KR20210026239A - Method and device for preventing unauthorized audio recording, and method and device for restoring original recording - Google Patents

Abstract

According to one embodiment of the present invention, a recording prevention method performed by a recording prevention device preventing unauthorized voice recording, includes the following steps of: transmitting original noise information to a user terminal agreeing with voice recording; generating an original noise within an audible frequency band based the original noise information; modulating the original noise into a set frequency set with a frequency band higher than the audible frequency band, through a modulator; and outputting the modulated original noise through an ultrasonic speaker. Moreover, according to another embodiment of the present invention, a method of restoring a recording through a recording restoration program installed in a user terminal includes the following steps of: receiving original noise information from a recording prevention device preventing recording; recording a noise outputted from the recording prevention device and a neighboring voice through a recorder of the user terminal; removing the noise from the voice recorded in the step by using the received original noise information; and storing the denoised voice.

Description

A recording blocking method and device to block unauthorized voice recording, and a recording restoration method and device for restoring the sound modulated by the method and device {METHOD AND DEVICE FOR PREVENTING UNAUTHORIZED AUDIO RECORDING, AND METHOD AND DEVICE FOR RESTORING ORIGINAL RECORDING}

The present invention relates to a recording prevention technology, and more particularly, the present invention is a recording blocking device using an ultrasonic generator so that a user with normal authority can restore the original voice by removing noise added by the recording blocking method and device. It relates to a method and apparatus. In addition, the present invention relates to a recording restoration method and apparatus for allowing a user with normal authority to restore an original voice by removing noise added by a recording blocking method and apparatus.

While the convenience of living has increased due to the development of information and communication technology, social problems due to information leakage are also emerging. With the development of various wireless communication devices and the use of various illegal eavesdroppers and hidden cameras that abuse them, there are many cases of infringing on personal privacy and human rights, and abnormal information leakage has become a serious social problem. The government is making efforts to prevent abnormal information leakage through legal regulations or policies, and there are cases where individuals use detection equipment to detect various eavesdropping devices.

In the existing technology to prevent eavesdropping to prevent abnormal information leakage, there is a method of preventing eavesdropping by a masking effect that outputs a frequency near an audible frequency of 20 kHz with a certain strength or more.

In addition, among the existing eavesdropping prevention technologies, there is a technology that prevents eavesdropping by generating acoustic waves of 23 kHz to 27 kHz in the air at a high sound pressure of about 110 dB in order to prevent being affected by high-frequency noise in the audible frequency domain.

Although such an eavesdropping prevention technology restricts an unspecified number of recordings for copyright protection and confidentiality, it is necessary to permit the recording of a party or a specific user. However, the conventional eavesdropping prevention technology has a problem in that it is not possible to record the user's own voice as well as others.

Republic of Korea Patent Registration No. 10-0901772 (Name of invention: device for preventing eavesdropping through speaker)

The present invention is to solve the above-described problems, and it is an object of the present invention to provide a recording blocking method and apparatus capable of easily blocking an act of unauthorized recording of a voice by a user who has not received prior consent in a situation such as a conversation or lecture. It is done.

In addition, it is an object of the present invention to provide a recording restoration method and apparatus capable of restoring an original voice by removing noise added for blocking recording by the recording blocking method and apparatus of the present invention.

However, the technical problem to be achieved by the present embodiment is not limited to the technical problem as described above, and other technical problems may exist.

As a technical means for achieving the above-described technical problem, the recording blocking method performed by the recording blocking device for blocking unconsent voice recording according to the first embodiment of the present invention includes original noise information to a user terminal that has consented to voice recording. Transmitting; Generating original noise in an audible frequency band based on the original noise information; Modulating the original noise to a set frequency set to a higher frequency band than the audible frequency band through a modulator; And outputting the modulated original noise through the ultrasonic speaker.

In addition, a recording restoration method through a recording restoration program installed in a user terminal according to a second embodiment of the present invention includes: receiving original noise information from a recording blocking device that blocks recording; Recording the surrounding voice and noise output from the recording blocking device through a recorder of the user terminal; Removing noise from the voice recorded in the step by using the received original noise information; And storing the sound from which the noise has been removed. In this case, the recording blocking device is a device that generates original noise in an audible frequency band based on the original noise information, modulates the original noise to a set frequency set to a higher frequency band than the audible frequency band, and outputs it through an ultrasonic speaker.

