CN114376609A - Nasal acoustic reflectometer, nasal airway measurement method, measurement equipment and medium - Google Patents

Abstract

The invention discloses a nasal sound reflectometer, a nasal airway measuring method, measuring equipment and a medium, wherein the method comprises the following steps: after the upper computer detects the starting detection signal, the electric spark generating device is controlled to periodically discharge based on the FPGA controller; recording a sound signal generated after the electric spark generating device carries out periodic discharge based on a microphone sampling device arranged in the sound wave guide pipe; after the sound signals in the microphone sampling device are read and stored through the FPGA controller, the sound signals stored in the FPGA controller are sent to an upper computer for calculation, and a nasal airway measuring result is obtained. Through with the sound source by the extremely short electric spark of pulse replacement for the speaker, shortened the length of required sound wave pipe, and then avoid the problem that the nasal air flue measurement accuracy descends because of helical structure's sound wave pipe leads to, through handling the calculation to the sound signal of gathering many times in succession, further promote nasal air flue measurement's stability and measurement accuracy.

Description

Nasal acoustic reflectometer, nasal airway measurement method, measurement equipment and medium

technical field

The present invention relates to the technical field of nasal acoustic reflectometers, in particular to a nasal acoustic reflectometer, a nasal airway measurement method, a measurement device and a computer-readable storage medium.

Background technique

Existing nasal acoustic reflectometers for nasal airway measurement usually use speakers as sound sources, and use microphones to collect echo information, then use WA algorithm or other inverse scattering calculation algorithms to calculate the cavity to be measured according to the impulse response of the incident signal. internal situation.

However, in the prior art, when calculating the impulse response of the incident signal, it is necessary to effectively separate the incident pulse and the echo signal, and because the loudspeaker as the sound source will make the pulse time longer, a longer sound wave must be used The catheter can ensure the effective separation of the incident pulse and the echo signal. In the design of the acoustic waveguide of the existing nasal acoustic reflector, the acoustic waveguide is usually made into a spiral structure to reduce the volume occupied in the nasal acoustic reflector. However, when a hose is used to make a spiral acoustic waveguide, the nasal acoustic reflectometer cannot accurately measure the internal conditions of the cavity to be measured due to the easy change of the inner diameter of the hose. The problem that the measurement accuracy is reduced due to the uneven cross-section of the inner diameter of the catheter.

Therefore, the existing nasal acoustic reflectometer has the problems of low accuracy and poor measurement stability in the output of nasal airway measurement results due to the design problem of the long helical structure of the acoustic waveguide.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to propose a nasal acoustic reflector, a nasal airway measurement method, a measuring device and a computer-readable storage medium, aiming at how to solve the design problem of the existing nasal acoustic reflector due to the long helical structure of the acoustic waveguide , a technical problem that leads to the problem of low accuracy in the output of nasal airway measurement results.

In order to achieve the above object, the present invention provides a nasal acoustic reflector, characterized in that the nasal acoustic reflector comprises:

host computer;

FPGA controller, the FPGA controller establishes a communication connection with the host computer;

an electric spark generating device, the electric spark generating device establishes a communication connection with the FPGA controller;

a sound wave guide, the sound wave guide is connected with the electric spark generating device;

a microphone sampling device disposed in the acoustic waveguide;

an FPGA controller, where the FPGA controller establishes a communication connection with the microphone sampling device.

Optionally, the electric spark generating device includes a control terminal, a discharge electrode, a first coil, a second coil, a third coil, a fourth coil, a fifth coil, a first resistor, a second resistor, a third resistor, a third Four resistors, fifth resistors, first diode, second diode, third diode, capacitor, triode and battery;

The output end of the control end is connected to one end of the first resistor, the other end of the first resistor is connected to the gate of the second diode, and the negative electrode of the second diode is connected to the negative electrode of the battery , the anode of the battery is connected to the emitter of the triode, the base of the triode is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the second coil, the second The other end of the coil is connected to one end of the second resistor, the other end of the second resistor is connected to the anode of the second diode, and one end of the first coil is connected to the second coil and the second resistor The other end of the first coil is connected to the collector of the triode;

One end of the third coil is connected to the third resistor, the other end of the third coil is connected to the anode of the first diode, and the cathode of the first diode is connected to one end of the capacitor , the other end of the capacitor is connected to one end of the fourth coil;

The fourth resistor and the fifth resistor are connected in series, the gate of the third diode is connected to the connection point of the fourth resistor and the fifth resistor, and the fourth resistor, the fifth resistor and the third a pole tube is connected in parallel with the fourth coil and the third coil;

The fifth coil is opposite to the fourth coil, and the discharge electrode is connected to both ends of the fifth coil;

The control terminal is used to receive the preset DC power supply sent by the FPGA controller;

The discharge electrode is configured to perform periodic discharge after the control terminal receives the preset DC power supply.

The present invention also provides a nasal airway measurement method, the nasal airway measurement method comprising the following steps:

After the start detection signal is detected by the host computer, the electric spark generating device is controlled to perform periodic discharge based on the FPGA controller;

Based on the microphone sampling device in the sound wave guide, recording the sound signal generated after the electric spark generating device performs periodic discharge;

After the sound signal in the microphone sampling device is read and stored by the FPGA controller, the first sound signal to be calculated stored in the FPGA controller is sent to the host computer for calculation , to obtain nasal airway measurements.

Optionally, the step of the FPGA controller controlling the electric spark generating device to perform periodic discharge includes:

Based on the FPGA controller applying a preset DC voltage to the control terminal of the electric spark generating device, the discharge electrode of the electric spark generating device is controlled to perform periodic discharge.

