JP2010068108A - Intercom system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more accurately perform discrimination such that a voice signal is a silent signal or a sound signal compliant with various conditions such as surrounding environment, sex, etc. while inserting loss compliant with a plurality of every frequency bands of the voice signal discriminated as the sound signal, suppressing noise components of the voice signal, and raising communication quality. <P>SOLUTION: The system respectively divides a reception side digital voice signal output from a master unit speaker of a living room master unit 2, and a transmission side digital voice signal output from a slave unit speaker as a reception signal into a plurality of frequency bands using band division processing circuits 250a, 250b of a voice processing unit 205. Signal discrimination circuits 253a, 253b perform discrimination of the digital voice signal divided into the plurality of the frequency bands whether the signals are the silent signal or the sound signal based on a signal discrimination threshold predetermined for the every frequency bands beforehand. Attenuators 254a, 254b controlled by an attenuator control circuit 256, insert loss for the plurality of the every frequency bands of the voice signal discriminated as the silent signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an interphone system that establishes a call by transmitting and receiving an audio signal between an entrance cordless handset and a room base phone connected via a wired transmission path or a wireless transmission path, and in particular, improves call quality. Related to the intercom system.

  Conventionally, it is possible to accurately discriminate a voice part by using a cepstrum analysis method with respect to a voice signal mixed with noise, and to predict noise with respect to the voice signal mixed with noise, and to remove the noise, thereby improving the quality. An audio signal processing device is disclosed that obtains an audio signal and cuts out the audio from the audio signal so that the audio can be accurately cut out and recognized by the audio (see, for example, Patent Document 1).

  Similarly to the voice signal processing apparatus described in Patent Document 1, it is possible to recognize a voice signal and determine whether the voice signal is a silence signal or a voice signal. The intercom system of Japanese Patent Application No. 2008-19063 has been filed in which the erroneous discrimination is prevented and the call quality is improved.

Japanese Patent No. 3106543

  According to the intercom system of Japanese Patent Application No. 2008-19063 among the background arts, a digital audio signal is divided into a plurality of frequency bands, a predetermined threshold value is set for each divided frequency band, and a comparison with this threshold value is also made. It is possible to determine whether the signal is a silent signal or a sound signal, but it does not have any function / action to remove the noise component that causes the erroneous determination, and the above threshold is fixed. Therefore, it could not cope with various conditions such as the surrounding environment and sex.

  The present invention has been made to solve this difficulty, and inserts losses for each of a plurality of frequency bands of a voice signal determined as a silence signal, thereby suppressing a noise component of the voice signal and improving a call quality. It is an object of the present invention to provide an intercom system that can determine whether the signal is a silent signal or a sound signal in accordance with various conditions such as the surrounding environment and sex, with higher accuracy.

  In order to achieve the above object, an interphone system according to a first aspect of the present invention is connected to an entrance cordless handset having a handset microphone and handset speaker via a wired transmission path or a wireless transmission path. In addition, there is provided a parent device microphone having a parent device microphone and a parent device speaker for inputting / outputting an audio signal for establishing a call between the child device microphone and the child device speaker of the entrance child device. In the living room master unit, the analog audio signal sent to the base unit microphone is converted into a digital audio signal to be sent, and the input signal is sent to the cordless handset microphone and transmitted via the transmission path. The base audio codec for digital / analog conversion of the incoming digital audio signal to the incoming analog audio signal and outputting it from the main speaker, and the transmission transmitted through the transmission line from the main audio codec to the transmission path And a voice processing unit for controlling transmission / reception of the digital voice signal and the received digital voice signal transmitted through the transmission line from the transmission path to the master voice codec. The voice processing unit includes a transmission side band division processing circuit for dividing a transmission digital voice signal into a plurality of frequency bands, and a reception side band division processing circuit for dividing the reception digital voice signal into a plurality of frequency bands. A transmission side noise level calculation circuit for calculating the noise level of the transmitted digital voice signal divided into a plurality of frequency bands by the transmission side band division processing circuit, and a plurality of reception side band division processing circuits. Based on the calculation result of the reception side noise level calculation circuit and the transmission side noise level calculation circuit for calculating the noise level of the received digital audio signal divided into the frequency bands of Pre-set based on the calculation results of the transmitter signal discrimination circuit and the receiver noise level calculator for determining whether the transmitted digital audio signal is a silence signal or a voice signal Based on the discrimination results of the receiver side signal discriminating circuit, the transmitter side signal discriminating circuit, and the receiver side signal discriminating circuit for discriminating whether the received digital audio signal is a silence signal or a voice signal based on the received signal discrimination threshold. In addition, the transmission side attenuator for attenuating the transmitted digital audio signal by an amount weighted for each divided band and the reception side attenuator for attenuating the received digital audio signal by an amount weighted for each divided band. An attenuator control circuit for controlling the attenuation level by inserting, a transmission side waveform synthesis processing circuit for processing a waveform so that a transmission digital voice signal of each frequency band from the transmission side attenuator is synthesized, A receiving-side waveform synthesis processing circuit for processing a waveform so as to synthesize a received digital voice signal of each frequency band from the receiving-side attenuator.

  The intercom system according to the second aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the transmission side noise level calculation circuit and the reception side noise level calculation circuit are different from each other in the input digital audio signal. The noise level is calculated by comparing the mean square sum derived in a plurality of frequency bands with a preset noise judgment threshold.

