TWI413112B - Method and apparatus for elimination noise background noise (1) - Google Patents

Abstract

The present invention is suitable for the technical field of voice communication, which provides a method and device for eliminating background noise of voice (1). The method includes the following steps: performing an effective value detection on the received audio signal, so as to obtain the output signal that reflects the average power of the audio signal; comparing the output signal that reflects the average power of the audio signal with a first threshold value, so as to generate a noise elimination control signal, wherein the first threshold value is a critical value for the average power of the voice signal and the average power of the noise signal; and performing a noise signal elimination process on the audio signal and performing a magnification process on the voice signal under the control of the noise elimination control signal. By converting the amplitude change of the audio signal into the output signal that reflects the average power change of the audio signal, the embodiment of the present invention is able to achieve the purpose of eliminating background noise of voice under the control of the output signal.

Description

Method and device for eliminating speech background noise (1)

The invention belongs to the field of voice communication, and in particular relates to a method and a device for eliminating speech background noise (1).

In the field of voice communication, due to the complicated environment of the caller, the audio signal collected by the audio device includes not only the voice signal of the caller but also the noise signal from other sources in the surrounding environment, such as the voice of other people. The sounds emitted by vehicles, etc., these noise signals seriously interfere with the quality of voice communication. Therefore, while maintaining efficient denoising, the technology of using fewer devices to remove the mixed noise signals in the voice signals has become a company. The focus of attention.

The object of the present invention is to provide a method for canceling speech background noise, which aims to solve the problem that the noise signal mixed in the speech signal seriously affects the quality of the speech communication.

The present invention is implemented in such a manner that a method for canceling speech background noise includes the following steps:

A. performing RMS detection on the received audio signal to obtain an output signal for reflecting the average power of the audio signal;

B. Comparing an output signal for reflecting an average power of the audio signal with a first threshold to generate a noise cancellation control signal, where the first threshold is a threshold value of an average power of the voice signal and an average power of the noise signal;

C. Under the control of the noise cancellation control signal, the noise signal in the audio signal is cancelled, and the voice signal is amplified.

Another object of the present invention is to provide a device for canceling speech background noise, the device comprising:

An RMS detecting unit configured to perform RMS detection on the received audio signal to obtain an output signal for reflecting an average power of the audio signal;

a noise reduction control signal generating unit, configured to compare an output signal generated by the effective value detecting unit for reflecting an average power of the audio signal with a first threshold to generate a noise canceling control signal, where the first threshold is a voice signal The average power and the critical value of the average power of the noise signal;

The noise cancellation amplifying unit is configured to perform cancellation processing on the noise signal in the audio signal under the control of the noise cancellation control signal generated by the noise cancellation control signal generating unit, and perform amplification processing on the voice signal.

In the embodiment of the present invention, an output signal for reflecting the average power of the audio signal is obtained by performing RMS detection on the received audio signal, by performing the output signal for reflecting the average power of the audio signal with the first threshold. Comparing, the denoising control signal is generated, and the noise signal in the audio signal is cancelled under the control of the denoising control signal, and the speech signal is amplified, thereby eliminating the background noise of the speech.

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the embodiment of the present invention, an output signal for reflecting the average power of the audio signal is obtained by performing RMS detection on the received audio signal, by performing the output signal for reflecting the average power of the audio signal with the first threshold. Comparing, generating a noise cancellation control signal, wherein the first threshold is a threshold value of an average power of the voice signal and an average power of the noise signal, and the noise signal in the audio signal is cancelled under the control of the noise cancellation control signal, The speech signal is amplified to achieve the elimination of speech background noise.

The first figure shows an implementation flow of a method for canceling speech background noise provided by an embodiment of the present invention, which is described in detail as follows:

In step S101, the received audio signal is subjected to an effective value (also referred to as root mean square value, Root Mean Square, RMS) detection to obtain an output signal for reflecting the average power of the audio signal.

In the embodiment of the present invention, the received audio signal may be an collected audio signal, or may be an audio signal transmitted from other devices. Since the environment in which the speaker is located is generally complicated, there are various sources of sound other than the speaker, such as the voices of other speakers around, the sounds of surrounding vehicles, etc., so that the received audio signal includes not only the voice of the speaker. The signal also includes noise signals from other sources in the speaker's surroundings. Since the received audio signal includes a voice signal and a noise signal, the amplitude level generated by the voice signal is generally different from the level of the noise generated by the noise signal, and the RMS value is detected by the received audio signal according to the amplitude of the audio signal. The change may produce an output signal for reflecting the average power of the audio signal, ie the output signal for reflecting the average power of the audio signal reflects the amplitude variation of the audio signal. By setting a threshold value of the average power of the voice signal and the average power of the noise signal according to the difference between the average power of the voice signal and the average power of the noise signal, as the first threshold, it can be used to reflect the audio. The output signal of the average power of the signal is compared with the first threshold to determine whether the audio signal is a speech signal or a noise signal, thereby generating a noise cancellation control signal.

Since the audio signal is generally continuous, there may be a delay in detecting the effective value of the received audio signal. In order to avoid the delay of the noise cancellation due to the RMS detection of the received audio signal, the accuracy of the speech denoising is reduced. In an embodiment, the step of performing RMS detection on the received audio signal to obtain an output signal for reflecting the average power of the audio signal specifically includes:

A. judging whether the received audio signal is a voice signal, and generating trigger information of the effective value detection according to the judgment result and the previously generated noise cancellation control signal, and when the trigger signal of the effective value detection indicates that the effective detection of the audio signal is required When the step B is performed, otherwise, step C is performed. The specific process is as follows:

A1: comparing the received audio signal with a second threshold, determining whether the audio signal is a voice signal, and obtaining a forward comparison result; wherein the second threshold is a minimum value of the forward voice signal, and the specific setting depends on the sensitivity of the microphone. And the case of the sensitivity of the collection of different sound pressure noise, the specific setting work should be combined with acoustic theory and experimental statistics. When comparing the received audio signal with the second threshold, when the audio signal is greater than the second threshold, determining that the audio signal is a voice signal, the forward comparison result is logically true; when the audio signal is less than the second threshold, determining The audio signal is a noise signal, and the result of the forward comparison is logically false.

