CN110988853B - Ultrasonic arrival time calculation method based on effective peak value - Google Patents
Ultrasonic arrival time calculation method based on effective peak value Download PDFInfo
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- CN110988853B CN110988853B CN201911343046.2A CN201911343046A CN110988853B CN 110988853 B CN110988853 B CN 110988853B CN 201911343046 A CN201911343046 A CN 201911343046A CN 110988853 B CN110988853 B CN 110988853B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S11/00—Systems for determining distance or velocity not using reflection or reradiation
- G01S11/14—Systems for determining distance or velocity not using reflection or reradiation using ultrasonic, sonic, or infrasonic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H17/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention discloses an ultrasonic arrival time calculation method based on an effective peak value, which comprises the following steps: s1, determining effective peak time T of ultrasonic wave receiving waveform valid The method comprises the steps of carrying out a first treatment on the surface of the S2, determining inherent delay t in the ultrasonic receiving and processing process; s3, effective peak time T valid The difference from the inherent delay t is taken as the arrival time of the ultrasonic wave. The ultrasonic arrival time calculation method based on the effective peak value is simple in measurement process and high in accuracy.
Description
Technical Field
The invention relates to the field of ultrasonic waves, in particular to an ultrasonic wave arrival time calculation method based on an effective peak value.
Background
Aiming at the determination method of the arrival time of the ultrasonic wave receiving waveform, research institutions at home and abroad commonly adopt a threshold method or a cross-correlation algorithm for research. The threshold method generally carries out level comparison on the rising edge of the received waveform according to a certain fixed threshold or a relative threshold to obtain the arrival time of ultrasonic waves, and the received waveform is relatively high in jitter due to flow field jitter or noise interference and the like, so that the arrival time of the comparison threshold is caused to move forward or backward by one period; the cross-correlation algorithm performs a correlation operation according to the reference waveform and the actual received waveform to obtain the arrival time of the ultrasonic wave, which has the disadvantage that the reference waveform is difficult to select.
Therefore, in order to solve the above problems, there is a need for an ultrasonic arrival time calculation method based on an effective peak, which can obtain accurate and reliable measurement results by a simple operation.
Disclosure of Invention
In view of the above, the present invention aims to overcome the defects in the prior art, and provide an ultrasonic arrival time calculation method based on an effective peak value, which can obtain an accurate and reliable measurement result through a simple operation.
The invention discloses an ultrasonic arrival time calculation method based on an effective peak value, which comprises the following steps:
s1, determining effective peak time T of ultrasonic wave receiving waveform valid ；
S2, determining inherent delay t in the ultrasonic receiving and processing process;
s3, effective peak time T valid The difference from the inherent delay t is taken as the arrival time of the ultrasonic wave.
Further, in step S1, the effective peak time T of the ultrasonic wave reception waveform is determined according to the following steps valid ：
S11, sampling an ultrasonic wave receiving signal to obtain a discretization amplitude sampling sequence y [ t ];
s12, constructing a relation graph Y-T taking amplitude as a Y axis and time as an X axis based on a discretized amplitude sampling sequence Y [ T ];
s13, determining the maximum value Y of the amplitude of the received waveform according to the relation diagram Y-T max And a maximum value y max Two adjacent peaks Y in the same Y-axis direction max-1 And y is max+1 And obtain the maximum value y max Peak value y max-1 Peak y max+1 Respectively corresponding time t max 、t max-1 T max+1 ；
S14, respectively calculating t max 、t max-1 T max+1 Surrounding areas S0, S1 and S2 of the ultrasonic wave receiving waveforms and the positive half shaft of time in three periods at the center moment; wherein, the ultrasonic wave receiving waveforms participating in calculation are in the same Y-axis direction;
s15, determining the maximum value S in the areas S0, S1 and S2 max And will be maximum S max The corresponding center moment is taken as the effective peak moment T valid 。
