CN107958671B - Echo cancellation device of law enforcement recorder - Google Patents
Echo cancellation device of law enforcement recorder Download PDFInfo
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- CN107958671B CN107958671B CN201711170245.9A CN201711170245A CN107958671B CN 107958671 B CN107958671 B CN 107958671B CN 201711170245 A CN201711170245 A CN 201711170245A CN 107958671 B CN107958671 B CN 107958671B
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0208—Noise filtering
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
- G10L19/04—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using predictive techniques
- G10L19/16—Vocoder architecture
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0208—Noise filtering
- G10L21/0216—Noise filtering characterised by the method used for estimating noise
- G10L21/0232—Processing in the frequency domain
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04L63/00—Network architectures or network communication protocols for network security
- H04L63/02—Network architectures or network communication protocols for network security for separating internal from external traffic, e.g. firewalls
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/01—Protocols
- H04L67/10—Protocols in which an application is distributed across nodes in the network
- H04L67/1097—Protocols in which an application is distributed across nodes in the network for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0208—Noise filtering
- G10L2021/02082—Noise filtering the noise being echo, reverberation of the speech
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Abstract
The invention discloses an echo cancellation device of a law enforcement recorder, which comprises a far-end user, a far-end user sound input device, a far-end user sound output device, a first signal converter, a radio transmission device, a sound processing device, a second signal converter, a local user sound output device, a local user sound input device and a local user, wherein the far-end user is connected with the local user through the far-end user sound input device, the first signal converter and the radio transmission device, the radio transmission device is connected with the local user through the sound processing device, the second signal converter and the far-end user sound output device, and the output end of the local user is connected with the input end of the second signal converter through the local user sound input device. The efficiency and effectiveness of echo cancellation are generally improved.
Description
Technical Field
The invention relates to the technical field of echo cancellation, in particular to an echo cancellation device of a law enforcement recorder.
Background
When a law enforcement recorder and a platform system talkback, real-time voice communication between two parties or multiple parties is required, usually an external loudspeaker is adopted for sound reproduction, so that an echo is inevitably generated, namely, after one party speaks, the sound is reproduced through the loudspeaker of the other party and then is collected by the microphone of the other party and transmitted back to the other party, if the echo is not processed, the communication quality is influenced, sound shock is formed, howling is generated, echo cancellation is required to be technically implemented, the existing echo cancellation device mainly utilizes an echo estimation value processor to compare an electric signal sent by a local user with an original electric signal sent by a far-end user, and when a comparison result is within a set threshold value range, a repeated electric signal in the electric signal sent by the local user is deleted, but the method has the following defects: the echo estimation processor is an algorithm or device which takes the estimation of the statistical characteristics of the input and output signals as the basis and adopts a specific algorithm to automatically adjust the processor coefficient to achieve the optimal filtering characteristic, the echo estimation processor updates and adjusts the weighting coefficient according to the specific algorithm for each sample value of the input signal sequence to ensure that the mean square error of the comparison between the output signal sequence and the expected output signal sequence is minimum, i.e., the output signal sequence approximates the desired signal sequence, in which the echo estimate processor is required to maintain the coefficients stable after convergence, to ensure no interference from the output data of the remote user in the local user voice input device, and on the other hand, the echo estimation value processor needs to keep an update state at any time, to ensure that a changing echo path can be tracked, the contradiction between the fast convergence and the high stability of the echo estimation processor restricts the development of the echo cancellation technology.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides an echo cancellation device of a law enforcement recorder.
In order to achieve the purpose, the invention adopts the following technical scheme:
an echo cancellation device of a law enforcement recorder comprises a far-end user, a far-end user sound input device, a far-end user sound output device, a first signal converter, a radio transmission device, a sound processing device, a second signal converter, a local user sound output device, a local user sound input device and a local user, wherein the far-end user is connected with the far-end user sound input device, the output end of the far-end user sound input device is connected with the input end of the first signal converter, the output end of the first signal converter is connected with the input end of the far-end user sound output device, the first signal converter is connected with the radio transmission device, the radio transmission device is connected with the sound processing device, the sound processing device is connected with the second signal converter, the output end of the second signal converter is connected with the input end of the local user sound output device, the output end of the local user sound output device is connected with the input end of the local user, the output end of the local user is connected with the input end of the local user sound input device, and the output end of the local user sound input device is connected with the input end of the second signal converter.
Preferably, the first signal converter is configured to convert an acoustic signal received by the remote user voice input device into an electrical signal.
Preferably, the first signal converter is adapted to transfer the electrical signal received by the radio transmission device to the remote user sound output device and to convert the electrical signal into an acoustic signal via the remote user sound output device.
Preferably, the sound processing device comprises a memory, an echo estimate processor, a sound frequency threshold processor and a sound loudness threshold processor, the output of the radio transmission device is connected to the input of the memory, the output of the memory is connected to the input of the second signal converter and the input of the echo estimate processor, respectively, the output of the echo estimate processor is connected to the input of the sound frequency threshold processor, the output of the sound frequency threshold processor is connected to the input of the sound loudness threshold processor, and the output of the sound loudness processor is connected to the input of the radio transmission device.
Preferably, the storage comprises a main storage (internal storage) of the law enforcement recorder, an auxiliary storage (external storage) of the law enforcement recorder, a network transmission module and a network cloud disk.
Preferably, the network cloud disk is connected with a firewall, the firewall comprises a key generator, a key controller, a key decryptor and an authentication module, the key generator, the key controller and the key decryptor are used for checking or managing the network cloud disk, the authentication module is used for a user to log in the network cloud disk, and the authentication module is a fingerprint unlocking device or a keyboard input device.
Preferably, the second signal converter is configured to transmit the electrical signal output by the radio transmission device to a local user sound output device, and to convert the electrical signal into an acoustic signal through the local user output device.
Preferably, the second signal converter is used for converting the acoustic signal received by the local user sound input device into an electric signal
The invention has the beneficial effects that:
1. the echo estimation value processor updates and adjusts the weighting coefficient for each sample value of the input signal sequence according to a specific algorithm, so that the mean square error of the comparison between the output signal sequence and the expected output signal sequence is minimum, in the process, the echo estimation value processor keeps the coefficient stable after convergence, and in a fixed time period after the coefficient is kept stable, the coefficient is kept unchanged, namely, the external interference amount of the geographical environment where the remote user and the local user are located is considered to be unchanged in the fixed time period, so that the interference of the output data of the remote user in the local user sound input device can be avoided, and the echo cancellation effect is improved.
2. The coefficient of the echo estimation value processor is kept unchanged in a fixed time period, and in order to ensure the reliability of echo cancellation in the time period, the output end of the echo estimation value processor is sequentially connected with the sound frequency threshold value processor and the sound loudness threshold value processor, so that the effect of echo cancellation in the time period is ensured, and the efficiency and the effect of echo cancellation are improved generally.
Drawings
Fig. 1 is a schematic block diagram of an echo cancellation device of a law enforcement recorder according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Referring to fig. 1, an echo cancellation device of a law enforcement recorder comprises a far-end user, a far-end user voice input device, a far-end user voice output device, a first signal converter, a radio transmission device, a voice processing device, a second signal converter, a local user voice output device, a local user voice input device and a local user, wherein the far-end user is connected with the far-end user voice input device, an output end of the far-end user voice input device is connected with an input end of the first signal converter, the first signal converter is used for converting a voice signal received by the far-end user voice input device into an electric signal, namely, the user converts the voice signal into the electric signal through the far-end user voice input device and the first signal converter, the first signal converter is connected with the radio transmission device, and the radio transmission device transmits the electric signal to one end of the local, the radio transmission device is connected with the sound processing device, the sound processing device comprises a memory, an echo estimation value processor, a sound frequency threshold processor and a sound loudness threshold processor, the output end of the radio transmission device is connected with the input end of the memory, the output end of the memory is respectively connected with the input end of the second signal converter and the input end of the echo estimation value processor, the output end of the echo estimation value processor is connected with the input end of the sound frequency threshold processor, the output end of the sound frequency threshold processor is connected with the input end of the sound loudness threshold processor, the output end of the sound loudness processor is connected with the input end of the radio transmission device, the memory comprises a main memory (internal memory) of a law enforcement recorder, an auxiliary memory (external memory) of the law enforcement recorder, a network transmission module and a network cloud disk, and the network cloud disk is connected with a firewall, the firewall comprises a key generator, a key controller, a key decryptor and an authentication module, wherein the key generator, the key controller and the key decryptor are used for checking or managing the network cloud disk, the authentication module is used for a user to log in the network cloud disk, the authentication module is a fingerprint unlocking device or a keyboard input device, a sound processing device stores electric signals through a memory and performs convergence calculation through an echo estimation value processor to obtain a model coefficient in a fixed time, the sound processing device is connected with a second signal converter, the output end of the second signal converter is connected with the input end of a local user sound output device, the second signal converter is used for transmitting the electric signals output by the radio transmission device to the local user sound output device and converting the electric signals into sound signals through the local user output device, and the output end of the local user sound output device is connected with the input end of a local user, the first information transmission is carried out, the output end of the local user is connected with the input end of the local user sound input device, the sound signal of the local user (including the sound signal of the local user and the sound signal of the far-end user) is transmitted to the local user sound input device, the output end of the local user sound input device is connected with the input end of a second signal converter, the second signal converter is used for converting the sound signal received by the local user sound input device into an electric signal and matching the electric signal in the echo estimation value processor, the electric signal with the matching degree within the threshold range is screened out and transmitted to the sound frequency threshold value processor, because the echo is overlapped in the process of transmitting between the far-end user and the local user, the echo can cause the gradual rise of the echo frequency, the electric signal with the frequency higher than the threshold value is screened and the electric signal is transmitted to the loudness threshold value processor, because the loudness of the echo is smaller than other sounds in the initial propagation stage, the electric signals with loudness lower than the threshold value are screened, the electric signals meeting all the conditions are deleted, the deleted electric signals are transmitted to the first signal converter through the radio transmission device, the output end of the first signal converter is connected with the input end of the far-end user sound output device, the electric signals received by the radio transmission device are transmitted to the far-end user sound output device, and the electric signals are converted into sound signals through the far-end user sound output device.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (5)
1. An echo cancellation device of a law enforcement recorder comprises a far-end user, a far-end user sound input device, a far-end user sound output device, a first signal converter, a radio transmission device, a sound processing device, a second signal converter, a local user sound output device, a local user sound input device and a local user, and is characterized in that the far-end user is connected with the far-end user sound input device, the output end of the far-end user sound input device is connected with the input end of the first signal converter, the output end of the first signal converter is connected with the input end of the far-end user sound output device, the first signal converter is connected with the radio transmission device, the radio transmission device is connected with the sound processing device, the sound processing device is connected with the second signal converter, the output end of the second signal converter is connected with the input end of the local user sound output device, the output end of the local user sound output device is connected with the input end of the local user, the output end of the local user is connected with the input end of the local user sound input device, and the output end of the local user sound input device is connected with the input end of the second signal converter; the sound processing device comprises a memory, an echo estimation value processor, a sound frequency threshold processor and a sound loudness threshold processor, wherein the output end of the radio transmission device is connected with the input end of the memory, the output end of the memory is respectively connected with the input end of the second signal converter and the input end of the echo estimation value processor, the output end of the echo estimation value processor is connected with the input end of the sound frequency threshold processor, the output end of the sound frequency threshold processor is connected with the input end of the sound loudness threshold processor, and the output end of the sound loudness processor is connected with the input end of the radio transmission device;
the memory comprises a main memory (internal memory) of the law enforcement recorder, an auxiliary memory (external memory) of the law enforcement recorder, a network transmission module and a network cloud disk; the network cloud disk is connected with a firewall, the firewall comprises a key generator, a key controller, a key decryptor and an authentication module, the key generator, the key controller and the key decryptor are used for checking or managing the network cloud disk, the authentication module is used for a user to log in the network cloud disk, and the authentication module is a fingerprint unlocking device or a keyboard input device;
the echo estimation value processor keeps the coefficient stable after convergence, and the coefficient is kept unchanged in a fixed time period after the coefficient is kept stable.
2. The echo cancellation device for a law enforcement recorder according to claim 1, wherein the first signal converter is configured to convert an acoustic signal received by the remote user voice input device into an electrical signal.
3. The echo cancellation device of a law enforcement recorder according to claim 1, wherein the first signal converter is configured to transmit the electrical signal received by the radio transmission device to the remote user voice output device and to convert the electrical signal to an acoustic signal via the remote user voice output device.
4. The echo cancellation device of claim 1, wherein the second signal converter is configured to transmit the electrical signal output by the radio transmission device to the local user sound output device, and to convert the electrical signal into an acoustic signal via the local user output device.
5. The echo cancellation device for a law enforcement recorder according to claim 1, wherein the second signal converter is configured to convert an acoustic signal received by the local user voice input device into an electrical signal.
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| CN201711170245.9A CN107958671B (en) | 2017-11-22 | 2017-11-22 | Echo cancellation device of law enforcement recorder |
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| CN201711170245.9A CN107958671B (en) | 2017-11-22 | 2017-11-22 | Echo cancellation device of law enforcement recorder |
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| CN107958671B true CN107958671B (en) | 2021-04-13 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108924462A (en) * | 2018-05-31 | 2018-11-30 | 广州市六体智能科技有限公司 | A kind of video talkback unit of law-enforcing recorder |
| CN109413522B (en) * | 2018-11-08 | 2020-09-04 | 深圳市云威物联科技有限公司 | Sound signal processing method, sound signal processing device and electronic equipment |
| CN110995950B (en) * | 2019-11-08 | 2022-02-01 | 杭州觅睿科技股份有限公司 | Echo cancellation self-adaption method based on PC (personal computer) end and mobile end |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102801881A (en) * | 2012-07-20 | 2012-11-28 | 中山银利智能科技股份有限公司 | Echo eliminating device |
| CN103491488A (en) * | 2013-09-30 | 2014-01-01 | 天脉聚源(北京)传媒科技有限公司 | Echo cancellation method and device for microphone |
| US8942370B2 (en) * | 2007-04-10 | 2015-01-27 | Microsoft Corporation | Filter bank optimization for acoustic echo cancellation |
| CN106161780A (en) * | 2016-06-22 | 2016-11-23 | 深圳市金悦通机器人技术有限公司 | There is communicator and the noise-reduction method thereof of speaker decrease of noise functions |
| CN206294301U (en) * | 2016-12-26 | 2017-06-30 | 重庆邮电大学 | A kind of speech talkback data secure device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100568884C (en) * | 2003-06-27 | 2009-12-09 | 诺基亚有限公司 | Use residual echo filter to strengthen acoustic echo and eliminate system and method |
| US8199927B1 (en) * | 2007-10-31 | 2012-06-12 | ClearOnce Communications, Inc. | Conferencing system implementing echo cancellation and push-to-talk microphone detection using two-stage frequency filter |
| US8634569B2 (en) * | 2010-01-08 | 2014-01-21 | Conexant Systems, Inc. | Systems and methods for echo cancellation and echo suppression |
| BR112013016222B1 (en) * | 2011-02-03 | 2020-12-15 | Telefonaktiebolaget L M Ericsson (Publ) | METHOD OF ESTIMATING ECO POWER, ECO SUPPRESSION METHOD, HARMONIC ECO POWER ESTIMATOR, ECO CANCELER, AND, USER EQUIPMENT |
| US9191493B2 (en) * | 2013-12-09 | 2015-11-17 | Captioncall, Llc | Methods and devices for updating an adaptive filter for echo cancellation |
| CN106303118A (en) * | 2015-06-05 | 2017-01-04 | 福建凯米网络科技有限公司 | Intelligent terminal realizes the method for microphone function, audio frequency playing method, equipment and system |
| CN107123430B (en) * | 2017-04-12 | 2019-06-04 | 广州视源电子科技股份有限公司 | Echo cancel method, device, meeting plate and computer storage medium |
-
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8942370B2 (en) * | 2007-04-10 | 2015-01-27 | Microsoft Corporation | Filter bank optimization for acoustic echo cancellation |
| CN102801881A (en) * | 2012-07-20 | 2012-11-28 | 中山银利智能科技股份有限公司 | Echo eliminating device |
| CN103491488A (en) * | 2013-09-30 | 2014-01-01 | 天脉聚源(北京)传媒科技有限公司 | Echo cancellation method and device for microphone |
| CN106161780A (en) * | 2016-06-22 | 2016-11-23 | 深圳市金悦通机器人技术有限公司 | There is communicator and the noise-reduction method thereof of speaker decrease of noise functions |
| CN206294301U (en) * | 2016-12-26 | 2017-06-30 | 重庆邮电大学 | A kind of speech talkback data secure device |
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