A2: comparing the received audio signal with a preset third threshold, determining whether the audio signal is a voice signal, and obtaining a reverse comparison result; wherein the third threshold is a maximum value of the reverse voice signal, which depends on the microphone Sensitivity, and the sensitivity of the situation depends on the collection of different sound pressure noise, the specific setting work should be combined with acoustic theory and experimental statistics. When comparing the received audio signal with a preset third threshold, if the audio signal is less than the third threshold, determining that the audio signal is a voice signal, the reverse comparison result is logically true; if the audio signal is greater than the third threshold Then, the audio signal is determined to be a noise signal, and the reverse comparison result is logically false.

A3. Perform logical processing on the forward comparison result and the reverse comparison result to determine whether the audio signal is a voice signal.

In the embodiment of the present invention, whether the received audio signal is a voice signal is determined by logically processing the forward comparison result and the reverse comparison result. When one of the forward comparison result or the reverse comparison result is logically true, the logical or processed result is logically true, the audio signal is determined to be a speech signal, and the output logic is true; when the forward comparison result and the reverse comparison result are When all are false, the logical or processed result is logically false, and the audio signal is determined to be a noise signal, and the output logic is false.

A4. The logical processing result is logically processed with the previously generated denoising control signal to generate a trigger signal for detecting the effective value.

In the embodiment of the present invention, by logically processing the logical processing result and the previously generated denoising control signal, when any one of the logical processing result or the previous generated denoising control signal is logically true, Then, it is determined that the RMS value of the audio signal needs to be detected, and the trigger signal of the output RMS detection is logically true; when the logic processing result and the previously generated denoising control signal are both logically false, it is determined that the audio signal is not required. The rms detection is performed, and the trigger signal of the output RMS detection is logically false.

In order to improve the processing precision of the audio signal and reduce the error when the amplitude of the audio signal is small, in another embodiment of the present invention, before determining whether the received audio signal is a voice signal, the method further includes the following steps. :

The pre-amplification process is performed on the received audio signal.

B. Performing an RMS detection on the audio signal to generate an output signal for reflecting the average power of the audio signal. The specific implementation process of detecting the effective value of the audio signal belongs to the prior art, and details are not described herein again.

C. The rms detection of the audio signal is not performed, and an output signal of an inherent initial value is maintained. The inherent initial value is used to reflect the average power of the noise signal in the audio signal.

In the embodiment of the present invention, by detecting the effective value of the voice signal in the audio signal, an output of the inherent initial value is maintained in the noise segment, so that in the specific circuit design, the effective value detecting portion can be prevented on the one hand. The delay condition at the start of detecting the average power of the speech signal, that is, the output signal with the RMS detection is smaller than the true value, and on the other hand, the output can be kept constant under the condition of noise, thereby saving power consumption.

In step S102, an output signal for reflecting the average power of the audio signal is compared with a first threshold to generate a noise canceling control signal.

In the embodiment of the present invention, according to the difference between the average power of the voice signal and the average power of the noise signal, a threshold between the average power of the voice signal and the average power of the noise signal is set, and the threshold is used as the first value. a threshold value, by comparing the output signal for reflecting the average power of the audio signal with the first threshold, the speech signal and the noise signal in the audio signal can be distinguished, thereby generating a denoising control for controlling the denoising process signal.

In order to achieve a more comfortable voice signal, in another embodiment of the present invention, the step of comparing the output signal for reflecting the average power of the audio signal with the first threshold, the step of generating the noise canceling control signal specifically includes:

A. Comparing an output signal for reflecting an average power of the audio signal with a fourth threshold, and extracting a control signal of the effective voice signal;

The fourth threshold is mainly used for detecting a valid voice signal, that is, setting a noise threshold. The setting depends on the sensitivity of the microphone, and the sensitivity of the case depends on the collection of different sound pressure noise. The specific setting work should be combined with acoustic theory and experimental statistics. In the embodiment of the present invention, when a valid voice signal is detected, the output logic is true, and when the valid voice signal is not detected, the logic is false.

B. Compensating the control signal of the extracted effective speech signal to obtain a control signal for compensating the processed effective speech signal;

C. Comparing the output signal for reflecting the average power of the audio signal with the fifth threshold, and extracting the control signal of the oversized signal; wherein the fifth threshold is mainly used for detecting the valid voice signal, that is, setting the noise threshold. The setting depends on the sensitivity of the microphone, and the sensitivity of the case depends on the collection of different sound pressure noise. The specific setting work should be combined with acoustic theory and experimental statistics. In the embodiment of the present invention, when the oversized speech signal is detected, the output logic is true, and when the oversized speech signal is not detected, the logic is false.

D. XOR processing the control signal of the compensated effective speech signal and the extracted super large signal to generate a denoising control signal.

In the embodiment of the present invention, when the control signal of the compensated effective voice signal and the control signal of the extracted oversized signal are XORed, if the logic value of the control signal of the effective voice signal and the control signal of the oversize signal is not When the same, the output logic is true, and when it is the same, the output logic is false. For example, when the control signal of the effective speech signal and the control signal of the extracted super-large signal are both logically true, it means that the valid speech signal is detected, and the super-large speech signal is detected, and after the exclusive-OR processing, the generated de-noise control signal is logic. False; when the control signal of the effective speech signal and the control signal of the extracted super-large signal are both logically false, it means that no valid speech signal is detected, and no over-large speech signal is detected, and the de-noise control is generated after the exclusive-OR processing The signal is still logically false; when the control signal of the effective speech signal is logically true, and the control signal of the extracted super-large signal is logically false, it means that the valid speech signal is detected, and the super-large speech signal is not detected, and the XOR is processed. The generated noise canceling control signal is logically true; when the control signal of the effective voice signal is logically false, and the control signal of the extracted oversized signal is logically true, it means that no valid voice signal is detected, and no excessive voice is detected. After the signal is processed by XOR, the generated noise cancellation control signal is logically true.

In step S103, under the control of the noise canceling control signal, the noise signal in the audio signal is subjected to cancellation processing, and the voice signal is amplified.