Further, in step S14, at time t max Starting with a rim less than time t max Sequentially selecting 5 adjacent time values (t 1, t1', t2, t2', t 3) with waveform amplitude value of 0 in the time axis direction; at time t max Starting at a border greater than time t max Sequentially selecting 5 adjacent time values (t 3', t4, t4', t5, t5 ') with the waveform amplitude of 0 in the time axis direction;
the surrounding area S0 is determined according to the following formula:
the surrounding area S1 is determined according to the following formula:
the surrounding area S2 is determined according to the following formula:
further, in step S2, the inherent delay t of the ultrasonic wave reception processing process is determined according to the following steps:
s21, setting the horizontal distance between a transmitting transducer and a receiving transducer as D1;
s22, transmitting ultrasonic waves to a receiving transducer by a transmitting transducer, and obtaining effective peak time T of an ultrasonic wave waveform by analogy in the steps S11-S15 D1 ；
S23 rootAccording to the horizontal distance D1 and the effective peak time T D1 Obtaining a calculation formula E: c (T) D1 -t) =d1; wherein C is the ultrasonic speed;
s24, setting the horizontal distance between the transmitting transducer and the receiving transducer as D2;
s25, transmitting ultrasonic waves to the receiving transducer by the transmitting transducer, and obtaining effective peak time T of ultrasonic wave waveforms by analogy in the steps S11-S15 D2 ；
S26, according to the horizontal distance D2 and the effective peak time T D2 Obtaining a calculation formula F: c (T) D2 -t) =d2; wherein C is the ultrasonic speed;
s27, combining the calculation formulas E and F to obtain the inherent delay t.
Further, in step S2, the inherent delay of the ultrasonic wave includes: the hardware circuitry and software processes inherent delays.
The beneficial effects of the invention are as follows: according to the ultrasonic arrival time calculating method based on the effective peak value, the received waveform amplitude of the ultrasonic wave is recorded, the relation diagram of the waveform amplitude and time is constructed, the effective peak value moment is calculated according to the relation diagram, the ultrasonic processing delay is calculated according to the simple ranging principle, and the arrival time of the ultrasonic wave is obtained by utilizing the difference value between the effective peak value moment and the ultrasonic processing delay.
Drawings
The invention is further described below with reference to the accompanying drawings and examples:
FIG. 1 is a schematic flow chart of the method of the present invention;
FIG. 2 is an ultrasonic wave reception waveform of the present invention;
FIG. 3 is a graph of waveform amplitude versus time according to the present invention;
FIG. 4 is a surrounding area S0 of the present invention;
FIG. 5 is a surrounding area S1 of the present invention;
FIG. 6 is a surrounding area S2 of the present invention;
fig. 7 is a schematic view of ultrasonic ranging according to the present invention.
Detailed Description
The invention is further described with reference to the accompanying drawings, in which:
the invention discloses an ultrasonic arrival time calculation method based on an effective peak value, which comprises the following steps:
s1, determining effective peak time T of ultrasonic wave receiving waveform valid ；
S2, determining inherent delay t in the ultrasonic receiving and processing process;
s3, effective peak time T valid The difference from the inherent delay t is taken as the arrival time of the ultrasonic wave.
Through researches, the actual receiving peak value can move forward or backward due to attenuation of the ultrasonic wave through a medium and interference of external noise in the transmitting and receiving processes. Searching the maximum value (marked as a pseudo peak value) and recording the maximum value moment (marked as a pseudo peak value moment) of the signal, searching and recording two peaks adjacent to the pseudo peak value and moments corresponding to the two peaks respectively, calculating the surrounding areas of three periodic receiving waveforms and a coordinate positive half shaft which are respectively centered on the three moments to obtain three surrounding area values, finally judging and comparing the maximum value in the three area values, and determining the effective peak value moment according to the maximum value.
In the present embodiment, in step S1, the effective peak time T of the ultrasonic wave reception waveform is determined according to the following steps valid ：
S11, a square wave is adopted to excite the transmitting transducer, and the receiving waveform of the tiny signal output by the receiving transducer after filtering and amplifying is spindle-shaped waveform (as shown in figure 2). Specifically, while the ultrasonic wave generates the excitation pulse, the analog-to-digital conversion of the received waveform is started, the sampling frequency is set to 50000000HZ, and a discretized amplitude sampling sequence y [ t ] is formed.
S12, based on a discretization amplitude sampling sequence Y [ T ] of the ultrasonic wave receiving waveform, taking the waveform amplitude as a Y-axis coordinate value of a two-dimensional coordinate system, and taking a moment value corresponding to the waveform amplitude as an X-axis coordinate value of the two-dimensional coordinate system, so as to obtain a change relation graph Y-T (shown in figure 3) of the waveform amplitude along with time.
S13, finding the maximum value Y of the absolute value of the amplitude of the received waveform according to the relation graph Y-T max And a maximum value y max Two adjacent peaks Y in the same Y-axis direction max-1 And y is max+1 And obtain the maximum value y max Peak value y max-1 Peak y max+1 Respectively corresponding time t max 、t max-1 T max+1 The method comprises the steps of carrying out a first treatment on the surface of the The same Y-axis direction refers to the same Y-axis positive direction (upward) or the same Y-axis negative direction (downward).
S14, respectively calculating t max 、t max-1 T max+1 Surrounding areas S0, S1 and S2 of the ultrasonic wave receiving waveforms and the positive half shaft of time in three periods at the center moment; wherein, the ultrasonic wave receiving waveforms participating in calculation are in the same Y-axis direction; specifically, at time t max Starting with a rim less than time t max Sequentially selecting 5 adjacent time values (t 1, t1', t2, t2', t 3) with waveform amplitude value of 0 in the time axis direction; at time t max Starting at a border greater than time t max Sequentially selecting 5 adjacent time values (t 3', t4, t4', t5, t5 ') with the waveform amplitude of 0 in the time axis direction;
the surrounding area S0 is determined according to the following formula:
the surrounding area S1 is determined according to the following formula:
the surrounding area S2 is determined according to the following formula:
the above three equations can be approximated as:
s15, comparing the sizes of S0, S1 and S2, if S0 is greater than S1 and S0 is greater than S2, the maximum value is S0, and the effective peak time T valid Time t corresponding to maximum S0 max The method comprises the steps of carrying out a first treatment on the surface of the If S1 > S0 and S1 > S2, the maximum value is S1, and the effective peak time T valid Time t corresponding to maximum value S1 max-1 The method comprises the steps of carrying out a first treatment on the surface of the If S2 > S0 and S2 > S1, the maximum value is S2, and the effective peak time T valid Time t corresponding to maximum value S2 max+1 。
In this embodiment, in step S2, since the effective peak time includes a hardware circuit delay and a software processing delay, the delay needs to be determined and removed to obtain an accurate ultrasonic wave receiving arrival time. The delay may be determined using ranging principles. Specifically, the inherent delay t of the ultrasonic wave reception processing (the sum of the hardware circuit delay and the software processing delay is set as the inherent delay t here) is determined according to the following steps:
s21, an ultrasonic ranging platform is built, namely a transmitting transducer and a receiving transducer are prepared, and the two transducers are placed on the same horizontal plane. Firstly, setting the horizontal distance between a transmitting transducer and a receiving transducer to D1=0.5m;
s22, starting the transmitting transducer to transmit ultrasonic waves to the receiving transducer, and receiving the ultrasonic waves by the receiving transducer. And by analogy to the steps S11-S15, the effective peak time T of the ultrasonic waveform can be obtained D1 ；
S23, according to the horizontal distance D1 and the effective peak time T D1 Obtaining a calculation formula E: c (T) D1 -t) =d1; wherein C is ultrasoundWave velocity;
s24, adjusting and setting the horizontal distance between the transmitting transducer and the receiving transducer to d2=1.0m;
s25, the transmitting transducer transmits ultrasonic waves to the receiving transducer again, and similarly, the effective peak time T of the ultrasonic wave is obtained by analogy in the steps S11-S15 D2 ；
S26, according to the horizontal distance D2 and the effective peak time T D2 Obtaining a calculation formula F: c (T) D2 -t) =d2; wherein C is the ultrasonic speed;
s27, utilizing the calculation formulas E and F, the inherent delay t can be obtained.
In this embodiment, in step S3, the effective peak time T valid The difference from the inherent delay T is taken as the arrival time of the ultrasonic wave Tof, i.e. tof=t valid -t. Furthermore, according to the working principle of the ultrasonic gas flowmeter, the ultrasonic gas flowmeter generally adopts a Z-method mounting structure, two ultrasonic transducers which are integrated into a whole are mounted on the same section of the pipeline, the included angle between the ultrasonic transducers and the central axis of the pipeline is theta, the pipe diameter is D, the gas flow rate is V, and the ultrasonic speed is C. The gas flow velocity V of the pipeline can be calculated according to the ultrasonic arrival time obtained by calculation:wherein t is up T down The arrival time of the ultrasonic wave measured when the two transducers are respectively used as transmitting transducers. Similarly, the gas flow Q of the pipeline can be further calculated (not described here).
Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered by the scope of the claims of the present invention.
Claims (4)
1. An ultrasonic arrival time calculating method based on an effective peak value is characterized in that: the method comprises the following steps:
s1, determining effective peak time T of ultrasonic wave receiving waveform valid ；
In step S1, the effective peak time T of the ultrasonic wave reception waveform is determined according to the following steps valid ：
S11, sampling an ultrasonic wave receiving signal to obtain a discretization amplitude sampling sequence y [ t ];
s12, constructing a relation graph Y-T taking amplitude as a Y axis and time as an X axis based on a discretized amplitude sampling sequence Y [ T ];
s13, determining the maximum value Y of the amplitude of the received waveform according to the relation diagram Y-T max And a maximum value y max Two adjacent peaks Y in the same Y-axis direction max-1 And y is max+1 And obtain the maximum value y max Peak value y max-1 Peak y max+1 Respectively corresponding time t max 、t max-1 T max+1 ；
S14, respectively calculating t max 、t max-1 T max+1 Surrounding areas S0, S1 and S2 of the ultrasonic wave receiving waveforms and the positive half shaft of time in three periods at the center moment; wherein, the ultrasonic wave receiving waveforms participating in calculation are in the same Y-axis direction;
s15, determining the maximum value S in the areas S0, S1 and S2 max And will be maximum S max The corresponding center moment is taken as the effective peak moment T valid ；
S2, determining inherent delay t in the ultrasonic receiving and processing process;
s3, effective peak time T valid The difference from the inherent delay t is taken as the arrival time of the ultrasonic wave.
2. The method for calculating the arrival time of ultrasonic waves based on the effective peak according to claim 1, wherein: in step S14, at time t max Starting with a rim less than time t max Sequentially selecting 5 adjacent time values (t 1, t1', t2, t2', t 3) with waveform amplitude value of 0 in the time axis direction; at time t max As a starting point, alongGreater than time t max Sequentially selecting 5 adjacent time values (t 3', t4, t4', t5, t5 ') with the waveform amplitude of 0 in the time axis direction;
the surrounding area S0 is determined according to the following formula:
the surrounding area S1 is determined according to the following formula:
the surrounding area S2 is determined according to the following formula:
3. the method for calculating the arrival time of ultrasonic waves based on the effective peak according to claim 1, wherein: in step S2, the inherent delay t of the ultrasonic wave receiving process is determined according to the following steps:
s21, setting the horizontal distance between a transmitting transducer and a receiving transducer as D1;
s22, transmitting ultrasonic waves to a receiving transducer by a transmitting transducer, and obtaining effective peak time T of an ultrasonic wave waveform by analogy in the steps S11-S15 D1 ；
S23, according to the horizontal distance D1 and the effective peak time T D1 Obtaining a calculation formula E: c (T) D1 -t) =d1; wherein C is the ultrasonic speed;
s24, setting the horizontal distance between the transmitting transducer and the receiving transducer as D2;
s25, transmitting ultrasonic waves to the receiving transducer by the transmitting transducer, and obtaining effective peak time T of ultrasonic wave waveforms by analogy in the steps S11-S15 D2 ；
S26, according to the horizontal distance D2Time of effective peak T D2 Obtaining a calculation formula F: c (T) D2 -t) =d2; wherein C is the ultrasonic speed;
s27, combining the calculation formulas E and F to obtain the inherent delay t.
4. The method for calculating the arrival time of ultrasonic waves based on the effective peak according to claim 1, wherein: in step S2, the inherent delay of the ultrasonic wave includes: the hardware circuitry and software processes inherent delays.
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| CN112698333B (en) * | 2021-03-24 | 2021-07-06 | 成都千嘉科技有限公司 | Ultrasonic flight time measuring method and system suitable for gas and liquid |
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