CN114578364A

CN114578364A - Ultrasonic detection system and method

Info

Publication number: CN114578364A
Application number: CN202210208584.6A
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: 2022-06-03

Abstract

The invention discloses an ultrasonic detection system and method. Wherein, this system includes: the mixed wave generating circuit is used for mixing and superposing at least two excitation waves with different frequencies; the ultrasonic wave generating module is used for generating at least two ultrasonic wave signals with different detection ranges; the correlation calculation circuit module comprises at least two correlation calculation circuits which are respectively used for calculating the correlation degree of the echo signals after the amplification and filtering processing and the corresponding reference waves; and the CPU processing unit is used for judging the distance information and the existing area of the measured object according to the calculation results of the correlation values of different detection ranges. According to the embodiment of the invention, the excitation waves with different frequencies are sent to the same ultrasonic generation module, so that the distance and the existing area of an object can be detected simultaneously by using an ultrasonic detection system with only one ultrasonic generation module, and the stability of the ultrasonic detection process is improved.

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 method based on mixed waves.

Background

In the principle of ultrasonic ranging, when an obstacle is detected by a wave emitted from an "ultrasonic microphone" and a reflected wave from an object being received, although the distance to the obstacle can be obtained, it is impossible to specify from which position of a concentric circle centered on the "ultrasonic microphone" the distance is reflected, and thus the specific position of the obstacle cannot be specified.

Therefore, in all of the ultrasonic detection systems on the market, a plurality of ultrasonic sensors are used in combination, and the region where the position of the object is located is determined from the results of the respective ultrasonic sensors. That is, most ultrasonic detection system products on the market currently determine an obstacle region by a plurality of ultrasonic sensors.

However, its disadvantages are very significant: 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 area and the specific position of the obstacle, and the normal use of a user is influenced.

Disclosure of Invention

The present invention provides an ultrasonic detection system and method, which can realize the simultaneous detection of the distance and the existing area of an object by using only one 'microphone' or one ultrasonic detection system without using a plurality of 'microphones' or an ultrasonic detection system using a plurality of ultrasonic sensors.

In a first aspect, an embodiment of the present invention provides an ultrasonic detection system, including: the ultrasonic wave amplification and filtering device comprises a mixed wave generating circuit, an ultrasonic wave generating module, an amplification and filtering circuit module, a related computing circuit module and a CPU (central processing unit);

the mixed wave generating circuit is used for mixing and superposing at least two excitation waves with different frequencies and outputting the excitation waves to the ultrasonic wave generating module;

the ultrasonic wave generating module is used for correspondingly generating at least two ultrasonic wave signals with different detection ranges according to the mixed and superposed excitation waves;

the amplification and filtering circuit module is used for performing amplification and filtering processing on the echo signal received by the ultrasonic wave generation module;

the correlation calculation circuit module comprises at least two correlation calculation circuits which are respectively used for carrying out correlation calculation on the echo signals after the amplification and filtering processing and the corresponding reference waves so as to obtain calculation results of correlation values in different detection ranges;

and the CPU processing unit comprises a presence area judgment processing module, and the presence area judgment processing module is used for judging the distance information and the presence area of the measured object according to the calculation results of the correlation values of different detection ranges.

Optionally, the CPU further includes an excitation wave generation processing module, configured to generate excitation waves of at least two different frequencies.

Optionally, the CPU further includes a reference wave generation processing module, configured to generate corresponding reference waves for the at least two ultrasonic signals with different detection ranges, respectively.

Optionally, the CPU further includes a presence area output module configured to output the distance to the object to be measured and the presence area.

Optionally, the presence area determination processing module is specifically configured to perform:

when the peak value of the correlation degree between the echo signal and the corresponding reference wave is larger than the threshold value of the correlation degree, the measured object is positioned in the ultrasonic detection area corresponding to the reference wave;

and obtaining the detection time of the detected object according to the correlation peak value, and calculating the distance information of the detected object according to the detection time.

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

simultaneously sending at least two mixed excitation waves with different frequencies to the same ultrasonic wave generation module so that the ultrasonic wave generation module correspondingly generates at least two ultrasonic wave signals with different detection ranges;

receiving echo signals of ultrasonic signals, and respectively carrying out correlation calculation on the echo signals and corresponding reference waves;

and determining the existence area and the distance information of the measured object according to the correlation calculation result value.