In the embodiment of the present invention, when the noise cancellation control signal is logic true, the audio signal is amplified, and when the noise cancellation control signal is logic false, the audio signal is cancelled, thereby eliminating the background noise of the voice and simultaneously amplifying Voice signal to eliminate the noise of the background background. In the control of the noise-cancellation control signal, the noise signal in the audio signal is cancelled, and the voice signal is amplified. For example, under the control of the noise-cancellation control signal, the audio signal is directly amplified. Times, or prohibits the output of the audio signal; the audio signal may also be in-phase or inverted under the control of the noise-cancellation control signal to eliminate the noise signal and amplify the voice signal. Of course, according to the noise cancellation control signal, the audio signal may be amplified and processed in other manners, and the audio signal may be cancelled, which will not be exemplified herein.

Since the audio is too large in the received audio signal, if the audio signal is not processed, the audio signal is subsequently enhanced, which will reduce the comfort of the listener. In order to improve the comfort of the listener, In another embodiment of the present invention, before step S103, the method further includes the following steps:

An output signal for reflecting the average power of the audio signal is compared to a sixth threshold to produce an attenuation control signal. The attenuation control signal is used to control different ratios of inverting amplification of the received audio signal to appropriately reduce the excessively large audio signal.

The sixth threshold is a preset maximum power of the allowable audio signal. In the embodiment of the present invention, when the output signal for reflecting the average power of the audio signal is greater than the sixth threshold, the output attenuation control signal is logic true, and the attenuation control signal is used to control a certain proportion of the received audio signal. Attenuating to appropriately reduce the excessive audio signal; when the output signal for reflecting the average power of the audio signal is less than or equal to the sixth threshold, then the output of the attenuation control signal is logically false, and the attenuation control signal is used for the audio signal The inversion amplification of the equal amplitude is performed, that is, the amplitude of the audio signal is not processed.

Under the control of the attenuation control signal, the received audio signal is inversely amplified in different proportions to appropriately reduce the excessive audio signal.

In the embodiment of the present invention, when the volume of the audio signal is in the normal range, the attenuation control signal controls to perform equal-amplitude inversion amplification on the audio signal, that is, the amplitude of the audio signal is not processed, and the inversely amplified signal is obtained; When the volume of the audio signal exceeds the normal range, the attenuation control signal controls a certain proportion of attenuation of the excessive audio signal, thereby appropriately reducing the excessively large audio signal to obtain an inverted amplified signal.

At this time, under the control of the noise canceling control signal, the inversely amplified audio signal is cancelled or amplified to eliminate the noise signal in the inverted amplified audio signal, and the amplified and inverted amplified audio signal is amplified. Voice signal.

The second figure shows the structure of the speech background noise canceling apparatus provided by the embodiment of the present invention. For the convenience of description, only the parts related to the embodiment of the present invention are shown. among them:

The effective value detecting unit (2) performs RMS detection on the received audio signal to obtain an output signal for reflecting the average power of the audio signal. The effective value detecting unit (2) includes a speech signal judging circuit (22), an effective value detecting control circuit (23), and an effective value detecting circuit (24). among them:

The speech signal judging circuit (22) judges whether the received audio signal is a speech signal. In the embodiment of the present invention, in order to improve the accuracy of the judgment, the voice signal determining circuit (22) includes a forward voice signal determining module (221), a reverse voice signal determining module (222), and a first logical processing module. Group (223).

The forward speech signal judging module (221) compares the received audio signal with a second threshold, determines whether the audio signal is a speech signal, and obtains a positive comparison result;

The second threshold is the minimum value of the forward speech signal. The specific setting depends on the sensitivity of the microphone, and the acquisition of different sound pressure noise in the case of the sensitivity. The specific setting work should be combined with acoustic theory and experimental statistics. When comparing the received audio signal with the second threshold, when the audio signal is greater than the second threshold, determining that the audio signal is a voice signal, the forward comparison result is logically true; when the audio signal is less than the second threshold, determining The audio signal is a noise signal, and the result of the forward comparison is logically false.

The reverse voice signal determining module (222) compares the received audio signal with a preset third threshold, determines whether the audio signal is a voice signal, and obtains a reverse comparison result;

The third threshold is the maximum value of the reverse speech signal, which depends on the sensitivity of the microphone, and the sensitivity of the case is different for the collection of different sound pressure noise. The specific setting work should be combined with acoustic theory and experimental statistics. . When comparing the received audio signal with a preset third threshold, if the audio signal is less than the third threshold, determining that the audio signal is a voice signal, the reverse comparison result is logically true; if the audio signal is greater than the third threshold Then, the audio signal is determined to be a noise signal, and the reverse comparison result is logically false.

The first logic processing module (223) logically processes the forward comparison result and the reverse comparison result to determine whether the received audio signal is a voice signal.

In the embodiment of the present invention, whether the received audio signal is a voice signal is determined by logically processing the forward comparison result and the reverse comparison result. When one of the forward comparison result or the reverse comparison result is logically true, the logical or processed result is logically true, the audio signal is determined to be a speech signal, and the output logic is true; when the forward comparison result and the reverse comparison result are When all are false, the logical or processed result is logically false, and the audio signal is determined to be a noise signal, and the output logic is false.

The RMS detection control circuit (23) logically processes the logic processing result output by the first logic processing module (223) and the previous noise cancellation control signal generated by the noise reduction control signal generating unit (3) to generate RMS detection. Trigger signal to control whether rms detection is performed on the audio signal.

In the embodiment of the present invention, the logic processing result is logically ORed with the previous noise cancellation control signal generated by the noise reduction control signal generating unit (3), when the logic processing result or the previous noise cancellation control signal When any one is logically true, it is determined that the audio signal needs to be detected by the effective value; when the logical processing result and the previous denoising control signal are both logically false, it is determined that the effective signal detection of the audio signal is not required.

The RMS detection circuit (24) performs RMS detection on the audio signal under the control of the RMS detection control circuit (23), generates an output signal for reflecting the average power of the audio signal, or does not perform RMS detection on the audio signal. Maintain an output signal of an inherent initial value. The inherent initial value is used to reflect the average power of the noise signal in the audio signal.