The recording blocking device for blocking unauthorized voice recording according to the third embodiment of the present invention includes a communication module, a processor, and a memory in which a recording blocking program is stored, and the processor records through the communication module according to the execution of the recording blocking program. The original noise information is transmitted to the user terminal of the user who has agreed to, and based on the original noise information, the original noise is generated within the audible frequency band, and the original noise is modulated to a set frequency set to a higher frequency band than the audible frequency band through a modulator. And, by outputting the modulated original noise through an ultrasonic speaker, the recording is blocked.

An apparatus for restoring a recording through a recording restoration program according to a fourth embodiment of the present invention includes: a recorder for recording voice; A memory in which a recording restoration restoration program is stored; And a processor that executes a program stored in the memory, wherein the processor receives original noise information from the recording blocking device according to the execution of the speech signal restoration program, and records surrounding voices and noise output from the recording blocking device through a recorder. And, by removing the noise from the recorded voice using the received original noise information, the voice from which the noise has been removed is restored. The recording cut-off device generates original noise in an audible frequency band based on information about the original noise, modulates the original noise to a set frequency set to a higher frequency band than the audible frequency band, and outputs it through an ultrasonic speaker.

According to any one of the above-described problem solving means, the original noise modulated by the recording blocking device, that is, the high frequency noise is recorded on a recording device located in the recording blocking area by the recording blocking device according to the magnitude of the high frequency noise in the inaudible band Unauthorized recording by users who disagree with recording can be disabled.

In addition, the present invention can restore the original sound to be recorded by removing the high-frequency noise by the recording blocking device based on the original noise information shared with each other in the recording restoration device of the user who agreed to record in advance.

1 is a block diagram illustrating a configuration of a recording blocking device and a restoration device according to an embodiment of the present invention.
2 is a flowchart illustrating a method of blocking and restoring recording according to an embodiment of the present invention.
3A is a diagram illustrating a process of sharing original noise information between a recording blocking device and a recording restoration device according to an embodiment of the present invention.
3B is a diagram illustrating a noise generation process using a key according to an embodiment of the present invention.
4 is a diagram illustrating a difference between a user having original noise information and an unauthorized device during operation of the recording blocking device according to an embodiment of the present invention.
5 is a diagram illustrating a recording restoration process according to an embodiment of the present invention.
6 is a diagram illustrating a recording restoration process when noise is distorted and recorded under the influence of a channel environment according to an embodiment of the present invention.
7 is a diagram illustrating a step of extracting a noise part from a recorded voice using a correlation coefficient during a recording restoration process according to an embodiment of the present invention.
8 is a diagram illustrating a graph of a correlation coefficient according to an embodiment of the present invention.
9 is a diagram illustrating a step of finding and removing a noise part from a recorded voice during a recording restoration process according to an embodiment of the present invention.
10 is a diagram illustrating a portion receiving a noise waveform due to an influence of a surrounding environment during noise recording according to an embodiment of the present invention.
11 is a view for explaining a process of extracting a channel through estimation from noise caused by an influence of a surrounding environment during noise recording according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected" with another part, this includes not only "directly connected" but also "electrically connected" with another element interposed therebetween. . In addition, when a part "includes" a certain component, it means that other components may be further included, and one or more other features, not excluding other components, unless specifically stated to the contrary. It is to be understood that it does not preclude the presence or addition of any number, step, action, component, part, or combination thereof.

The following examples are detailed descriptions for aiding understanding of the present invention, and do not limit the scope of the present invention. Accordingly, the invention of the same scope performing the same function as the present invention will also belong to the scope of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The original noise information is information about the type of noise recorded by a recorder to block recording, and is noise information within the audible frequency band before being modulated into high-frequency noise by a modulator. When white noise is generated using a random seed having an integer value within a set range as a key, the integer value, that is, the key may be shared instead of the original noise information. In this case, the recording restoration apparatus 200 may have the same original noise information as the recording blocking apparatus 100 by using the shared key.

1 is a diagram showing the configuration of a recording blocking device and a recording restoration device according to an embodiment of the present invention.

As shown, the recording blocking device 100 includes a memory 110, a processor 120, a communication module 130, and an ultrasonic speaker 140.

A recording blocking program is stored in the memory 110. Various types of data generated in the process of executing an operating system or a recording blocking program for driving the recording blocking device 100 are stored in the memory 110.