Optionally, determining the existence region and the distance information of the measured object according to the correlation calculation result value includes:

when the peak value of the correlation between the echo signal and the corresponding reference wave is larger than the threshold value of the correlation, the measured object is positioned in the ultrasonic detection area corresponding to the reference wave;

According to the embodiment of the invention, the ultrasonic signals in different detection ranges are generated by sending the excitation waves with different frequencies to the same ultrasonic generation module, and the distance information and the existence area of the object to be detected are determined according to the correlation values of the echo signals of the ultrasonic waves and the corresponding reference signals. The ultrasonic detection system can simultaneously detect the distance and the existing area of an object by only using one microphone or one ultrasonic sensor under the condition of the ultrasonic detection system without using a plurality of microphones or a plurality of ultrasonic sensors, and improves the stability of the ultrasonic detection process.

Drawings

FIG. 1 shows a prior art system architecture diagram;

fig. 2 shows a Chirp wave property diagram of the prior art;

FIG. 3 is a diagram illustrating a related value calculation method according to the prior art;

FIG. 4 shows a prior art object detection schematic;

FIG. 5 is a block diagram of an ultrasonic inspection system according to the present invention;

FIG. 6a is a schematic view showing the ultrasonic wave directivity characteristics of example 1 of the present invention;

FIG. 6b is a schematic view showing the ultrasonic impedance characteristics of example 1 of the present invention;

FIG. 6c is a schematic diagram showing the ultrasonic wave transmitting and receiving sensitivity of embodiment 1 of the present invention;

FIG. 7 is a schematic view showing the detection region range (after correction of K) in example 1 of the present invention;

FIG. 8 is a system configuration diagram according to embodiment 1 of the present invention;

fig. 9 shows a Chirp wave mixing diagram of embodiment 1 of the present invention;

FIG. 10 is a schematic view showing a correlation value calculation method of example 1 of the present invention;

FIG. 11 is a schematic view showing a correlation value calculation method of example 1 of the present invention;

FIG. 12 is a schematic view showing a method of calculating a correlation value of object position.3 in example 1 of the present invention;

fig. 13 is a schematic view showing the result of determination of the existence region in example 1 of the present invention;

FIG. 14 is a system architecture diagram showing embodiment 2 of the present invention;

FIG. 15 is a schematic diagram showing mixing of Pulse waves in example 2 of the present invention;

FIG. 16 is a schematic view showing a correlation value calculation method of example 2 of the present invention;

FIG. 17 is a schematic view showing a correlation value calculation method of example 2 of the present invention;

fig. 18 is a schematic view showing a method of calculating correlation values of object position.3 in example 2 of the present invention.

Detailed Description

The present invention will be described in further detail 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 of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In order to better understand the technical solution of the embodiment of the present invention, an ultrasonic testing method commonly used in the prior art is introduced. A system architecture of an ultrasonic detection system in the prior art is shown in fig. 1, and the system includes a Chirp wave generation circuit, an ultrasonic generation module, an amplification filter circuit, a correlation calculation circuit, and a CPU processing unit. Wherein:

(1) a Chirp wave generating circuit: the ultrasonic generator is used for generating a Chirp wave and driving the ultrasonic generating module to transmit ultrasonic waves.

(2) An ultrasonic wave generation module: for transmitting Chirp type ultrasonic waves.

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

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

(5) A CPU processing unit: all the relevant signals in the control and processing system process the results output from the relevant calculating circuit, judge the distance of the object and output the detection results.

Fig. 2 shows the properties of a Chirp wave in the prior art. 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 Chirp waves. The Chirp wave has various types of frequencies that increase linearly, decrease linearly or nonlinearly, decrease nonlinearly, and the like with time, and fig. 2 shows the type in which the frequency of the Chirp wave increases linearly with time. After the Chirp wave is generated, the Chirp ultrasonic wave is sent through the ultrasonic wave generating module, the reflected wave from the object is received, and then the reflected wave enters the amplifying and filtering circuit to obtain an output signal of the amplifying and filtering circuit. Here, the reception time of the reflected signal from the object is t 2.

Fig. 3 shows a related value calculation method in the prior art. First, a correlation value at time t0 is calculated as follows: the "reference wave _ 0000" and the "amplified filter loop output" are multiplied, and the multiplication results are accumulated, and the accumulated value obtained is stored as the correlation value at time t0 in the "correlation value calculation result". Next, "reference wave _ 0001" is obtained by delaying for 1 cycle, and "reference wave _ 0001" and "amplification filter loop output" are multiplied, and the multiplication results are accumulated, and the obtained accumulated value is used as the correlation value at time t 1. This process is repeated in sequence as follows. 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 "amplified filter loop output" increases, and therefore the value of the "correlation value calculation result" also increases.