In the embodiment of the present invention, by detecting the effective value of the voice signal in the audio signal, an output of the inherent initial value is maintained in the noise segment, so that in the specific circuit design, the effective value detecting portion can be prevented on the one hand. The delay condition at the start of detecting the average power of the speech signal, that is, the output signal with the RMS detection is smaller than the true value, and on the other hand, the output can be kept constant under the condition of noise, thereby saving power consumption.

In order to improve the processing precision of the audio signal and reduce the error when the amplitude of the audio signal is small, in another embodiment of the invention, the apparatus further comprises a signal preamplifying circuit (21). The input end of the signal pre-amplifying circuit (21) is connected to the audio collecting unit (1), and the output end thereof is respectively matched with the forward speech signal judging module (221), the inverted speech signal judging module (222), and the effective value detection. The circuit (24) is connected, and the signal preamplifying circuit (21) performs selective preamplification processing on the received audio signal. At this time, the forward speech signal judging module (221) compares the audio signal outputted by the signal preamplifying circuit (21) with the second threshold, determines whether the audio signal is a speech signal, and obtains a forward comparison result; the reverse speech signal The determining module (222) compares the audio signal outputted by the signal preamplifying circuit (21) with a preset third threshold value, determines whether the audio signal is a voice signal, and obtains a reverse comparison result; the effective value detecting circuit (24) is Under the control of the effective value detection control circuit (23), the audio signal output from the signal preamplification circuit (21) is subjected to RMS detection to generate an output signal for reflecting the average power of the audio signal. In another embodiment of the present invention, under the control of the rms detection control circuit (23), the audible value of the audio signal is not detected, and an output signal of an inherent initial value is maintained.

Since the environment in which the speaker is located is generally complicated, there are various sources of sound other than the speaker, such as the voices of other speakers around, the sounds of surrounding vehicles, etc., so that the received audio signal includes not only the voice of the speaker. The signal also includes noise signals from other sources in the speaker's surroundings.

In the embodiment of the present invention, the received audio signal may be an collected audio signal, or may be an audio signal transmitted from other devices. When the received audio signal is an acquired audio signal, the apparatus further includes an audio collection unit (1). The audio collection unit (1) collects audio signals, wherein the audio signals include voice signals and noise signals. Please refer to the third figure for the specific circuit structure of the audio collection unit (1). It will not be described in detail here.

The noise canceling control signal generating unit (3) compares the output signal generated by the effective value detecting unit (3) for reflecting the average power of the audio signal with the first threshold to generate a noise canceling control signal. The noise cancellation control signal is used to control the noise cancellation amplification unit to perform noise cancellation processing on the audio signal. The first threshold is a threshold between the average power of the preset voice signal and the average power of the noise signal. By comparing the output signal for reflecting the average power of the audio signal with the first threshold, the speech signal and the noise signal in the audio signal can be distinguished, thereby generating a denoising for controlling the denoising amplification unit to the audio signal. The noise canceling control signal processed. The noise reduction control signal generating unit (3) includes an effective voice signal comparison module (31), a large voice signal comparison module (32), a control signal compensation module (33), and a second logic processing module (34). among them:

The effective speech signal comparison module (31) compares the output signal generated by the effective value detecting unit (2) for reflecting the average power of the audio signal with a fourth threshold, and extracts a control signal of the effective speech signal;

The fourth threshold is mainly used for detecting a valid voice signal, that is, setting a noise threshold. The setting depends on the sensitivity of the microphone, and the sensitivity of the case depends on the collection of different sound pressure noise. The specific setting work should be combined with acoustic theory and experimental statistics. In the embodiment of the present invention, when a valid voice signal is detected, the output logic is true, and when the valid voice signal is not detected, the logic is false.

The control signal compensation module (33) compensates the control signal of the effective speech signal extracted by the effective speech signal comparison module (31) to obtain a control signal for compensating the processed effective speech signal;

The oversized speech signal comparison module (32) compares the output signal generated by the effective value detecting unit (2) for reflecting the average power of the audio signal with a fifth threshold, and extracts a control signal of the oversized signal;

The fifth threshold is mainly used for detecting a valid voice signal, that is, setting a noise threshold. The setting depends on the sensitivity of the microphone, and the sensitivity of the case depends on the collection of different sound pressure noise. The specific setting work should be combined with acoustic theory and experimental statistics. In the embodiment of the present invention, when the oversized speech signal is detected, the output logic is true, and when the oversized speech signal is not detected, the logic is false.

The second logic processing module (34) performs an exclusive OR process on the control signal for compensating the processed effective voice signal and the extracted control signal of the oversized signal to generate a noise cancellation control signal.

The noise canceling amplifying unit (4) performs the canceling processing on the noise signal in the audio signal under the control of the noise canceling control signal generated by the noise canceling control signal generating unit (3), and amplifies the voice signal.

The noise canceling amplifying unit (4) cancels the noise signal in the audio signal under the control of the noise canceling control signal, and performs various methods for amplifying the voice signal, such as under the control of the noise canceling control signal, directly The audio signal is amplified by a preset multiple, or the audio signal is prohibited from being outputted; or the audio signal may be in-phase or inverted under the control of the noise-cancelling control signal to eliminate the noise signal and amplify the voice signal. Of course, according to the denoising control signal, the audio signal may be amplified by other methods, and the audio signal is cancelled. Only a specific structure of the noise canceling amplifying unit (4) is provided, which includes the controllable inversion. (41), a first inverting follower (42), a second inverting follower (43), an inverting adder (44), and a low pass filter (45).

Since the audio is too large in the received audio signal, if the audio signal is not processed, the audio signal is subsequently enhanced, which will reduce the comfort of the listener. In order to improve the comfort of the listener, In another embodiment of the invention, the apparatus further includes an attenuation control signal generating unit (5) and an audio controllable attenuation unit (6). among them:

The attenuation control signal generating unit (5) compares the output signal generated by the effective value detecting unit (2) for reflecting the average power of the audio signal with a sixth threshold to generate an attenuation control signal. The attenuation control signal is used to control the audio controllable attenuation unit (6) to perform different proportions of inversion amplification on the received audio signal to appropriately reduce the excessive audio signal.

The sixth threshold is a preset maximum power of the allowable audio signal. In the embodiment of the present invention, when the output signal for reflecting the average power of the audio signal is greater than the sixth threshold, the output attenuation control signal is logic true; when the output signal for reflecting the average power of the audio signal is less than or equal to the first When the threshold is six, the output attenuation control signal is logically false.

The audio controllable attenuation unit (6) performs different proportions of inversion amplification on the received audio signal under the control of the attenuation control signal to appropriately reduce the excessive audio signal.

In the embodiment of the present invention, when the volume of the audio signal is in the normal range, the attenuation control signal controls to perform equal-amplitude inversion amplification on the audio signal, that is, the amplitude of the audio signal is not processed, and the inversely amplified signal is obtained; When the volume of the audio signal exceeds the normal range, the attenuation control signal controls a certain proportion of attenuation of the excessive audio signal, thereby appropriately reducing the excessively large audio signal to obtain an inverted amplified signal.

At this time, the noise canceling amplifying unit (2) cancels or amplifies the audio signal outputted by the audio controllable attenuation unit (6) under the control of the noise canceling control signal to eliminate the impurity in the inverted amplified audio signal. The signal is amplified to amplify the voice signal in the amplified audio signal.

The third figure shows the circuit principle of the audio collecting unit (1) provided by the embodiment of the present invention. The audio collecting unit (1) includes a voltage dividing circuit, a DC blocking circuit and an inverse follower, wherein the piezoelectric routing The microphone 1a is composed of a resistor R1, the DC blocking circuit is composed of a capacitor C1, and the inverter follower is composed of an operational amplifier U1, a resistor R2 and a resistor R3. The microphone is a omnidirectional microphone, such as a conventional microphone such as a mobile phone, for sensing an external audio signal and converting the sound signal into an electrical signal. The electrical signal obtained by the microphone is subjected to a DC blocking process by a DC blocking circuit composed of the first capacitor C1, and the electrical signal is converted into an alternating current signal, and then an inverted follower output signal is output. .

The fourth figure shows the circuit principle of the signal preamplifying circuit (21) provided by the embodiment of the present invention. The signal preamplifier circuit (21) includes an operational amplifier U7, a resistor R16 coupled to one of the inputs of the operational amplifier U7, and a resistor R17 coupled across the input and output terminals of the operational amplifier. The signal pre-amplification circuit (21) realizes the output signal to the signal acquisition unit (1) by adjusting the ratio of the resistor R16 and the resistor R17 according to the processing precision actually required by the system. Performing a pre-amplification process to obtain a pre-amplified signal .

The fifth figure shows the circuit principle of the forward speech signal judging module (221) and the reverse speech signal judging module (222) provided by the embodiment of the present invention.

The forward speech signal judging module (221) and the reverse speech signal judging module (222) each include a comparator U8 and a Schmitt inverter (U9, U10), and the comparator U8 uses a signal preamplifying circuit (21). ) processed audio signal Comparing with the preset first threshold, and then shaping the noise through the Schmitt inverter (U9, U10), and obtaining a comparison result signal The audio signal processed by the signal preamplifier circuit (21) Comparing with the preset second threshold, and then shaping the noise by the Schmitt inverter (U9, U10), and obtaining the comparison result signal .

The sixth figure shows the circuit principle of the first logic processing module (223) provided by the embodiment of the present invention.

The first logic processing module (223) is composed of a logic or gate U11, and the two input signals of the logic or gate U11 are respectively output signals of the forward speech signal judging module (221). And the output signal of the reverse speech signal judging module (222) When the forward speech signal judges the output signal of the module (221) And the output signal of the reverse speech signal judging module (222) When any one of them is true, that is, when any one of the forward speech signal judging module (221) and the reverse speech signal judging module (222) determines that the audio signal is a speech signal, after being processed by the logic or gate U11 Its output signal True, that is, after processing by logic or gate U11, it is determined that the audio signal is a voice signal, otherwise, the audio signal is determined to be a noise signal.

The seventh figure shows the circuit principle of the RMS detection control circuit (23) and the RMS detection circuit (24) provided by the embodiment of the present invention.

The rms detection control circuit (23) includes a logic OR gate U13 and a second selection switch S3. The two input ends of the logic OR gate U13 are respectively connected to the output end of the first logic processing module (223), and the other input end and the second logic processing module included in the noise canceling control signal generating unit (3) ( The output terminal of 34) is connected, the output signal of the logic or gate U13 is used as the control signal of the second selection switch S3, and the effective value detection circuit (24) is controlled by the second selection switch S3 to detect the effective value of the audio signal. The output of the inherent initial value V1 is directly maintained by the output signal reflecting the average power of the audio signal or without the rms detection of the audio signal. The circuit works as follows:

The logic OR gate U13 outputs the output signal of the first logic processing module (223) And the output signal of the second logic processing module (34) Performing or processing to obtain a control signal as an alternative selection switch S3 ,control signal Controlling the output signal of the second selection switch in the signal preamplifier circuit (21) Switching between the preset natural initial value V1 and obtaining the output signal Through the output signal Controlling the output signal of the effective value detecting circuit (24) to the signal preamplifying circuit (21) The effective value detection is performed, and an output signal DD for reflecting the average power of the audio signal is generated, or the output of the inherent initial value V1 is directly maintained without performing rms detection on the audio signal.

The eighth figure shows the circuit principle of the effective speech signal comparison module (31) and the oversized speech signal comparison module (32) provided by the embodiments of the present invention.

The effective speech signal comparison module (31) includes a comparator U15 and a Schmitt inverter (U17, U18), and the comparator U15 performs the output signal DD of the rms detection circuit (24) with a preset fourth threshold. Comparison, outputting control signals for effective speech signals, outputting control signals for effective speech . The fourth threshold is mainly used for detecting a valid voice signal, that is, setting a noise threshold. The setting depends on the sensitivity of the microphone, and the sensitivity of the situation depends on the collection of different sound pressure noise. The specific setting work should be combined with acoustic theory and experimental statistics. When the comparison is made, when the signal DD is greater than the fourth threshold, the output of the effective speech signal comparison module (31) is logically true, representing the speech signal. When it is less than the fourth threshold, the output logic of the effective speech signal comparison module (31) is false, representing a noise signal.