In this case, the memory 110 collectively refers to a nonvolatile storage device that continuously maintains stored information even when power is not supplied, and a volatile storage device that requires power to maintain the stored information.

In addition, the memory 110 may perform a function of temporarily or permanently storing data processed by the processor 120. Here, the memory 110 may include a magnetic storage media or a flash storage media in addition to a volatile storage device requiring power to maintain stored information, but the scope of the present invention is limited thereto. It does not become.

The processor 120 executes a recording blocking program stored in the memory 110. As the processor 120 executes the recording blocking program, the communication module 130 transmits the original noise information to the user terminal of the user who has consented to recording, and generates the original noise in the audible frequency band based on the original noise information. Then, the original noise is modulated to a frequency in a preset range higher than the audible frequency band through a modulator, and the modulated original noise is output through the ultrasonic speaker 140.

That is, the processor 120 executes the recording blocking program stored in the memory 110, transmits the original noise information to the recording restoration device 200, generates noise in the audible frequency band using the original noise information, and generates One noise is modulated at a set frequency set to be higher than the audible frequency band, and the modulated original noise is output through an ultrasonic speaker.

The recording blocking program includes an information sharing module that shares original noise information, a noise generation module that generates original noise in an audible frequency band, and a modulation module that modulates the original noise to a set frequency higher than the audible frequency band. At this time, the modulation module modulates the frequency in software and, in some cases, can physically act as a modulator through an analog circuit.

The processor 120 may include all types of devices capable of processing data. For example, it may refer to a data processing device embedded in hardware having a circuit that is physically structured to perform a function represented by a code or command included in a program. As an example of the data processing device built into the hardware as described above, a microprocessor, a central processing unit (CPU), a processor core, a multiprocessor, and an application-specific application-specific device (ASIC) Integrated circuit) and processing devices such as a field programmable gate array (FPGA) may be covered, but the scope of the present invention is not limited thereto.

The communication module 130 provides a communication interface between the user terminal, the recording blocking device 100 and the recording restoration device 200 by interworking with a communication network. Through this, it may serve to transmit and receive data between the recording blocking device 100 and the recording restoration device 200.

In particular, the recording blocking device 100 transmits the original noise information to the user terminal of the user who has consented to the recording through the communication module 130.

Here, the communication module 130 may be a device including hardware and software necessary to transmit/receive a signal such as a control signal or a data signal through a wired or wireless connection with another network device.

The ultrasonic speaker 140 outputs the original noise (high frequency noise) modulated by the recording blocking device 100 to the outside. The ultrasonic speaker 140 is a device that generates a high frequency of 20 kHz or more, which is an audible frequency, and vibrates rapidly by passing a high-frequency current through a piezoelectric element to generate high-frequency noise, or by changing a magnetic field to a magnetic object to vibrate. You can use the way it occurs.

In the case of a general speaker having insufficient output and frequency for generating ultrasonic waves, an ultrasonic speaker function may be implemented in the form of separately attaching an ultrasonic generator module to the general speaker.

The ultrasonic speaker 140 may be embedded in the recording blocking device 100 or may be implemented in a form in which the recording blocking device 100 is embedded in the ultrasonic speaker 140. In addition, after the recording blocking device 100 and the ultrasonic speaker 140 are implemented in separate and independent forms, the ultrasonic speaker 140 may be externally connected to the recording blocking device 100. The ultrasonic speaker and the recording blocking device may be formed in a detachable type.

Meanwhile, the ultrasonic speaker 140 may be composed of at least one ultrasonic speaker.

As shown in FIG. 1, the recording and restoration apparatus 200 includes a memory 210, a processor 220, a communication module 230, and a recorder 240.

The memory 210 stores a recording restoration program and data recorded through the recorder 240. In addition, various types of data generated in the process of executing an operating system for driving the recording restoration apparatus 200 or a recording restoration program are stored.

The recording restoration program includes a module that receives original noise information, a module that stores data recorded through a recorder, and a module that removes noise from recorded data using the received noise information. In this case, the recording restoration program may be configured separately from the recording restoration device.

The processor 220 digitally converts the data recorded through the recorder 240 and stores it in the memory 210.

The processor 220 executes a recording restoration program stored in the memory 210. As the processor 220 executes the recording restoration program, the processor 220 receives the original noise information transmitted to the user terminal of the user who consented to the recording through the communication module 230, and reduces the noise from the recorded data based on the original noise information. And provide the user with voice data from which noise has been removed.

Since the recorder 240 has nonlinearity, when a high-frequency signal is received, the signal may be transmitted to a low-frequency band. Since the recorder 240 includes a low pass filter, it is possible to exclude a signal in a high frequency region from among recorded signals.

The recording restoration device 200 uses the original noise information received from the recording blocking device 100 even though the high-frequency noise for blocking recording is recorded in the data stored in the memory 210 through the recorder 240. 100) can remove high-frequency noise, and noise canceling is possible using channel estimation even when the high-frequency noise is reflected or distorted.

In processing the recorded data to restore the voice, the recording restoration apparatus 200 includes a maximum likelihood estimation, a multi-channel AR filter, or a finite impulse response filter for radial ultrasound. Recording data can be processed with robust resilience using at least one of (FIR filter).

The recording restoration apparatus 200 may find and remove a portion that most overlaps with a portion corresponding to the original noise by performing a cross correlation operation in the recorded signal.

In addition, the recording restoration apparatus 200 is a portable terminal capable of basically performing a recording function, and may be implemented in the form of a smart terminal such as a smart phone, a notebook computer, or a tablet PC.

2 is a flowchart illustrating a method of blocking and restoring recording according to an embodiment of the present invention.

First, the recording blocking device 100 provides original noise information to the recording restoration device 200 of the user who consented to the recording in advance (S110). In this case, providing the original noise information by the recording blocking device 100 may include not only transmitting through direct P2P communication, but also providing through other communication means. In addition, the recording blocking device 100 stores the original noise information in a pre-designated site, and the recording restoration device 200 of the authenticated user downloads the pre-stored original noise information.

The recording blocking device 100 generates the original noise in the audible frequency band using the original noise information (S120), and modulates the generated noise into a preset frequency band to be higher than the audible frequency band (S130).

At this time, the recording blocking device 100 may modulate the original noise in the audible frequency band through an analog circuit or software.

Next, the recording blocking device 100 outputs the original noise modulated in step S130 through an ultrasonic speaker to block unconsent recording (S140).

The recording blocking device 100 transmits the original noise information to the user terminals of users who consented to the recording in advance, for example, the recording restoration device 200, and removes the original noise through the corresponding recording restoration device 200, and To be able to restore it.

The recording blocking device 100 may be configured around a software program that performs such a function, but some functions may be configured to implement the function through a hardware element.

The recording and restoration apparatus 200 records the voice by the user's operation, and in the process, the high-frequency noise generated by the recording blocking apparatus 100 is recorded together (S210). Noise is removed from the recorded voice by using the original noise information shared by the recording blocking device 100, which was first received in the previous step (S110), and the original voice data to be recorded is restored (S220).

The above process executed by the recording restoration apparatus 200 may be executed through a software program.

3A is a diagram illustrating a process of sharing original noise information between a recording blocking device and a recording restoration device according to an embodiment of the present invention.

Recording is blocked in an area where high frequency noise is generated by the recording blocking device 100, and the range of the recording blocking area may be changed according to the output and number of ultrasonic speakers.

In the case of a user who has received permission for voice recording, the original noise information is shared in advance through the user terminal (for example, the recording restoration device 200), and noise is removed from the recorded signal using this original noise information. You can restore the recording.

In order to share the original noise information, the recording blocking device 100 may store the original noise information in a predetermined server, and an approved client may access the server and download the corresponding information.

As another method for sharing the original noise information, the recording blocking device 100 may directly transmit the original noise information to a registered individual user using a P2P method or a broadcasting method.

For example, when the voice is restored by sharing a key for the original noise, the recording restoration device 200 transmits a registration request message for registering that the user is an authorized user to the recording blocking device 100, and the recording blocking device 100 ) Registers the corresponding recording restoration device 200 in response to the registration request message. In this case, the recording blocking device 100 may authenticate the recording restoration device 200 in response to an authentication request from the recording restoration device 200 and securely share the key.

Information on the authorized user may be received from the recording restoration device 200 when the recording blocking device 100 is used, or the authorized recording restoration device 200 may be predetermined using predetermined information. May be.

At this time, it is possible to register that the user is a permitted user through a separate server instead of the recording blocking device 100, and share the original noise information, and instead of the recording restoration device 200, a PC, tablet PC, notebook, netbook, PDA, PMP, You can get original noise information by connecting to the server with devices such as MP3 players, recorders, mobile phones, and smart phones.

