CN114578363B - Ultrasonic detection system and method - Google Patents

Abstract

The invention discloses an ultrasonic detection system and method, wherein the system includes: a Chirp wave generation circuit, an ultrasonic wave generation module, a Chirp wave amplification and filtering circuit module, a low-frequency amplification and filtering circuit module, a Chirp wave correlation calculation circuit module, a low-frequency correlation Calculation circuit module and CPU processing unit; wherein, the long-distance determination processing module in the CPU processing unit is used to determine the long-distance detection information of the measured object based on the echo signal correlation value of the Chirp wave ultrasonic wave; the short-distance determination processing module is used It is used to determine the close detection information of the measured object based on the correlation value of the frequency difference signal between the echo signal of the measured object and the transmitted Chirp wave, thereby realizing the "ultrasonic wave" using only one "microphone" or an ultrasonic sensor. "Detection system" can detect objects at close range and long distance at the same time.

Description

Ultrasonic detection system and method

Technical field

Embodiments of the present invention relate to the technical field of ultrasonic detection, and in particular, to an ultrasonic detection system and method.

Background technique

In the principle of ultrasonic distance measurement, when obstacles are detected by using the waves emitted by the "ultrasonic microphone" and then receiving the reflected waves from the object, although the distance of the obstacle can be obtained, it cannot be determined whether the distance is from the "ultrasonic microphone" Which position of the concentric circles is reflected, so the specific location of the obstacle cannot be determined. Therefore, the ultrasonic detection systems currently on the market use multiple ultrasonic sensors in combination, and then determine which area the object is located based on the results of each ultrasonic sensor. In other words, most ultrasonic detection system products currently on the market use multiple ultrasonic sensors to determine obstacle areas.

Not only that, most ultrasonic detection system products currently on the market also have problems such as large blind areas, inability to detect close objects, and low distance accuracy when performing long-distance detection. In the actual product installation and use process, when the number of ultrasonic sensors installed is limited or one or more of the multiple ultrasonic sensors fails, the ultrasonic detection system cannot achieve the function of determining the obstacle area and specific location, let alone Detect objects that are too close or too far away, affecting the normal use of the user.

Contents of the invention

The present invention provides an ultrasonic detection system and method, which uses only one "microphone" or an "ultrasonic detection system" of one ultrasonic sensor without the need to use multiple "microphones" or the "ultrasonic detection system" of multiple ultrasonic sensors. "Ultrasonic detection system" can achieve "close detection" and "long-distance detection" of objects at the same time.

In a first aspect, embodiments of the present invention provide an ultrasonic detection system, including: a Chirp wave generation circuit, an ultrasonic wave generation module, a Chirp wave amplification and filtering circuit module, a low-frequency amplification and filtering circuit module, a Chirp wave related calculation circuit module, and a low-frequency related calculation Circuit module and CPU processing unit;

Among them, the Chirp wave generation circuit is used to generate Chirp waves and output the generated Chirp waves to the microphone;

Ultrasonic wave generation module, used to generate ultrasonic signals;

Chirp wave amplification and filtering circuit module, used to amplify and filter the ultrasonic echo signal;

The low-frequency amplification filter circuit module is used to amplify the frequency difference signal between the echo signal from the measured object and the transmitted Chirp wave;

Chirp wave correlation calculation circuit module, used to calculate the first correlation value between the echo signal of the ultrasonic wave and the corresponding reference wave, and input the first correlation value into the CPU processing unit;

A low-frequency correlation calculation circuit module, used to calculate the second correlation value between the frequency difference signal and each reference wave under different reference periods, and input the second correlation value into the CPU processing unit;

The CPU processing unit includes a long-distance determination processing module and a short-distance determination processing module. The long-distance determination processing module is used to determine the long-distance detection information of the measured object based on the time corresponding to the maximum value in the first correlation value; The short distance determination processing module is configured to determine the short distance detection information of the measured object according to the second correlation value.

Optionally, the short distance determination processing module is specifically configured to perform:

According to the reference wave period corresponding to the maximum value of the second correlation value and the distance transformation values corresponding to different reference wave periods, the close range detection information of the measured object is determined.