The oversized speech signal comparison module (32) includes a comparator U16 and a Schmitt inverter (U19, U20), and the comparator U16 performs the output signal DD of the rms detection circuit (24) with a preset fifth threshold. Comparison, in order to extract the control signal for the super large signal, output the control signal of the super large signal . In the process of communication, it is inevitable that wind noise will appear in the communication environment, and the sudden large noise will give the receiver (listener) a harsh sound. In this case, the large voice signal comparison module (32) The control signal is extracted for the oversized signal, so that the noise canceling amplifying unit (4) cancels the oversized signal and improves the hearing comfort of the listener.

The ninth figure shows the circuit principle of the control signal compensation module (33) provided by the embodiment of the present invention.

The control signal compensation module (33) includes a multivibrator U21 and or a gate U22. The multivibrator U21 detects the falling edge of the output pulse of the effective speech signal comparison module (31). Once the falling edge is detected, the multivibrator outputs a pulse signal of a unique width, and the valid speech can be obtained after the U22 gate The output pulse of the signal comparison module (31) compensates for the unique pulse width, and obtains the control signal of the effective speech after the compensation process. . In this way, at the end of the voice, the loss of voice and the high-quality restored voice can be reduced.

The tenth figure shows the circuit principle of the second logic processing module (34) provided by the embodiment of the present invention.

The second logic processing module (34) is comprised of a logical exclusive OR gate U23. Control signal compensation module (33) output signal And the output signal of the module (32) compared with the oversized speech signal And respectively sent to the input end of the second logic processing module (34), the two signals are XORed to form a noise canceling control signal , the noise canceling control signal The control noise cancellation amplifying unit (4) performs denoising processing on the audio signal processed by the audio controllable attenuation unit (6).

The eleventh diagram shows the circuit principle of the attenuation control signal generating unit (5) provided by the embodiment of the present invention.

The attenuation control signal generating unit (5) is constituted by a comparator U12, and one of the input signals of the comparator U12 is an output signal DD output by the effective value detecting circuit (24) for reflecting the average power of the audio signal, and the other input The signal is a preset sixth threshold, and the comparator U12 compares the output signal DD with a preset sixth threshold to generate an attenuation control signal. . Attenuation control signal The audio controllable attenuation unit (6) is used to perform different proportions of inversion amplification on the audio signal output by the audio collection unit (1). In the embodiment of the present invention, when the output signal for reflecting the average power of the audio signal is greater than the preset sixth threshold, the generated attenuation control signal The control audio controllable attenuation unit (6) performs equal-amplitude inversion amplification on the audio signal, that is, does not attenuate the amplitude of the audio signal; when the output signal for reflecting the average power of the audio signal is less than or equal to the preset number Attenuation control signal generated at six thresholds The control audio controllable attenuation unit (6) attenuates the excessively large audio signal by a certain proportion to appropriately reduce the excessive audio signal.

Figure 12 shows the circuit principle of the audio controllable attenuation unit (6) provided by the embodiment of the present invention.

The audio controllable attenuation unit (6) includes an operational amplifier U2, a control switch S1, and resistors R3, R4, and R5. The resistor R3 and the resistor R4 are connected in series and connected to the input end of the operational amplifier U2. The control switch S1 is connected in parallel across the resistor R3, and the resistor R5 is connected across the input end and the output end of the operational amplifier U2. The control signal of the control switch S1 is derived from the attenuation control signal generated by the attenuation control signal generating unit (5) Attenuation control signal Controlling the on and off of the control switch to implement an audio signal output to the audio collection unit (1) Perform different ratios of inverting amplification to obtain an inverted amplified signal . In the embodiment of the present invention, when the volume of the audio signal is in the normal range, the attenuation control signal is Controlling the audio controllable attenuation unit (6) to perform equal-amplitude inversion amplification on the audio signal, that is, not processing the amplitude of the audio signal to obtain an inverted amplified signal Attenuation control signal when the volume of the audio signal is outside the normal range Controlling the audio controllable attenuation unit (6) to attenuate a certain proportion of the excessively large audio signal, thereby appropriately reducing the excessively large audio signal to obtain an inverted amplified signal .

Figure 13 shows the circuit principle of the controllable inverter (41) provided by the embodiment of the present invention.

The two inputs of the controllable inverter (41) are respectively connected to the output of the audio controllable attenuation unit (6) and the second logic processing module (34). The controllable inverter (41) comprises an operational amplifier U3, resistors R6, R7 and a second selection switch S2, wherein the resistor R6 is connected to one of the input terminals of the operational amplifier U3, and the resistor R7 is connected across the input of the operational amplifier U3. End and output, two select one switch S2 in the noise canceling control signal Inverted amplified signal Perform in-phase or inverting processing to obtain a signal . Enhance the inverted amplified signal when performing in-phase processing , get the signal Eliminate noise and get a signal when performing inversion processing .

The fourteenth and fifteenth figures illustrate the circuit principle of the first inverting follower (42) and the second inverting follower (43) provided by the embodiment of the present invention.

The input of the first inverting follower (42) is connected to the output of the audio controllable attenuation unit (6), and the output thereof is connected to the input of the inverting adder (41). The first inverting follower (42) includes an operational amplifier U4, a resistor R8 coupled to one of the inputs of the operational amplifier U4, and a resistor R9 coupled across the input and output terminals of the operational amplifier U4. The input signal is the output signal of the audio controllable attenuation unit (6) ,output signal The input of the second inverting follower (43) is connected to the controllable inverter (41), and the output thereof is connected to the input of the inverting adder. The second inverting follower (43) includes an operational amplifier U5, a resistor R10 coupled to one of the inputs of the operational amplifier U5, and a resistor R11 coupled across the input and output terminals of the operational amplifier U5. The input signal is the output signal of the inverting adder (41) ,output signal .