Optionally, the step of reading and storing the sound signal in the microphone sampling device by the FPGA controller includes:

The sound signal in the microphone sampling device is read by the FPGA controller;

Judging whether the read sound signal is the first to-be-calculated sound signal with an initial portion;

If the read sound signal is the first sound signal to be calculated with a starting part, the voltage of the control terminal is pulled down, and the first sound signal to be calculated is stored at the same time;

If the read sound signal is not the first to-be-calculated sound signal with the starting part, the high voltage of the control terminal is maintained, and the sound signal is eliminated.

Optionally, the step of judging whether the read sound signal is the first to-be-calculated sound signal with an initial portion includes:

Judging whether the address where the sound signal is located belongs to the loop storage area in the memory database of the FPGA controller;

If the address at which the sound signal is located belongs to the cyclic storage area in the memory database of the FPGA controller, then it is determined that the sound signal read is the first sound signal to be calculated with an initial portion;

If the address where the sound signal is located does not belong to the cyclic storage area in the memory database of the FPGA controller, then determine whether the sound signal triggers a preset storage condition;

If the sound signal triggers the preset storage condition, it is determined that the read sound signal is the first to-be-calculated sound signal having a starting part.

Optionally, the step of sending the first to-be-calculated sound signal stored in the FPGA controller to the host computer for calculation, and obtaining a nasal airway measurement result includes:

Sending the first sound signal to be calculated to the host computer through the FPGA controller;

After compressing and reducing the dimension of the first sound signal to be calculated by the PCA dimensionality reduction space method, a first low-dimensional sound signal to be calculated is obtained in the dimensionality reduction space;

Based on the preset ratio, the abnormal signals that deviate from the center position of the first low-dimensional sound signal to be calculated are eliminated from the first low-dimensional sound signal to be calculated to obtain a second low-dimensional sound signal to be calculated;

Taking the second low-dimensional sound signal to be calculated as an extraction sample, extracting the to-be-calculated sound signal corresponding to the second low-dimensional to-be-calculated sound signal in the first to-be-calculated sound signal to obtain a second to-be-calculated sound signal. calculate the sound signal;

Splitting the second sound signal to be calculated based on the cross-correlation localization method to obtain the first sound incident wave pulse signal, the first sound echo signal and the baseline signal;

The baseline signal in the first sound incident wave pulse signal and the first sound echo signal is removed by a compensation method to obtain a second sound incident wave pulse signal and a second sound echo signal;

Fast Fourier transform is performed on the second sound incident wave pulse signal and the second sound echo signal based on the fast Fourier transform algorithm to obtain the third sound incident wave pulse signal and the third sound echo signal;

Calculate the h(t) value of the impulse response based on the third sound incident wave pulse signal and the third sound echo signal to obtain the h(t) value, and after averaging the h(t) value, based on The WA algorithm performs calculations to obtain the nasal airway measurements.

Optionally, after the step of obtaining the nasal airway measurement result, it also includes:

The nasal airway measurement result is displayed through the display end of the upper computer.

In addition, in order to achieve the above object, the present invention also provides a measuring device, the measuring device includes a nasal acoustic reflectometer, a memory, a processor and a computer program stored in the memory and running on the processor, the computer program being The processor implements the steps of the above-mentioned nasal airway measurement method when executed.

In addition, in order to achieve the above object, the present invention also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned nasal airway measurement method are realized .

In the present invention, the electric spark that can be generated by the electric spark generating device is used as the sound source, so as to solve the problem of the incident pulse and echo information in the transmission process caused by having to use the long sound wave guide of the helical structure due to the long pulse time. Instability, the output nasal airway measurement results have the problem of low accuracy. By storing the sound signal collected by the microphone, it avoids the transmission of the serial port communication speed with the host computer is lower than the signal sampling rate. For the problem of sound signal loss in the process, the collected sound signals are calculated and processed by using the cross-correlation localization method, the PCA dimensionality reduction space elimination algorithm and the impulse response ht averaging algorithm, so as to improve the accuracy of the calculation results and the anti-interference ability.

Description of drawings

1 is a schematic diagram of a terminal structure of a hardware operating environment involved in an embodiment of the present invention;

Fig. 2 is the structure schematic diagram of the nasal acoustic reflector of the present invention FPGA controller and the host computer combined control electric spark generating device;

3 is a schematic diagram of a discharge control circuit of an electric spark generating device;

4 is a schematic flowchart of an embodiment of a nasal airway measurement method of the present invention;

FIG. 5 is a schematic diagram of the refinement process of step S30 in FIG. 4;

FIG. 6 is a schematic diagram of the refinement process of step S30 in FIG. 4;

7 is a schematic diagram of a sound signal captured by a microphone sampling device;

FIG. 8 is a schematic diagram of the area divided by the 12-bit AD sampling chip of the FPGA controller;

FIG. 9 is a schematic diagram of the distribution of the first low-dimensional sound signal to be calculated in the reduced-dimensional space.

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The main solution of the embodiment of the present invention is: by combining the FPGA controller and the host computer to control the design of the electric spark generating device to generate the electric spark, the pulse time of the sound signal can be reduced, and the sound wave used can be reduced due to the reduction of the pulse time. The length of the catheter and the volume occupied by the nasal acoustic reflectometer can avoid the instability of the collected acoustic signals and the low accuracy of the output nasal airway measurement results due to the long and curved characteristics of the acoustic waveguide used.

In the prior art, the nasal acoustic reflector uses a loudspeaker as the sound source, but due to the long pulse time of the sound signal generated by the loudspeaker, the sound waveguide used needs to have a sufficient length to better respond to the incident pulse and echo. The wave signal is separated and processed, and in order to reduce the volume occupied by the long acoustic wave guide in the nasal acoustic reflectometer, the long acoustic wave guide is usually made into a helical structure, but whether a hose or a steel pipe is used as the long acoustic wave guide of the helical structure, There are always problems that the collected sound signal is unstable and the accuracy of the obtained nasal airway measurement results is low.