Optionally, determine the distance transformation values corresponding to different reference wave periods, including:

The maximum detection distance is determined based on the transmission duration of the Chirp wave;

The distance transformation corresponding to different reference periods is determined according to the maximum detection distance, the frequency difference and the Chirp frequency bandwidth corresponding to different reference wave periods.

Optionally, the CPU processing unit also includes:

Chirp wave generation processing module, used to generate Chirp waves;

Reference wave generation processing module, used to generate reference waves;

The output processing module is used to output the short-range detection information and long-range detection information of the measured object.

In a second aspect, embodiments of the present invention also provide an ultrasonic detection method based on any of the above-mentioned ultrasonic detection systems, including:

Calculate the first correlation value between the echo signal of the Chirp type ultrasonic wave and the corresponding reference wave, and determine the long-distance detection information of the measured object according to the time corresponding to the maximum value of the first correlation value;

Obtain the frequency difference signal between the echo signal of the Chirp type ultrasonic wave and the transmitted Chirp wave, calculate the second correlation value between the frequency difference signal and each reference wave under different reference periods, and determine the measured object based on the second correlation value Object close range detection information.

Optionally, determining the close range detection information of the measured object based on the second correlation value includes:

According to the reference wave period corresponding to the maximum value of the second correlation value and the distance transformation values corresponding to different reference wave periods, the close range detection information of the measured object is determined.

Optionally, determine the distance transformation values corresponding to different reference periods, including:

The maximum detection distance is determined based on the transmission duration of the Chirp wave;

The distance transformation corresponding to different reference periods is determined according to the maximum detection distance, the frequency difference and the Chirp frequency bandwidth corresponding to different reference wave periods.

The technical solution of the embodiment of the present invention realizes close range detection by calculating the correlation value of the frequency difference signal (Beat wave) between the echo signal of the measured object and the transmitted Chirp wave. Through "Chirp wave correlation calculation" To achieve long-distance detection, the "ultrasonic detection system" using only one "microphone" or an ultrasonic sensor can simultaneously perform "close detection" and "long-distance detection" of objects.

Description of the drawings

Figure 1 shows the system architecture diagram of previous case 1;

Figure 2 shows the schematic diagram of Chirp waves in previous case 1;

Figure 3 shows a schematic diagram of the correlation value calculation method of previous case 1;

Figure 4 shows a schematic diagram of close range detection in Embodiment 1 of the present invention;

Figure 5 shows the schematic diagram of distance detection in previous case 1;

Figure 6 shows the system architecture diagram of previous case 2;

Figure 7 shows the FMCW wave schematic diagram of previous case 2;

Figure 8 shows the schematic diagram of long-distance detection in previous case 2;

Figure 9 shows a system architecture diagram of an embodiment of the present invention;

Figure 10 shows a schematic diagram of Chirp waves in an embodiment of the present invention;

Figure 11 shows a schematic diagram of the correlation value calculation method according to the embodiment of the present invention;

Figure 12 shows a schematic diagram of a Beat wave according to an embodiment of the present invention;

Figure 13 shows a schematic diagram of the Beat wave correlation value calculation method according to the embodiment of the present invention;

Figure 14 is a schematic diagram showing the relationship between correlation values and distance transformation values in the embodiment of the present invention;

FIG. 15 shows a schematic diagram of short-distance detection/long-distance detection according to the embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It can be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for convenience of description, only some but not all structures related to the present invention are shown in the drawings.

In order to better understand the technical solutions of the embodiments of the present invention, let us first introduce the ultrasonic detection methods commonly used in previous cases.

The system architecture diagram of the ultrasonic inspection system in previous case 1 is shown in Figure 1. The system includes a Chirp wave generation circuit, a microphone, an amplification filter circuit, related computing circuits and a CPU processing unit. in:

(1) Chirp wave generation circuit: used to generate Chirp waves and drive the microphone to send ultrasonic waves.

(2) Microphone: used to send Chirp type ultrasonic waves.

(3) Amplification filter circuit: used to amplify the reflected received wave from the object to obtain the output signal of the amplification filter circuit.

(4) Correlation calculation circuit: A device capable of high-speed calculation processing such as DSP is used to perform correlation calculations on the "reference wave output" generated from the Chirp wave.