After the correlation values at all times are calculated, when the correlation value calculation result is judged by the threshold value, and when the correlation value calculation result is larger than the correlation threshold value, it is considered that an 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 an object distance, the detection distance to the object can be calculated.

Although the distance of an object can be output in the prior art, as shown in fig. 4, this scheme cannot determine from which position of a concentric circle centered on the "ultrasonic microphone" the distance is reflected, and cannot determine the existence region of the object.

Based on the defects in the prior art, the embodiment of the invention provides an ultrasonic detection system, which sends at least two excitation waves with different frequencies to the same ultrasonic generation module to simultaneously obtain the detection of the distance and the existing area of the object to be detected. With further reference to fig. 5, the system includes a mixed wave generating circuit, an ultrasonic wave generating module, an amplifying and filtering circuit module, a correlation calculating circuit module, and a CPU processing unit.

The mixed wave generating circuit is used for mixing and superposing at least two excitation waves with different frequencies and outputting the excitation waves to the ultrasonic wave generating module. The excitation wave in this embodiment may be in the form of a Chirp wave, a pulse wave, or the like, and fig. 5 illustrates an example of outputting excitation waves of three different frequencies.

And the ultrasonic wave generation module is used for correspondingly generating at least two ultrasonic wave signals with different detection ranges according to the mixed and superposed excitation waves. Optionally, the ultrasonic wave generating module in this embodiment may be a microphone, an ultrasonic wave sensor, or the like.

the CPU processing unit comprises a presence area judging processing module, an exciting wave generating processing module, a reference wave generating processing module and a presence area output module.

The existence area judgment processing module is used for judging the distance information and the existence area of the object to be detected according to the calculation results of the correlation values of different detection ranges; the excitation wave generation processing module is used for generating at least two excitation waves with different frequencies; the reference wave generation processing module is used for respectively generating corresponding reference waves for the ultrasonic signals with different detection ranges; and the existence area output module is used for outputting the distance and the existence area of the measured object.

Specifically, the presence area determination processing module is specifically configured to execute:

In this embodiment, excitation waves of different frequencies are transmitted to the same ultrasonic wave generation module to generate ultrasonic wave signals of different detection ranges, and according to the correlation values between the echo signals of the ultrasonic waves and the corresponding reference signals, not only can the distance signals of the object to be measured be determined, but also the existence regions of the object to be measured can be further determined.

Next, the above technical solution is explained in one step by using two embodiments.

Example 1

In the present embodiment, an example in which a plurality of different Chirp waves are used is explained, and fig. 6a to 6c show ultrasonic directivity generation of the system. Generally, an ultrasonic microphone used in an ultrasonic detection device is configured by attaching a piezoelectric element to a metal case made of aluminum or the like, and exciting the piezoelectric element with a transmission wave applied thereto to generate vibration, thereby emitting an ultrasonic wave. The radiation intensity of the transmitted wave has a specific radiation intensity depending on the diameter and frequency of the vibration source. The characteristic of the radiation intensity of the ultrasonic wave is called a directivity characteristic.

In the present invention, by using a plurality of frequencies, different directivity characteristics are generated. In addition, since there is a resonance point in the "ultrasonic microphone", the sensitivity of transmission/reception is high in the vicinity of the resonance point, but if it is away from the resonance point frequency, the sensitivity K is lowered, and therefore, it is necessary to perform correction of the sensitivity.

In the present embodiment, 3 use frequencies of fm1 ═ 40[ kHz ], fm2 ═ 60[ kHz ], and fm3 ═ 80[ kHz ] are used as examples. Based on the sensitivity of fm1 ═ 40[ kHz ], since K60 to 40[ dB ] is reduced in fm2 ═ 60[ kHz ] compared to fm1 ═ 40[ kHz ], and K80 to 40[ dB is reduced in fm3 ═ 80[ kHz ] compared to fm1 ═ 40[ kHz ], these values are corrected in the subsequent calculations.

FIG. 7 illustrates the detection range of an ultrasonic mixed wave detection system according to the present invention. Since the corrections of K60-40[ dB ] and K80-40[ dB ] are performed, the Detection region ranges are designated as Detection Area _ fm1, Detection Area _ fm2, 60[ kHz ], and Detection Area _ fm3, 80[ kHz ] in the following schemes.