The present invention provides a solution that only needs to replace the loudspeaker as the sound source with an electric spark generating device, and utilizes the characteristic of the short pulse time of the sound signal generated by the electric spark to achieve the effect of reducing the length of the sound waveguide, thereby avoiding the There are a series of problems that are not conducive to improving the stability and test accuracy of the nasal acoustic reflector, which is caused by the use of a long acoustic waveguide with a spiral structure to collect and process sound signals.

As shown in FIG. 1 , FIG. 1 is a schematic diagram of a terminal structure of a hardware operating environment involved in an embodiment of the present invention.

The nasal airway measurement device in the embodiment of the present invention may be a PC, or may be a mobile terminal device with a display function, such as a tablet computer and a portable computer.

As shown in FIG. 1 , the terminal may include: a processor 1001 , such as a CPU, a network interface 1004 , a user interface 1003 , a memory 1005 , and a communication bus 1002 . Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. Optionally, the network interface 1004 may include a standard wired interface and a wireless interface (eg, a WI-FI interface). The memory 1005 may be high-speed RAM memory, or may be non-volatile memory, such as disk memory. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001 . The terminal is positioned on the nasal acoustic reflectometer.

Optionally, the nasal airway measurement device may further include a camera, an RF (Radio Frequency, radio frequency) circuit, a sensor, an audio circuit, a WiFi module, and the like. Among them, sensors such as light sensors, motion sensors and other sensors. Specifically, the light sensor may include an ambient light sensor and a proximity sensor, wherein the ambient light sensor may adjust the brightness of the display screen according to the brightness of the ambient light, and the proximity sensor may turn off the display screen and/or turn off the display screen when the mobile terminal is moved to the ear. Backlight. As a kind of motion sensor, the gravitational acceleration sensor can detect the magnitude of acceleration in all directions (generally three axes), and can detect the magnitude and direction of gravity when it is stationary, and can be used for applications that recognize the posture of mobile terminals (such as horizontal and vertical screen switching, related games, magnetometer attitude calibration), vibration recognition related functions (such as pedometer, tapping), etc.; of course, the mobile terminal can also be equipped with other sensors such as gyroscope, barometer, hygrometer, thermometer, infrared sensor, etc. No longer.

Those skilled in the art can understand that the structure of the nasal airway measurement device shown in FIG. 1 does not constitute a limitation to the nasal airway measurement device, and may include more or less components than those shown in the figure, or combine certain components, Or a different component arrangement.

As shown in FIG. 1 , the memory 1005 as a computer storage medium may include an operating system, a network communication module, a user interface module and a computer program.

In the terminal shown in FIG. 1 , the network interface 1004 is mainly used to connect to the background server and perform data communication with the background server; the user interface 1003 is mainly used to connect to the client (client) and perform data communication with the client; and the processor 1001 can be used to invoke a computer program stored in memory 1005 and perform the following operations:

After the start detection signal is detected by the host computer, the electric spark generating device is controlled to perform periodic discharge based on the FPGA controller;

Based on the microphone sampling device in the sound wave guide, recording the sound signal generated after the electric spark generating device performs periodic discharge;

After the sound signal in the microphone sampling device is read and stored by the FPGA controller, the first sound signal to be calculated stored in the FPGA controller is sent to the host computer for calculation , to obtain nasal airway measurements.

Further, the processor 1001 can call the computer program stored in the memory 1005, and also perform the following operations:

The step of controlling the electric spark generating device to perform periodic discharge based on the FPGA controller includes: applying a preset DC voltage to the control terminal of the electric spark generating device based on the FPGA controller to control the electric spark generating device The discharge electrodes of the device are periodically discharged.

Further, the processor 1001 can call the computer program stored in the memory 1005, and also perform the following operations:

The step of reading and storing the sound signal in the microphone sampling device by the FPGA controller includes: reading the sound signal in the microphone sampling device by the FPGA controller;

Judging whether the read sound signal is the first to-be-calculated sound signal with an initial portion;

If the read sound signal is the first sound signal to be calculated with a starting part, the voltage of the control terminal is pulled down, and the first sound signal to be calculated is stored at the same time;

If the read sound signal is not the first to-be-calculated sound signal with the starting part, the high voltage of the control terminal is maintained, and the sound signal is eliminated.

Further, the processor 1001 can call the computer program stored in the memory 1005, and also perform the following operations:

The step of judging whether the read sound signal is the first sound signal to be calculated with the initial part comprises: judging whether the address where the sound signal is located belongs to the loop storage area in the memory database of the FPGA controller;

If the address at which the sound signal is located belongs to the cyclic storage area in the memory database of the FPGA controller, then it is determined that the sound signal read is the first sound signal to be calculated with an initial portion;

If the address where the sound signal is located does not belong to the cyclic storage area in the memory database of the FPGA controller, then determine whether the sound signal triggers a preset storage condition;

If the sound signal triggers the preset storage condition, it is determined that the read sound signal is the first to-be-calculated sound signal having a starting part.

Further, the processor 1001 can call the computer program stored in the memory 1005, and also perform the following operations:

Send the sound signal stored in the FPGA controller to the host computer for calculation, and the steps of obtaining the nasal airway measurement result include: sending the first sound signal to be calculated to the host computer through the FPGA controller. in the above-mentioned host computer;

After compressing and reducing the dimension of the first sound signal to be calculated by the PCA dimensionality reduction space method, a first low-dimensional sound signal to be calculated is obtained in the dimensionality reduction space;

Based on the preset ratio, the abnormal signals that deviate from the center position of the first low-dimensional sound signal to be calculated are eliminated from the first low-dimensional sound signal to be calculated to obtain a second low-dimensional sound signal to be calculated;

Taking the second low-dimensional sound signal to be calculated as an extraction sample, extracting the to-be-calculated sound signal corresponding to the second low-dimensional to-be-calculated sound signal in the first to-be-calculated sound signal to obtain a second to-be-calculated sound signal. calculate sound signals;

Splitting the second sound signal to be calculated based on the cross-correlation localization method to obtain the first sound incident wave pulse signal, the first sound echo signal and the baseline signal;

The baseline signal in the first sound incident wave pulse signal and the first sound echo signal is removed by a compensation method to obtain a second sound incident wave pulse signal and a second sound echo signal;

Fast Fourier transform is performed on the second sound incident wave pulse signal and the second sound echo signal based on the fast Fourier transform algorithm to obtain the third sound incident wave pulse signal and the third sound echo signal;

Calculate the h(t) value of the impulse response based on the third sound incident wave pulse signal and the third sound echo signal to obtain the h(t) value, and after averaging the h(t) value, based on The WA algorithm performs calculations to obtain the nasal airway measurements.

