Flow velocity determination method, device and equipment

Abstract

The invention provides a flow velocity determination method, device and equipment. The method comprises the following steps: acquiring a first original time domain signal acquired by a first transducer and a second original time domain signal acquired by a second transducer; performing frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal, and performing frequency domain transformation based on the second original time domain signal to obtain a second target frequency domain signal; determining a first cross-correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and determining a target cross-correlation frequency domain signal based on the first cross-correlation frequency domain signal; performing time domain transformation based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, wherein the cross-correlation time domain signal comprises signal values of a plurality of positions; determining a flight time difference based on the target position corresponding to the maximum signal value; the flight time difference is used for determining the flow speed of the fluid passing through the pipeline. Through the technical scheme of the invention, the flight time difference can be accurately determined, the precision of the flight time difference is relatively high, and the error is relatively small.

Description

Technical Field

[0001] The present application relates to the technical field of flow meters, and in particular to a method, device and equipment for determining flow velocity. Background Art

[0002] Ultrasonic flowmeter (ultrasonic flowmeter) is used to measure the flow rate of fluid. Ultrasonic flowmeter has the advantages of non-contact, no pressure loss, and fast response speed. It is widely used in the flow rate measurement of fluids such as water, gas, and oil.

[0003] The ultrasonic flow meter may include a pipeline, a first transducer and a second transducer, wherein the first transducer and the second transducer are installed on both sides of the pipeline. When the fluid passes through the pipeline, the first transducer sends ultrasonic waves to the second transducer, and the second transducer sends ultrasonic waves to the first transducer. Considering that the propagation speed of ultrasonic waves in the fluid will be affected by the flow of the fluid, the propagation speed in the downstream direction is accelerated and the propagation speed in the upstream direction is slowed down. Based on this, by measuring the time of flight (TOF) difference of ultrasonic waves in the downstream direction and the upstream direction, the flow rate of the fluid can be calculated based on the time of flight difference.

[0004] In order to determine the flight time difference, it is necessary to measure the flight time of the sound wave from the first transducer to the second transducer, and measure the flight time of the sound wave from the second transducer to the first transducer, and the difference between the two sound wave flight times is the flight time difference. However, when measuring the sound wave flight time, the sound wave flight time cannot be accurately measured, the measurement accuracy of the sound wave flight time is low, and the error of the sound wave flight time is large. When calculating the flight time difference based on the sound wave flight time, the accuracy of the flight time difference is low and the error is large. Summary of the invention

[0005] The present application provides a method for determining flow velocity. A first transducer and a second transducer are respectively installed on both sides of a pipeline. When a fluid passes through the pipeline, the first transducer sends an ultrasonic wave to the second transducer, and the second transducer sends an ultrasonic wave to the first transducer. The method includes: Acquire a first original time domain signal acquired by the first transducer and a second original time domain signal acquired by the second transducer; perform frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal, and perform frequency domain transformation based on the second original time domain signal to obtain a second target frequency domain signal; Determine a first mutual correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and determine a target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal; A time domain transform is performed based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, wherein the cross-correlation time domain signal includes signal values ​​at multiple positions; a flight time difference is determined based on the target position corresponding to the maximum signal value; wherein the flight time difference is the time difference between the propagation of the ultrasonic wave in the downstream direction and the upstream direction; and the flight time difference is used to determine the flow velocity of the fluid when passing through the pipeline.

[0006] The present application provides a flow velocity determination device, wherein a first transducer and a second transducer are respectively installed on both sides of a pipeline, and when a fluid passes through the pipeline, the first transducer sends an ultrasonic wave to the second transducer, and the second transducer sends an ultrasonic wave to the first transducer. The device comprises: An acquisition module, configured to acquire a first original time domain signal acquired by a first transducer and a second original time domain signal acquired by a second transducer; perform a frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal, and perform a frequency domain transformation based on the second original time domain signal to obtain a second target frequency domain signal; a determination module, configured to determine a first mutual correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and determine a target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal; A processing module is used to perform time domain transformation based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, wherein the cross-correlation time domain signal includes signal values ​​at multiple positions; a flight time difference is determined based on the target position corresponding to the maximum signal value; wherein the flight time difference is the time difference for the propagation of the ultrasonic wave in the downstream direction and the upstream direction; and the flight time difference is used to determine the flow velocity of the fluid when it passes through the pipeline.

[0007] The present application provides an electronic device, comprising: a processor and a machine-readable storage medium, wherein the machine-readable storage medium stores machine-executable instructions that can be executed by the processor; the processor is used to execute the machine-executable instructions to implement the flow rate determination method of the above example.

[0008] The present application provides a computer program product, which may include a computer program. When the computer program is executed by a processor, the flow rate determination method of the above example is implemented.

[0009] The present application provides a machine-readable storage medium, which stores machine-executable instructions that can be executed by a processor; wherein the processor is used to execute the machine-executable instructions, and when the machine-executable instructions are executed, the flow rate determination method of the above example is implemented.

[0010] It can be seen from the above technical scheme that in the embodiment of the present application, the original time domain signal is transformed in the frequency domain to obtain the target frequency domain signal, the cross-correlated frequency domain signal is determined based on the two target frequency domain signals, the cross-correlated frequency domain signal is transformed in the time domain to obtain the cross-correlated time domain signal, and the flight time difference is determined based on the target position corresponding to the maximum signal value in the cross-correlated time domain signal, thereby directly determining the flight time difference based on the original time domain signal without measuring the acoustic wave flight time from the first transducer to the second transducer and the acoustic wave flight time from the second transducer to the first transducer, which can avoid the low accuracy of the flight time difference caused by the low measurement accuracy of the acoustic wave flight time. In this way, the flight time difference can be accurately determined, the accuracy of the flight time difference is high, the error of the flight time difference is small, the calculation accuracy of the flight time difference is improved, the accurate calculation of the phase difference between the uplink signal and the downlink signal of the ultrasonic wave is achieved, and the anti-interference performance against noise is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a flow chart of a method for determining flow rate in one embodiment of the present application; Figure 2 is a schematic structural diagram of an ultrasonic flowmeter in one embodiment of the present application; Figure 3 is a flow chart of a method for determining flow rate in one embodiment of the present application; Figure 4 It is a schematic diagram of a process for obtaining a target cross-correlation frequency domain signal in one embodiment of the present application; Figure 5 is a schematic structural diagram of a flow rate determination device in one embodiment of the present application; Figure 6 It is a hardware structure diagram of an electronic device in one embodiment of the present application. DETAILED DESCRIPTION

[0012] In an embodiment of the present application, a flow rate determination method is proposed, which is applied to an electronic device, and the electronic device can be a flow rate determination device for determining the flow rate of a fluid. For example, the electronic device can determine the flow rate of the fluid based on data collected by an ultrasonic flow meter. The ultrasonic flow meter may include a pipeline, a first transducer and a second transducer, the first transducer and the second transducer are respectively installed on both sides of the pipeline, and the fluid passes through the pipeline, the first transducer sends an ultrasonic wave to the second transducer, and the second transducer sends an ultrasonic wave to the first transducer.

[0013] See also Figure 1 FIG. 4 is a flow chart of the flow rate determination method, which may include: Step 101, obtaining a first original time domain signal collected by a first transducer and a second original time domain signal collected by a second transducer; performing a frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal, and performing a frequency domain transformation based on the second original time domain signal to obtain a second target frequency domain signal.

[0014] Step 102: determine a first mutual correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and determine a target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal.

[0015] Step 103: Perform time domain transformation based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, which includes signal values ​​at multiple positions; determine the flight time difference based on the target position corresponding to the maximum signal value, the target position is the most similar position between the first original time domain signal and the second original time domain signal, and the flight time difference represents the phase difference of the target position. The flight time difference is the time difference between the ultrasonic wave propagating in the downstream direction and the upstream direction; the flight time difference is used to determine the flow velocity of the fluid when it passes through the pipeline.

[0016] Exemplarily, determining the first mutually correlated frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal may include, but is not limited to: determining the first complex conjugate frequency domain signal of the first target frequency domain signal, and performing a convolution operation on the first complex conjugate frequency domain signal and the second target frequency domain signal to obtain the first mutually correlated frequency domain signal. Alternatively, determining the second complex conjugate frequency domain signal of the second target frequency domain signal, and performing a convolution operation on the first target frequency domain signal and the second complex conjugate frequency domain signal to obtain the first mutually correlated frequency domain signal.

[0017] Exemplarily, determining the target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal may include but is not limited to: determining the first mutual correlation frequency domain signal as the target mutual correlation frequency domain signal; or, moving the zero-frequency component in the first mutual correlation frequency domain signal to the frequency center to obtain the second mutual correlation frequency domain signal, and determining the second mutual correlation frequency domain signal as the target mutual correlation frequency domain signal; or, moving the zero-frequency component in the first mutual correlation frequency domain signal to the frequency center to obtain the second mutual correlation frequency domain signal, filtering the second mutual correlation frequency domain signal to obtain a filtered frequency domain signal; setting the amplitude of the frequency corresponding to the noise signal in the filtered frequency domain signal to 0 to obtain a third mutual correlation frequency domain signal, performing frequency domain interpolation on the third mutual correlation frequency domain signal to obtain a fourth mutual correlation frequency domain signal, and determining the fourth mutual correlation frequency domain signal as the target mutual correlation frequency domain signal.

