CN114578363B

CN114578363B - Ultrasonic detection system and method

Info

Publication number: CN114578363B
Application number: CN202210208128.1A
Authority: CN
Inventors: 吕英超; 东直哉
Original assignee: Suzhou Youdasi Automobile Technology Co ltd
Current assignee: Suzhou Youdasi Automobile Technology Co ltd
Priority date: 2022-03-04
Filing date: 2022-03-04
Publication date: 2023-10-13
Anticipated expiration: 2042-03-04
Also published as: CN114578363A

Abstract

The invention discloses an ultrasonic detection system and method, wherein the system comprises: 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 remote judging and processing module in the CPU processing unit is used for determining remote detection information of the detected object according to the echo signal correlation value of the Chirp wave type ultrasonic wave; the near-distance judging and processing module is used for determining near-distance detection information of the detected object according to the correlation value of the frequency difference signal between the echo signal of the detected object and the transmitted Chirp wave, so that the near-distance detection and the far-distance detection of the object can be simultaneously carried out by using only one microphone or an ultrasonic detection system of an ultrasonic sensor.

Description

Ultrasonic detection system and method

Technical Field

The embodiment of the invention relates to the technical field of ultrasonic detection, in particular to an ultrasonic detection system and an ultrasonic detection method.

Background

In the ultrasonic ranging principle, when detecting an obstacle by receiving a wave from an "ultrasonic microphone" and receiving a reflected wave from an object, although the distance of the obstacle can be obtained, it is impossible to determine from which position of a concentric circle centered on the "ultrasonic microphone the distance is reflected, and thus it is impossible to determine the specific position of the obstacle. Therefore, in the ultrasonic detection systems currently on the market, a plurality of ultrasonic sensors are combined and used, and then the position of the object is determined in which region based on the results of the ultrasonic sensors. That is, most ultrasonic detection system products on the market today use a plurality of ultrasonic sensors to determine the obstacle region.

Moreover, most ultrasonic detection system products in the current market also have the problems that the blind area is large, the short-distance objects cannot be detected, and the distance precision is too low when the long-distance detection is performed. In the actual product installation and use process, when the installation number of the ultrasonic sensors is limited or one or more of the ultrasonic sensors fails, the ultrasonic detection system cannot realize the function of determining the obstacle area and the specific position, and objects too close or too far away from the obstacle area cannot be detected, so that normal use of users is affected.

Disclosure of Invention

The invention provides an ultrasonic detection system and method, which can realize the short-distance detection and the long-distance detection of an object simultaneously by using only one microphone or an ultrasonic detection system of one ultrasonic sensor without using a plurality of microphones or an ultrasonic detection system of a plurality of ultrasonic sensors.

In a first aspect, an embodiment of the present invention provides an ultrasonic detection system, including: 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.

Optionally, 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.

Optionally, determining the distance conversion value corresponding to the different reference wave periods includes:

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.

Optionally, the CPU processing unit further includes:

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.

In a second aspect, an embodiment of the present invention further provides an ultrasonic detection method based on the ultrasonic detection system described in any one of the above, including:

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.

Optionally, determining the close range detection information of the detected object according to the second correlation value includes:

Optionally, determining the distance conversion value corresponding to the different reference periods includes:

According to the technical scheme, short-distance detection is achieved by calculating the correlation value of the echo signal of the detected object and the frequency difference signal (Beat wave) between the transmitted Chirp waves, long-distance detection is achieved by 'Chirp wave correlation calculation', and the object can be simultaneously detected in a short-distance mode and in a long-distance mode by only using one microphone or an ultrasonic detection system of an ultrasonic sensor.