Fig. 8 shows a system architecture of embodiment 1 of the present invention. The system comprises a mixed wave generating circuit, a microphone, an amplifying and filtering circuit module, a related calculating circuit module and a CPU processing unit. Wherein:

(1) hybrid wave generation circuit: and mixing and superposing different Chirp waves generated by the Chirp wave generation processing module, and outputting the Chirp waves to the microphone.

(2) A microphone: ultrasonic signals of different detection ranges are generated.

(3) The amplifying and filtering circuit module: and amplifying and filtering the reflected echo received by the microphone.

(4) The correlation calculation circuit module: the correlation calculation circuit includes a plurality of correlation calculation circuits each of which uses a device capable of performing high-speed calculation processing such as DSP, performs correlation calculation processing on the signal after the amplification filtering processing and a "reference wave output" generated from the Chirp wave, inputs the processing result to the existence region determination module to process the processing result, obtains an existence region determination result, and outputs the result through the existence region output processing module, and at the same time, the distance may be calculated and output in synchronization with the result.

(5) A CPU processing unit: the device comprises a plurality of Chirp wave generating and processing modules, a reference wave generating and processing module corresponding to the Chirp waves, an existing region judging and processing module for processing correlation calculation results and an output processing module thereof, wherein the distance and the existing region of an object are judged according to the calculation results output by the correlation calculation circuit module, and a detection result is output.

Fig. 9 shows Chirp wave mixing in an ultrasonic mixed wave detection system according to the present invention. The transmission time of the plurality of Chirp waves is between t0 and t1, and the scanning frequencies are Fc1_0-Fc1_1, Fc2_ 0-Fc 2_1 and Fc3_ 0-Fc 3_1 respectively. These frequencies use the fm 1-40 [ kHz ], fm 2-60 [ kHz ], and fm 3-80 [ kHz ] bands described above. After the Chirp mixed wave is sent by the microphone, the microphone receives the reflected wave from the object and enters the amplifying and filtering loop module for processing. Here, the reception time of the reflected wave from the object is t 2.

Fig. 10-12 are schematic diagrams illustrating correlation calculation of an ultrasonic hybrid detection system according to the present invention. Fig. 9 is a correlation calculation result of the object position.1, fig. 10 is a correlation calculation result of the object position.2, and fig. 11 is a correlation calculation result of the object position.3.

In fig. 10, the correlation operation between the "reference wave.1" and the "amplified filter circuit output", the correlation operation between the "reference wave.2" and the "amplified filter circuit output", and the correlation operation between the "reference wave.3" and the "amplified filter circuit output" are processed in parallel. The correlation calculation is illustrated in fig. 3. In the case where the object is present in the front direction, the object position 1 is in the range of Detection Area _ fm1 ═ 40[ kHz ], Detection Area _ fm2 ═ 60[ kHz ], and Detection Area _ fm3 ═ 80[ kHz ], and therefore receives the "correlation value.1 calculation result", "correlation value.2 calculation result", and "correlation value.3 calculation result" all exceed the "correlation value threshold value" at the time t 2.

In the case of an object at a position slightly off the center line, the object is in the range of Detection Area _ fm1 ═ 40[ kHz ], Detection Area _ fm2 ═ 60[ kHz ], but not in the range of Detection Area _ fm3 ═ 80[ kHz ] in fig. 11, so that the "correlation value.1 calculation result" and the "correlation value.2 calculation result" exceed the "correlation value threshold" but the "correlation value.3 calculation result" does not exceed the "correlation value threshold" at the reception time t 2.

In the case of an object outside the vehicle, the object position.3 in fig. 12 is in the range of Detection Area _ fm1 being 40[ kHz ], but not in the range of Detection Area _ fm2 being 60[ kHz ], and Detection Area _ fm3 being 80[ kHz ], so that the "correlation value.1 calculation result" exceeds the "correlation value threshold" but the "correlation value.2 calculation result" and the "correlation value.3 calculation result" do not exceed the "correlation value threshold" at the reception time t 2.

Fig. 13 is a schematic diagram showing the result of determination of the presence region of an ultrasonic mixed wave detection system according to the present invention. As described above, by performing comparison determination on the "correlation value.1 calculation result", the "correlation value.2 calculation result", and the "correlation value.3 calculation result", it is possible to simultaneously detect the "distance" and the "existence region" in which the object exists.

Example 2

The excitation wave used in the system of embodiment 2 of the present invention is a multiple Pulse (Pulse) wave.