[0018] Exemplarily, the filtered frequency domain signal includes amplitudes of multiple frequencies. For each frequency, if the frequency is less than a first frequency value, or the frequency is greater than a second frequency value, and the second frequency value may be greater than the first frequency value, then the frequency is the frequency corresponding to the noise signal; wherein the first frequency value may be determined based on a configured sampling frequency and a first coefficient, and the first coefficient is greater than 0 and less than 1, and the second frequency value may be determined based on a configured sampling frequency and a second coefficient, and the second coefficient is greater than 1.

[0019] Exemplarily, when frequency domain interpolation is performed on the third mutually correlated frequency domain signal to obtain a fourth mutually correlated frequency domain signal, the third mutually correlated frequency domain signal includes L The amplitude of the frequency, the fourth cross-correlation frequency domain signal includes L1 The amplitude of the frequency, and L1 Greater than L ; Wherein, for the first k frequency, k The values ​​are from 0 to L1-1 , then the following method is used to determine the k Target amplitude for each frequency: like L The value of is an odd number. When , the target amplitude is the third cross-correlation frequency domain signal k The amplitude of a frequency; or, When , the target amplitude is 0; or, When , the target amplitude is the third cross-correlation frequency domain signal k The amplitude of a frequency; or, if L The value of is an even number. When , the target amplitude is the third cross-correlation frequency domain signal k The amplitude of a frequency; or, When , the target amplitude is the third cross-correlation frequency domain signal k half the amplitude of the frequency; or, When , the target amplitude is 0; or, When , the target amplitude is the third cross-correlation frequency domain signal half the amplitude of the frequency; or, When , the target amplitude is the third cross-correlation frequency domain signal k The amplitude of a frequency.

[0020] Exemplarily, determining the flight time difference based on the target position corresponding to the maximum signal value may include, but is not limited to: determining the flight time difference based on the target position corresponding to the maximum signal value, the total number of positions in the cross-correlated time domain signal, and the configured target resolution of the flight time difference.

[0021] Exemplarily, the flight time difference may be determined using the following formula: ;in, It can represent the flight time difference, It can be said that the target position is the first Locations, It can represent the total number of positions, Can indicate the target resolution.

[0022] Exemplarily, performing a frequency domain transform based on the first original time domain signal to obtain a first target frequency domain signal may include but is not limited to: preprocessing the first original time domain signal to obtain a first target time domain signal, filtering the first target time domain signal to obtain a first filtered time domain signal; then, performing a frequency domain transform on the first filtered time domain signal to obtain the first original frequency domain signal, and setting the amplitude of the frequency corresponding to the noise signal in the first original frequency domain signal to 0 to obtain the first target frequency domain signal.

[0023] Exemplarily, preprocessing the first original time domain signal to obtain the first target time domain signal may include but is not limited to: deleting abnormal values ​​in the first original time domain signal to obtain the first target time domain signal; or, removing the DC component in the first original time domain signal to obtain the first target time domain signal; or, deleting abnormal values ​​in the first original time domain signal and removing the DC component in the first original time domain signal to obtain the first target time domain signal. The first original time domain signal includes signal values ​​at multiple locations; For each position, multiple signal values ​​of the position are selected from the first original time domain signal and the first historical time domain signal, and a first quartile and a second quartile are determined based on the multiple signal values; based on the first quartile and the second quartile, whether the signal value of the position is an abnormal value is determined; For each position, the DC component of the position is determined based on the average value of multiple signal values ​​of the position, or based on the average value of all signal values ​​of the first original time domain signal, or based on the average value of all signal values ​​of the first original time domain signal and the first historical time domain signal.

[0024] It can be seen from the above technical scheme that in the embodiment of the present application, the original time domain signal is transformed in the frequency domain to obtain the target frequency domain signal, the cross-correlated frequency domain signal is determined based on the two target frequency domain signals, the cross-correlated frequency domain signal is transformed in the time domain to obtain the cross-correlated time domain signal, and the flight time difference is determined based on the target position corresponding to the maximum signal value in the cross-correlated time domain signal, thereby directly determining the flight time difference based on the original time domain signal without measuring the acoustic wave flight time from the first transducer to the second transducer and the acoustic wave flight time from the second transducer to the first transducer, which can avoid the low accuracy of the flight time difference caused by the low measurement accuracy of the acoustic wave flight time. In this way, the flight time difference can be accurately determined, the accuracy of the flight time difference is high, the error of the flight time difference is small, the calculation accuracy of the flight time difference is improved, the accurate calculation of the phase difference between the uplink signal and the downlink signal of the ultrasonic wave is achieved, and the anti-interference performance against noise is improved.

[0025] The above technical solutions of the embodiments of the present application are described below in combination with specific application scenarios.

[0026] The ultrasonic flow meter (also referred to as an ultrasonic flow meter, the ultrasonic flow meter of this embodiment may be an external clamp-on ultrasonic flow meter or other types of ultrasonic flow meters) may include a pipeline, a first transducer and a second transducer, see Figure 2 The figure shows the structure of the ultrasonic flowmeter. Transducer 1 is used as the first transducer, and transducer 2 is used as the second transducer. The first transducer and the second transducer can be installed on both sides of the pipeline, such as the first transducer is installed on the lower side of the pipeline, and the second transducer is installed on the upper side of the pipeline.

[0027] When the fluid passes through the pipe (such as moving from right to left), the first transducer sends ultrasonic waves to the second transducer, and the second transducer sends ultrasonic waves to the first transducer. Based on this, the flight time of the sound wave from the first transducer to the second transducer is measured, and the flight time of the sound wave from the second transducer to the first transducer is measured, and the difference between the two sound wave flight times is the flight time difference (Time of Flight, TOF). The flight time difference is the flight time difference of the ultrasonic wave in the downstream direction and the upstream direction, which is used to calculate the flow rate of the fluid.

[0028] For example, see Figure 2 As shown, the sound wave transmission length (the straight-line distance between the first transducer and the second transducer inside the pipe section) is L , the pipe section diameter (i.e. the vertical distance inside the pipe) is D , the angle between the sound wave transmission path and the pipeline (i.e. the angle between the sound wave transmission length direction and the pipe section diameter) is Φ , the acoustic wave flight time from the first transducer to the second transducer is T 12 , the acoustic wave flight time from the second transducer to the first transducer isT 21 , the speed of ultrasound in the medium (i.e. fluid) is c On this basis, based on the mathematical relationship, the following formula can be obtained: , Then, by deriving the above formula, we can know that , In combination with the above formula, the following formula (1) can be used to calculate the flow rate of the fluid. Of course, formula (1) is only an example and there is no limitation to it.

[0029] Formula (1) In formula (1), the sound wave transmission length L , Angle Φ are all known values, so by measuring the flight time of the sound wave from the first transducer to the second transducer , measuring the time of flight of the sound wave from the second transducer to the first transducer , the flow rate of the fluid can be calculated In formula (1), the flight time difference , that is, based on the flight time difference Calculate the flow rate of the fluid .

[0030] However, in measuring the time of flight of sound waves and sound wave flight time The sound wave flight time cannot be accurately measured. and sound wave flight time , sound wave flight time and sound wave flight time The measurement accuracy is low, and the sound wave flight time and sound wave flight time The error is large. In this way, when calculating the flight time difference based on the sound wave flight time, The flight time difference The accuracy is low and the error is large.

[0031] In response to the above findings, a flow rate determination method is proposed in an embodiment of the present application, which can determine the time of flight (TOF) of the ultrasonic flowmeter and can determine the high-precision time of flight difference, and then determine the fluid flow rate based on the high-precision time of flight difference to obtain an accurate and reliable fluid flow rate.

[0032] Exemplarily, the flow rate determination method can be applied to an electronic device (such as a flow rate determination device), and the electronic device can measure the flow rate of the fluid based on the data collected by the ultrasonic flow meter. For example, the electronic device can be an ultrasonic flow meter, that is, after the ultrasonic flow meter collects data, the ultrasonic flow meter measures the flow rate of the fluid based on the data. Alternatively, the electronic device can be a management device of the ultrasonic flow meter, that is, after the ultrasonic flow meter collects data, the ultrasonic flow meter sends the data to the management device, and the management device measures the flow rate of the fluid based on the data.