Drawings

Fig. 1 is a system architecture diagram of a conventional case 1;

FIG. 2 shows a schematic diagram of a Chirp wave of conventional case 1;

fig. 3 is a schematic diagram showing a correlation value calculation method of a conventional case 1;

FIG. 4 shows a schematic diagram of the close-up detection of example 1 of the present invention;

fig. 5 is a schematic diagram showing distance detection in conventional case 1;

fig. 6 shows a system architecture diagram of conventional case 2;

fig. 7 shows a schematic diagram of an FMCW wave of conventional case 2;

fig. 8 is a schematic diagram showing remote detection in conventional case 2;

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

FIG. 10 shows a schematic diagram of a Chirp wave of an embodiment of the present invention;

FIG. 11 is a schematic diagram showing a correlation value calculation method according to an embodiment of the present invention;

FIG. 12 shows a Beat wave schematic of an embodiment of the present invention;

FIG. 13 is a schematic diagram showing a method for calculating the Beat wave correlation value according to an embodiment of the present invention;

FIG. 14 is a diagram showing correlation values and distance conversion values according to an embodiment of the present invention;

fig. 15 shows a schematic diagram of short-range detection/long-range detection according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

In order to better understand the technical scheme of the embodiment of the invention, an ultrasonic detection method commonly used in the prior case is introduced.

As shown in fig. 1, a system configuration diagram of an ultrasonic inspection system in conventional case 1 includes a Chirp wave generating circuit, a microphone, an amplifying filter circuit, a correlation calculating circuit, and a CPU processing unit. Wherein:

(1) A Chirp wave generation circuit: for generating Chirp waves, and driving the microphone to transmit ultrasonic waves.

(2) A microphone: for transmitting Chirp-type ultrasound.

(3) An amplifying and filtering circuit: for amplifying the reflected received wave from the object to obtain an amplified filter loop output signal.

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

(5) CPU processing unit: and controlling and processing all relevant signals in the system, processing the result output from the relevant calculation circuit, judging the distance of the object, and outputting a detection result.

Fig. 2 shows a Chirp wave in the prior case 1. Defining the time difference between t0 and t1 as the transmission time of the Chirp wave; the corresponding fc1_0-fc1_1 is defined as the frequency range of the Chirp wave. (it is illustrated that the Chirp wave has various types of frequency linearly increasing/decreasing or non-linearly increasing/non-linearly decreasing with time, and fig. 2 shows the type of frequency linearly increasing with time). After the Chirp wave is generated, the Chirp type ultrasonic wave is sent through the microphone, the reflected wave from the object is received, and then the reflected wave enters the amplifying filter circuit, so that the output signal of the amplifying filter circuit is obtained. Here, the time at which the reflected wave from the object is received is set to t2.

Fig. 3 shows a correlation value calculation method in the conventional case 1. First, a correlation value at time t0 is calculated as follows: the "reference wave—0000" and the "amplification and filter circuit output" are multiplied together, the multiplied results are accumulated, and the obtained accumulated value is stored in the "correlation value calculation result" as a correlation value at time 0. Then, the reference wave 0001 is obtained by delaying for 1 cycle, the reference wave 0001 and the amplification filter loop output are multiplied, and the multiplication result is accumulated, and the obtained accumulated value is used as the correlation value at time t 1. The process is repeated in this order. That is, the correlation value operation corresponds to the calculation of 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, and thus the value of the "correlation value calculation result" also increases.

When the correlation value calculation result is determined by the threshold after the correlation values at all times are calculated, if the correlation value calculation result is greater than the threshold, it is considered that the obstacle is detected, and the time t2 at which the peak of the correlation value appears is searched. Thus, if the reception time is converted into the object distance, the detection distance to the object can be calculated.

When an object approaches, a reflected reception wave t2 from the object is superimposed on the transmitted channel, and the "correlation value calculation result" calculated by the transmitted channel control of the reflected reception wave component from the object becomes a small value. That is, a short-range region cannot be detected. Fig. 4 shows a schematic diagram of the short-distance detection in the conventional case 1.

As described above, when the transfer time of the area (Dead zone) where the short-distance detection cannot be performed is t1=3.0 [ msec ], the minimum detection distance is lin≡50[ cm ]. Fig. 5 shows a schematic diagram of distance detection in conventional case 1.

As shown in fig. 6, a system configuration diagram of an ultrasonic inspection system in conventional case 2 includes an FMCW wave generating circuit, a microphone, an amplification filter circuit, a correlation calculating circuit, and a CPU processing unit. Wherein:

(1) FMCW wave generation circuit: for generating FMCW waves, and driving the microphone to transmit ultrasonic waves.

(2) A microphone: for transmitting Chirp-type ultrasound.