Further, the processor 1001 can call the computer program stored in the memory 1005, and also perform the following operations:

After the step of obtaining the nasal airway measurement result, the nasal airway measurement result is displayed through the display end of the upper computer.

Referring to FIG. 2, an embodiment of the present invention provides a nasal acoustic reflector, which includes:

The upper computer (that is, the 1 mark in the figure);

FPGA controller (ie, the 2 in the figure), the FPGA controller establishes a communication connection with the host computer;

An electric spark generating device (namely, the number 4 in the figure), the electric spark generating device establishes a communication connection with the FPGA controller;

A sound wave guide (namely, the number 7 in the figure), the sound wave guide is connected with the electric spark generating device;

a microphone sampling device (namely 6 in the figure), the microphone sampling device is arranged in the acoustic waveguide;

an FPGA controller, where the FPGA controller establishes a communication connection with the microphone sampling device.

In this embodiment, the communication connection between the host computer, the FPGA controller, the electric spark generating device and the acoustic waveguide is a connection established through a signal line (ie, the number 3 in the figure). When the electric spark generating device receives the FPGA control After the preset current sent by the device, the discharge electrode (ie, the 5 mark in the figure) will be controlled to perform the discharge operation.

Further, referring to FIG. 3 , the electric spark generating device includes a control end, a discharge electrode, a first coil, a second coil, a third coil, a fourth coil, a fifth coil, a first resistor, a second resistor, a third coil resistor, fourth resistor, fifth resistor, first diode, second diode, third diode, capacitor, triode and battery;

The output end of the control end is connected to one end of the first resistor, the other end of the first resistor is connected to the gate of the second diode, and the negative electrode of the second diode is connected to the negative electrode of the battery , the anode of the battery is connected to the emitter of the triode, the base of the triode is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the second coil, the second The other end of the coil is connected to one end of the second resistor, the other end of the second resistor is connected to the anode of the second diode, and one end of the first coil is connected to the second coil and the second resistor The other end of the first coil is connected to the collector of the triode;

One end of the third coil is connected to the third resistor, the other end of the third coil is connected to the anode of the first diode, and the cathode of the first diode is connected to one end of the capacitor , the other end of the capacitor is connected to one end of the fourth coil;

The fourth resistor and the fifth resistor are connected in series, the gate of the third diode is connected to the connection point of the fourth resistor and the fifth resistor, the fourth resistor, the fifth resistor and the third a pole tube is connected in parallel with the fourth coil and the third coil;

The fifth coil is opposite to the fourth coil, and the discharge electrode is connected to both ends of the fifth coil;

The control terminal is used to receive the preset DC power supply sent by the FPGA controller, and based on the preset DC power supply, the circuit of the electric spark generating device (ie the circuit in FIG. 3 ) enters the running state

The discharge electrode is used to change the current in the fourth coil L4 after the control terminal receives the preset DC power supply, while the current in the fifth coil L5 opposite to the fourth coil L4 will change. The magnetic flux will also change, and an induced current will flow through the discharge electrode for discharge, and every time the FPGA controller records a complete sound signal, sound incident wave pulse signal and sound echo signal, it will send it to the control terminal again. The preset DC power is sent, so that the circuit of the electric spark generating device enters the discharge state again, thereby forming a periodic discharge.

In this embodiment, the first coil L1, the second coil L2, and the third coil L3 are connected by a magnetic core, and the fourth coil and the fifth coil are connected by a winding coil, but this embodiment only provides an example, the coil The connection mode between them is not limited to this embodiment, and the specific connection mode can be changed according to the actual usage scenario.

4, an embodiment of the present invention also provides a nasal airway measurement method, the nasal airway measurement method includes:

Step S10, after the host computer detects the startup detection signal, controls the electric spark generating device to perform periodic discharge based on the FPGA controller;

In the present invention, the used host computer is a PC (Personal Computer, personal computer) host computer, PC host computer, FPGA (Field Programmable Gate Array, Field Programmable Gate Array) controller, electric spark generating device, microphone sampling Signal lines are used for connection and communication between the device and the sound waveguide, so the transmission and sampling rate of sound signals can be accelerated.

After the user inputs the detection signal to start the detection of the cavity to be measured on the PC, the detection signal is transmitted to the FPGA controller through the signal line. After the FPGA controller detects the detection signal, the The electric spark generating device is controlled, and the electric spark generating device is controlled to perform periodic discharge.

Among them, the periodic discharge means that every time the FPGA controller records a complete sound incident wave pulse signal and sound echo signal, it will control the electric spark generator to enter a new discharge process before receiving the stop detection signal. , so as to generate a new sound incident wave pulse signal and sound echo signal.

Optionally, the step of controlling the electric spark generating device to perform periodic discharge based on the FPGA controller in step S10 includes:

Step A, referring to FIG. 3 , based on the FPGA controller applying a preset DC voltage to the control terminal of the spark generating device, the discharge electrode of the spark generating device is controlled to perform periodic discharge.

Fig. 3 is the discharge control circuit of the electric spark generating device as the sound source in the present invention. The FPGA controller applies a DC voltage of 3.3V to the control terminal of the discharge control circuit, so that the electric spark generating device can be operated. When the current in the coil L4 changes, the magnetic flux in the opposite coil L5 also changes, and an induced current flows through the discharge electrode, so that the discharge electrode discharges, and then the spark generator generates a sound signal.