[0033] For example, the ultrasonic flow meter may include a pipeline, a first transducer and a second transducer, the first transducer and the second transducer are respectively installed on both sides of the pipeline, and when the fluid passes through the pipeline, the first transducer sends ultrasonic waves to the second transducer, and the second transducer sends ultrasonic waves to the first transducer. Figure 2 As shown, transducer 1 is used as the first transducer, transducer 2 is used as the second transducer, and transducer 1 and transducer 2 are installed on both sides of the pipeline, such as transducer 1 is installed on the lower side of the pipeline, and transducer 2 is installed on the upper side of the pipeline.

[0034] When the first transducer sends an ultrasonic wave to the second transducer, the first transducer acts as a transmitter of the ultrasonic wave and the second transducer acts as a receiver of the ultrasonic wave. When the second transducer sends an ultrasonic wave to the first transducer, the second transducer acts as a transmitter of the ultrasonic wave and the first transducer acts as a receiver of the ultrasonic wave.

[0035] See also Figure 3 FIG. 4 is a flow chart of the flow rate determination method, which may include: Step 301: Acquire a first original time domain signal collected by a first transducer and a second original time domain signal collected by a second transducer. The first original time domain signal is an ultrasonic signal sent by the second transducer to the first transducer, and the second original time domain signal is an ultrasonic signal sent by the first transducer to the second transducer.

[0036] For example, when the second transducer sends ultrasonic waves to the first transducer, the ultrasonic waves may be signals of a specific frequency, such as sinusoidal signals, pulse signals, or square wave signals, without limitation, and the frequency of the ultrasonic waves may be between 20 kHz and 100 kHz. On this basis, the first transducer may collect ultrasonic signals, and the collected signals are referred to as first original time domain signals.

[0037] For example, the first original time domain signal may include signal values ​​at multiple positions. For example, the signal acquisition time interval may be divided into 100 sampling points (i.e., 100 sampling moments), 100 sampling points correspond to 100 positions, and the first original time domain signal may include the signal value collected at the 0th sampling point, the signal value collected at the 1st sampling point, ..., the signal value collected at the 99th sampling point.

[0038] The signal value collected at the 0th sampling point is the signal value of the ultrasonic wave collected by the first transducer at the sampling moment. The signal value can be the sound wave amplitude, or it can be a voltage signal value or a numerical signal value. There is no limitation on this. The signal value collected at the 0th sampling point is used as the signal value of position 0, and so on. In this way, the first original time domain signal can include signal values ​​of 100 positions.

[0039] Exemplarily, when the first transducer sends ultrasonic waves to the second transducer, the second transducer can collect the ultrasonic wave signal. The collected signal is called the second original time domain signal. The second original time domain signal can include signal values ​​at multiple positions, such as the second original time domain signal includes signal values ​​at 100 positions.

[0040] Step 302: preprocess the first original time domain signal to obtain a first target time domain signal, and preprocess the second original time domain signal to obtain a second target time domain signal. Alternatively, the first original time domain signal is used as the first target time domain signal, and the second original time domain signal is used as the second target time domain signal.

[0041] Exemplarily, when the first original time domain signal is preprocessed to obtain the first target time domain signal, the abnormal value in the first original time domain signal can be deleted to obtain the first target time domain signal; or, the DC component in the first original time domain signal can be removed to obtain the first target time domain signal; or, the abnormal value in the first original time domain signal can be deleted, and the DC component in the first original time domain signal can be removed to obtain the first target time domain signal. For example, the first target time domain signal can be obtained by the following steps: Step 3021: Delete abnormal values ​​in the first original time domain signal to obtain a first intermediate time domain signal.

[0042] Exemplarily, the first original time domain signal includes signal values ​​at multiple positions. For each position, if the signal value at the position is an abnormal value, the signal value at the position is deleted. If the signal value at the position is not an abnormal value, the signal value at the position is retained. After the signal value at each position is processed as above, a first intermediate time domain signal can be obtained. Assuming that the first original time domain signal includes signal values ​​at S1 positions and the first intermediate time domain signal includes signal values ​​at S2 positions, S2 can be less than or equal to S1.

[0043] For example, for each position, multiple signal values ​​of the position are selected from the first original time domain signal and the first historical time domain signal. The first historical time domain signal is the original time domain signal before the first original time domain signal (collected by the first transducer, and the collection process is similar to the first original time domain signal). Based on this, N signal values ​​of the position can be selected from the first original time domain signal and the previous multiple original time domain signals, and the value of N can be 8, 16, 32 or 64, etc., without limitation. For example, N signal values ​​are randomly selected, or N signal values ​​are selected in sequence from back to front in the order of collection time, or N signal values ​​are selected in intervals from back to front in the order of collection time (such as 1st, 3rd, 5th, 7th, etc.). Of course, the above are just a few examples, as long as N signal values ​​of the position can be selected.

[0044] This location is the location j For example, the position is selected from the first original time domain signal j The signal value of is selected from the first original time domain signal before the first original time domain signal j The signal value of is selected from the second original time domain signal in front of the first original time domain signal j signal value, and so on.

[0045] For example, for each position, after obtaining multiple signal values ​​at the position, the first quartile and the second quartile can be determined based on the multiple signal values. The first quartile is the first quartile. , the second quartile is the second quartile , or, the first quartile is the first quartile , the second quartile is the third quartile , or, the first quartile is the first quartile , the second quartile is the fourth quartile , or, the first quartile is the second quartile , the second quartile is the third quartile , or, the first quartile is the second quartile , the second quartile is the fourth quartile , or, the first quartile is the third quartile , the second quartile is the fourth quartile For the convenience of description, the first quartile is the first quartile , the second quartile is the third quartile Take this as an example to illustrate.

[0046] Based on the multiple signal values ​​at this position, the multiple signal values ​​at this position can be sorted in order from small to large, and then the value at the 25% position of the signal value can be used as the first quartile. , the value at 75% of the signal value can be used as the third quartile .

[0047] For example, after obtaining the first quartile and the second quartile, it can be determined whether the signal value at the location is an outlier based on the first quartile and the second quartile. j The first quartile of and the third quartile , the interquartile range can be calculated R , .

[0048] If the location j The signal value If the following relationship is satisfied, the position j The signal value is an outlier. If the position j The signal value If the following relationship is not satisfied, the position j The signal value Not an outlier.

[0049] or

[0050] In the above relationship, Indicates the outlier removal coefficient, outlier removal coefficient Can be configured based on experience, such as outlier removal coefficient The value of is between 1 and 3. It can be an integer or a decimal.

[0051] In summary, for each position in the first original time domain signal, the above method can be used to determine whether the signal value at the position is an abnormal value, and then the abnormal value is deleted to obtain the first intermediate time domain signal.

[0052] Step 3022: Remove the DC component in the first intermediate time domain signal to obtain a first target time domain signal.

[0053] Exemplarily, the first intermediate time domain signal includes signal values ​​at multiple positions, and for each position, the DC component of the position is calculated, and the DC component is subtracted from the signal value at the position to obtain the signal value after the DC component is removed at the position. After the signal value at each position is processed as above, the signal value after the DC component is removed at each position is obtained, and the first target time domain signal includes the signal value after the DC component is removed at each position.

[0054] For example, for each position, the DC component of the position is determined based on the average value of multiple signal values ​​of the position (such as the N signal values ​​of the position that have been selected), such as the average value is used as the DC component. Alternatively, the DC component of the position is determined based on the average value of all signal values ​​of the first original time domain signal, such as the average value is used as the DC component, that is, all positions correspond to the same DC component. Alternatively, the DC component of the position is determined based on the average value of all signal values ​​of the first original time domain signal and the first historical time domain signal, such as the average value is used as the DC component, that is, all positions correspond to the same DC component.

[0055] For example, based on location j For example, assuming the location j The DC component of ,Location j The signal value is ,Location j After removing the DC component, the signal value is ,but .

[0056] In summary, the first original time domain signal can be preprocessed to obtain the first target time domain signal.

[0057] Exemplarily, when preprocessing the second original time domain signal to obtain the second target time domain signal, the outliers in the second original time domain signal can be deleted to obtain the second target time domain signal; or, the DC component in the second original time domain signal can be removed to obtain the second target time domain signal; or, the outliers in the second original time domain signal can be deleted and the DC component in the second original time domain signal can be removed to obtain the second target time domain signal. The implementation process refers to the first target time domain signal acquisition process.

[0058] Step 303: Filter the first target time domain signal to obtain a first filtered time domain signal, and filter the second target time domain signal to obtain a second filtered time domain signal. Alternatively, use the first target time domain signal as the first filtered time domain signal, and use the second target time domain signal as the second filtered time domain signal.

[0059] Exemplarily, when filtering the first target time domain signal to obtain the first filtered time domain signal, the first target time domain signal can be mean filtered to obtain the first filtered time domain signal; or, the first target time domain signal can be band-pass filtered to obtain the first filtered time domain signal; or, the first target time domain signal can be mean filtered and band-pass filtered to obtain the first filtered time domain signal.

[0060] For example, the following steps can be used to obtain the first filtered time domain signal: Step 3031: Perform mean filtering on the first target time domain signal to obtain a mean filtered time domain signal.