Figure 16 shows the circuit principle of the inverting adder (44) provided by the embodiment of the present invention.

The two input terminals of the inverting adder (44) are respectively connected to the outputs of the first inverting follower (42) and the second inverting follower (43), which comprise an operational amplifier U6, and an operational amplifier U6 A resistor R12 connected to one input terminal and a resistor R13 connected to the other input terminal of the operational amplifier U6 are connected across the input end of the resistor R13 of the operational amplifier U6 and the resistor R14 at the output end of the operational amplifier U6. The two input signals of the inverting adder (44) are respectively input signals of the first inverting follower (42) Output signal of the second inverting follower (43) ,output signal .

Figure 17 shows the circuit principle of the low pass filter (45) provided by the embodiment of the present invention.

The input of the low pass filter is coupled to the output of the inverting adder (44). It includes a first resistor R15 and a capacitor C2. The low pass filter (44) filters out additional out-of-band noise in the device, preserving the frequency components within the speech band.

In the embodiment of the present invention, an output signal for reflecting the average power of the audio signal is obtained by performing RMS detection on the received audio signal, by performing the output signal for reflecting the average power of the audio signal with the first threshold. Comparing, the denoising control signal is generated, and the noise signal in the audio signal is cancelled under the control of the denoising control signal, and the speech signal is amplified, thereby eliminating the background noise of the speech. At the same time, by comparing the output signal for reflecting the average power of the audio signal with the sixth threshold, an attenuation control signal is generated, and the received audio signal is inversely amplified in different proportions under the control of the attenuation control signal to appropriately reduce Excessive audio signal improves the hearing comfort of the receiver.

In summary, this creation can indeed achieve the above functions and purposes, so this creation should meet the requirements of the patent application, and apply in accordance with the law.

(1)‧‧‧Input and audio acquisition unit

(2) ‧ ‧ RMS detection unit

(21)‧‧‧Signal preamplifier circuit

(22)‧‧‧Voice signal judgment circuit

(221)‧‧‧ Forward speech signal judgment module

(222)‧‧‧Reverse voice signal judgment module

(223)‧‧‧First logic processing module

(23)‧‧‧effective value detection control circuit

(24)‧‧‧effective value detection circuit

(3) ‧‧‧Denoising control signal generating unit

(31)‧‧‧Efficient voice signal comparison module

(32)‧‧‧Oversized speech signal comparison module

(33)‧‧‧Control signal compensation module

(34)‧‧‧Second logic processing module

(4) ‧ ‧ denoising amplification unit

(41) ‧‧‧Controllable inverter

(42)‧‧‧First Inverting Follower

(43)‧‧‧Second inverting follower

(44)‧‧‧Inverse adder

(45)‧‧‧Low-pass filter

(5) ‧‧‧Attenuation control signal generation unit

(6) ‧‧‧Audio controllable attenuation unit

The first figure is a flowchart for implementing a method for canceling speech background noise provided by an embodiment of the present invention;

The second figure is a structural block diagram of a voice background noise canceling apparatus provided by an embodiment of the present invention;

The third figure is a circuit schematic diagram of an audio collection unit provided by an embodiment of the present invention;

The fourth figure is a circuit schematic diagram of a signal preamplification circuit provided by an embodiment of the present invention;

The fifth figure is a circuit schematic diagram of the forward speech signal judging module and the reverse speech signal judging module provided by the embodiment of the invention;

The sixth figure is a circuit schematic diagram of the first logic processing module provided by the embodiment of the present invention;

The seventh figure is a circuit schematic diagram of the RMS detection control circuit and the RMS detection circuit provided by the embodiment of the present invention;

The eighth figure is a circuit schematic diagram of an effective voice signal comparison module and a large voice signal comparison module provided by an embodiment of the present invention;

The ninth figure is a circuit schematic diagram of a control signal compensation module provided by an embodiment of the present invention;

FIG. 10 is a circuit schematic diagram of a second logic processing module according to an embodiment of the present invention;

11 is a circuit schematic diagram of an attenuation control signal generating unit provided by an embodiment of the present invention;

Figure 12 is a circuit schematic diagram of an audio controllable attenuation unit provided by an embodiment of the present invention;

Figure 13 is a circuit schematic diagram of a controllable inverter provided by an embodiment of the present invention;

The fourteenth and fifteenth drawings are circuit schematic diagrams of the first inverting follower and the second inverting follower provided by the embodiment of the present invention;

Figure 16 is a circuit schematic diagram of an inverting adder according to an embodiment of the present invention;

Figure 17 is a circuit schematic diagram of a low pass filter provided by an embodiment of the present invention.

(1)‧‧‧Audio acquisition unit

(2) ‧ ‧ RMS detection unit

(21)‧‧‧Signal preamplifier circuit

(22)‧‧‧Voice signal judgment circuit

(23)‧‧‧effective value detection control circuit

(24)‧‧‧effective value detection circuit

(3) ‧‧‧Denoising control signal generating unit

(31)‧‧‧Efficient voice signal comparison module

(32)‧‧‧Oversized speech signal comparison module

(33)‧‧‧Control signal compensation module

(34)‧‧‧Second logic processing module

(4) ‧ ‧ denoising amplification unit

(41) ‧‧‧Controllable inverter

(42)‧‧‧First Inverting Follower

(43)‧‧‧Second inverting follower

(44)‧‧‧Inverse adder

(45)‧‧‧Low-pass filter

(5) ‧‧‧Attenuation control signal generation unit

(6) ‧‧‧Audio controllable attenuation unit

Claims (16)