The original noise information may include all information for reproducing the noise, such as the frequency and size of the noise by time. Instead of the noise type information, which is the original noise information, a key for generating white noise may be shared, but in this case, the recording restoration device 200 uses the key to generate noise information identical to the noise generated by the recording blocking device 100. You should be able to have it. The original noise information is shared with a licensed user for use in noise reduction in the recording restoration step, and is not limited to the above embodiment.

3B is a diagram illustrating a noise generation process using a key value according to an embodiment of the present invention, and shows a graph of white noise generated by using a selected integer key as a random seed.

The recording blocking device 100 selects an integer within a preset range as a key, and generates white noise by using the key as a random seed.

In order to restore the recording, the recording blocking device 100 shares original noise information with the recording restoration device 200, and may share information on the shape of the generated noise or a key used to generate the noise.

4 is a diagram illustrating a signal waveform in a noise generation and recording process according to an embodiment of the present invention.

When generating the original noise information, any noise type in the audible frequency band may be possible, and for example, the noise may be White Gaussian Noise.

The recording blocking device 100 may generate white noise by receiving a preset integer value as a key and using the key as a random seed.

The form of noise is not limited to the above embodiment, and may be any form, and only the form of the generated noise is shared with the recording and restoration apparatus 200.

During noise modulation, the frequency difference of the transmitted sound can be made equal to the frequency of the desired sound. For example, if the desired sound band is fm and the sound band to be modulated is fc, it can be modulated as shown in Equation 1 below. t is the time x(t) is a function of the time of the original noise, and g(t) is a function of the time of the modulated noise.

[Equation 1]

The recording blocking device 100 outputs the modulated high-frequency noise using the ultrasonic speaker 140 as in step S140 described above. If the sound range of the original noise was f _m , the modulated high-frequency noise is output in the _{range f m} + f _{c that} is added as much as the sound band f _{c to be modulated.} In this case, the ultrasonic speaker 140 may be composed of one or a plurality of ultrasonic speakers.

Since it is difficult to implement the recording blocking function targeted by the recording blocking device 100 due to insufficient output with speakers built into user terminals such as mobile phones, tablet PCs, and laptops, recording blocking programs are used in mobile phones, tablet PCs, notebooks, etc. A separate ultrasonic generator module is required to implement it.

Meanwhile, the recording restoration apparatus 200 receives modulated original noise, that is, high-frequency noise, output through the ultrasonic speaker of the recording blocking apparatus 100.

At this time, when high-frequency noise is recorded, the noise is recorded in the audible frequency region due to the nonlinearity of the recording device, and since the noise exists in the same frequency region as the recorded voice, the sound in the corresponding band is buried in the noise. Therefore, there is an effect that the voice recording is practically disabled.

Since high-frequency noise is inaudible to the user's ear, it can be used in meetings, lectures, and classes, and only the recorder can be disabled. Many recorders in recent years have non-linearity, so when a high-frequency sound is received, it is a harmonic signal caused by the non-linearity. The sound is recorded in the low-frequency band as well, and people usually use it for conversation. The sound in the range of 0~5000Hz is buried in the noise.

Meanwhile, as shown in FIG. 4, noise in a region higher than the audible frequency may be removed by a low-pass filter (LPF) in the recorder.

FIG. 5 is a diagram illustrating a recording restoration process according to an embodiment of the present invention, in which (a) is a waveform diagram showing a waveform for generated noise, and (b) is a waveform diagram showing a voice to be recorded. Since noise and voice are generated at the same time in the field, the data recorded on the recorder of the recording and restoration apparatus 200 generates a waveform in the form of overlapping the waveform of (a) and the waveform of (b), as shown in (c). .

Since the recording restoration apparatus 200 having information about the noise knows (d), which is the information of the original noise, a technique such as cross-correlation is used to determine the original noise ( By removing d), you can get the same waveform as the voice (e) that was initially recorded. (e) is the waveform of the restored voice with noise removed.

The recording restoration apparatus 200 may restore the voice by removing a noise portion having the highest correlation with the original noise information by using a cross-correlation from data recorded together with noise and voice.

ve cross-correlation), 적응상관관계(Adaptive cross-correlation), 최대우도추정(Maximum Likelihood Estimation), 카이제곱최소화(chi-squared minimization) 와 같은 방법을 통해 상관도가 높은 부분을 구할 수 있다.In this case, in addition to the cross-correlation, the natural correlation (Na

High correlation can be obtained through methods such as ve cross-correlation), adaptive cross-correlation, maximum likelihood estimation, and chi-squared minimization.