[0061] Exemplarily, the first target time domain signal includes signal values ​​of multiple positions. For each position, multiple signal values ​​of the position are selected from the first target time domain signal and the first historical time domain signal. Taking N signal values ​​as an example, the value of N can be 8, 16, 32 or 64, etc., and there is no limitation on this. The first historical time domain signal is the target time domain signal preceding the first target time domain signal (the acquisition process is similar to that of the first target time domain signal). j For example, the position is selected from the first target time domain signal j The signal value of the first target time domain signal is selected from the first target time domain signal in front of the first target time domain signal. j The signal value of is selected from the second target time domain signal in front of the first target time domain signal j signal value, and so on.

[0062] Location-based j The N signal values ​​can be used to determine the position j The signal value is mean filtered to obtain the signal value after mean filtering. For example, the following formula (2) can be used for mean filtering.

[0063] Formula (2) In formula (2), Can indicate location j The mean filtered signal value, when i=1, Can indicate location j The corresponding first signal value, when i=2, Can indicate location j The corresponding second signal value, and so on, when i=N, Can indicate location j The corresponding Nth signal value.

[0064] Obviously, for each position of the first target time domain signal, the mean filtered signal value of the position can be obtained, and the mean filtered time domain signal includes the mean filtered signal value of each position.

[0065] Step 3032: Perform bandpass filtering on the mean-filtered time-domain signal to obtain a first filtered time-domain signal.

[0066] Exemplarily, after obtaining the mean filtered time domain signal, a bandpass filter can be used to bandpass filter the mean filtered time domain signal to obtain a bandpass filtered time domain signal. The bandpass filtered time domain signal can be called the first filtered time domain signal, and there is no restriction on this bandpass filtering process.

[0067] For example, the time domain signal after mean filtering includes signal values ​​at multiple positions. For each position, the position is the position j For example, the following formula (3) can be used for bandpass filtering.

[0068] Formula (3) In formula (3), Can indicate location j The signal value after bandpass filtering, that is, the position in the time domain signal after the first filtering j The signal value of Can represent position ( ) of the bandpass filtered signal value, Can represent filter coefficients, which can be configured constants, Can be the order of the filter.

[0069] Can represent position ( ), that is, the position ( ) signal value, It can represent filter coefficients and can be configured constants.

[0070] Taking the case of a second-order IIR (Infinite Impulse Response) bandpass filter as an example, if the sampling frequency is 80MHz and the bandpass frequency range of the bandpass filter is 0.3MHz~4MHz, then: .

[0071] In summary, the first target time domain signal may be filtered to obtain a first filtered time domain signal.

[0072] Exemplarily, when filtering the second target time domain signal to obtain the second filtered time domain signal, the second target time domain signal can be mean filtered to obtain the second filtered time domain signal; or, the second target time domain signal can be band-pass filtered to obtain the second filtered time domain signal; or, the second target time domain signal can be mean filtered and band-pass filtered to obtain the second filtered time domain signal.

[0073] Step 304: Perform frequency domain transformation on the first filtered time domain signal to obtain a first original frequency domain signal, and perform frequency domain transformation on the second filtered time domain signal to obtain a second original frequency domain signal.

[0074] Exemplarily, the first filtered time domain signal is a time domain signal, and the first original frequency domain signal is a frequency domain signal. Therefore, by performing a time domain signal to frequency domain signal conversion operation (i.e., frequency domain transformation) on the first filtered time domain signal, the first original frequency domain signal can be obtained. For example, the following formula (4) can be used to perform frequency domain transformation on the first filtered time domain signal to obtain the first original frequency domain signal.

[0075] Formula (4) In formula (4), assuming that the first filtered time domain signal includes signal values ​​at L positions, the first original frequency domain signal includes amplitudes at L frequencies. Represents the first filtered time domain signal j The signal value at each position, and . Indicates the first original frequency domain signal k The amplitude of the frequency, and Obviously, in k When is 0, the amplitude of the first frequency in the first original frequency domain signal is calculated by formula (4). k When is 1, the amplitude of the second frequency in the first original frequency domain signal is calculated by formula (4), and so on, a total of L frequency amplitudes can be obtained.

[0076] In summary, the first filtered time domain signal may be transformed in the frequency domain to obtain a first original frequency domain signal, and the first original frequency domain signal includes amplitudes of multiple frequencies, such as amplitudes of L frequencies.

[0077] Similarly, the second filtered time domain signal may be transformed in the frequency domain to obtain a second original frequency domain signal, and the second original frequency domain signal includes amplitudes of multiple frequencies, such as amplitudes of L frequencies.

[0078] Step 305: Set the amplitude of the frequency corresponding to the noise signal in the first original frequency domain signal to 0 (the process of setting the amplitude to 0 is frequency domain filtering) to obtain a first target frequency domain signal, and set the amplitude of the frequency corresponding to the noise signal in the second original frequency domain signal to 0 to obtain a second target frequency domain signal. Alternatively, use the first original frequency domain signal as the first target frequency domain signal, and use the second original frequency domain signal as the second target frequency domain signal.

[0079] Exemplarily, the first original frequency domain signal includes the amplitudes of multiple frequencies (amplitudes of L frequencies), and for each frequency (i.e., spectrum), if the frequency is less than the third frequency value, or the frequency is greater than the fourth frequency value, then the frequency is the frequency corresponding to the noise signal, and the amplitude of the frequency in the first original frequency domain signal is set to 0. If the frequency is not less than the third frequency value, and the frequency is not greater than the fourth frequency value, then the frequency is not the frequency corresponding to the noise signal, and the amplitude of the frequency in the first original frequency domain signal remains unchanged.

[0080] The third frequency value can be determined based on the configured sampling frequency and the third coefficient, and the fourth frequency value can be determined based on the configured sampling frequency and the fourth coefficient. For example, the third coefficient and the fourth coefficient can be configured based on experience, and as long as the fourth coefficient is greater than the third coefficient, there is no restriction on the values ​​of the third coefficient and the fourth coefficient. For example, the third coefficient can be greater than 0 and less than 1, and the fourth coefficient can be greater than 1. For example, the third coefficient can be 0.3, 0.4, etc., and the fourth coefficient can be 3, 4, etc.

[0081] For example, the sampling frequency can be configured based on experience, indicating the sampling frequency used to distinguish noise signals. For example, when the sampling frequency is 20MHZ, if the third coefficient is 0.3 and the fourth coefficient is 3, 6MHZ (20MHZ*0.3) is used as the third frequency value, and the interference below the third frequency value is regarded as a noise signal. 60MHZ (20MHZ*3) is used as the fourth frequency value, and the interference above the fourth frequency value is regarded as a noise signal.

[0082] In summary, for each frequency, if the frequency is less than 6 MHZ, or the frequency is greater than 60 MHZ, the frequency is the frequency corresponding to the noise signal, and the amplitude of the frequency in the first original frequency domain signal is set to 0.

[0083] Exemplarily, the second original frequency domain signal includes amplitudes of multiple frequencies, and for each frequency, if the frequency is less than the third frequency value or greater than the fourth frequency value, the frequency is the frequency corresponding to the noise signal, and the amplitude of the frequency in the second original frequency domain signal is set to 0. If the frequency is not less than the third frequency value and not greater than the fourth frequency value, the frequency is not the frequency corresponding to the noise signal, and the amplitude of the frequency remains unchanged.

[0084] Step 306: determine a first mutual correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal. The first mutual correlation frequency domain signal can reflect the correlation between the first target frequency domain signal and the second target frequency domain signal, and is a correlation signal between the first target frequency domain signal and the second target frequency domain signal.

[0085] Exemplarily, a first complex conjugate frequency domain signal of a first target frequency domain signal may be determined, and a convolution operation is performed on the first complex conjugate frequency domain signal and the second target frequency domain signal to obtain a first mutually correlated frequency domain signal. Alternatively, a second complex conjugate frequency domain signal of a second target frequency domain signal may be determined, and a convolution operation is performed on the first target frequency domain signal and the second complex conjugate frequency domain signal to obtain a first mutually correlated frequency domain signal.

[0086] For example, the first cross-correlation frequency domain signal can be calculated using the following formula (5): Formula (5) In formula (5), represents the first cross-correlation frequency domain signal, represents the first target frequency domain signal, represents the second target frequency domain signal, The second complex conjugate frequency domain signal representing the second target frequency domain signal. Including the amplitude of L frequencies, the second target frequency domain signal The first cross-correlation frequency domain signal includes the amplitudes of L frequencies.

[0087] Step 307: Determine a target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal, and the target mutual correlation frequency domain signal can reflect the correlation between the first target frequency domain signal and the second target frequency domain signal.