Fig. 14 shows a system architecture of embodiment 2 of the present invention. The system comprises a mixed wave generating circuit, a microphone, an amplifying and filtering circuit module, a related calculating circuit module and a CPU processing unit. Wherein:

(1) hybrid wave generation circuit: and mixing and superposing different Pulse waves generated by the Pulse wave generation processing module, and outputting the different Pulse waves to the microphone.

(2) A microphone: an ultrasonic signal is generated.

(4) The correlation calculation circuit module: the correlation calculation circuit includes a plurality of correlation calculation circuits each of which uses a device capable of performing high-speed calculation processing such as DSP, performs correlation calculation processing on a signal subjected to amplification filtering processing and a "reference wave output" generated from a Pulse wave, inputs a processing result to the existence region determination module to perform processing, obtains an existence region determination result, and outputs the result through the existence region output processing module, and at the same time, calculates and outputs a distance in synchronization with the result.

(5) A CPU processing unit: the detection device includes a generation processing module including a plurality of Pulse waves, a reference wave generation processing module corresponding to the Pulse waves, and a presence area determination processing module and an output processing module thereof for processing a correlation calculation result.

FIG. 15 shows Pulse wave mixing in example 2 of the present invention. The transmission time of the plurality of Pulse waves is between t0 and t1, and the frequencies are single frequencies of Fc1, Fc2 and Fc3 respectively. These frequencies use the fm 1-40 [ kHz ], fm 2-60 [ kHz ], fm 3-80 [ kHz ] frequency band.

Fig. 16 to 18 show correlation value calculations in example 2 of the present invention. Fig. 16 is a calculation result of the object position.1, fig. 17 is a calculation result of the object position.2, and fig. 18 is a calculation result of the object position.3. The correlation calculation method has been described in fig. 3, and the calculation method is the same although the waveform of the correlation value calculation result is different for the Pulse wave.

In the object position.1 in fig. 16, when there is an object in the front direction, the object is in the range of Detection Area _ fm1 ═ 40[ kHz ], Detection Area _ fm2 ═ 60[ kHz ], and Detection Area _ fm3 ═ 80[ kHz ], so that the "correlation value.1 calculation result", "correlation value.2 calculation result", and "correlation value.3 calculation result" all exceed "the correlation value threshold value" at the reception time t2 are received.

In the case of an object at a position slightly off the center line, the object is in the range of Detection Area _ fm 1-40 [ kHz ], Detection Area _ fm 2-60 [ kHz ], but not in the range of Detection Area _ fm 3-80 [ kHz ] in fig. 17, so that the "correlation value.1 calculation result" and the "correlation value.2 calculation result" exceed the "correlation value threshold" but the "correlation value.3 calculation result" does not exceed the "correlation value threshold" at the reception time t 2.

In the case of an object outside the vehicle at the object position.3 in fig. 18, the object is in the range of Detection Area _ fm1 being 40[ kHz ], but not in the range of Detection Area _ fm2 being 60[ kHz ], and Detection Area _ fm3 being 80[ kHz ], so that the "correlation value.1 calculation result" exceeds the "correlation value threshold" but the "correlation value.2 calculation result" and the "correlation value.3 calculation result" do not exceed the "correlation value threshold" at the reception time t 2.

By comparing and determining the "correlation value.1 calculation result", the "correlation value.2 calculation result", and the "correlation value.3 calculation result", it is possible to simultaneously detect the "distance" and the "existence region" in which the object exists.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. 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, although the present invention has been described in some detail by the above embodiments, the invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the invention, and the scope of the invention is determined by the scope of the appended claims.

Claims

1. An ultrasonic inspection system, comprising:

the ultrasonic wave amplification and filtering device comprises a mixed wave generating circuit, an ultrasonic wave generating module, an amplification and filtering circuit module, a related computing circuit module and a CPU (central processing unit);

2. The system of claim 1, wherein the CPU further comprises an excitation wave generation processing module for generating excitation waves of at least two different frequencies.

3. The system according to claim 1, wherein the CPU further comprises a reference wave generation processing module for generating corresponding reference waves for the at least two ultrasonic signals with different detection ranges.

4. The system of claim 1, wherein the CPU further comprises a presence area output module for outputting the distance and the presence area of the object to be measured.

5. The system according to claim 1, wherein the presence area determination processing module is specifically configured to perform:

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

7. The method of claim 6, wherein determining the presence area and distance information of the object to be measured from the correlation calculation result value includes: