Photoacoustic signal quality enhancement method and system adopting multi-laser synergistic sound production

Abstract

The invention provides an opto-acoustic signal quality enhancement method and system adopting multi-laser cooperative sound production, and the method comprises the steps: collecting an external sound signal, and converting the collected external sound signal into an electric signal; performing band-pass filtering of different frequencies on the electric signals to obtain filtered electric signals; modulating according to the characteristics of the filtered electric signals to obtain laser control information; and controlling the laser to output laser signals according to the laser control information, and irradiating the plurality of laser signals to the ear position. Two or more acoustic laser beams are adopted to irradiate the ears, and acoustic signals with higher quality are excited in the ears.

Description

Technical Field

[0001] The present invention relates to the field of laser acoustic technology, and in particular to a method and system for enhancing the quality of photoacoustic signals by using multi-laser cooperative acoustic generation. Background Art

[0002] Laser sound technology is a technology that uses lasers to generate sound on specific media. Depending on the sound-generating mechanism, laser sound technology can be divided into three different types: laser thermal expansion sound, vaporization sound, and light breakdown sound.

[0003] Laser thermal expansion-induced sound is the interaction between laser and matter. That is, when the laser irradiates the surface of the material, the photons interact with the molecules of the material, causing the molecules to vibrate. The laser energy is absorbed by the material and converted into heat energy, causing the local temperature of the material to rise. The material undergoes thermal expansion, and this expansion propagates outward in the form of waves, thereby generating sound waves or sound fields.

[0004] The acoustic signal excited by the laser is determined by the laser pulse spectrum function, laser energy, laser spot radius, etc. That is, by adjusting the parameters such as the laser pulse spectrum function, laser energy, laser spot radius, etc., a specific sound can be generated in the medium.

[0005] However, problems may occur in the process of controlling the laser output, that is, the waveform of the laser output cannot be accurately controlled. The main reasons include the working principle of the laser, design complexity, limitations of control technology, influence of environmental factors, etc. The following is a specific analysis of these reasons:

[0006] 1. The complexity of the working principle of the laser makes it impossible to accurately control the waveform of the laser output. The operation of the laser is based on exciting atoms or molecules to an excited state, and then releasing photons through the process of stimulated radiation. This process involves transitions between multiple energy levels and is affected by many factors, such as the stability of the excitation source and the properties of the laser medium. At the same time, the optical cavity in the laser is formed by a reflector, and the photons are reflected and amplified multiple times in the cavity, eventually forming a laser output. In this process, the feedback mechanism of the optical cavity may cause waveform instability. Therefore, the complexity of the working principle of the laser makes it impossible to accurately control the waveform of the laser output.

[0007] 2. The limitations of laser control technology make it impossible to accurately control the waveform of the laser output. Although modern control technology is constantly improving, it still has limitations. For example, the accuracy and response time of the control circuit may affect the precise control of the laser output waveform.

[0008] 3. The influence of environmental factors makes it impossible to accurately control the waveform of the laser output. Lasers are sensitive to temperature changes. Temperature fluctuations may cause changes in the properties of the laser medium, thereby affecting the stability of the output waveform. External vibrations and shocks may cause displacement or damage to the internal components of the laser, thereby affecting the accuracy of the output waveform.

[0009] According to the thermal expansion-induced acoustic mechanism described above, since the waveform of the laser output by the laser cannot be precisely controlled, the acoustic signal excited in the ear by a single laser beam has distortion problems related to the frequency response.

[0010] Therefore, in order to stimulate clearer, more natural, more powerful, and higher-fidelity sound signals in the ears, the accuracy of controlling the laser output waveform must be improved. Summary of the invention

[0011] In view of the defects in the prior art, the object of the present invention is to provide a method and system for enhancing the quality of photoacoustic signals by using multi-laser cooperative sound generation.

[0012] According to the present invention, a photoacoustic signal quality enhancement system using multi-laser cooperative sound generation is provided, comprising:

[0013] Sound collection module: collects external sound signals and converts the collected external sound signals into electrical signals;

[0014] A plurality of different bandpass filters are electrically connected to the sound collection module, and respectively perform bandpass filtering of different frequencies on the electrical signal to obtain filtered electrical signals;

[0015] A plurality of modulators are electrically connected to the bandpass filters in a one-to-one correspondence, and modulate the electrical signal according to the characteristics of the filtered signal to obtain laser control information;

[0016] A plurality of lasers are electrically connected to the modulator in a one-to-one correspondence, and laser signals are generated according to laser control information, and the laser signals are irradiated at the ear position.

[0017] Further, the plurality of different bandpass filters include two: a low frequency bandpass filter and a high frequency bandpass filter.

[0018] Furthermore, the bandwidth parameter of the low-frequency band-pass filter includes 20 Hz-2000 Hz, and the bandwidth parameter of the high-frequency band-pass filter includes 2000 Hz-20000 Hz.

[0019] Furthermore, the multiple laser signals are time-synchronized, or the time difference between the multiple laser signals is smaller than the time difference for ears to distinguish sounds.

[0020] Furthermore, the sound collection module collects external sound signals in a manner including: acquiring a stereo channel signal or a surround channel signal, wherein the stereo channel signal or the surround channel signal includes a plurality of channel signals, and outputting corresponding electrical signals respectively.

[0021] Further, the stereo channel signal includes a left channel signal and a right channel signal, or includes a left channel signal, a right channel signal and a subwoofer signal.

[0022] Further, the surround sound channel signal includes a left channel signal, a center channel signal, a right channel signal, a left surround channel signal, a right surround channel signal and a subwoofer channel signal, or includes a left channel signal, a center channel signal, a right channel signal, a left surround channel signal, a right surround channel signal, a subwoofer channel signal, a side left channel signal, a side right channel signal and a sky channel signal.

[0023] Furthermore, after acquiring the stereo channel signal or the surround sound channel signal, the generated multiple laser signals are irradiated on the corresponding left ear or right ear position.

[0024] Furthermore, the expression of the transfer function H(ω) from laser to acoustic signal is as follows:

[0025]

[0026] In the above formula, e is a natural constant, j is an imaginary unit, r is the distance from the receiving end to the sound source, θ is the observation angle of the receiving end, ω is the laser angular frequency, μ is the laser absorption coefficient of the medium, and a is the radius of the laser spot.

[0027] According to the present invention, a method for enhancing the quality of photoacoustic signals using multi-laser cooperative acoustic generation is provided, comprising:

[0028] Step S1, collecting external sound signals, and converting the collected external sound signals into electrical signals;

[0029] Step S2, performing bandpass filtering of different frequencies on the electrical signal to obtain a filtered electrical signal;

[0030] Step S3, modulating the filtered electrical signals according to their characteristics to obtain laser control information;

[0031] Step S4, controlling the laser to output laser signals according to the laser control information, and irradiating multiple laser signals at the ear position.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention can be applied to laser acoustic hearing aids, or other various voice communication systems using the laser thermal expansion acoustic mechanism, using two or more acoustic laser beams to irradiate the ear, thereby stimulating higher quality acoustic signals in the ear. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0035] Figure 1 is a schematic diagram of a first embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of a second embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of a third embodiment of the present invention;

[0038] Figure 4 FIG. 4 is a schematic diagram of a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0039] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, the present invention provides a photoacoustic signal quality enhancement system using multi-laser collaborative sound generation, including: a sound collection module 1, a low-frequency bandpass filter 21, a high-frequency bandpass filter 22, a modulator 1 31, a modulator 2 32, a laser 1 41 and a laser 2 42.

[0042] The sound collection module 1 collects external sound signals, converts the collected external sound signals into electrical signals, and transmits them to the low-frequency bandpass filter 21 and the high-frequency bandpass filter 22. The sound collection module 1 can use a microphone, which can be a single microphone or a microphone array installed inside the device, or an external wired or wireless microphone.

[0043] The low-frequency bandpass filter 21 performs low-frequency bandpass filtering on the electrical signal, and the bandwidth parameter of the low-frequency bandpass can be adjusted as needed, and the typical value can be selected from 20Hz-2000Hz. The high-frequency bandpass filter 22 performs high-frequency bandpass filtering on the electrical signal, and the bandwidth parameter of the high-frequency bandpass can be adjusted as needed, and the typical value can be selected from 2000Hz-20000Hz.

[0044] Modulator 1 31 performs modulation according to the characteristics of the electrical signal after low-frequency bandpass filtering to obtain first laser control information, and modulator 2 32 performs modulation according to the characteristics of the electrical signal after high-frequency bandpass filtering to obtain second laser control information.

[0045] The process of the controller converting electrical signals into laser control signals includes:

[0046] Step S1, obtaining the electrical signal of the sound signal.

[0047] Step S2: performing time-frequency analysis on the electrical signal.

[0048] Step S3: extracting acoustic signal features according to the time-frequency analysis results.

[0049] Step S4: Generate a control signal by modulating the extracted acoustic signal features.

[0050] Step S5, controlling the laser to output acoustic laser according to the control signal.

[0051] In step S1, the method for acquiring the electrical signal includes receiving the electrical signal in real time, amplifying the signal strength as required, and then outputting the electrical signal to a time-frequency analysis.

[0052] In step S2, the time-frequency analysis method includes analyzing the electrical signal in the time domain and the frequency domain, with the time domain focusing on analyzing the signal strength and the frequency domain focusing on analyzing the signal spectrum, and the maximum processing delay time of this step is 1 millisecond.

[0053] In step S3, the method for extracting the characteristics of the electrical signal includes filtering the acoustic signal, and the filtering range can be set, and the typical value can refer to the normal human hearing range, that is, 20Hz-20000Hz. The characteristics of the filtered electrical signal are extracted, and the characteristics include the start time of the positive pulse of the electrical signal, the time when the positive pulse reaches the maximum amplitude, the maximum amplitude, and the spectrum of the electrical signal, and the maximum amplitude is a voltage value.

[0054] In step S4, the control signal generated by modulation includes a pulse sequence. In the pulse sequence, the start time of each pulse is the start time of the positive pulse of the electrical signal, and the end time is the time when the positive pulse of the electrical signal reaches the maximum amplitude. In the pulse sequence, the amplitude of each pulse is the normalized amplitude of the positive pulse of the electrical signal multiplied by an amplification parameter. The normalized amplitude can be the normalized result of the maximum amplitude of the positive pulse of the electrical signal, the normalized result of the peak signal amplitude on the electrical signal spectrum, or the normalized result of the control voltage corresponding to the maximum output amplitude of the acoustic laser. The amplification parameter is adjusted according to the type of laser that specifically outputs the acoustic laser.

[0055] Laser 1 41 generates a first laser signal 51 according to the first laser control information, and laser 2 42 generates a second laser signal 52 according to the second laser control information. The first laser signal 51 and the second laser signal 52 are irradiated at the ear position of the user 6 (right ear position 61 in the figure). The two beams of acoustic lasers irradiate the human ear in a coordinated manner, which can stimulate a clearer, natural, powerful, and high-fidelity sound signal in the human ear. The first laser signal 51 and the second laser signal 52 must be synchronized in time, and the synchronization time difference must be less than the time difference for the human ear to distinguish sounds (also called the auditory discrimination threshold, a typical value of 50 milliseconds).

[0056] The equation for thermal expansion laser-induced acoustics is as follows:

[0057]

[0058] In the above formula, p is the sound pressure caused by laser thermal expansion, c is the sound speed, and C p is the specific heat capacity of the medium, I(x,y,z,t) is the laser energy absorbed by the medium, where x, y, z are the three-dimensional coordinates of the acoustic signal receiving point, t is the time, and β is the expansion coefficient of the medium.