[0088] Exemplarily, after obtaining the first mutually correlated frequency domain signal, the first mutually correlated frequency domain signal is determined as the target mutually correlated frequency domain signal. Alternatively, the zero-frequency component in the first mutually correlated frequency domain signal is moved to the frequency center to obtain the second mutually correlated frequency domain signal, and the second mutually correlated frequency domain signal is determined as the target mutually correlated frequency domain signal. Alternatively, the zero-frequency component in the first mutually correlated frequency domain signal is moved to the frequency center to obtain the second mutually correlated frequency domain signal, and the second mutually correlated frequency domain signal is adjusted to obtain the target mutually correlated frequency domain signal. Of course, the above are just a few examples, and there is no limitation on the method for obtaining the target mutually correlated frequency domain signal.

[0089] In one possible implementation, see Figure 4 As shown in FIG. 1 , a flow chart of obtaining a target cross-correlation frequency domain signal is provided. The target cross-correlation frequency domain signal can be obtained by using the following steps: Step 401: Move the zero frequency component in the first cross-correlation frequency domain signal to the frequency center to obtain a second cross-correlation frequency domain signal, that is, the zero frequency component in the second cross-correlation frequency domain signal is located at the frequency center. Alternatively, the first cross-correlation frequency domain signal can be directly used as the second cross-correlation frequency domain signal.

[0090] Exemplarily, after obtaining the first cross-correlation frequency domain signal Afterwards, the first cross-correlation frequency domain signal can be determined For example, the first cross-correlation frequency domain signal includes the amplitudes of L frequencies. If the amplitude of a certain frequency is 0, then the amplitude is the zero-frequency component. The zero-frequency component (i.e., amplitude 0) is moved to the frequency center (i.e., the central area of ​​the L frequencies). After moving the zero-frequency component to the frequency center, the amplitudes of the frequencies in the first cross-correlation frequency domain signal can be reordered, and the reordered first cross-correlation frequency domain signal is used as the second cross-correlation frequency domain signal, recorded as the second cross-correlation frequency domain signal .

[0091] When the amplitudes of the frequencies are reordered, if the amplitude 0 of the first frequency on the left side of the frequency center is moved to the frequency center, the amplitude of each frequency between the frequency center and the first frequency is moved to the left.

[0092] When the amplitudes of the frequencies are reordered, if the amplitude 0 of the second frequency on the right side of the frequency center is moved to the frequency center, the amplitude of each frequency between the frequency center and the second frequency is moved to the right.

[0093] Assume that the first cross-correlation frequency domain signal Including the amplitude 1 of frequency a1, the amplitude 0 of frequency a2, the amplitude 2 of frequency a3, the amplitude 3 of frequency a4, the amplitude 4 of frequency a5, the amplitude 5 of frequency a6, and the amplitude 3 of frequency a7, then the amplitude 0 of frequency a2 is the zero-frequency component, and frequency a4 is the frequency center. Move the zero-frequency component to frequency a4, reorder the amplitudes of each frequency, and obtain the second cross-correlation frequency domain signal , the second cross-correlation frequency domain signal Including amplitude 1 of frequency a1, amplitude 2 of frequency a2 (that is, the amplitude of frequency a3 is moved to frequency a2), amplitude 3 of frequency a3 (that is, the amplitude of frequency a4 is moved to frequency a2), amplitude 0 of frequency a4, amplitude 4 of frequency a5, amplitude 5 of frequency a6, and amplitude 3 of frequency a7.

[0094] Step 402: Filter the second cross-correlation frequency domain signal to obtain a filtered frequency domain signal. Alternatively, the second cross-correlation frequency domain signal may be directly used as the filtered frequency domain signal.

[0095] For example, at least one of a low-pass filter, a high-pass filter, a band-pass filter, and a band-stop filter may be used to filter the second cross-correlation frequency domain signal, and there is no limitation on the filtering process.

[0096] Step 403: Set the amplitude of the frequency corresponding to the noise signal in the filtered frequency domain signal to 0 to obtain a third cross-correlation frequency domain signal. Alternatively, the filtered frequency domain signal may be used as the third cross-correlation frequency domain signal.

[0097] Exemplarily, the filtered frequency domain signal includes the amplitudes of multiple frequencies (amplitudes of L frequencies). For each frequency, if the frequency is less than the first frequency value, or the frequency is greater than the second frequency value, and the second frequency value is greater than the first frequency value, then the frequency is the frequency corresponding to the noise signal, and the amplitude of the frequency in the filtered frequency domain signal is set to 0. If the frequency is not less than the first frequency value, and the frequency is not greater than the second frequency value, then the frequency is not the frequency corresponding to the noise signal, and the amplitude of the frequency in the filtered frequency domain signal remains unchanged.

[0098] The first frequency value may be determined based on the configured sampling frequency and the first coefficient, and the second frequency value may be determined based on the configured sampling frequency and the second coefficient. For example, the first coefficient and the second coefficient may be configured based on experience, and as long as the second coefficient is greater than the first coefficient, there is no restriction on the values ​​of the first coefficient and the second coefficient. For example, the first coefficient may be greater than 0 and less than 1, and the second coefficient may be greater than 1. For example, the first coefficient may be 0.5, 0.6, etc., and the second coefficient may be 2, 3, etc.

[0099] For example, the sampling frequency can be configured based on experience, indicating the sampling frequency used to distinguish noise signals. For example, when the sampling frequency is 20MHZ, if the first coefficient is 0.5 and the second coefficient is 2, 10MHZ (20MHZ*0.5) is used as the first frequency value, and the interference below the first frequency value is regarded as a noise signal. 40MHZ (20MHZ*2) is used as the second frequency value, and the interference above the second frequency value is regarded as a noise signal.

[0100] In summary, for each frequency, if the frequency is less than 10 MHZ, or the frequency is greater than 40 MHZ, the frequency is the frequency corresponding to the noise signal, and the amplitude of the frequency in the filtered frequency domain signal is set to 0.

[0101] Step 404: Perform frequency domain interpolation on the third mutual correlation frequency domain signal to obtain a fourth mutual correlation frequency domain signal. Alternatively, the third mutual correlation frequency domain signal may be directly used as the fourth mutual correlation frequency domain signal.

[0102] Exemplarily, when frequency domain interpolation is performed on the third mutually correlated frequency domain signal to obtain a fourth mutually correlated frequency domain signal, the third mutually correlated frequency domain signal includes L The amplitude of the frequency, the fourth cross-correlation frequency domain signal includes L1 The amplitude of the frequency, and L1 Greater than L , that is, increase ( L1 - L ) frequency amplitude.

[0103] Regarding the number of frequencies L1 The value of can be configured based on experience. L1 The value of can also be calculated by some algorithm. L1 There is no restriction on the value of L1 Greater than L That's it.

[0104] For example, based on the time resolution, the configured target resolution of the time difference of flight and the number of frequencies in the third cross-correlation frequency domain signal L , determine the number of frequencies in the fourth cross-correlation frequency domain signal L1For example, the frequency number can be determined using the following formula L1 : .

[0105] In the above formula, It represents the time resolution, that is, the time resolution corresponding to the sampling frequency. Assuming that the frequency range of the third cross-correlation frequency domain signal (the fourth cross-correlation frequency domain signal) is 80 MHz, the time resolution is 12500 ps. represents the target resolution, that is, the resolution of the flight time difference is expected to be , such as the target resolution is 10ps. Based on this, the above formula can be equivalent to: .

[0106] Exemplarily, for the first k frequencies, since the fourth cross-correlation frequency domain signal includes L1 The amplitude of the frequency, therefore, k The values ​​are from 0 to L1-1 Based on this, if the number of frequencies in the third cross-correlation frequency domain signal is L If the value of is an odd number, then the formula (6) can be used to determine the fourth cross-correlation frequency domain signal k Of course, formula (6) is only an example, and there is no limitation on the method of determining the target amplitude. k The target amplitude of each frequency is sufficient.

[0107] Formula (6) In formula (6), represents the fourth cross-correlation frequency domain signal k The target amplitude of the frequency, represents the third cross-correlation frequency domain signal k The amplitude of the frequency. From formula (6), it can be seen that When the target amplitude is the third cross-correlation frequency domain signal k The amplitude of the frequency; When , the target amplitude is 0; When the target amplitude is the third cross-correlation frequency domain signal k The amplitude of a frequency.

[0108] If the number of frequencies in the third cross-correlation frequency domain signal L If the value of is an even number, then the formula (7) can be used to determine the fourth cross-correlation frequency domain signal k Of course, formula (7) is only an example, and there is no limitation on the method of determining the target amplitude. kThe target amplitude of each frequency is sufficient.

[0109] Formula (7) In formula (7), represents the fourth cross-correlation frequency domain signal k The target amplitude of the frequency, represents the third cross-correlation frequency domain signal k The amplitude of the frequency. From formula (7), it can be seen that When the target amplitude is the third cross-correlation frequency domain signal k The amplitude of the frequency; When the target amplitude is the third cross-correlation frequency domain signal k The amplitude of the frequency (i.e. ) half; When , the target amplitude is 0; When the target amplitude is the third cross-correlation frequency domain signal The amplitude of the frequency (i.e. ) half; When the target amplitude is the third cross-correlation frequency domain signal k The amplitude of a frequency.

