Method, device and system for preventing eavesdropping and secret recording in meetings

Abstract

Embodiments of the present invention disclose a method, device, and system for preventing eavesdropping or secret recording in meetings. The method includes any one or more of the following steps: omnidirectionally transmitting N first sound wave signals; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; N is an integer greater than or equal to 1; directionally transmitting a second sound wave signal to one or more of the X audio collectors in the meeting; wherein the first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of a reverse sequence; the reverse sequence is obtained based on N specific signal sequences; and X is an integer greater than or equal to 1. Embodiments of the present invention improve the confidentiality of meeting content.

Description

Technical Field

[0001] The embodiments of the present invention relate to, but are not limited to, the field of communications and video conferencing technology, and in particular to a method, device, and system for preventing eavesdropping and secret recording in a conference. Background Art

[0002] The widespread use of video conferencing equipment has brought significant convenience to users. However, this has also led to new demands for the equipment itself, tailored to specific usage scenarios. The security and confidentiality of meeting content is a pressing issue. Currently, maintaining confidentiality in meetings often relies on manual labor, requiring personnel to conduct a security check of the venue beforehand. However, with technological advancements, eavesdropping and recording devices are becoming smaller and more concealed, making manual inspections difficult to guarantee venue security and confidentiality. Summary of the Invention

[0003] The embodiments of the present invention provide a method, device and system for preventing eavesdropping and secret recording in a conference, which can improve the confidentiality of conference content.

[0004] An embodiment of the present invention provides a method for preventing eavesdropping or secret recording in a conference, comprising any one or more of the following steps:

[0005] Transmitting N first sound wave signals in all directions; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; and N is an integer greater than or equal to 1;

[0006] A second sound wave signal is directionally transmitted toward one or more of the X audio collectors in the conference; wherein the first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is frequency modulated by a reverse sequence; the reverse sequence is obtained based on N specific signal sequences; and X is an integer greater than or equal to 1.

[0007] An embodiment of the present invention provides a device for preventing eavesdropping or secret recording in a meeting, comprising a processor and a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions are executed by the processor, any of the above-mentioned methods for preventing eavesdropping or secret recording in a meeting is implemented.

[0008] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the steps of any of the above-mentioned methods for preventing eavesdropping or secret recording in a conference.

[0009] An embodiment of the present invention provides a device for preventing eavesdropping or secret recording in a conference, comprising any one or more of the following modules: N first transmitting modules, X second transmitting modules; wherein X and N are integers greater than or equal to 1;

[0010] The first transmitting module is configured to transmit one of the N first sound wave signals in an omnidirectional manner; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold;

[0011] The second transmitting module is used to transmit a second sound wave signal directionally to one of the X audio collectors of the conference;

[0012] The first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of the reverse sequence; and the reverse sequence is obtained based on N specific signal sequences.

[0013] An embodiment of the present invention provides a system for preventing eavesdropping and secret recording in a conference, comprising:

[0014] N first transmitting modules and X second transmitting modules; wherein X and N are integers greater than or equal to 1; each first transmitting module and each second transmitting module is an independent device;

[0015] The first transmitting module is configured to transmit one of the N first sound wave signals in an omnidirectional manner; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold;

[0016] The second transmitting module is used to transmit a second sound wave signal directionally to one of the X audio collectors of the conference;

[0017] The first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of the reverse sequence; and the reverse sequence is obtained based on N specific signal sequences.

[0018] An embodiment of the present invention includes any one or more of the following steps: omnidirectionally transmitting N first sound wave signals; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; N is an integer greater than or equal to 1; directionally transmitting a second sound wave signal to each of X audio collectors of the conference; wherein the frequencies of the first sound wave signal and the second sound wave signal are the same and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of a reverse sequence; the reverse sequence is obtained based on the N specific signal sequences; and X is an integer greater than or equal to 1. The embodiment of the present invention transmits N first sound wave signals in all directions. Since the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, the signal-to-noise ratio of any eavesdropping or secretly recording device that may be present in the meeting is low when recording the meeting content, and only a "buzzing" noise can be collected. Therefore, the first sound wave signal shields and interferes with any eavesdropping or secretly recording device that may be present in the meeting, eliminates loopholes caused by human factors, is effective for all audio collectors, and effective meeting content cannot be separated out through post-processing; and, a second sound wave signal is directionally transmitted to the audio collector of the meeting, so that the first sound wave signal and the second sound wave signal cancel each other out at the audio collector of the meeting, thereby achieving active noise reduction and ensuring that the audio collector of the meeting can smoothly collect the meeting content; and, the frequencies of the first sound wave signal and the second sound wave signal are both within a frequency band that is imperceptible to humans; therefore, the confidentiality of the meeting content is improved without affecting the normal progress of the meeting or causing discomfort to the participants.

[0019] Other features and advantages of the embodiments of the present invention will be described in the following description, and in part will become apparent from the description, or may be understood by practicing the embodiments of the present invention. The objectives and other advantages of the embodiments of the present invention can be achieved and obtained through the structures particularly pointed out in the description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the technical solutions of the embodiments of the present invention and constitute a part of the specification. Together with the embodiments of the embodiments of the present invention, they are used to explain the technical solutions of the embodiments of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention.

[0021] Figure 1 A flowchart of a method for preventing eavesdropping or secret recording in a meeting, proposed by one embodiment of the present invention;

[0022] Figure 2 A flowchart of a method for preventing eavesdropping or secret recording in a meeting, proposed in another embodiment of the present invention;

[0023] Figure 3 A flowchart of a method for preventing eavesdropping or secret recording in a meeting, proposed in another embodiment of the present invention;

[0024] Figure 4 A flowchart of a method for preventing eavesdropping or secret recording in a meeting, proposed in another embodiment of the present invention;

[0025] Figure 5 A schematic diagram of the structure of a device for preventing eavesdropping or secret recording in a meeting, according to another embodiment of the present invention;

[0026] FIG6( a ) is a schematic diagram showing the structure of a device for preventing eavesdropping or secret recording in a meeting according to another embodiment of the present invention;

[0027] FIG6( b ) is a schematic diagram showing the structural composition of the interference shielding module and the noise reduction module in FIG6( a );

[0028] FIG7( a ) is a schematic diagram showing the structure of a device for preventing eavesdropping or secret recording in a meeting according to another embodiment of the present invention;

[0029] FIG7( b ) is a schematic diagram showing the structural composition of the interference shielding module and the noise reduction module in FIG7( a );

[0030] FIG8( a ) is a schematic diagram showing the structure of a device for preventing eavesdropping or secret recording in a meeting according to another embodiment of the present invention;

[0031] FIG8( b ) is a schematic diagram showing the structural composition of the interference shielding module and the noise reduction module in FIG8( a );

[0032] FIG9 (a) is a schematic diagram of the arrangement of a system for preventing eavesdropping and secretly recording in a meeting according to an embodiment of the present invention (ie, the anti-secret recording system in the figure). Figure 1 ;

[0033] FIG9( b ) is a schematic diagram of the arrangement of a system for preventing eavesdropping and secret recording in a meeting according to an embodiment of the present invention. Figure 2 ;

[0034] FIG9(c) is a schematic diagram of the arrangement of a system for preventing eavesdropping and secret recording in a meeting according to an embodiment of the present invention. Figure 3 . DETAILED DESCRIPTION

[0035] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the absence of any conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other in any manner.

[0036] The steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions. Also, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be performed in an order different from that shown here.

[0037] See also Figure 1 One embodiment of the present invention provides a method for preventing eavesdropping or secret recording in a meeting, comprising any one or more of the following steps:

[0038] Step 100: omnidirectionally transmit N first sound wave signals; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; N is an integer greater than or equal to 1.

[0039] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0040] In the embodiment of the present invention, the N first sound wave signals may be sent at the same location of the meeting, or may be sent at different locations of the meeting, which is not limited in the embodiment of the present invention.

[0041] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0042] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0043] The embodiment of the present invention uses the first sound wave signal as noise instead of white noise because white noise is random noise generated by random sequence modulation and has randomness, and it is difficult to effectively filter out the white noise.

[0044] Step 101: Directly transmit a second sound wave signal to one or more of X audio collectors in the conference; wherein the first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of a reverse sequence; the reverse sequence is obtained based on N specific signal sequences; and X is an integer greater than or equal to 1.

[0045] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0046] Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

[0047] In an embodiment of the present invention, the reverse sequence is obtained according to N specific signal sequences and includes any one of the following:

[0048] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0049] When N is greater than or equal to 2, according to the formula generating the reverse sequence;

[0050] Wherein, f(t) is the amplitude of the reverse sequence at time t, f i (t) is the amplitude of the i-th specific signal sequence at time t, t is time, d is the distance between the emission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector, and v is the speed of sound propagation in the air.

[0051] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0052] The embodiment of the present invention transmits different first sound wave signals among N first sound wave signals in all directions at different positions of the meeting. Since the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, the signal-to-noise ratio of any eavesdropping or secretly recording device that may be present in the meeting is low when recording the meeting content, and only a "buzzing" noise can be collected. Therefore, the first sound wave signal shields and interferes with any eavesdropping or secretly recording device that may be present in the meeting, eliminates loopholes caused by human factors, is effective for all audio collectors, and effective meeting content cannot be separated out through post-processing; and, a second sound wave signal is directionally transmitted to the audio collector of the meeting, so that the first sound wave signal and the second sound wave signal cancel each other at the audio collector of the meeting, thereby achieving active noise reduction and ensuring that the audio collector of the meeting can smoothly collect the meeting content; and the frequencies of the first sound wave signal and the second sound wave signal are both within a frequency band that is imperceptible to humans; therefore, the confidentiality of the meeting content is improved without affecting the normal progress of the meeting or causing discomfort to the participants.

[0053] See also Figure 2 Another embodiment of the present invention provides a method for preventing eavesdropping and secret recording in a meeting, including any one or more of the following:

[0054] Step 200: Generate N specific signal sequences; for each of the specific signal sequences, modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; and transmit the N first sound wave signals in an omnidirectional manner; wherein the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, and N is an integer greater than or equal to 1.

[0055] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0056] In the embodiment of the present invention, the N first sound wave signals may be sent at the same location of the meeting, or may be sent at different locations of the meeting, which is not limited in the embodiment of the present invention.

[0057] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0058] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0059] Step 201: Generate X reverse sequences based on the N specific signal sequences. For each reverse sequence, modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans. Directively transmit a second sound wave signal to one or more of the X audio collectors of the conference. The first sound wave signal and the second sound wave signal have the same frequency. X is an integer greater than or equal to 1.

[0060] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0061] Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

[0062] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0063] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0064] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0065] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0066] When N is greater than or equal to 2,

[0067] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0068] See also Figure 3 Another embodiment of the present invention provides a method for preventing eavesdropping and secret recording in a meeting, including any one or more of the following:

[0069] Step 300: Generate M specific signal sequences; for each generated specific signal sequence, copy the specific signal sequence into P copies to obtain P specific signal sequences; for each specific signal sequence, modulate the specific signal sequence into the first sound wave signal with a frequency within a frequency band imperceptible to humans; and transmit N first sound wave signals in all directions; wherein, the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, M and P are integers greater than or equal to 1, and M×P=N.

[0070] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0071] In the embodiment of the present invention, the N first sound wave signals may be sent at the same location of the meeting, or may be sent at different locations of the meeting, which is not limited in the embodiment of the present invention.

[0072] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0073] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0074] Step 301: Generate X reverse sequences based on the N specific signal sequences. For each reverse sequence, modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans. Directively transmit a second sound wave signal to one or more of the X audio collectors of the conference. The first sound wave signal and the second sound wave signal have the same frequency. X is an integer greater than or equal to 1.

[0075] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0076] Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

[0077] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0078] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0079] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0080] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0081] When N is greater than or equal to 2,

[0082] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0083] See also Figure 4Another embodiment of the present invention provides a method for preventing eavesdropping and secret recording in a meeting, including any one or more of the following:

[0084] Step 400: Generate M specific signal sequences; for each generated specific signal sequence, modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; for each first sound wave signal, copy the first sound wave signal into P parts to obtain P first sound wave signals; and transmit N first sound wave signals in all directions; wherein, the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, M and P are integers greater than or equal to 1, and M×P=N.

[0085] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0086] In the embodiment of the present invention, the N first sound wave signals may be sent at the same location of the meeting, or may be sent at different locations of the meeting, which is not limited in the embodiment of the present invention.

[0087] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0088] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0089] Step 401: Generate X reverse sequences based on the N specific signal sequences. For each reverse sequence, modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans. Directively transmit a second sound wave signal to one or more of the X audio collectors of the conference. The first sound wave signal and the second sound wave signal have the same frequency. X is an integer greater than or equal to 1.

[0090] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0091] Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

[0092] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0093] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0094] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0095] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0096] When N is greater than or equal to 2,

[0097] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0098] Another embodiment of the present invention provides a device for preventing eavesdropping or secret recording in a meeting, including a processor and a computer-readable storage medium. The computer-readable storage medium stores instructions. When the instructions are executed by the processor, any of the above-mentioned methods for preventing eavesdropping or secret recording in a meeting is implemented.

[0099] Another embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the steps of any of the above-mentioned methods for preventing eavesdropping or secret recording in a meeting.

[0100] See also Figure 5 Another embodiment of the present invention provides a device for preventing eavesdropping and secret recording in a conference, comprising any one or more of the following modules: N first transmitting modules, X second transmitting modules; wherein X and N are integers greater than or equal to 1;

[0101] The first transmitting module 501 is configured to transmit one of the N first sound wave signals in all directions; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold;

[0102] The second transmitting module 502 is used to transmit a second sound wave signal in a directionally directed manner to one of the X audio collectors of the conference; wherein the first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of a reverse sequence; and the reverse sequence is obtained based on N specific signal sequences.

[0103] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0104] In the embodiment of the present invention, different first transmitting modules may be located at the same location of the meeting or at different locations of the meeting; different second transmitting modules may be located at the same location of the meeting or at different locations of the meeting.

[0105] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0106] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0107] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0108] Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

[0109] In an embodiment of the present invention, the reverse sequence is obtained according to N specific signal sequences and includes any one of the following:

[0110] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0111] When N is greater than or equal to 2, according to the formula generating the reverse sequence;

[0112] Wherein, f(t) is the amplitude of the reverse sequence at time t, f i (t) is the amplitude of the i-th specific signal sequence at time t, t is time, d is the distance between the emission position of the second sound wave signal and the audio collector, d iis the distance between the emission position of the i-th first sound wave signal and the audio collector, and v is the speed of sound propagation in the air.

[0113] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0114] The embodiment of the present invention transmits different first sound wave signals among N first sound wave signals in all directions at different positions of the meeting. Since the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, the signal-to-noise ratio of any eavesdropping or secretly recording device that may be present in the meeting is low when recording the meeting content, and only a "buzzing" noise can be collected. Therefore, the first sound wave signal shields and interferes with any eavesdropping or secretly recording device that may be present in the meeting, eliminates loopholes caused by human factors, is effective for all audio collectors, and effective meeting content cannot be separated out through post-processing; and, a second sound wave signal is directionally transmitted to the audio collector of the meeting, so that the first sound wave signal and the second sound wave signal cancel each other at the audio collector of the meeting, thereby achieving active noise reduction and ensuring that the audio collector of the meeting can smoothly collect the meeting content; and the frequencies of the first sound wave signal and the second sound wave signal are both within a frequency band that is imperceptible to humans; therefore, the confidentiality of the meeting content is improved without affecting the normal progress of the meeting or causing discomfort to the participants.

[0115] 6( a ), another embodiment of the present invention provides a device for preventing eavesdropping and secret recording in a meeting, comprising any one or more of the following modules: N interference shielding modules 601 , X noise reduction modules 602 ;

[0116] As shown in FIG6( b ), each interference shielding module 601 includes: a signal generating module 6011, a first sound wave modulation module 6012, and a first transmitting module 6013; each noise reduction module 602 includes: a reverse signal generating module 6021, a second sound wave modulation module 6022, and a second transmitting module 6023;

[0117] The signal generating module 6011 is configured to generate a specific signal sequence; wherein the average amplitude of the specific signal sequence is greater than or equal to a preset threshold;

[0118] The first sound wave modulation module 6012 is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans;

[0119] The first transmitting module 6013 is configured to transmit one first sound wave signal among N first sound wave signals in all directions;

[0120] The reverse signal generating module 6021 is configured to generate the reverse sequence according to the N specific signal sequences;

[0121] The second sound wave modulation module 6022 is used to modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans;

[0122] The second transmitting module 6023 is configured to transmit a second sound wave signal directionally to one of the X audio collectors in the conference.

[0123] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0124] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0125] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0126] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0127] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0128] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0129] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0130] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0131] When N is greater than or equal to 2,

[0132] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0133] In the embodiment of the present invention, the signal generating module 6011 may send a specific signal sequence to the reverse signal generating module 6021 in a wired or wireless manner.

[0134] 7( a ), another embodiment of the present invention provides a device for preventing eavesdropping or secret recording in a conference, comprising any one or more of the following modules: M interference shielding modules 701 , X noise reduction modules 702 ;

[0135] As shown in FIG7( b ), each interference shielding module 701 includes: a signal generating module 7011, P first sound wave modulation modules 7012 and P first transmitting modules 7013; each noise reduction module 702 includes: a reverse signal generating module 7021, a second sound wave modulation module 7022 and a second transmitting module 7023;

[0136] The signal generating module 7011 is configured to generate a specific signal sequence; for each generated specific signal sequence, the specific signal sequence is copied into P copies to obtain P specific signal sequences; wherein P is an integer greater than or equal to 1, and M×P=N;

[0137] The first sound wave modulation module 7012 is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans;

[0138] The first transmitting module 7013 is configured to transmit one first sound wave signal among N first sound wave signals in all directions;

[0139] The reverse signal generating module 7021 is configured to generate the reverse sequence according to the N specific signal sequences;

[0140] The second sound wave modulation module 7022 is used to modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans;

[0141] The second transmitting module 7023 is configured to transmit a second sound wave signal directionally to one of the X audio collectors in the conference.

[0142] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0143] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0144] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0145] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0146] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0147] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0148] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0149] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0150] When N is greater than or equal to 2,

[0151] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0152] In the embodiment of the present invention, the signal generating module 7011 may send a specific signal sequence to the reverse signal generating module 7021 in a wired or wireless manner.

[0153] 8( a ), another embodiment of the present invention provides a device for preventing eavesdropping or secret recording in a conference, comprising any one or more of the following modules: M interference shielding modules 801 , X noise reduction modules 802 ;

[0154] As shown in FIG8( b ), each interference shielding module 801 includes: a signal generating module 8011, a first sound wave modulation module 8012 and P first transmitting modules 8013; each noise reduction module 802 includes: a reverse signal generating module 8021, a second sound wave modulation module 8022 and a second transmitting module 8023;

[0155] The signal generating module 8011 is configured to generate a specific signal sequence;

[0156] The first sound wave modulation module 8012 is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; for each first sound wave signal, the first sound wave signal is replicated into P copies to obtain P sound wave signals; where P is an integer greater than or equal to 1, and M×P=N;

[0157] The first transmitting module 8013 is configured to transmit one first sound wave signal among N first sound wave signals in all directions;

[0158] The reverse signal generating module 8021 is configured to generate the reverse sequence according to the N specific signal sequences;

[0159] The second sound wave modulation module 8022 is configured to modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans;

[0160] The second transmitting module 8023 is configured to transmit a second sound wave signal directionally to one of the X audio collectors in the conference.

[0161] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0162] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0163] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0164] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0165] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0166] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0167] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0168] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0169] When N is greater than or equal to 2,

[0170] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0171] In the embodiment of the present invention, the signal generating module 8011 may send a specific signal sequence to the reverse signal generating module 8021 in a wired or wireless manner.

[0172] See also Figure 5 Another embodiment of the present invention provides a system for preventing eavesdropping and secret recording in a meeting, comprising:

[0173] N first transmitting modules 501 and X second transmitting modules 502; wherein different first transmitting modules are located at different locations in the conference; X and N are integers greater than or equal to 1; each first transmitting module is an independent device, and each second transmitting module is an independent device;

[0174] The first transmitting module 501 is configured to transmit one of the N first sound wave signals in all directions; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold;

[0175] The second transmitting module 502 is configured to transmit a second sound wave signal directionally to one of the X audio collectors of the conference;

[0176] The first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of the reverse sequence; and the reverse sequence is obtained based on N specific signal sequences.

[0177] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0178] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0179] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0180] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0181] Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

[0182] In an embodiment of the present invention, the reverse sequence is obtained according to N specific signal sequences and includes any one of the following:

[0183] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0184] When N is greater than or equal to 2, according to the formula generating the reverse sequence;

[0185] Wherein, f(t) is the amplitude of the reverse sequence at time t, f i (t) is the amplitude of the i-th specific signal sequence at time t, t is time, d is the distance between the emission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector, and v is the speed of sound propagation in the air.

[0186] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0187] The embodiment of the present invention transmits N first sound wave signals in all directions. Since the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold, the signal-to-noise ratio of any eavesdropping or secretly recording device that may be present in the meeting is low when recording the meeting content, and only a "buzzing" noise can be collected. Therefore, the first sound wave signal shields and interferes with any eavesdropping or secretly recording device that may be present in the meeting, eliminates loopholes caused by human factors, is effective for all audio collectors, and effective meeting content cannot be separated out through post-processing; and, a second sound wave signal is directionally transmitted to the audio collector of the meeting, so that the first sound wave signal and the second sound wave signal cancel each other out at the audio collector of the meeting, thereby achieving active noise reduction and ensuring that the audio collector of the meeting can smoothly collect the meeting content; and, the frequencies of the first sound wave signal and the second sound wave signal are both within a frequency band that is imperceptible to humans; therefore, the confidentiality of the meeting content is improved without affecting the normal progress of the meeting or causing discomfort to the participants.

[0188] 6( a ), another embodiment of the present invention provides a system for preventing eavesdropping and secret recording in a conference, comprising: N interference shielding modules 601 and X noise reduction modules 602 ; wherein each interference shielding module is an independent device, and each noise reduction module is an independent device;

[0189] As shown in FIG6( b ), each interference shielding module 601 includes: a signal generating module 6011, a first sound wave modulation module 6012, and a first transmitting module 6013; each noise reduction module 602 includes: a reverse signal generating module 6021, a second sound wave modulation module 6022, and a second transmitting module 6023;

[0190] The signal generating module 6011 is configured to generate a specific signal sequence; wherein the average amplitude of the specific signal sequence is greater than or equal to a preset threshold;

[0191] The first sound wave modulation module 6012 is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans;

[0192] The first transmitting module 6013 is configured to transmit one first sound wave signal among N first sound wave signals in all directions;

[0193] The reverse signal generating module 6021 is configured to generate the reverse sequence according to the N specific signal sequences;

[0194] The second sound wave modulation module 6022 is used to modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans;

[0195] The second transmitting module 6023 is configured to transmit a second sound wave signal directionally to one of the X audio collectors in the conference.

[0196] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0197] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0198] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0199] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0200] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0201] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0202] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0203] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0204] When N is greater than or equal to 2,

[0205] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0206] In the embodiment of the present invention, the signal generating module 6011 may send a specific signal sequence to the reverse signal generating module 6021 in a wired or wireless manner.

[0207] 7( a ), another embodiment of the present invention provides a system for preventing eavesdropping and secret recording in a conference, comprising: M interference shielding modules 701 and X noise reduction modules 702 ; wherein each interference shielding module is an independent device, and each noise reduction module is an independent device;

[0208] As shown in FIG7( b ), each interference shielding module 701 includes: a signal generating module 7011, P first sound wave modulation modules 7012 and P first transmitting modules 7013; each noise reduction module 702 includes: a reverse signal generating module 7021, a second sound wave modulation module 7022 and a second transmitting module 7023;

[0209] The signal generating module 7011 is configured to generate a specific signal sequence; for each generated specific signal sequence, the specific signal sequence is copied into P copies to obtain P specific signal sequences; wherein P is an integer greater than or equal to 1, and M×P=N;

[0210] The first sound wave modulation module 7012 is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans;

[0211] The first transmitting module 7013 is configured to transmit one first sound wave signal among N first sound wave signals in all directions;

[0212] The reverse signal generating module 7021 is configured to generate the reverse sequence according to the N specific signal sequences;

[0213] The second sound wave modulation module 7022 is used to modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans;

[0214] The second transmitting module 7023 is configured to transmit a second sound wave signal directionally to one of the X audio collectors in the conference.

[0215] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0216] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0217] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0218] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0219] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0220] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0221] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0222] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0223] When N is greater than or equal to 2,

[0224] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0225] In the embodiment of the present invention, the signal generating module 7011 may send a specific signal sequence to the reverse signal generating module 7021 in a wired or wireless manner.

[0226] 8( a ), another embodiment of the present invention provides a system for preventing eavesdropping and secret recording in a conference, comprising: M interference shielding modules 801 and X noise reduction modules 802 ; wherein each interference shielding module is an independent device, and each noise reduction module is an independent device;

[0227] As shown in FIG8( b ), each interference shielding module 801 includes: a signal generating module 8011, a first sound wave modulation module 8012 and P first transmitting modules 8013; each noise reduction module 802 includes: a reverse signal generating module 8021, a second sound wave modulation module 8022 and a second transmitting module 8023;

[0228] The signal generating module 8011 is configured to generate a specific signal sequence;

[0229] The first sound wave modulation module 8012 is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; for each first sound wave signal, the first sound wave signal is replicated into P copies to obtain P sound wave signals; where P is an integer greater than or equal to 1, and M×P=N;

[0230] The first transmitting module 8013 is configured to transmit one first sound wave signal among N first sound wave signals in all directions;

[0231] The reverse signal generating module 8021 is configured to generate the reverse sequence according to the N specific signal sequences;

[0232] The second sound wave modulation module 8022 is configured to modulate the reverse sequence into the second sound wave signal having a frequency within a frequency band imperceptible to humans;

[0233] The second transmitting module 8023 is configured to transmit a second sound wave signal directionally to one of the X audio collectors in the conference.

[0234] In the embodiment of the present invention, the conference may refer to a video conference or a non-video conference.

[0235] In the embodiment of the present invention, performing frequency modulation is performing spectrum shifting, that is, shifting the spectrum of a specific signal sequence to a frequency band that is imperceptible to humans.

[0236] In the embodiment of the present invention, the specific signal sequence may be, for example, a sine sequence or a square wave sequence, or a random sequence. The present invention does not limit the specific form of the specific signal sequence.

[0237] In this embodiment of the present invention, the transmission power of the second acoustic wave signal is:

[0238] In an embodiment of the present invention, generating X reverse sequences based on N specific signal sequences may be generating one reverse sequence based on N specific signal sequences and then copying the generated reverse sequence into X parts; or, for each reverse sequence, generating a reverse sequence based on N specific signal sequences; or, generating A reverse sequences based on N specific signal sequences and then copying each of the A generated reverse sequences into B parts, A×B=X.

[0239] Generating A reverse sequences according to N specific signal sequences means that for each reverse sequence, a reverse sequence is generated according to N specific signal sequences.

[0240] Generating a reverse sequence according to N specific signal sequences includes any one of the following:

[0241] When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign;

[0242] When N is greater than or equal to 2,

[0243] In the embodiment of the present invention, the frequency imperceptible to humans includes any one or more of the following: 0-20 Hz, and above 20 kHz.

[0244] In the embodiment of the present invention, the signal generating module 8011 may send a specific signal sequence to the reverse signal generating module 8021 in a wired or wireless manner.

[0245] For example, as shown in FIG9( a ), a system for preventing eavesdropping or secretly recording in a meeting (ie, the anti-secret recording system in the figure) is arranged in the meeting.

[0246] For another example, as shown in FIG9( b ), multiple interference shielding modules, a noise reduction module, and an audio collector are arranged in a conference. The noise reduction module is bound to the audio collector, and the noise reduction module transmits a second sound wave signal directionally toward the audio collector.

[0247] For another example, as shown in FIG9(c), multiple interference shielding modules, multiple noise reduction modules and multiple audio collectors are provided in the conference step, each noise reduction module is bound to an audio collector, and the noise reduction module transmits a second sound wave signal in a direction toward the audio collector with the binding relationship.

[0248] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As is well known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable, and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those skilled in the art that communication media generally embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0249] Although the embodiments disclosed in the embodiments of the present invention are as described above, the contents described are only embodiments adopted to facilitate understanding of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Any person skilled in the art in the field to which the embodiments of the present invention belong may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the embodiments of the present invention. However, the scope of patent protection of the embodiments of the present invention shall still be based on the scope defined by the attached claims.

Claims

1. A method for preventing eavesdropping and secret recording in a meeting, comprising any one or more of the following steps: N first sound wave signals are transmitted in all directions; wherein, For each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; N is an integer greater than or equal to 1; Directively transmitting a second sound wave signal to one or more of the X audio collectors of the conference, so that the N first sound wave signals and the second sound wave signal can cancel each other out at the audio collector; wherein the first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of an inverse sequence; the inverse sequence is obtained based on N specific signal sequences; and X is an integer greater than or equal to 1. The reverse sequence is obtained according to N specific signal sequences and includes any one of the following: When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign; When N is greater than or equal to 2, according to the formula generating the reverse sequence; Wherein, f(t) is the amplitude of the reverse sequence at time t, f i (t) is the amplitude of the i-th specific signal sequence at time t, t is time, d is the distance between the emission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector, and v is the speed of sound propagation in the air.

2. The method according to claim 1, characterized in that in, The first sound wave signal is generated by any of the following methods: Generate N specific signal sequences; for each specific signal sequence, modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; Generate M specific signal sequences; for each generated specific signal sequence, copy the specific signal sequence into P copies to obtain P specific signal sequences; for each specific signal sequence, modulate the specific signal sequence into the first sound wave signal with a frequency within a frequency band imperceptible to humans; wherein M and P are integers greater than or equal to 1, and M×P=N; Generate M specific signal sequences; for each generated specific signal sequence, modulate the specific signal sequence into the first sound wave signal with a frequency within a frequency band imperceptible to humans; for each first sound wave signal, copy the first sound wave signal into P parts to obtain P first sound wave signals; wherein M and P are integers greater than or equal to 1, and M×P=N.

3. The method according to claim 1, characterized in that in, The second sound wave signal is generated in the following manner: X reverse sequences are generated according to N specific signal sequences, and each reverse sequence is modulated into the second sound wave signal having a frequency within a frequency band imperceptible to humans.

4. The method according to any one of claims 1 to 3, characterized in that in, The transmission power of the second sound wave signal is: Wherein, P is the transmission power of the second sound wave signal, P i is the transmission power of the i-th first sound wave signal, α is the attenuation coefficient, d is the distance between the transmission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector.

5. The method according to any one of claims 1 to 3, characterized in that in, The frequencies imperceptible to humans include any one or more of the following: 0-20 Hz, and above 20 kHz.

6. A device for preventing eavesdropping or secret recording in a meeting, comprising a processor and a computer-readable storage medium, wherein the computer-readable storage medium stores instructions, characterized in that: When the processor executes the instruction, the method for preventing eavesdropping or secret recording in a meeting according to any one of claims 1 to 5 is implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for preventing eavesdropping or secret recording in a meeting as claimed in any one of claims 1 to 5 are implemented.

8. A device for preventing eavesdropping or secret recording in a meeting, comprising any one or more of the following modules: N first transmitting modules, X second transmitting modules; wherein: X, N are integers greater than or equal to 1; The first transmitting module is configured to transmit one of the N first sound wave signals in an omnidirectional manner; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; The second transmitting module is used to transmit a second sound wave signal directionally to one of the X audio collectors of the conference, so that the N first sound wave signals and the second sound wave signal can cancel each other out at the audio collector; The first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of a reverse sequence; and the reverse sequence is obtained based on N specific signal sequences; The reverse sequence is obtained according to N specific signal sequences and includes any one of the following: When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign; When N is greater than or equal to 2, according to the formula generating the reverse sequence; Wherein, f(t) is the amplitude of the reverse sequence at time t, f i (t) is the amplitude of the i-th specific signal sequence at time t, t is time, d is the distance between the emission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector, and v is the speed of sound propagation in the air.

9. The device according to claim 8, characterized in that It also includes any one or more of the following modules: N signal generation modules and N first sound wave modulation modules; X reverse signal generation modules and X second sound wave modulation modules; Wherein, the signal generating module is used to generate the specific signal sequence; The first sound wave modulation module is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; The reverse signal generating module is configured to generate the reverse sequence according to the N specific signal sequences; The second sound wave modulation module is used to modulate the reverse sequence into the second sound wave signal with a frequency within a frequency band imperceptible to humans.

10. The device according to claim 8, characterized in that It also includes any one or more of the following modules: M signal generation modules and N first sound wave modulation modules; X reverse signal generation modules and X second sound wave modulation modules; The signal generation module is configured to generate a specific signal sequence; for each generated specific signal sequence, the specific signal sequence is copied into P copies to obtain P specific signal sequences; wherein P is an integer greater than or equal to 1, and M×P=N; The first sound wave modulation module is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; The reverse signal generating module is configured to generate the reverse sequence according to the N specific signal sequences; The second sound wave modulation module is used to modulate the reverse sequence into the second sound wave signal with a frequency within a frequency band imperceptible to humans.

11. The device according to claim 8, characterized in that It also includes any one or more of the following modules: M signal generation modules and M first sound wave modulation modules; X reverse signal generation modules and X second sound wave modulation modules; Wherein, the signal generating module is used to generate the specific signal sequence; The first sound wave modulation module is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; for each of the first sound wave signals, the first sound wave signal is copied into P copies to obtain P sound wave signals; wherein P is an integer greater than or equal to 1, and M×P=N; The reverse signal generating module is configured to generate the reverse sequence according to the N specific signal sequences; The second sound wave modulation module is used to modulate the reverse sequence into the second sound wave signal with a frequency within a frequency band imperceptible to humans.

12. A system for preventing eavesdropping and secret recording during a meeting, comprising: N first transmitting modules and X second transmitting modules; wherein X and N are integers greater than or equal to 1; each first transmitting module and each second transmitting module is an independent device; The first transmitting module is configured to transmit one of the N first sound wave signals in an omnidirectional manner; wherein, for each first sound wave signal, the first sound wave signal is obtained by frequency modulation of a specific signal sequence, and the average amplitude of the specific signal sequence is greater than or equal to a preset threshold; The second transmitting module is used to transmit a second sound wave signal directionally to one of the X audio collectors of the conference, so that the N first sound wave signals and the second sound wave signal can cancel each other out at the audio collector; The first sound wave signal and the second sound wave signal have the same frequency and are within a frequency band imperceptible to humans; the second sound wave signal is obtained by frequency modulation of a reverse sequence; and the reverse sequence is obtained based on N specific signal sequences; The reverse sequence is obtained according to N specific signal sequences and includes any one of the following: When N is 1, the absolute values ​​of the amplitudes of the reverse sequence and the specific signal sequence at any time are equal and opposite in sign; When N is greater than or equal to 2, according to the formula generating the reverse sequence; Wherein, f(t) is the amplitude of the reverse sequence at time t, f i (t) is the amplitude of the i-th specific signal sequence at time t, t is time, d is the distance between the emission position of the second sound wave signal and the audio collector, d i is the distance between the emission position of the i-th first sound wave signal and the audio collector, and v is the speed of sound propagation in the air.

13. The system according to claim 12, wherein: Also includes: N signal generating modules and N first sound wave modulation modules; X reverse signal generating modules and X second sound wave modulation modules; Wherein, the signal generating module is used to generate the specific signal sequence; The first sound wave modulation module is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; The reverse signal generating module is configured to generate the reverse sequence according to the N specific signal sequences; The second sound wave modulation module is used to modulate the reverse sequence into the second sound wave signal with a frequency within a frequency band imperceptible to humans.

14. The system according to claim 12, wherein: Also includes: M signal generation modules and N first sound wave modulation modules; X reverse signal generation modules and X second sound wave modulation modules; The signal generation module is configured to generate a specific signal sequence; for each generated specific signal sequence, the specific signal sequence is copied into P copies to obtain P specific signal sequences; wherein P is an integer greater than or equal to 1, and M×P=N; The first sound wave modulation module is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; The reverse signal generating module is configured to generate the reverse sequence according to the N specific signal sequences; The second sound wave modulation module is used to modulate the reverse sequence into the second sound wave signal with a frequency within a frequency band imperceptible to humans.

15. The system according to claim 12, wherein: Also includes: M signal generation modules and M first sound wave modulation modules; X reverse signal generation modules and X second sound wave modulation modules; Wherein, the signal generating module is used to generate the specific signal sequence; The first sound wave modulation module is configured to modulate the specific signal sequence into the first sound wave signal having a frequency within a frequency band imperceptible to humans; for each of the first sound wave signals, the first sound wave signal is copied into P copies to obtain P sound wave signals; wherein P is an integer greater than or equal to 1, and M×P=N; The reverse signal generating module is configured to generate the reverse sequence according to the N specific signal sequences; The second sound wave modulation module is used to modulate the reverse sequence into the second sound wave signal with a frequency within a frequency band imperceptible to humans.

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