Because the FPGA controller will re-apply 3.3V DC voltage to the control end of the spark generating device after recording a complete sound signal, so that the spark generating device will discharge again, so as to achieve the effect of periodic discharge.

Compared with the existing loudspeaker as a sound source, the pulse time of the electric spark generating device is shorter, which can effectively shorten the required length of the sound wave guide, and the shortening of the length of the sound wave guide can avoid the need for reducing the noise of the sound wave guide in the nose. The helical structure needs to be adopted due to the volume occupied in the reflectometer, thereby avoiding the problem that the measurement accuracy of the nasal airway is lowered due to the acoustic waveguide of the helical structure.

Step S20, referring to FIG. 7, recording the sound signal generated after the electric spark generating device performs periodic discharge based on the microphone sampling device in the acoustic waveguide;

After the electric spark generating device discharges, the generated sound signal will be captured by the microphone sampling device with a sampling rate of 500 kHz. The characteristics of the sound signal captured by the microphone sampling device are shown in Figure 7. The microphone sampling device first receives The electromagnetic sound signal is followed by the sound incident wave pulse signal of the electric spark generating device, and after a period of time, the sound echo signal generated by the sound incident wave pulse signal.

It should be noted that because the spark generating device is discharged periodically, there are multiple sets of sound signals.

As one of the important factors affecting the measurement accuracy of the nasal airway, the acoustic waveguide is more irregular in shape, the greater the impact on the output accuracy of the nasal airway measurement, and the acoustic waveguide used in the present invention can avoid it being designed into a spiral structure. The irregular shape improves the accuracy of nasal airway measurement to a certain extent.

Step S30, after the sound signal in the microphone sampling device is read and stored by the FPGA controller, the first sound signal to be calculated stored in the FPGA controller is sent to the host computer Calculations were performed in , and the nasal airway measurement results were obtained.

After the FPGA controller reads and stores multiple sets of sound signals in the microphone sampling device through the signal line, it will send the stored multiple sets of sound signals to the PC host computer for processing and calculation.

The FPGA controller can also process and calculate the stored multiple groups of sound signals, but because the processing and computing capability of the FPGA controller is slightly inferior to that of the PC host computer, the embodiment of the present invention is to perform processing and calculation on the stored multiple groups of sound signals in the PC host computer. If the sound signal is processed and calculated, the processing and calculation rate of multiple groups of sound signals can be accelerated.

It should be noted that the first sound signal to be calculated refers to the sound signal to be calculated before being sent to the upper computer for calculation processing.

Optionally, after the step of obtaining the nasal airway measurement result in step S30, it also includes:

Step B, displaying the nasal airway measurement result through the display end of the upper computer.

After the PC host computer processes and calculates the multiple sets of sound signals stored in the FPGA controller, the change of the nasal airway cross-sectional area of the cavity to be measured with the nasal cavity axial distance will be obtained, that is, the nasal airway measurement results. The opportunity to display the nasal airway measurement results on the display terminal, such as the display screen of the PC host computer, can also be broadcast by voice, so that the user can clearly understand the nasal airway measurement of the cavity to be measured.

In this embodiment, the nasal acoustic reflector is controlled by using the FPGA controller to control the electric spark generating device in combination with the host computer, so that the electric spark generating device can be controlled to perform multiple discharges in a short period of time, and the FPGA controller can sample through the microphone. The device performs multiple reading and storage, and the calculation method based on multiple sets of sound signals can improve the accuracy of the output nasal airway measurement results. By replacing the sound source in the existing nasal acoustic reflector with an electric spark, The pulse time of the sound signal is shortened, and the shortening of the pulse time can effectively shorten the length of the required sound wave guide, and the shortening of the length of the sound wave guide can avoid the need to reduce the volume occupied by the sound wave guide in the nasal acoustic reflector. The situation of the helical structure needs to be adopted, thereby avoiding the problem that the measurement accuracy of the nasal airway is reduced due to the acoustic waveguide of the helical structure.

Further, referring to FIG. 5 , an embodiment of the present invention provides a nasal airway measurement method. Based on the embodiment shown in step S30 above, the sound in the microphone sampling device is sampled by the FPGA controller. The steps after the signal is read and stored include:

Step S31, reading the sound signal in the microphone sampling device through the FPGA controller;

Step S32, judging whether the read sound signal is the first to-be-calculated sound signal with a starting part;

Step S33, if the read sound signal is the first sound signal to be calculated with the starting part, then the voltage of the control terminal is pulled down, and the first sound signal to be calculated is stored simultaneously;

Step S34, if the read sound signal is not the first sound signal to be calculated with the starting part, the high voltage of the control terminal is maintained, and the sound signal is eliminated.

After the electric spark generating device performs periodic discharge, the generated sound signal will be captured by the microphone sampling device, and the captured sound signal will be read by the FPGA controller through the signal line, and the FPGA controller will read it. Take the sound signal to judge, because not all the read sound signals are a sound signal with a complete start cycle, so it must be judged whether it has a complete start sound signal, and the read sound signal must be judged. Whether the sound signal is a complete set of start cycles, if the read sound signal is a set of complete start cycles, the sound signal corresponding to the start cycle can be classified as the sound signal to be calculated, then the FPGA After the controller pulls down the voltage of the control terminal of the electric spark generating device, the sound signal to be calculated is stored in the memory database of the FPGA controller, which is convenient for later calculation based on the effective sound signal and improves the accuracy of the output nasal airway measurement results. Spend.

If the read sound signal is not a complete set of initial cycles, the FPGA controller keeps the high voltage of the control terminal of the spark generating device unchanged, and at the same time changes the sound signal read in the time period when the control terminal is high voltage Abandoned to avoid incomplete acoustic signals affecting the output nasal airway measurements.