[0059] The above equation is a partial differential equation. One solution of this equation can be written as follows:

[0060]

[0061] In the above formula, P(ω) is the spectrum intensity of the photoacoustic signal, ω is the laser angular frequency, I0(ω) is the spectrum function of the laser pulse, A is the refractive index of the laser in the medium, P0 is the laser energy, β is the expansion coefficient of the medium, and C p is the specific heat capacity of the medium, H(ω) represents the transfer function from the laser signal to the acoustic signal, and the expression is as follows:

[0062]

[0063] In the above formula, e is a natural constant, j is an imaginary unit, r is the distance from the receiving end to the sound source, θ is the observation angle of the receiving end, ω is the laser angular frequency, μ is the laser absorption coefficient of the medium, and a is the radius of the laser spot.

[0064] Example 2

[0065] like Figure 2As shown, the present invention also provides a photoacoustic signal quality enhancement system using multiple lasers to synergize sound. On the basis of Example 1, more laser signals are used to irradiate the ear position, that is, the bandpass filter also includes other bandpass filters n23 with different bandwidths, and corresponding modulators n33 and lasers n43. More sound-generating lasers irradiate the human ear in a synergistic manner, which can stimulate clearer, more natural, more powerful, and high-fidelity sound signals in the human ear.

[0066] Example 3

[0067] like Figure 3 As shown, the present invention also provides a photoacoustic signal quality enhancement system using multi-laser cooperative sound generation. On the basis of embodiment 1 or embodiment 2, the sound collection module 1 obtains a stereo channel signal. The stereo channel signal includes a 2.0 channel signal and a 2.1 channel signal.

[0068] The 2.0 channel signal includes a left channel signal and a right channel signal, and the 2.1 channel signal includes a left channel signal, a right channel signal and a subwoofer signal. Each signal is configured with a corresponding filter, a modulator and a laser. Taking the 2.1 channel signal as an example, after the right channel signal is filtered, the first laser signal 51 is output to the right ear position 61 via the modulator 1 31 and the laser 1 41, and after the left channel signal is filtered, the third laser signal 53 is output to the left ear position 62 via the modulator 3 33 and the laser 3 43. After the subwoofer signal is filtered, the second laser signal 52 is output to the right ear position 61 via the modulator 2 32 and the laser 2 42, and the fourth laser signal 54 is output to the left ear position 62 via the modulator 4 34 and the laser 4 44, thereby achieving a stereo effect.

[0069] Example 4

[0070] like Figure 4 As shown, the present invention also provides a photoacoustic signal quality enhancement system using multi-laser collaborative sound. On the basis of Example 1 or Example 2, the sound collection module 1 obtains the surround sound channel signal. The surround sound channel signal can be a 5.1 channel signal, a 7.1 channel signal or an advanced version thereof such as 5.1.2, 7.1.4 and other different channel signals. The surround sound channel signal includes a left channel signal, a center channel signal, a right channel signal, a left surround channel signal, a right surround channel signal and a subwoofer channel signal, or includes a left channel signal, a center channel signal, a right channel signal, a left surround channel signal, a right surround channel signal, a subwoofer channel signal, a side left channel signal, a side right channel signal and a sky channel signal. Referring to Example 3, except that the laser signals corresponding to the left channel signal, the right channel signal, the left surround channel signal and the right surround channel signal need to irradiate the corresponding ear positions, the laser signals corresponding to the remaining signals need to irradiate the left and right ear positions at the same time, thereby achieving a surround sound effect.

[0071] The present invention also provides a method for enhancing the quality of photoacoustic signals using multi-laser cooperative sound generation, comprising:

[0072] Step S1, collecting external sound signals, and converting the collected external sound signals into electrical signals.

[0073] Step S2: performing bandpass filtering of different frequencies on the electrical signal to obtain a filtered electrical signal.

