature demodulation is done to echo-signal to generate IQ letter Numerical relation between the demodulation bandwidth of the low-pass filter used during number designs the coefficient of the fast termporal filter,

Transform sequence is filtered by the fast termporal filter respectively before M group is filtered, to obtain M group filtering transformation sequence Column.

6. pulse Doppler wall filtering processing system according to claim 5, which is characterized in that the fast time-triggered protocol mould Block is specifically used for:

Transform sequence does FFT transform and obtains FFT transform sequence before M group filters before filtering respectively to every group of M group；

Retain before M group filters respectively in FFT transform sequence it is negative quadrature demodulation is done to echo-signal to generate I/Q signal during Frequency component between the demodulation bandwidth of the low-pass filter of use and the corresponding frequency displacement cutoff frequency of the pre-set velocity threshold value, And other components are set to 0；

FFT transform sequence does inverse FFT transformation before the filtering retained M group, to obtain multiple groups filtering transformation sequence.