(5)CPU processing unit: controls and processes all relevant signals in the system, processes the results output from the "related calculation circuit", determines the "distance" of the object, and outputs the detection result.

Figure 2 shows a Chirp wave in previous case 1. The time difference between t0 and t1 is defined as the sending time of the Chirp wave; the corresponding Fc1_0–Fc1_1 is defined as the frequency range of the Chirp wave. (Explanation: Chirp waves have multiple types in which the frequency increases/decreases linearly with time or increases/decreases non-linearly with time. Figure 2 shows the type in which the frequency increases linearly with time.) After the Chirp wave is generated, it is sent through the microphone. Chirp type ultrasonic wave receives the reflected wave from the object, and then enters the "amplification filter circuit" to obtain the output signal of the amplification filter circuit. Here, let the time at which the reflected wave from the object is received be t2.

Figure 3 shows the correlation value calculation method in previous case 1. First, calculate the correlation value at time t0. The method is as follows: multiply "reference wave_0000" and "amplification filter loop output", and accumulate the multiplication results. The obtained accumulated value is used as the correlation value at time 0 and is stored in " Correlation value calculation results". Then, delay one cycle to obtain "reference wave_0001", multiply "reference wave_0001" and "amplification filter circuit output", and accumulate the multiplication results. The accumulated value is used as the correlation value at time t1. Hereafter, this process is repeated in order. That is, the correlation value calculation is equivalent to calculating the correlation between the two. In the vicinity of t2 where there is a reflected wave from the object, the correlation value between the "reference wave" and the "amplification filter circuit output" becomes large, so the value of the "correlation value calculation result" also increases.

After calculating the correlation values at all times, when the correlation value calculation result is judged through the threshold, when the correlation value calculation result is greater than the threshold, it is considered that the presence of an obstacle is detected, and the time t2 when the peak value of the correlation value occurs is retrieved. From this, if the reception time is converted into the object distance, the detection distance to the object can be calculated.

When an object approaches, the reflected received wave t2 from the object is superimposed on the sending channel, and the "correlation value calculation result" calculated by the reflected received wave component from the object controlled by the sending channel will become a very small value. That is, close range areas cannot be detected. Figure 4 shows the schematic diagram of close range detection in previous case 1.

As described above, when the transmission time of the dead zone in which close range detection is not possible is t1 = 3.0 [msec], the minimum detection distance is Lin≈50 [cm]. Figure 5 shows the schematic diagram of distance detection in previous case 1.

The system architecture diagram of the ultrasonic inspection system in previous case 2 is shown in Figure 6. The system includes an FMCW wave generation circuit, a microphone, an amplification filter circuit, related computing circuits and a CPU processing unit. in:

(1) FMCW wave generation circuit: used to generate FMCW waves and drive the microphone to send ultrasonic waves.

(2) Microphone: used to send Chirp type ultrasonic waves.

(3) Low-frequency amplification filter circuit: used to amplify the frequency difference (Beat wave component) between the reflected received wave from the object and the transmitted Chirp wave to obtain the amplified filter circuit output signal.

(4) Beat wave correlation calculation circuit: A device capable of high-speed calculation processing such as DSP is used to perform correlation calculation processing on the "reference wave output" generated from the beat wave.

(5)CPU processing unit: controls and processes all relevant signals in the system, processes the results output from the "related calculation circuit", determines the "distance" of the object, and outputs the detection result.

Figure 7 shows a schematic diagram of the FMCW wave in conventional case 2. The transmission time of FMCW wave is between t0-t1, and the frequency sweep range is Fc1_0-Fc1_1. FMCW waves are sent through an ultrasonic microphone, and the "low-frequency amplification and filter circuit" module amplifies and filters the frequency difference (Beat wave component) between the reflected received wave from the object and the transmitted Chirp wave. Here, let the reflected wave received from the object be t2.

In a distance detection system using FMCW waves, the output of the above-mentioned "low-frequency amplification filter circuit", that is, the frequency component of the Beat wave, can be determined and converted into distance. Generally speaking, when corresponding to long-distance detection, the FMCW wave used in the FMCW method uses a long-term sweep signal to output.