(3) A low frequency amplifying and filtering circuit: for amplifying the frequency difference (Beat wave component) of the reflected received wave from the object and the transmitted Chirp wave, resulting in an amplified filter loop output signal.

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

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

In a distance detection system to which an FMCW wave is applied, the output of the "low-frequency amplification filter circuit", that is, the frequency component of the bean wave, is determined and converted into a distance. In general, the FMCW wave used in the FMCW mode is output using a sweep signal of a long period of time when corresponding to long-range detection.

Fig. 8 shows an example of the long-distance detection of the conventional case 2 (the setting conditions of this example are shown in the figure). As calculated in FIG. 7 above, the maximum detection distance Lmax may be detected at approximately 500[ cm ], but the distance resolution ΔL is approximately 50 cm. That is, the detection distance resolution is about 50[ cm ], which is very coarse distance accuracy because the FMCW method is adopted.

Aiming at the problem that the short-distance detection cannot be performed in the prior case 1 and the problem that the long-distance detection precision is low in the prior case 2, the embodiment of the invention provides an ultrasonic detection system, which comprises the following components: the ultrasonic wave generating device comprises a Chirp wave generating circuit, an ultrasonic wave generating module, a Chirp wave amplifying and filtering circuit module, a low-frequency amplifying and filtering circuit module, a Chirp wave related calculating circuit module, a low-frequency related calculating circuit module and a CPU processing unit.

The Chirp wave generation circuit is used for receiving the output of the Chirp wave generation processing module, generating Chirp wave generation and outputting the generated Chirp wave to the microphone.

The ultrasonic wave generating module is configured to generate an ultrasonic wave signal, and optionally, the ultrasonic wave generating module in this embodiment may be a microphone, an ultrasonic wave sensor, and the like, and further referring to fig. 9, the microphone is taken as an example of the ultrasonic wave generating module in this embodiment.

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

The low-frequency amplification filter circuit module is used for amplifying a frequency difference signal (Beat wave component) between an echo signal from a measured object and a transmitted Chirp wave.

The Chirp wave correlation calculation circuit module uses a device capable of performing high-speed operation processing such as DSP, and is used for calculating a first correlation value between an echo signal of an ultrasonic wave and a corresponding reference wave, and inputting the first correlation value into the CPU processing unit.

The low frequency (Beat wave) correlation calculation circuit module uses a device capable of performing high-speed operation processing such as DSP, and is used for calculating a second correlation value between the frequency difference signal and each reference wave under different reference periods and inputting the second correlation value into the CPU processing unit.

Further, the CPU processing unit further includes: 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.

Specifically, the close range determination processing module is specifically configured to perform:

Wherein determining distance conversion values corresponding to different reference wave periods includes:

In this embodiment, the Chirp wave type ultrasonic wave realizes the remote detection of the object, and the remote information of the object to be detected is determined by calculating the correlation value between the echo signal and the corresponding reference wave and determining the detection time of the object to be detected according to the peak value of the correlation value.

Referring specifically to fig. 10, fig. 10 shows a Chirp wave of an ultrasonic mixed wave detection system according to the present invention. Chirp wave has a transmission time of t0-t1 and a sweep frequency of Fc1_0-Fc1_1. (it is illustrated that: the Chirp wave has various types of linear increase/decrease or nonlinear increase/decrease in frequency with time, and fig. 10 shows the type of linear increase in frequency with time.) after generating Chirp, a Chirp-type ultrasonic wave is transmitted through a microphone, a reflected wave from an object is received, and then the reflected wave enters an "amplification filter circuit", to obtain an amplification filter circuit output signal. Here, the time at which the reflected wave from the object is received is set to t2.

Fig. 11 shows a correlation value calculation method of an ultrasonic mixed wave detection system according to the present invention. First, a correlation value at time t0 is calculated as follows: the "reference wave—0000" and the "amplification and filter circuit output" are multiplied together, the multiplied results are accumulated, and the obtained accumulated value is stored in the "correlation value calculation result" as a correlation value at time 0. Then, the reference wave 0001 is obtained by delaying for 1 cycle, the reference wave 0001 and the amplification filter loop output are multiplied, and the multiplication result is accumulated, and the obtained accumulated value is used as the correlation value at time t 1. The process is repeated in this order. That is, the correlation value operation corresponds to the calculation of 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, and thus the value of the "correlation value calculation result" also increases. When the correlation value at all times is calculated and the "correlation value calculation result" is determined by the "threshold value", the presence of the obstacle is considered to be detected when the correlation value calculation result is greater than the threshold value, and the time t2 at which the peak of the correlation value appears is searched, whereby if the reception time is converted into the object distance, the detection distance to the object can be calculated.