[Equation 2]

Assuming that the noise is injected into the recorder as intended, the most correlated part, that is, the most overlapping part, can be obtained by comparing the recorded noise while sliding the predefined noise using the correlation function.

In order to obtain a correlation between the previously defined original noise information f(t) and the recorded noise g(t), a cross-correlation function according to Equation 2 may be used.

When high-frequency noise (X) is radiated and input (Y) to the device by receiving the surrounding environment, the high-frequency noise X vector of time t ~ t+k and the sound recorded on the device of time t ~ t+k are each Y vector. define.

When the high-frequency noise (X) comes in immediately, the noise can be found using Equation 3 below.

[Equation 3]

(

는 상수, n은 주변 노이즈)

(

Is a constant, n is the ambient noise)

When the high-frequency noise (X) comes in and is reflected in the surrounding environment, the noise can be estimated using Equation 4 below.

[Equation 4]

In Equation 4, H denotes a channel state information matrix.

6 is a diagram illustrating a recording restoration process when noise is distorted and recorded under the influence of a channel environment according to an embodiment of the present invention.

(a) shows the waveform for the generated noise, and (b) shows the waveform for the voice to be recorded.

Since noise and voice are generated at the same time in the field, the data recorded on the recorder of the recording restoration apparatus 200 is in the form of overlapping (a) and (b) as shown in (c). However, unlike the case of FIG. 5, since noise is reflected or distorted according to the recording environment, a different form from the original noise waveform (a) may be recorded together with (c). At this time, the information on the recording environment is called channel information and corresponds to h among the functions indicated in (c).

Since the recording restoration device 200 having information about the noise knows the information (d) of the original noise, it uses a technique such as cross-correlation to create the original noise (d) in the recorded signal (c) in which the noise is superimposed using a technique such as cross-correlation. By removing ), you can get the same waveform as the voice (e) to be recorded initially. Even if the noise is partially deformed, the noise part can be removed from the recorded data through channel estimation. Here, by removing (d) from (c) by using a technique such as cross-correlation, a waveform like (e) can be obtained. (e) is the waveform of the restored voice with noise removed.

(c) is a waveform diagram for Equation 5 below.

[Equation 5]

In Equation 5, = sound recorded by the receiver, = modulated original noise (high frequency noise), = voice, = channel state information).

7A and 7B are diagrams for explaining a step of finding a noise part in a recorded voice using a correlation coefficient during a recording restoration process according to an embodiment of the present invention.

When the noise is input to the recorder as it is, the previously defined noise (original noise information) is moved in the horizontal axis direction and compared with the recorded noise.

At this time, the correlation coefficient is calculated using Equation 2 above. 7B is a state when the correlation coefficient is the largest, and when the correlation is highest and the form of noise overlaps the most.

8 is a graph showing a change in the correlation coefficient obtained in FIG. 7A, and FIGS. 9A and 9B are diagrams illustrating a step of finding and removing a noise part from a recorded voice during a recording restoration process according to an embodiment of the present invention. , FIG. 10 is a diagram illustrating a portion affected by a surrounding environment when recording noise according to an embodiment of the present invention.

As shown in Fig. 8, the portion marked as'overlapping point' is the state of Fig. 7B. 9A is a graph of the result of recording modulated original noise (high-frequency noise) generated by the recording blocking device 100 together with the voice on a recorder, and FIG. 9B is a graph of data recorded with noise using a correlation coefficient. This is a graph showing the state of finding and removing the part that best matches the original noise information.

J corresponds to the ultrasonic speaker 140 included in the recording blocking device 100, and A corresponds to a location such as a voice to be recorded. B is a recorder 240 included in the recording and restoration apparatus 200, and E is a location of a non-consent user who is not permitted to record voice.

In the case of FIG. 10, the modulated original noise (high-frequency noise) affects the sequence input first by the surrounding structure and the sequence input later.

In this case, the core process is to obtain the modeled channel state information H with reference to Equation 4 and FIG. 6 for noise reduction.

11A, 11B, and 11C are diagrams illustrating a part of a process of estimating a channel when an ambient environment is affected during noise recording according to an embodiment of the present invention.

11A shows a case where the original noise is an impulse function, and the sequence input first affects the sequence input later due to the influence of the surrounding structure. When the original noise is estimated using the channel state information H, the estimated impulse response of the channel is shown in the graph on the right.