A method for canceling speech background noise, the method comprising the steps of: A: performing an effective value detection on a received audio signal to obtain an output signal for reflecting an average power of the audio signal; and B, which is to be used for reflecting the audio signal. The output signal of the average power is compared with the first threshold to generate a noise cancellation control signal, the first threshold being a threshold value of the average power of the voice signal and the average power of the noise signal; C. at the noise cancellation control signal Under control, the noise signal in the audio signal is cancelled, and the voice signal is amplified. The method for canceling speech background noise according to claim 1, wherein the step A specifically includes: A1, determining whether the received audio signal is a speech signal, and according to the judgment result and the previous denoising control The signal generates a trigger signal for detecting the effective value; A2, detecting the effective value of the audio signal according to the trigger signal detected by the effective value, and generating an output signal for reflecting the average power of the audio signal. The method for canceling speech background noise according to claim 2, wherein the step A1 comprises the following steps: performing selective pre-amplification processing on the received audio signal. The method for canceling speech background noise according to claim 2, wherein the step A1 comprises: comparing the received audio signal with a second threshold, determining whether the audio signal is a speech signal, and obtaining a positive comparison result. Comparing the received audio signal with a preset third threshold to determine whether the audio signal is a speech signal, and obtaining a reverse comparison result; performing logical processing on the forward comparison result and the reverse comparison result to determine whether the audio signal is The voice signal is logically processed by the logic processing result and the previously generated noise cancellation control signal to generate a trigger signal for detecting the effective value. The method for canceling speech background noise according to claim 1, wherein the step B comprises: B1, comparing an output signal for reflecting an average power of the audio signal with a fourth threshold, and extracting an effective speech signal. Control signal; B2, compensating the control signal of the extracted effective speech signal to obtain a control signal for compensating the processed effective speech signal; B3, comparing the output signal for reflecting the average power of the audio signal with the fifth threshold And extracting a control signal of the super-large signal; B4, performing an exclusive-OR processing on the control signal of the compensated effective speech signal and the extracted super-large signal control signal to generate a de-noise control signal. The method for canceling speech background noise according to claim 1, wherein the step A comprises: comparing an output signal for reflecting an average power of the audio signal with a sixth threshold to generate an attenuation control signal; Under the control of the attenuation control signal, the received audio signal is subjected to different proportions of inversion amplification to appropriately reduce the excessively large audio signal. A voice background noise cancellation device includes: an effective value detecting unit configured to perform an effective value detection on a received audio signal to obtain an output signal for reflecting an average power of the audio signal; and a noise cancellation control signal generating unit And comparing the output signal generated by the effective value detecting unit for reflecting the average power of the audio signal with the first threshold to generate a noise canceling control signal, where the first threshold is the average power of the voice signal and the noise signal a threshold value of the average power; a noise cancellation amplifying unit, configured to cancel the noise signal in the audio signal under the control of the noise canceling control signal generated by the noise canceling control signal generating unit, and perform amplification processing on the voice signal . The apparatus for canceling speech background noise according to claim 7, wherein the effective value detecting unit comprises: a speech signal judging circuit, configured to determine whether the received audio signal is a speech signal; and an effective value detection control circuit, And performing logic processing according to the determination result of the voice signal determination circuit and the previously generated noise cancellation control signal to generate a trigger signal for detecting the effective value; and the effective value detection circuit is configured to generate the detection circuit according to the effective value The trigger signal of the rms detection detects the rms value of the audio signal to generate an output signal for reflecting the average power of the audio signal. The apparatus for canceling speech background noise according to claim 8, wherein the effective value detecting unit comprises: a signal preamplifying circuit, wherein an output end thereof is respectively connected to the speech signal judging circuit and the effective value detecting circuit, For selective pre-amplification processing of the received audio signal. The apparatus for eliminating speech background noise according to claim 8, wherein the speech signal judging circuit comprises: a forward speech signal judging module, configured to compare the received audio signal with a second threshold, and determine Whether the audio signal is a voice signal, and a forward comparison result is obtained; the reverse voice signal determining module is configured to compare the received audio signal with a preset third threshold, determine whether the audio signal is a voice signal, and obtain a reverse comparison. a first logic processing module, configured to logically or logically process the forward comparison result obtained by the forward speech signal judgment module and the reverse comparison result obtained by the reverse speech signal judgment module, to determine whether the audio signal is For voice signals. The apparatus for canceling speech background noise according to claim 10, wherein the forward speech signal judging module and the reverse speech signal judging module are each composed of a comparator and a Schmitt inverter. The apparatus for canceling speech background noise according to claim 8, wherein the rms detection control circuit comprises a logic OR gate and a second selection switch connected to an output of the logic or gate. The apparatus for canceling a voice background noise according to the seventh aspect of the invention, wherein the noise cancellation control signal generating unit comprises: an effective voice signal comparison module, configured to reflect the generated by the effective value detecting unit The output signal of the average power of the audio signal is compared with a fourth threshold to extract a control signal of the effective voice signal; and the control signal compensation module is configured to compensate the control signal of the effective voice signal extracted by the effective voice signal comparison module Obtaining a control signal for the processed effective voice signal; the oversized voice signal comparison module is configured to compare the output signal generated by the effective value detecting unit for reflecting the average power of the audio signal with a fifth threshold, and extract a control signal of the super-large signal; a second logic processing module, configured to perform an exclusive OR of the control signal of the effective speech signal after the control signal compensation module compensates the processing and the control signal of the super-large signal extracted by the super-large speech signal comparison module Processing, generating a noise cancellation control signal. The apparatus for canceling a voice background noise according to claim 13 , wherein the control signal compensation module comprises: a multivibrator for detecting a falling edge of an output pulse of the effective voice signal comparison module Once a falling edge is detected, a pulse signal of a unique width is output; or a gate is used to compensate the output pulse of the effective speech signal comparison module to widen the pulse signal of the unique width output by the multivibrator. The apparatus for canceling speech background noise according to claim 7, wherein the apparatus further comprises: an attenuation control signal generating unit, configured to reflect an average power generated by the effective value detecting unit for reflecting the audio signal The output signal is compared with a sixth threshold to generate an attenuation control signal. The audio controllable attenuation unit is configured to perform different ratios on the received audio signal under the control of the attenuation control signal generated by the attenuation control signal generating unit. Zoom in to properly shrink the oversized audio signal. The apparatus for canceling speech background noise according to claim 7, wherein the noise cancellation amplifying unit comprises a first inverting follower and a controllable inverter, and an output of the controllable inverter a connected second inverting follower, an inverting adder coupled to an output of the first inverting follower and the second inverting follower, respectively, and a low connection to an output of the inverting adder Pass filter.