Further, the present embodiment realizes the close-range detection of the object by calculating the correlation value of the beacon wave and the reference wave under the corresponding reference period. The detection distance values corresponding to different reference periods are calculated by calculating the correlation values of the Beat and the reference waves under different reference periods respectively, and the short-distance detection data of the object to be detected is determined according to the reference period corresponding to the maximum value of the correlation values.

Referring specifically to fig. 12, fig. 12 shows the beacon wave of an ultrasonic mixed wave detection system according to the present invention. The Chirp wave used in the system has a sweep frequency range Fc1_0-Fc1_1 between t0 and t1 in transmission time. Since the bet wave includes a frequency difference signal (bet wave component) between the reflected reception wave from the object and the transmitted Chirp wave, after the low frequency region is amplified by the "low frequency amplification filter circuit", frequency difference information (bet wave) of the two waves can be output.

Fig. 13 illustrates a method for calculating a bet-wave correlation value in an ultrasonic mixed wave detection system according to the present invention.

First, a reference wave 1_0000 having a first Δf_chirp of "0.5kHz" is multiplied by the output of the "low-frequency amplification filter circuit", the multiplied results are accumulated, and the obtained accumulated value is used as the bet wave correlation value calculation result 1 at time 0. Next, a "reference wave_0001" is obtained by delaying for 1 cycle, the outputs of the "reference wave 1_0001" and the "low-frequency amplification filter circuit" are multiplied, and the multiplied results are accumulated, and the obtained accumulated value is used as the correlation value at time t 1. The process is repeated in this order. That is, the "Beat wave correlation value calculation result.1" when Δf_Chirp is "0.5kHz" is obtained, and the maximum value in the "Beat wave correlation value calculation result.1" is stored as "Vout.1".

Then, the reference wave 2_0000 having Δf_chirp of "1.0kHz" is multiplied by the output of the "low-frequency amplification filter circuit", the multiplied results are accumulated, and the obtained accumulated value is used as the bet wave correlation value calculation result 2 at time t 0. Then, the "reference wave 2_0001" is obtained by delaying for 1 period, the outputs of the "reference wave 2_0001" and the "low-frequency amplification filter circuit" are multiplied, and the multiplication result is accumulated, and the obtained accumulation value is used as the correlation value at time t 1. The 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 of the "Beat wave correlation value calculation result.2" is stored as "Vout.2".

The above calculation is repeated until the calculation of Δf_Chirp to "10.0kHz" is completed.

The conversion relationship between the Vout output value and the "distance value" of the "bet wave-related value calculation result. N" shown in the following table is equivalent to the distance resolution Δl in the previous analysis:

the distance value at vout.max, which is the relationship of Vo and distance in the Vout output value shown in fig. 14, represents the detected distance L at which the object exists. Note that when a plurality of objects exist within the detection distance range, a plurality of maximum values "vout.max" occur, and thus the detection distance L at which a plurality of objects exist can be determined.

Wherein, the setting conditions in the table above are as follows:

chirp wave start frequency Fc0=50 [ kHz ];

the 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 Δf_chirp=0.5 [ khz ] of the bet wave, the detection performance parameters thereof are as follows:

maximum detection distance lmax=340 [ m/s ] ×t1ms ]/(2×1000×100) ≡50[ cm ];

distance determination resolution Δl=lmax/Δfc/Δf_chirp≡5cm.

In this embodiment, the maximum detection distance Lmax can be detected about 50 cm, and the distance determination resolution Δl is about 5cm, and the detection distance resolution is about 5cm, so that a high distance accuracy can be obtained.

Fig. 15 is a schematic diagram of a near-distance detection/far-distance detection of an ultrasonic hybrid wave detection system according to the present invention, which can detect near-distance objects and far-distance objects at the same time.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims

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;

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

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

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;

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

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

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