Optionally, referring to FIG. 8 , the step of judging in step S32 whether the read sound signal is the first sound signal to be calculated with a starting part includes:

Step S35, judge whether the address where the sound signal is located belongs to the loop storage area in the memory database of the FPGA controller;

Step S36, if the address at which the sound signal is located belongs to the cyclic storage area in the memory database of the FPGA controller, then it is determined that the sound signal read is the first sound signal to be calculated with an initial portion;

Step S37, if the address where the sound signal is located does not belong to the cyclic storage area in the memory database of the FPGA controller, then judge whether the sound signal triggers a preset storage condition;

In step S38, if the sound signal triggers the preset storage condition, it is determined that the read sound signal is the first sound signal to be calculated having a starting part.

As can be seen from FIG. 8, the present invention divides the 12-bit AD (Analog-to-Digital, analog/digital conversion) sampling chip of the FPGA controller into two parts, and a small part is a circular storage area, which is used to judge the read sound. Whether the signal is the first sound signal to be calculated with a start part, most of which are storage areas, used to store the first sound signal to be calculated with a start part, the sound signal stored in this area is to be sent to the PC host computer for processing and calculation.

After the FPGA controller detects a new startup detection signal, it will initialize the previously stored sound signal, so as to avoid the influence of the data of the previous cavity on the output result of the new cavity.

After the FPGA controller detects that the microphone sampling device has captured the sound signal, it reads the captured sound signal, writes the read sound signal into the loop storage area, and judges the read sound signal in the loop storage area. Whether the address belongs to the loop storage area, the address of the read sound signal belongs to the loop storage area, then the sound signal is classified as the first sound signal to be calculated, and the first sound signal to be calculated is stored in the storage area. in the area.

If the address of the read sound signal does not belong to the cyclic storage area, in order to avoid the omission of the sound signal and improve the accuracy of the output nasal airway measurement result, the present invention will perform a secondary measurement on the sound signal that does not belong to the cyclic storage area. Judgment, to judge whether it triggers the storage condition.

Among them, the storage condition refers to whether the read sound signal has an obvious starting segment of the sound signal segment, that is, whether it is obvious whether there is a complete electromagnetic pulse signal in a segment of the sound signal, and if there is a complete starting segment of the sound signal , then it is determined that the storage condition is triggered, and the sound signal is classified as the first sound signal to be calculated and stored in the storage area.

After the storage is over, the signals stored in the storage area and the circulation storage area are transmitted to the PC host computer for processing.

If after two judgments, there is a sound signal that does not satisfy the two judgment conditions, the address of the sound signal will be reset to zero, and it will be covered by another group of sound signals to avoid affecting the newly read Judgment operation of sound signal.

It should be noted that when the FPGA controller detects that the memory of the storage area is full, the FPGA controller at this time no longer needs to judge and store the subsequently read sound signals, and directly stops the reading operation of the microphone sampling device. , and send multiple groups of sound signals in the storage area to the PC host computer through the signal line for the next step.

In this embodiment, by performing secondary judgment on the read multiple sets of sound signals, the influence of abnormal measurement signals on the measurement results can be avoided, the judgment operation of the system can be effectively improved, and the accuracy of the output nasal airway measurement results can be improved. .

Further, referring to FIG. 6, an embodiment of the present invention provides a nasal airway measurement method, based on the above step S30, the first to-be-calculated sound signal stored in the FPGA controller is sent to the host computer for processing. After the steps of calculating and obtaining the nasal airway measurement results, it also includes:

Step S39, sending the first sound signal to be calculated to the host computer through the FPGA controller;

Step S40, after compressing and reducing the dimension of the first sound signal to be calculated by the PCA dimensionality reduction space method, obtain a first low-dimensional sound signal to be calculated in the dimensionality reduction space;

Step S41, based on a preset ratio, remove abnormal signals from the first low-dimensional sound signal to be calculated that deviate from the center position of the first low-dimensional sound signal to be calculated to obtain a second low-dimensional sound signal to be calculated ;

Step S42, referring to FIG. 9, taking the second low-dimensional sound signal to be calculated as an extraction sample, and performing the sound signal to be calculated corresponding to the second low-dimensional sound signal to be calculated in the first sound signal to be calculated. extraction, to obtain the second sound signal to be calculated;

Aiming at the problems existing in the existing nasal acoustic reflectometer, the present invention proposes to use multiple groups of continuously collected sound signals for data analysis, and use the PCA dimensionality reduction space method to compress and reduce the dimension of the first sound signal to be calculated, and obtain After compressing and reducing the dimension, the first low-dimensional sound signal to be calculated is located in the dimensionality reduction space. As shown in Figure 9, a total of 10 groups of low-dimensional sound signals to be calculated from 0 to 9 are obtained in the compression and dimension reduction, which are preset in this embodiment. Therefore, the three groups of low-dimensional signals to be calculated that are farthest from the center position (ie, the star-shaped signal in the figure) are classified as abnormal signals, and are eliminated, and the remaining low-dimensional acoustic signals to be calculated are eliminated. That is, the second low-dimensional sound signal to be calculated.

The second low-dimensional sound signal to be calculated is used as a control group, and the corresponding sound signal to be calculated is extracted from the first sound signal to be calculated according to the second low-dimensional sound signal to be calculated. For example, as shown in Figure 9, the second low-dimensional sound signal to be calculated The sound signals are 0, 1, 5, 6, 7, 8, and 9, so 0, 1, 5, 6, 7, 8, and 9 in the first sound signal to be calculated are extracted correspondingly as the second sound signal to be calculated. , so as to ensure the stability of the output nasal airway measurement results.