[0074] Step S3: modulate the electrical signal according to the characteristics of the filtered signal to obtain laser control information.

[0075] Step S4, controlling the laser to output laser signals according to the laser control information, and irradiating multiple laser signals at the ear position.

[0076] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0077] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A photoacoustic signal quality enhancement system using multi-laser cooperative sound generation, characterized in that: include: Sound collection module: collects external sound signals and converts the collected external sound signals into electrical signals; A plurality of different bandpass filters are electrically connected to the sound collection module, and respectively perform bandpass filtering of different frequencies on the electrical signal to obtain filtered electrical signals; A plurality of modulators are electrically connected to the bandpass filters in a one-to-one correspondence, and modulate the electrical signal according to the characteristics of the filtered signal to obtain laser control information; A plurality of lasers are electrically connected to the modulator in a one-to-one correspondence, and laser signals are generated according to laser control information, and the laser signals are irradiated at the ear position.

2. The photoacoustic signal quality enhancement system using multi-laser cooperative acoustic generation according to claim 1 is characterized in that: The plurality of different bandpass filters include two: a low frequency bandpass filter and a high frequency bandpass filter.

3. The photoacoustic signal quality enhancement system using multi-laser cooperative sounding according to claim 2 is characterized in that: The bandwidth parameters of the low-frequency band-pass filter include 20 Hz-2000 Hz, and the bandwidth parameters of the high-frequency band-pass filter include 2000 Hz-20000 Hz.

4. The photoacoustic signal quality enhancement system using multi-laser cooperative acoustic generation according to claim 1 is characterized in that: The multiple laser signals are time synchronized, or the time difference between the multiple laser signals is smaller than the time difference for the ear to distinguish sound.

5. The photoacoustic signal quality enhancement system using multi-laser cooperative acoustic generation according to claim 1 is characterized in that: The sound collection module collects external sound signals in the following manner: obtaining stereo channel signals or surround channel signals, wherein the stereo channel signals or surround channel signals include multiple channel signals, and outputting corresponding electrical signals respectively.

6. The photoacoustic signal quality enhancement system using multi-laser cooperative acoustic generation according to claim 5 is characterized in that: The stereo channel signal includes a left channel signal and a right channel signal, or includes a left channel signal, a right channel signal and a subwoofer signal.

7. The photoacoustic signal quality enhancement system using multi-laser cooperative sounding according to claim 5 is characterized in that: The surround sound channel signal includes a left channel signal, a center channel signal, a right channel signal, a left surround channel signal, a right surround channel signal and a subwoofer channel signal, or includes a left channel signal, a center channel signal, a right channel signal, a left surround channel signal, a right surround channel signal, a subwoofer channel signal, a side left channel signal, a side right channel signal and a sky channel signal.

8. The photoacoustic signal quality enhancement system using multi-laser cooperative acoustic generation according to claim 5 is characterized in that: After acquiring the stereo channel signal or the surround sound channel signal, the generated multiple laser signals are irradiated on the corresponding left ear or right ear position.

9. The photoacoustic signal quality enhancement system using multi-laser cooperative acoustic generation according to claim 1, characterized in that: The expression of the transfer function H(ω) is as follows: In the above formula, e is a natural constant, j is an imaginary unit, r is the distance from the receiving end to the sound source, θ is the observation angle of the receiving end, ω is the laser angular frequency, μ is the laser absorption coefficient of the medium, and a is the radius of the laser spot.

10. A method for enhancing the quality of photoacoustic signals using multi-laser cooperative sound generation, characterized in that: include: Step S1, collecting external sound signals, and converting the collected external sound signals into electrical signals; Step S2, performing bandpass filtering of different frequencies on the electrical signal to obtain a filtered electrical signal; Step S3, modulating the filtered electrical signals according to their characteristics to obtain laser control information; Step S4, controlling the laser to output laser signals according to the laser control information, and irradiating multiple laser signals at the ear position.

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