Figure 8 is an example of long-distance detection in conventional case 2 (the figure shows the setting conditions of this example). As calculated in Figure 7 above, the maximum detection distance Lmax can detect ≈500 [cm], but the distance resolution ΔL≈50 cm. That is, the detection distance resolution is about 50 [cm], which is a very rough distance accuracy because the FMCW method is used.

In order to solve the problem that short-range detection cannot be performed in the previous case 1 and the long-distance detection accuracy is low in the previous case 2, embodiments of the present invention provide an ultrasonic detection system, including: a Chirp wave generation circuit, an ultrasonic wave generation module, and a Chirp wave amplification Filter circuit module, low frequency amplification filter circuit module, Chirp wave related calculation circuit module, low frequency related calculation circuit module and CPU processing unit.

Among them, the Chirp wave generation circuit is used to receive the output of the "Chirp wave generation processing" module and generate Chirp waves, which are output to the microphone.

An ultrasonic wave generation module is used to generate ultrasonic signals. Optionally, the ultrasonic wave generation module in this embodiment can be a microphone, an ultrasonic sensor, and other components. Referring further to Figure 9, in this embodiment, a microphone is used as an ultrasonic wave generation module as an example.

Chirp wave amplification and filtering circuit module is used to amplify and filter the ultrasonic echo signal.

The low-frequency amplification filter circuit module is used to amplify the frequency difference signal (Beat wave component) between the echo signal from the measured object and the transmitted Chirp wave.

The Chirp wave correlation calculation circuit module uses a device capable of high-speed computing processing such as DSP to calculate the first correlation value between the ultrasonic echo signal and the corresponding reference wave, and input the first correlation value into the CPU for processing unit.

The low-frequency (Beat wave) correlation calculation circuit module uses a device capable of high-speed computing processing such as DSP to calculate the second correlation value between the frequency difference signal and each reference wave under different reference periods, and convert the second correlation value The relevant values are fed into the CPU processing unit.

The CPU processing unit includes a long-distance determination processing module and a short-distance determination processing module. The long-distance determination processing module is used to determine the long-distance detection information of the measured object based on the time corresponding to the maximum value in the first correlation value; The short distance determination processing module is configured to determine the short distance detection information of the measured object according to the second correlation value.

Further, the CPU processing unit also includes: a Chirp wave generation processing module, used to generate Chirp waves; a reference wave generation processing module, used to generate a reference wave; and an output processing module, used to output close range detection information of the measured object. and remote detection information.

Specifically, the short distance determination processing module is specifically used to execute:

According to the reference wave period corresponding to the maximum value of the second correlation value and the distance transformation values corresponding to different reference wave periods, the close range detection information of the measured object is determined.

Among them, the distance transformation values corresponding to different reference wave periods are determined, including:

The maximum detection distance is determined based on the transmission duration of the Chirp wave;

The distance transformation corresponding to different reference periods is determined according to the maximum detection distance, the frequency difference and the Chirp frequency bandwidth corresponding to different reference wave periods.

In this embodiment, Chirp wave ultrasonic wave is used to realize long-distance detection of objects. By calculating the correlation value between the echo signal and the corresponding reference wave, the detection time of the measured object is determined according to the peak value of the correlation value, thereby determining the distance of the measured object. distance information.

Refer to Figure 10 specifically, which shows the Chirp wave of an ultrasonic hybrid wave detection system in the present invention. The transmission time of the Chirp wave is between t0-t1, and the frequency sweep range is between Fc1_0-Fc1_1. (Explanation: Chirp waves have multiple types in which the frequency increases/decreases linearly with time or non-linearly increases/decreases non-linearly. Figure 10 shows the type in which the frequency increases linearly with time.) After the Chirp wave is generated, it is sent through the microphone Chirp type ultrasonic wave receives the reflected wave from the object, and then enters the "amplification filter circuit" to obtain the output signal of the amplification filter circuit. Here, let the time at which the reflected wave from the object is received be t2.