[0110] In summary, we can get the fourth cross-correlation frequency domain signal k The target amplitude of the frequency is k The values ​​are from 0 to L1-1 When L1 The target amplitude of each frequency is L1 The target amplitudes of the frequencies form a fourth cross-correlation frequency domain signal, thereby obtaining a fourth cross-correlation frequency domain signal.

[0111] Step 405: determine the target mutual correlation frequency domain signal based on the fourth mutual correlation frequency domain signal. For example, the fourth mutual correlation frequency domain signal can be determined as the target mutual correlation frequency domain signal, or the fourth mutual correlation frequency domain signal can be optimized and the optimized frequency domain signal can be used as the target mutual correlation frequency domain signal.

[0112] At this point, step 307 is completed, and the target cross-correlation frequency domain signal can be obtained.

[0113] Step 308: Perform a time domain transform based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal.

[0114] Exemplarily, the target cross-correlation frequency domain signal may be a frequency domain signal, and the cross-correlation time domain signal may be a time domain signal. Therefore, by performing a frequency domain signal to time domain signal conversion operation (i.e., time domain transformation) on the target cross-correlation frequency domain signal, the cross-correlation time domain signal may be obtained. For example, the following formula (8) may be used to perform a time domain transformation on the target cross-correlation frequency domain signal to obtain the cross-correlation time domain signal.

[0115] Formula (8) In formula (8), it is assumed that the target cross-correlation frequency domain signal includes L1 The amplitude of the frequency (target amplitude), then the cross-correlation time domain signal includes L1 The signal value at each position. represents the first k The amplitude of the frequency, and . represents the first n The signal value at each position, and Obviously, in When is 0, the signal value of the first position in the cross-correlated time domain signal is calculated by formula (8). When it is 1, the signal value of the second position in the cross-correlated time domain signal is calculated by formula (8), and so on, a total of L1 The signal value at each position is L1 The signal values ​​at each position can form a cross-correlated time domain signal.

[0116] Step 309, the cross-correlated time domain signal includes signal values ​​at multiple positions, and the flight time difference is determined based on the target position corresponding to the maximum signal value. The target position can be the most similar position between the first original time domain signal and the second original time domain signal, and the flight time difference can represent the phase difference of the target position.

[0117] Exemplarily, based on the signal value of each position in the cross-correlated time domain signal, the maximum signal value can be selected from these signal values, and the position corresponding to the maximum signal value is called the target position, which is recorded as , It can be said that the target position is the first For example, if If it is 3, it means that the signal value at the third position in the cross-correlated time domain signal is the maximum signal value.

[0118] Exemplarily, the time of flight difference may be determined based on the target position corresponding to the maximum signal value, the total number of positions in the cross-correlated time domain signals, and a configured target resolution of the time of flight difference.

[0119] For example, the flight time difference may be determined using the following formula (9). Of course, formula (9) is only an example, and there is no limitation on the determination method, as long as the flight time difference is related to the target position.

[0120] Formula (9) In formula (9), It can represent the flight time difference, which can be the time difference between the propagation of ultrasound in the downstream direction and the upstream direction. For example, the flight time of the sound wave from the first transducer to the second transducer The time of flight of the sound wave from the second transducer to the first transducer The difference between .

[0121] In formula (9), The total number of positions can be expressed, for example, if the cross-correlated time domain signal consists of L1 The signal value of each position, then the total number of positions in the cross-correlated time domain signal is L1 . represents the target resolution, that is, the resolution of the flight time difference is expected to be , such as the target resolution is 10ps.

[0122] Exemplarily, when the signal value at the target position is the maximum signal value, it indicates that the first original time domain signal and the second original time domain signal are most similar at the target position, so that the phase difference at the target position can be used as the flight time difference between the first original time domain signal and the second original time domain signal. Regarding how to determine the phase difference at the target position, please refer to formula (9), that is, the phase difference is used as the flight time difference. For example, for the phase difference at the target position, the phase difference can refer to the difference between the signal value of the target position in the first original time domain signal and the signal value of the target position in the second original time domain signal.

[0123] In one possible implementation, the cross-correlation function RxY ( τ ) is defined as a signal x ( t ) and signal y ( t ) at different time delays τ The physical meaning of cross-correlation is to measure the similarity of two signals at different time offsets. y ( t ) Delay to a value τ When the cross-correlation signal RxY ( τ ) will have a maximum value, which indicates that the shapes of the two signals are closest at this time, that is, the two signals are best aligned in time.

[0124] Based on the above principle, in this embodiment, the position corresponding to the maximum value in the cross-correlation time domain signal (i.e., the target position) is the phase difference (i.e., time difference) between the two signals (the first original time domain signal and the second original time domain signal). This phase difference is the flight time difference. , .

[0125] In this embodiment, , is a discretized representation. Signal y ( t ) moves backwards to correspond to Negative, signal y ( t ) moves forward to correspond to is positive, the length of the cross-correlation time domain signal is L1 ,Signal y ( t ) moved backwards , moved forward , plus a point that does not move itself, because n This sequence number starts from 0, so you need to subtract , that is, we get formula (9).

[0126] For example, after obtaining the flight time difference, it can also be determined whether the flight time difference is an abnormal value. If the flight time difference is an abnormal value, the flight time difference is discarded, and the flow velocity of the fluid passing through the pipeline is not determined based on the flight time difference. If the flight time difference is not an abnormal value, the flight time difference is retained, and the flow velocity of the fluid passing through the pipeline can be determined based on the flight time difference.

[0127] For example, based on the flight time difference and the historical flight time differences (i.e., the flight time differences obtained in the past, the number of historical flight time differences may be multiple), the average of these flight time differences may be calculated. and standard deviation Based on the mean and standard deviation Determine whether the flight time difference is an outlier. For example, if the flight time difference satisfies or , then the flight time difference is an abnormal value. If the flight time difference does not satisfy or , then the flight time difference is not an outlier. In the above relationship, The flight time difference can be expressed as Can represent configured constants, The value range of can be 0.5~2, and there is no restriction on this.

[0128] For example, after the flight time difference is obtained, the flow velocity of the fluid passing through the pipe can be determined based on the flight time difference. For example, the flow velocity of the fluid can be determined using the following formula (10).

[0129] * c 2 * / 2D Formula (10) represents the flight time difference, c It represents the speed of sound of ultrasonic wave in the medium (i.e. fluid). Indicates the flow rate of a fluid as it passes through a pipe. Figure 2 As shown, Φ It represents the angle between the sound wave transmission path and the pipe (the angle between the sound wave transmission length direction and the pipe section diameter). D Represents the pipe segment diameter (the inside vertical distance of the pipe).

[0130] It can be seen from the above technical solutions that in the embodiment of the present application, it is not necessary to measure the acoustic wave flight time from the first transducer to the second transducer and the acoustic wave flight time from the second transducer to the first transducer, which can avoid the low accuracy of the flight time difference caused by the low measurement accuracy of the acoustic wave flight time, and can accurately obtain the flight time difference, the accuracy of the flight time difference is high, the error of the flight time difference is small, and the calculation accuracy of the flight time difference is improved, and the accurate calculation of the phase difference between the uplink signal and the downlink signal of the ultrasonic wave is realized, and the anti-interference performance to noise is improved. By adopting the frequency domain interpolation method, the information of the signal of any length can be used, and the invalid noise can be filtered to improve the anti-interference performance to noise, and the influence of signal noise and signal asymmetry on the calculation accuracy can be eliminated, thereby greatly improving the time resolution and interpolation accuracy, and improving the calculation accuracy of the flight time difference.

[0131] Based on the same application concept as the above method, a flow velocity determination device is proposed in an embodiment of the present application. A first transducer and a second transducer are respectively installed on both sides of a pipeline. When a fluid passes through the pipeline, the first transducer sends an ultrasonic wave to the second transducer, and the second transducer sends an ultrasonic wave to the first transducer. Figure 5 FIG. 1 is a schematic diagram of the structure of the device, and the device may include: An acquisition module 51 is used to acquire a first original time domain signal acquired by a first transducer and a second original time domain signal acquired by a second transducer; a first target frequency domain signal is obtained by performing a frequency domain transformation based on the first original time domain signal, and a second target frequency domain signal is obtained by performing a frequency domain transformation based on the second original time domain signal; a determination module 52 is used to determine a first cross-correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and a target cross-correlation frequency domain signal is determined based on the first cross-correlation frequency domain signal; a processing module 53 is used to perform a time domain transformation based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, and the cross-correlation time domain signal includes signal values ​​at multiple positions; a flight time difference is determined based on the target position corresponding to the maximum signal value; wherein the flight time difference is the time difference between the propagation of ultrasonic waves in the downstream direction and the upstream direction; the flight time difference is used to determine the flow velocity of the fluid when passing through the pipeline.

[0132] Exemplarily, when determining the first mutually correlated frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, the determination module 52 is specifically used to: determine the first complex conjugate frequency domain signal corresponding to the first target frequency domain signal, and perform a convolution operation on the first complex conjugate frequency domain signal and the second target frequency domain signal to obtain the first mutually correlated frequency domain signal; or, determine the second complex conjugate frequency domain signal corresponding to the second target frequency domain signal, and perform a convolution operation on the first target frequency domain signal and the second complex conjugate frequency domain signal to obtain the first mutually correlated frequency domain signal.

[0133] Exemplarily, when the determination module 52 determines the target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal, it is specifically used to: determine the first mutual correlation frequency domain signal as the target mutual correlation frequency domain signal; or, move the zero-frequency component in the first mutual correlation frequency domain signal to the frequency center to obtain a second mutual correlation frequency domain signal, and determine the second mutual correlation frequency domain signal as the target mutual correlation frequency domain signal; or, move the zero-frequency component in the first mutual correlation frequency domain signal to the frequency center to obtain a second mutual correlation frequency domain signal, and filter the second mutual correlation frequency domain signal to obtain a filtered frequency domain signal; set the amplitude of the frequency corresponding to the noise signal in the filtered frequency domain signal to 0 to obtain a third mutual correlation frequency domain signal, perform frequency domain interpolation on the third mutual correlation frequency domain signal to obtain a fourth mutual correlation frequency domain signal, and determine the fourth mutual correlation frequency domain signal as the target mutual correlation frequency domain signal.

[0134] Exemplarily, the filtered frequency domain signal includes amplitudes of multiple frequencies, and for each frequency, if the frequency is less than a first frequency value, or the frequency is greater than a second frequency value, then the frequency is the frequency corresponding to the noise signal; wherein the first frequency value is determined based on a configured sampling frequency and a first coefficient, the first coefficient is greater than 0 and the first coefficient is less than 1, and the second frequency value is determined based on the configured sampling frequency and the second coefficient, and the second coefficient is greater than 1.

[0135] Exemplarily, when frequency domain interpolation is performed on the third mutually correlated frequency domain signal to obtain a fourth mutually correlated frequency domain signal, the third mutually correlated frequency domain signal includes L The fourth cross-correlation frequency domain signal includes L1 The amplitude of the frequency, and L1 Greater than L ; Wherein, for the first k frequency, k The values ​​are from 0 to L1-1 The determining module 52 determines the first k The target amplitude of the frequency: L The value of is an odd number. When , the target amplitude is the first k The amplitude of a frequency; or, When , the target amplitude is 0; or When , the target amplitude is the first k the amplitude of a frequency; or, like L The value of is an even number. When , the target amplitude is the first k The amplitude of a frequency; or, When , the target amplitude is the first k half the amplitude of the frequency; or, When , the target amplitude is 0; or When , the target amplitude is the first half the amplitude of the frequency; or, When , the target amplitude is the first k The amplitude of a frequency.

[0136] Exemplarily, when the processing module 53 determines the flight time difference based on the target position corresponding to the maximum signal value, it is specifically used to: determine the flight time difference based on the target position corresponding to the maximum signal value, the total number of positions in the cross-correlated time domain signal, and the configured target resolution of the flight time difference; wherein, the processing module 53 determines the flight time difference using the following formula: ; in, represents the flight time difference, Indicates that the target position is the first Locations, represents the total number of positions, Indicates the target resolution.

[0137] Exemplarily, when the acquisition module 51 performs a frequency domain transform based on the first original time domain signal to obtain a first target frequency domain signal, it is specifically used to: preprocess the first original time domain signal to obtain a first target time domain signal, and filter the first target time domain signal to obtain a first filtered time domain signal; perform a frequency domain transform on the first filtered time domain signal to obtain a first original frequency domain signal, and set the amplitude of the frequency corresponding to the noise signal in the first original frequency domain signal to 0 to obtain the first target frequency domain signal.

[0138] Exemplarily, when the acquisition module 51 preprocesses the first original time domain signal to obtain the first target time domain signal, it is specifically used to: delete the abnormal values ​​in the first original time domain signal to obtain the first target time domain signal; or, remove the DC component in the first original time domain signal to obtain the first target time domain signal; or, delete the abnormal values ​​in the first original time domain signal and remove the DC component in the first original time domain signal to obtain the first target time domain signal; wherein, the first original time domain signal includes signal values ​​at multiple positions; for each position, multiple signal values ​​at the position are selected from the first original time domain signal and the first historical time domain signal, and a first quartile and a second quartile are determined based on the multiple signal values; based on the first quartile and the second quartile, it is determined whether the signal value at the position is an abnormal value; for each position, the DC component of the position is determined based on the average value of the multiple signal values ​​at the position, or, based on the average value of all signal values ​​of the first original time domain signal, or, based on the average value of all signal values ​​of the first original time domain signal and the first historical time domain signal.

[0139] Based on the same application concept as the above method, an electronic device is proposed in the embodiment of the present application, see Figure 6As shown, the electronic device includes: a processor 61 and a machine-readable storage medium 62, the machine-readable storage medium 62 stores machine-executable instructions that can be executed by the processor 61; the processor 61 is used to execute the machine-executable instructions to implement the flow rate determination method disclosed in the above example of this application.

[0140] Based on the same application concept as the above method, an embodiment of the present application also provides a machine-readable storage medium, on which a number of computer instructions are stored. When the computer instructions are executed by a processor, the flow rate determination method disclosed in the above example of the present application can be implemented.

[0141] The above-mentioned machine-readable storage medium may be any electronic, magnetic, optical or other physical storage device, which may contain or store information, such as executable instructions, data, etc. For example, the machine-readable storage medium may be: RAM (Radom Access Memory), volatile memory, non-volatile memory, flash memory, storage drive (such as hard disk drive), solid state drive, any type of storage disk (such as optical disk, DVD, etc.), or similar storage medium, or a combination thereof.

[0142] Based on the same application concept as the above method, an embodiment of the present application further provides a computer program product, which may include a computer program. When the computer program is executed by a processor, it can implement the flow rate determination method disclosed in the above example.

[0143] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0144] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for determining flow velocity, characterized in that: A first transducer and a second transducer are respectively installed on both sides of a pipeline, and fluid passes through the pipeline, the first transducer sends an ultrasonic wave to the second transducer, and the second transducer sends an ultrasonic wave to the first transducer. The method includes: Acquire a first original time domain signal acquired by the first transducer and a second original time domain signal acquired by the second transducer; perform frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal, and perform frequency domain transformation based on the second original time domain signal to obtain a second target frequency domain signal; Determine a first mutual correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and determine a target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal; A time domain transform is performed based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, wherein the cross-correlation time domain signal includes signal values ​​at multiple positions; a flight time difference is determined based on the target position corresponding to the maximum signal value; wherein the flight time difference is the time difference for propagation of the ultrasonic wave in the downstream direction and the upstream direction; wherein the flight time difference is used to determine the flow velocity of the fluid when it passes through the pipeline.

2. The method according to claim 1, characterized in that The determining a first mutually correlated frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal comprises: determining a first complex conjugate frequency domain signal of the first target frequency domain signal, and performing a convolution operation on the first complex conjugate frequency domain signal and the second target frequency domain signal to obtain a first cross-correlation frequency domain signal; or, A second complex conjugate frequency domain signal of the second target frequency domain signal is determined, and a convolution operation is performed on the first target frequency domain signal and the second complex conjugate frequency domain signal to obtain a first cross-correlation frequency domain signal.

3. The method according to claim 1, characterized in that The determining a target cross-correlation frequency domain signal based on the first cross-correlation frequency domain signal comprises: determining the first cross-correlation frequency domain signal as the target cross-correlation frequency domain signal; or, Move the zero-frequency component in the first cross-correlation frequency domain signal to the frequency center to obtain a second cross-correlation frequency domain signal, and determine the second cross-correlation frequency domain signal as the target cross-correlation frequency domain signal; or, The zero-frequency component in the first mutually correlated frequency domain signal is moved to the frequency center to obtain a second mutually correlated frequency domain signal, and the second mutually correlated frequency domain signal is filtered to obtain a filtered frequency domain signal; the amplitude of the frequency corresponding to the noise signal in the filtered frequency domain signal is set to 0 to obtain a third mutually correlated frequency domain signal, the third mutually correlated frequency domain signal is interpolated in the frequency domain to obtain a fourth mutually correlated frequency domain signal, and the fourth mutually correlated frequency domain signal is determined as the target mutually correlated frequency domain signal.