Step S43, splitting the second sound signal to be calculated based on the cross-correlation localization method to obtain the first sound incident wave pulse signal, the first sound echo signal and the baseline signal;

Step S44, removing the baseline signal in the first sound incident wave pulse signal and the first sound echo signal by a compensation method to obtain a second sound incident wave pulse signal and a second sound echo signal;

When the existing nasal acoustic reflectometer processes and calculates the sound signal, it usually directly uses the WA algorithm to process and calculate the sound incident wave pulse signal, but the read sound signal is usually easily affected by external factors and causes WA. The nasal airway measurement results output by the algorithm deviate from the actual values.

Therefore, in combination with the above calculation steps, before calculating the impulse response of the sound incident wave pulse signal, it is necessary to separate the sound incident wave pulse signal and the sound echo signal for the sound signal to be calculated. The waveforms are basically the same, so before the implementation of the present invention, the pre-recorded artificial incident wave sound signal will be used as a reference, and the position where the maximum value appears will be marked as the actual measured initial sound incident wave pulse signal. The distance from the microphone sampling device is fixed. Therefore, the sampling point between the sound incident wave pulse signal and the starting position of the sound echo signal is fixed. As long as the starting position of the sound incident wave pulse signal is determined, it can be determined. The starting position of the sound echo signal, so as to realize the separation of the sound incident wave pulse signal and the sound echo signal.

The formula of the cross-correlation localization method of the sound incident wave pulse signal and the sound echo signal is as follows:

The first sound incident pulse signal and the first sound echo signal both refer to the sound signals separated by the cross-correlation localization method.

It should be noted that the first sound incident wave pulse signal and the first sound echo signal are lost due to the gap between the sound waveguide and the cavity to be measured, so the sound echo signal is lost when the first sound incident is detected. When there is signal loss in the wave pulse signal and the first sound echo signal, the first sound echo signal will be input into the compensation module for sound signal compensation and baseline signal extraction, and the second sound output after compensation is incident The wave pulse signal and the second sound echo signal can enter the next step of processing calculation.

Step S45, performing fast Fourier transform on the second sound incident wave pulse signal and the second sound echo signal based on the fast Fourier transform algorithm to obtain the third sound incident wave pulse signal and the third sound echo signal;

Step S46, calculate the h(t) value of the impulse response based on the third sound incident wave pulse signal and the third sound echo signal, obtain the h(t) value, and average the h(t) value Then, the nasal airway measurement result is obtained by calculation based on the WA algorithm.

After Fourier transform is performed on the second sound incident wave pulse signal and the second sound echo signal based on the fast Fourier transform algorithm, the Fourier transformed third sound incident wave pulse signal and the third sound echo signal are obtained. Then, calculate the impulse response h(t) based on the Fourier-transformed third sound incident wave pulse signal and the third sound echo signal

where the formula for the impulse response h(t) is:

和

分别代表第三声音入射波脉冲信号和第三声音回波信号，*号代表计算去共轭复数，

代表数字滤波器

的数量，而

的数量有快速傅里叶变换的窗口大小确定，

是一个参数，其大小决定了计算得到的h(t)的平滑程度，

值越大，h(t)就越平滑，一般情况下取值在0.1左右。而数字滤波器

的计算公式如下：Among them, in the above formula

and

respectively represent the third sound incident wave pulse signal and the third sound echo signal, and the * sign represents the calculation of the deconjugated complex number,

stands for digital filter

number, while

The number of FFTs is determined by the window size of the fast Fourier transform,

is a parameter whose size determines how smooth the computed h(t) is,

The larger the value, the smoother h(t) is, and the value is generally around 0.1. while the digital filter

The calculation formula is as follows:

，最后，通过WA算法进行计算得到待测腔体的鼻气道横截面积随鼻腔轴向距离变化的情况，即鼻气道测量结果。After the h(t) value is obtained by calculation, it is necessary to average the h(t) value to obtain the average impulse response of this group of test results.

, and finally, the WA algorithm is used to calculate the change of the nasal airway cross-sectional area of the cavity to be measured with the axial distance of the nasal cavity, that is, the nasal airway measurement result.

In this embodiment, by performing the cross-correlation localization method, the PCA dimension reduction space elimination method, the fast Fourier transform algorithm and the WA algorithm on the multiple groups of sound signals stored in the storage area of the FPGA controller in the PC host computer, The problems of low test accuracy and poor anti-interference ability existing in the existing algorithm only using the WA algorithm are avoided, and the stability and test accuracy of the nasal acoustic reflector are improved.

In addition, an embodiment of the present invention also provides a measurement device, the measurement device includes a nasal acoustic reflectometer, a memory, a processor, and a computer program stored on the memory and executable on the processor, the computer The program implements the steps of the nasal airway measurement method described above when executed by the processor.

In addition, the present invention also provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above nasal airway measurement method are implemented.

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or system comprising a series of elements includes not only those elements, It also includes other elements not expressly listed or inherent to such a process, method, article or system. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article or system that includes the element.

The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages or disadvantages of the embodiments.

From the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus a necessary general hardware platform, and of course hardware can also be used, but in many cases the former is better implementation. Based on such understanding, the technical solutions of the present invention can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products are stored in a storage medium (such as ROM/RAM) as described above. , magnetic disk, optical disk), including several instructions to make a terminal device (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) execute the methods described in the various embodiments of the present invention.

The above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields , are similarly included in the scope of patent protection of the present invention.