Figure 11 shows a correlation value calculation method of an ultrasonic mixed wave detection system in the present invention. First, calculate the correlation value at time t0. The method is as follows: multiply "reference wave_0000" and "amplification filter loop output", and accumulate the multiplication results. The obtained accumulated value is used as the correlation value at time 0 and is stored in " Correlation value calculation results". Then, delay one cycle to obtain "reference wave_0001", multiply "reference wave_0001" and "amplification filter circuit output", and accumulate the multiplication results. The accumulated value is used as the correlation value at time t1. Hereafter, this process is repeated in order. That is, the correlation value calculation is equivalent to calculating the correlation between the two. In the vicinity of t2 where there is a reflected wave from the object, the correlation value between the "reference wave" and the "amplification filter circuit output" becomes large, so the value of the "correlation value calculation result" also increases. After calculating the correlation values at all times, when judging the "correlation value calculation result" through the "threshold", when the correlation value calculation result is greater than the threshold, it is considered that the existence of an obstacle is detected, and the time t2 when the peak of the correlation value occurs is retrieved. , whereby if the reception time is converted into object distance, the detection distance to the object can be calculated.

Furthermore, this embodiment achieves close-range detection of objects by calculating the correlation value between the Beat wave and the reference wave in the corresponding reference period. By separately calculating the correlation values between Beat and reference waves at different reference periods, the detection distance values corresponding to different reference periods are calculated, and the close range detection data of the measured object is determined based on the reference period corresponding to the maximum correlation value.

Refer to Figure 12 for details. Figure 12 shows the Beat wave of an ultrasonic hybrid wave detection system in the present invention. The Chirp wave used in this system has a transmission time between t0-t1 and a frequency sweep range of Fc1_0-Fc1_1. Since the Beat wave includes the frequency difference signal (Beat wave component) between the reflected received wave from the object and the transmitted Chirp wave, when the low frequency area is amplified by the "low frequency amplification filter circuit", the frequency difference information of the two waves can be output (Beat wave).

Figure 13 illustrates the Beat wave correlation value calculation method of an ultrasonic hybrid wave detection system in the present invention.

First, multiply the first reference wave .1_0000 with Δf_Chirp of "0.5kHz" by the output of the "low-frequency amplification filter circuit", and accumulate the multiplication results. The accumulated value is used as the Beat wave correlation value calculation result at time 0 .1. Then, delay one cycle to obtain the "reference wave_0001", multiply the "reference wave.1_0001" and the output of the "low frequency amplification filter circuit", and accumulate the multiplication results. The accumulated value is used as the correlation value at time t1 . Hereafter, this process is repeated in order. That is, the "Beat wave correlation value calculation result.1" when Δf_Chirp is "0.5kHz" is obtained, and the maximum value among the "Beat wave correlation value calculation result.1" is saved as "Vout.1".

Then, multiply the reference wave.2_0000 with Δf_Chirp of "1.0kHz" by the output of the "low-frequency amplification filter circuit", and accumulate the multiplication results. The accumulated value is used as the Beat wave correlation value calculation result at time t0.2. Then, delay one cycle to obtain "reference wave.2_0001", multiply "reference wave.2._0001" and the output of the "low frequency amplification filter circuit", and accumulate the multiplication results. The accumulated value obtained is used as the value at time t1. related values. This process is repeated sequentially thereafter. That is, the "Beat wave correlation value calculation result.2" when Δf_Chirp is "1kHz" is obtained, and the maximum value among the "Beat wave correlation value calculation result.2" is saved as "Vout.2".

Repeat the above calculation until Δf_Chirp is "10.0kHz" and the calculation ends.

The conversion relationship between the Vout output value and the "distance value" of the "Beat wave correlation value calculation result.n" shown in the table below is equivalent to the distance resolution ΔL in the previous analysis:

The relationship between Vo and distance in the Vout output value shown in Figure 14. The distance value at Vout.max represents the detection distance L of the object's presence. Note that when multiple objects exist within the detection distance range, multiple maximum values "Vout.max" appear, so the detection distance L where multiple objects exist can be determined.

Among them, the setting conditions in the above table are as follows:

Chirp wave starting frequency Fc0=50[kHz];

Chirp wave end frequency Fc1=60[kHz];

Chirp bandwidth ΔFc=10[kHz];

Chirp wave time width t1=3.0 [msec].