4. The method according to claim 3, characterized in that The filtered frequency domain signal includes amplitudes of multiple frequencies, and for each frequency, if the frequency is less than a first frequency value, or the frequency is greater than a second frequency value, then the frequency is a frequency corresponding to the noise signal; wherein the first frequency value is determined based on a configured sampling frequency and a first coefficient, the first coefficient is greater than 0 and less than 1, and the second frequency value is determined based on the configured sampling frequency and the second coefficient, the second coefficient is greater than 1; When frequency domain interpolation is performed on the third mutually correlated frequency domain signal to obtain a fourth mutually correlated frequency domain signal, the third mutually correlated frequency domain signal includes L The fourth cross-correlation frequency domain signal includes L1 The amplitude of the frequency, and L1 Greater than L ; Wherein, for the first k frequency, k The values ​​are from 0 to L1-1 , then the following method is used to determine the k Target amplitude for each frequency: like L The value of is an odd number. When , the target amplitude is the first k The amplitude of a frequency; or, When , the target amplitude is 0; or When , the target amplitude is the first k the amplitude of a frequency; or, like L The value of is an even number. When , the target amplitude is the first k The amplitude of a frequency; or, When , the target amplitude is the first k half the amplitude of the frequency; or, When , the target amplitude is 0; or When , the target amplitude is the first half the amplitude of the frequency; or, When , the target amplitude is the first k The amplitude of a frequency.

5. The method according to claim 1, characterized in that: The determining of the flight time difference based on the target position corresponding to the maximum signal value includes: determining the time of flight difference based on the target position corresponding to the maximum signal value, the total number of positions in the cross-correlated time domain signal, and a configured target resolution of the time of flight difference; The flight time difference is determined by the following formula: ; in, represents the flight time difference, Indicates that the target position is the first Locations, represents the total number of positions, Indicates the target resolution.

6. The method according to any one of claims 1 to 5, characterized in that: The performing frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal includes: Preprocessing the first original time domain signal to obtain a first target time domain signal; Filtering the first target time domain signal to obtain a first filtered time domain signal; Performing frequency domain transformation on the first filtered time domain signal to obtain a first original frequency domain signal, and setting the amplitude of the frequency corresponding to the noise signal in the first original frequency domain signal to 0 to obtain a first target frequency domain signal.

7. The method according to claim 6, characterized in that The preprocessing of the first original time domain signal to obtain the first target time domain signal includes: deleting abnormal values ​​in the first original time domain signal to obtain the first target time domain signal; or removing a DC component in the first original time domain signal to obtain the first target time domain signal; or deleting abnormal values ​​in the first original time domain signal and removing a DC component in the first original time domain signal to obtain the first target time domain signal; Wherein, the first original time domain signal includes signal values ​​at multiple positions; For each position, select multiple signal values ​​of the position from the first original time domain signal and the first historical time domain signal, determine a first quartile and a second quartile based on the multiple signal values; determine whether the signal value of the position is an abnormal value based on the first quartile and the second quartile; For each position, the DC component of the position is determined based on the average value of multiple signal values ​​of the position, or based on the average value of all signal values ​​of the first original time domain signal, or based on the average value of all signal values ​​of the first original time domain signal and the first historical time domain signal.

8. A flow rate determination device, characterized in that: A first transducer and a second transducer are respectively installed on both sides of the pipeline. When the fluid passes through the pipeline, the first transducer sends ultrasonic waves to the second transducer, and the second transducer sends ultrasonic waves to the first transducer. The device includes: An acquisition module, configured to acquire a first original time domain signal acquired by a first transducer and a second original time domain signal acquired by a second transducer; perform a frequency domain transformation based on the first original time domain signal to obtain a first target frequency domain signal, and perform a frequency domain transformation based on the second original time domain signal to obtain a second target frequency domain signal; a determination module, configured to determine a first mutual correlation frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, and determine a target mutual correlation frequency domain signal based on the first mutual correlation frequency domain signal; A processing module is used to perform time domain transformation based on the target cross-correlation frequency domain signal to obtain a cross-correlation time domain signal, wherein the cross-correlation time domain signal includes signal values ​​at multiple positions; a flight time difference is determined based on the target position corresponding to the maximum signal value; wherein the flight time difference is the time difference for the propagation of the ultrasonic wave in the downstream direction and the upstream direction; and the flight time difference is used to determine the flow velocity of the fluid when it passes through the pipeline.

9. The device according to claim 8, characterized in that in, When the determination module determines the first mutually correlated frequency domain signal based on the first target frequency domain signal and the second target frequency domain signal, it is specifically used to: determine the first complex conjugate frequency domain signal of the first target frequency domain signal, and perform a convolution operation on the first complex conjugate frequency domain signal and the second target frequency domain signal to obtain the first mutually correlated frequency domain signal; or determine the second complex conjugate frequency domain signal of the second target frequency domain signal, and perform a convolution operation on the first target frequency domain signal and the second complex conjugate frequency domain signal to obtain the first mutually correlated frequency domain signal; Among them, when the determination module determines the target mutually correlated frequency domain signal based on the first mutually correlated frequency domain signal, it is specifically used to: determine the first mutually correlated frequency domain signal as the target mutually correlated frequency domain signal; or, move the zero-frequency component in the first mutually correlated frequency domain signal to the frequency center to obtain a second mutually correlated frequency domain signal, and determine the second mutually correlated frequency domain signal as the target mutually correlated frequency domain signal; or, move the zero-frequency component in the first mutually correlated frequency domain signal to the frequency center to obtain a second mutually correlated frequency domain signal, and filter the second mutually correlated frequency domain signal to obtain a filtered frequency domain signal; set the amplitude of the frequency corresponding to the noise signal in the filtered frequency domain signal to 0 to obtain a third mutually correlated frequency domain signal, perform frequency domain interpolation on the third mutually correlated frequency domain signal to obtain a fourth mutually correlated frequency domain signal, and determine the fourth mutually correlated frequency domain signal as the target mutually correlated frequency domain signal; The filtered frequency domain signal includes amplitudes of multiple frequencies, and for each frequency, if the frequency is less than a first frequency value, or the frequency is greater than a second frequency value, then the frequency is a frequency corresponding to the noise signal; wherein the first frequency value is determined based on a configured sampling frequency and a first coefficient, the first coefficient is greater than 0 and the first coefficient is less than 1, and the second frequency value is determined based on the configured sampling frequency and the second coefficient, and the second coefficient is greater than 1; When the third mutually correlated frequency domain signal is subjected to frequency domain interpolation to obtain a fourth mutually correlated frequency domain signal, the third mutually correlated frequency domain signal includes L The fourth cross-correlation frequency domain signal includes L1 The amplitude of the frequency, and L1 Greater than L ; Wherein, for the first k frequency, k The values ​​are from 0 to L1-1 The determination module determines the first k The target amplitude of the frequency: L The value of is an odd number. When , the target amplitude is the first k The amplitude of a frequency; or, When , the target amplitude is 0; or When , the target amplitude is the first k the amplitude of a frequency; or, like L The value of is an even number. When , the target amplitude is the first k The amplitude of a frequency; or, When , the target amplitude is the first k half the amplitude of the frequency; or, When , the target amplitude is 0; or When , the target amplitude is the first half the amplitude of the frequency; or, When , the target amplitude is the first k The amplitude of a frequency; Wherein, when the processing module determines the flight time difference based on the target position corresponding to the maximum signal value, it is specifically used to: determine the flight time difference based on the target position corresponding to the maximum signal value, the total number of positions in the cross-correlated time domain signal and the configured target resolution of the flight time difference; wherein, the processing module determines the flight time difference using the following formula: ; in, represents the flight time difference, Indicates that the target position is the first Locations, represents the total number of positions, represents the target resolution; Wherein, when the acquisition module performs frequency domain transformation based on the first original time domain signal to obtain the first target frequency domain signal, it is specifically used to: preprocess the first original time domain signal to obtain the first target time domain signal, filter the first target time domain signal to obtain the first filtered time domain signal; perform frequency domain transformation on the first filtered time domain signal to obtain the first original frequency domain signal, and set the amplitude of the frequency corresponding to the noise signal in the first original frequency domain signal to 0 to obtain the first target frequency domain signal; Wherein, when the acquisition module preprocesses the first original time domain signal to obtain the first target time domain signal, it is specifically used to: delete the abnormal values ​​in the first original time domain signal to obtain the first target time domain signal; or, remove the DC component in the first original time domain signal to obtain the first target time domain signal; or, delete the abnormal values ​​in the first original time domain signal, and remove the DC component in the first original time domain signal to obtain the first target time domain signal; wherein, the first original time domain signal includes signal values ​​at multiple positions; for each position, multiple signal values ​​at the position are selected from the first original time domain signal and the first historical time domain signal, and a first quartile and a second quartile are determined based on the multiple signal values; based on the first quartile and the second quartile, determine whether the signal value at the position is an abnormal value; For each position, the DC component of the position is determined based on the average value of multiple signal values ​​of the position, or based on the average value of all signal values ​​of the first original time domain signal, or based on the average value of all signal values ​​of the first original time domain signal and the first historical time domain signal.

10. An electronic device, characterized in that: include: a processor and a machine-readable storage medium storing machine-executable instructions executable by the processor; The processor is used to execute machine executable instructions to implement the method described in any one of claims 1-7.

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