11B is a sink impulse and a rect impulse.

11C is a graph showing a result of a sync impulse being recorded by the recorder 240 of the recording and reconstruction apparatus 200.

Channel compensation is performed based on the obtained H, and Equation 6 below may be referred to.

[Equation 6]

H ^-1 (H*X+n) = Y+n'

Meanwhile, the recording blocking method or the recording restoration method according to an embodiment of the present invention may be implemented in the form of a recording medium including instructions executable by a computer such as a program module executed by a computer. Computer-readable media can be any available media that can be accessed by a computer, and includes both volatile and nonvolatile media, removable and non-removable media. Further, the computer-readable medium may include a computer storage medium. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Although the methods and systems of the present invention have been described in connection with specific embodiments, some or all of their components or operations may be implemented using a computer system having a general-purpose hardware architecture.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: recording blocking device
110: memory
120: processor
130: communication module
140: ultrasonic speaker
200: recording restoration device
210: memory
220: processor
230: communication module
240: Recorder (MIC)

Claims (12)

In the recording blocking method performed by the recording blocking device for blocking unconsent voice recording,
Transmitting original noise information to a user terminal that has consented to voice recording;
Generating original noise in an audible frequency band based on the original noise information;
Modulating the original noise to a set frequency set to a higher frequency band than the audible frequency band through a modulator; And
Outputting the modulated original noise through an ultrasonic speaker;
Recording blocking method comprising a. The method of claim 1,
The step of outputting the modulated original noise through an ultrasonic speaker,
A recording blocking method of outputting the modulated original noise through at least one ultrasonic speaker. The method of claim 1,
Generating the original noise,
White Gaussian Noise is generated by using an integer value within a preset range as a random seed,
The original noise information is information on the random seed recording blocking method. In the recording restoration method through the recording restoration program installed in the user terminal,
Receiving original noise information from a recording blocking device that blocks recording;
Recording surrounding voices and noise output from the recording blocking device through a recorder of the user terminal;
Removing noise from the voice recorded in the step by using the received original noise information; And
Including; storing the sound from which the noise has been removed,
The recording blocking device generates original noise in an audible frequency band based on the original noise information, modulates the original noise to a set frequency set to a frequency band higher than the audible frequency band, and outputs it through an ultrasonic speaker.
How to restore the recording. The method of claim 4,
The step of removing the noise,
And when the original noise is deformed by a channel environment, extracting the deformed original noise using channel estimation. The method of claim 4,
The step of removing the noise,
Cross-correlation, natural correlation (Na

ve cross-correlation), adaptive cross-correlation, maximum likelihood estimation, and chi-squared minimization. In the recording blocking device for blocking unconsent voice recording,
Communication module,
Processor and
Includes a memory in which a recording blocking program is stored,
The processor transmits original noise information to a user terminal of a user who has consented to recording through the communication module according to the execution of the recording blocking program, and generates original noise in an audible frequency band based on the original noise information, The recording blocker device modulates the original noise to a set frequency set to a higher frequency band than the audible frequency band through a modulator, and outputs the modulated original noise through an ultrasonic speaker. The method of claim 7,
The recording blocking device further comprises at least one ultrasonic speaker outputting the modulated original noise. The method of claim 7,
The original noise is white noise (White Gaussian Noise) generated by using an integer value within a preset range as a random seed recording blocking device. In the device for restoring the recording through a recording restoration program,
A recorder for recording voice;
A memory in which the recording restoration program is stored; And
A processor that executes a program stored in the memory,
According to the execution of the recording restoration program, the processor receives original noise information from the recording blocking device, records surrounding voices and noise output from the recording blocking device through the recorder, and uses the received original noise information. By removing the noise from the recorded voice, restoring the voice from which the noise has been removed,
The recording blocking device generates original noise in an audible frequency band based on the original noise information, modulates the original noise to a set frequency set to a frequency band higher than the audible frequency band, and outputs it through an ultrasonic speaker.
Recording restoration device. The method of claim 10,
The processor is
When the original noise is deformed and recorded by a channel environment, the original noise is extracted using channel estimation when the deformed original noise is removed. The method of claim 10,
The processor,
In order to remove the noise, cross-correlation, natural correlation (Na

ve cross-correlation), adaptive cross-correlation, maximum likelihood estimation, and chi-squared minimization.

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