At this time, assuming that the resolution of the Beat wave Δf_Chirp = 0.5 [kHz], its detection performance parameters are as follows:

Maximum detection distance Lmax=340[m/s]*t1[ms]/(2*1000*100)≈50[cm];

Distance judgment resolution ΔL=Lmax/ΔFc/Δf_Chirp≈5cm.

In this embodiment, the maximum detection distance Lmax can detect ≈50 [cm]. At the same time, the distance judgment resolution ΔL≈5cm, and the detection distance resolution is about 5 [cm], which can achieve higher distance accuracy.

Figure 15 shows a schematic diagram of short-distance detection/long-distance detection of an ultrasonic hybrid wave detection system in the present invention. According to the technical solution of the present invention, the system can detect short-distance objects and long-distance objects at the same time.

Note that the above are only the preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the present invention The scope is determined by the scope of the appended claims.

Claims (7)

1. An ultrasonic detection system, comprising: the device comprises a Chirp wave generation circuit, an ultrasonic wave generation module, a Chirp wave amplification filter circuit module, a low-frequency amplification filter circuit module, a Chirp wave correlation calculation circuit module, a low-frequency correlation calculation circuit module and a CPU processing unit;

the Chirp wave generation circuit is used for generating a Chirp wave and outputting the generated Chirp wave to the microphone;

the ultrasonic wave generation module is used for generating an ultrasonic wave signal;

the Chirp wave amplifying and filtering circuit module is used for amplifying and filtering the echo signals of the ultrasonic waves;

the low-frequency amplifying and filtering circuit module is used for amplifying a frequency difference signal between an echo signal from a measured object and a transmitted Chirp wave;

the Chirp wave correlation calculation circuit module is used for calculating a first correlation value between an echo signal of the ultrasonic wave and a corresponding reference wave and inputting the first correlation value into the CPU processing unit;

the low-frequency correlation calculation circuit module is used for calculating a second correlation value of the frequency difference signal and each reference wave under different reference periods and inputting the second correlation value into the CPU processing unit;

the CPU processing unit comprises a long-distance judging processing module and a short-distance judging processing module, wherein the long-distance judging processing module is used for determining long-distance detection information of the detected object according to the time corresponding to the maximum value in the first correlation value; the close range judging and processing module is used for determining close range detection information of the detected object according to the second correlation value.

2. The system according to claim 1, wherein the close range determination processing module is specifically configured to perform:

and determining the short-distance detection information of the object to be detected according to the reference wave period corresponding to the maximum value in the second correlation values and the distance conversion values corresponding to different reference wave periods.

3. The system of claim 1, wherein determining distance transform values for different reference wave periods comprises:

determining the maximum detection distance according to the transmission time length of the Chirp wave;

and determining distance conversion corresponding to different reference periods according to the maximum detection distance, and the frequency difference and the Chirp frequency bandwidth corresponding to different reference wave periods.

4. The system of claim 1, wherein the CPU processing unit further comprises:

the Chirp wave generation processing module is used for generating Chirp waves;

a reference wave generation processing module for generating a reference wave;

and the output processing module is used for outputting the short-distance detection information and the long-distance detection information of the detected object.

5. An ultrasonic testing method based on the ultrasonic testing system according to any one of claims 1 to 4, comprising:

calculating a first correlation value between an echo signal of the Chirp type ultrasonic wave and a corresponding reference wave, and determining remote detection information of a detected object according to the time corresponding to the maximum value in the first correlation value;

acquiring a frequency difference signal between an echo signal of the Chirp type ultrasonic wave and the transmitted Chirp wave, calculating second correlation values of the frequency difference signal and each reference wave under different reference periods, and determining close-range detection information of the detected object according to the second correlation values.

6. The method of claim 5, wherein determining proximity detection information of the object under test based on the second correlation value comprises:

and determining the short-distance detection information of the object to be detected according to the reference wave period corresponding to the maximum value in the second correlation values and the distance conversion values corresponding to different reference wave periods.

7. The method of claim 6, wherein determining distance transform values for different reference periods comprises:

determining the maximum detection distance according to the transmission time length of the Chirp wave;

and determining distance conversion corresponding to different reference periods according to the maximum detection distance, and the frequency difference and the Chirp frequency bandwidth corresponding to different reference wave periods.