Claims (10)

1. a nasal acoustic reflector, is characterized in that, described nasal acoustic reflector comprises: host computer; FPGA controller, the FPGA controller establishes a communication connection with the host computer; an electric spark generating device, the electric spark generating device establishes a communication connection with the FPGA controller; a sound wave guide, the sound wave guide is connected with the electric spark generating device; a microphone sampling device disposed in the acoustic waveguide; an FPGA controller, where the FPGA controller establishes a communication connection with the microphone sampling device. 2. A nasal acoustic reflector as claimed in claim 1, wherein the electric spark generating device comprises a control end, a discharge electrode, a first coil, a second coil, a third coil, a fourth coil, a fifth coil coil, first resistor, second resistor, third resistor, fourth resistor, fifth resistor, first diode, second diode, third diode, capacitor, triode and battery; The output end of the control end is connected to one end of the first resistor, the other end of the first resistor is connected to the gate of the second diode, and the negative electrode of the second diode is connected to the negative electrode of the battery , the anode of the battery is connected to the emitter of the triode, the base of the triode is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the second coil, the second The other end of the coil is connected to one end of the second resistor, the other end of the second resistor is connected to the anode of the second diode, and one end of the first coil is connected to the second coil and the second resistor The other end of the first coil is connected to the collector of the triode; One end of the third coil is connected to the third resistor, the other end of the third coil is connected to the anode of the first diode, and the cathode of the first diode is connected to one end of the capacitor , the other end of the capacitor is connected to one end of the fourth coil; The fourth resistor and the fifth resistor are connected in series, the gate of the third diode is connected to the connection point of the fourth resistor and the fifth resistor, and the fourth resistor, the fifth resistor and the third a pole tube is connected in parallel with the fourth coil and the third coil; The fifth coil is opposite to the fourth coil, and the discharge electrode is connected to both ends of the fifth coil; The control terminal is used to receive the preset DC power supply sent by the FPGA controller; The discharge electrode is configured to perform periodic discharge after the control terminal receives the preset DC power supply. 3. A nasal airway measurement method, wherein the nasal airway measurement is applied to the nasal acoustic reflectometer according to any one of claims 1 to 2, and the nasal airway measurement method comprises the following steps: After the start detection signal is detected by the host computer, the electric spark generating device is controlled to perform periodic discharge based on the FPGA controller; Based on the microphone sampling device in the sound wave guide, recording the sound signal generated after the electric spark generating device performs periodic discharge; After the sound signal in the microphone sampling device is read and stored by the FPGA controller, the first sound signal to be calculated stored in the FPGA controller is sent to the host computer for calculation , to obtain nasal airway measurements. 4. The nasal airway measurement method as claimed in claim 3, wherein the step of controlling the electric spark generating device to perform periodic discharge based on the FPGA controller comprises: Based on the FPGA controller applying a preset DC voltage to the control terminal of the electric spark generating device, the discharge electrode of the electric spark generating device is controlled to perform periodic discharge. 5. nasal airway measurement method as claimed in claim 4, is characterized in that, the described step after described sound signal in described microphone sampling device is read and stored by described FPGA controller comprises: The sound signal in the microphone sampling device is read by the FPGA controller; Judging whether the read sound signal is the first to-be-calculated sound signal with an initial portion; If the read sound signal is the first sound signal to be calculated with a starting part, the voltage of the control terminal is pulled down, and the first sound signal to be calculated is stored at the same time; If the read sound signal is not the first to-be-calculated sound signal with the starting part, the high voltage of the control terminal is maintained, and the sound signal is eliminated. 6. The nasal airway measurement method as claimed in claim 5, wherein the step of judging whether the read sound signal is the first sound signal to be calculated with an initial part comprises: Judging whether the address where the sound signal is located belongs to the loop storage area in the memory database of the FPGA controller; If the address at which the sound signal is located belongs to the cyclic storage area in the memory database of the FPGA controller, then it is determined that the sound signal read is the first sound signal to be calculated with an initial portion; If the address where the sound signal is located does not belong to the cyclic storage area in the memory database of the FPGA controller, then determine whether the sound signal triggers a preset storage condition; If the sound signal triggers the preset storage condition, it is determined that the read sound signal is the first to-be-calculated sound signal having a starting part. 7. nasal airway measurement method as claimed in claim 5, is characterized in that, the described first sound signal to be calculated that is stored in described FPGA controller is sent to described host computer to carry out calculation, obtain nasal air The steps for measuring results include: Sending the first sound signal to be calculated to the host computer through the FPGA controller; After compressing and reducing the dimension of the first sound signal to be calculated by the PCA dimensionality reduction space method, a first low-dimensional sound signal to be calculated is obtained in the dimensionality reduction space; Based on the preset ratio, the abnormal signals that deviate from the center position of the first low-dimensional sound signal to be calculated are eliminated from the first low-dimensional sound signal to be calculated to obtain a second low-dimensional sound signal to be calculated; Taking the second low-dimensional sound signal to be calculated as an extraction sample, extracting the to-be-calculated sound signal corresponding to the second low-dimensional to-be-calculated sound signal in the first to-be-calculated sound signal to obtain a second to-be-calculated sound signal. calculate the sound signal; Splitting the second sound signal to be calculated based on the cross-correlation localization method to obtain the first sound incident wave pulse signal, the first sound echo signal and the baseline signal; The baseline signal in the first sound incident wave pulse signal and the first sound echo signal is removed by a compensation method to obtain a second sound incident wave pulse signal and a second sound echo signal; Fast Fourier transform is performed on the second sound incident wave pulse signal and the second sound echo signal based on the fast Fourier transform algorithm to obtain the third sound incident wave pulse signal and the third sound echo signal; Calculate the h(t) value of the impulse response based on the third sound incident wave pulse signal and the third sound echo signal to obtain the h(t) value, and after averaging the h(t) value, based on The WA algorithm performs calculations to obtain the nasal airway measurements. 8. nasal airway measurement method as claimed in claim 7, is characterized in that, after the described step of obtaining nasal airway measurement result, also comprises: The nasal airway measurement result is displayed through the display end of the upper computer. 9. A measuring device, characterized in that, the measuring device comprises the nasal acoustic reflectometer according to any one of claims 1 to 2, a memory, a processor, and a device that is stored on the memory and can run on the processor. A computer program, when the processor executes the computer program, implements the steps of the nasal airway measurement method according to any one of claims 3-8. 10. A computer-readable storage medium, characterized in that, a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the nosepiece described in any one of claims 3-8 is implemented. Steps of the airway measurement method.

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