  Further, the interphone system according to the third aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the transmission side noise level calculation circuit and the reception side noise level calculation circuit are different from each other in the inputted digital audio signal. A noise level is calculated by comparing a correlation value of autocorrelation derived in a plurality of frequency bands with a preset noise determination threshold value.

  The interphone system according to the fourth aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the transmitting side noise level calculating circuit and the receiving side noise level calculating circuit are different from each other in the inputted digital audio signal. The noise level is calculated by comparing the correlation value of the cross correlation between frames derived in a plurality of frequency bands with a preset noise determination threshold.

  The interphone system according to the fifth aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the transmitting side signal discriminating circuit and the receiving side signal discriminating circuit each have a plurality of different input digital audio signals. The mean square sum derived in the frequency band is compared with a preset signal discrimination threshold to determine whether the signal is a silence signal or a sound signal.

  The interphone system according to the sixth aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the transmitting side signal discriminating circuit and the receiving side signal discriminating circuit each have a plurality of different input digital audio signals. The autocorrelation correlation value derived in the frequency band is compared with a preset signal discrimination threshold to determine whether the signal is a silence signal or a sound signal.

  The intercom system according to the seventh aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the transmitting side signal discriminating circuit and the receiving side signal discriminating circuit each have a plurality of different input digital audio signals. The correlation value of the inter-frame cross-correlation derived in the frequency band is compared with a preset signal determination threshold value to determine whether the signal is a silence signal or a sound signal.

  In the intercom system according to the eighth aspect of the present invention, in the fifth to seventh aspects of the present invention, the comparison operations performed by the transmitting side signal determining circuit and the receiving side signal determining circuit, respectively, This is based on a comparison with a signal discrimination threshold within a certain time.

  The intercom system according to the ninth aspect of the present invention is the interphone system according to the fifth to eighth aspects of the present invention, wherein the signal discrimination threshold is determined by the transmission side band division processing circuit and the reception side band division processing circuit. It is dynamically updated based on the average intensity for each of a plurality of divided frequency bands.

  According to the intercom system of the present invention, an incoming call is received from a master unit speaker of a base unit connected to the entrance unit via a wired transmission line or a wireless transmission line. Receiver digital audio signal to be output as voice, and input to the base unit microphone of the home base unit, and connected to the home base unit via a wired transmission line or a wireless transmission path. Each of the digital audio signals on the transmitting side to be output as the received voice from is divided into a plurality of frequency bands by the band division processing circuit constituting the voice processing unit of the living room master unit, and the digital divided into the plurality of frequency bands For audio signals, a signal discrimination circuit discriminates a silence signal or a sound signal based on a signal discrimination threshold set in advance for each frequency band. For each frequency band, by inserting a loss in the attenuator, which is controlled by the attenuator control circuit, it is possible to suppress the noise component of the audio signal, it is possible to improve the call quality.

  Further, according to the intercom system of the present invention, the noise level of the digital audio signal calculated by the transmitting side noise level calculating circuit and the receiving side noise level calculating circuit is set to a plurality of different frequencies of the input digital audio signal. Comparison between the mean square sum derived in the band and a noise determination threshold value within a predetermined time, and a correlation value of autocorrelation derived in a plurality of different frequency bands of the input digital audio signal Comparison with a noise determination threshold value within a certain time, a correlation value of cross-correlation between frames derived in a plurality of different frequency bands of the input digital audio signal and a noise determination threshold value within a predetermined time period Based on the comparison, the accuracy can be improved with accuracy.

  Furthermore, according to the intercom system of the present invention, whether the digital audio signal performed by the transmitting side signal discriminating circuit and the receiving side signal discriminating circuit is a silent signal or a voiced signal is inputted. Comparison between the mean square sum derived in a plurality of different frequency bands and a preset signal discrimination threshold, and a correlation value of autocorrelation derived in a plurality of different frequency bands of the input digital audio signal Based on the comparison with the signal discrimination threshold, and the comparison between the correlation value of the cross-correlation between frames derived in different frequency bands of the input digital audio signal and the preset signal discrimination threshold. This signal discrimination threshold is an average for each of a plurality of frequency bands divided by the transmission side band division processing circuit and the reception side band division processing circuit. Because it is dynamically updated based on time, it becomes easy to respond to various conditions such as environment and gender.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments to which an intercom system of the invention is applied will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an intercom system according to an embodiment of the present invention. This intercom system is installed outside the dwelling unit, and the entrance cordless handset 1 for a visitor to call a resident in the dwelling unit to establish a call, and a descent line L1a or There is provided a room master unit 2 for a resident who has responded to a call from the front cordless handset 1 connected via the wireless transmission line L1b to establish a call with the visitor.

  Further, the entrance slave unit 1 includes a slave unit operation unit 100, a camera 101, a slave unit video processing unit 102, a slave unit microphone 103, a slave unit speaker 104, a slave unit audio codec 105, and a slave unit I / F (interface) 106. Is provided.

  In this entrance child device 1, the child device operation unit 100 is operated by a visitor to call a resident, and is configured by, for example, a call button.

  The camera 101 is for capturing a video of a visitor who has performed a call operation and a video in the vicinity of the surroundings (monitoring video) outside the dwelling unit, and is configured by various imaging media such as a CCD and a CMOS, for example. Yes. The slave unit video processing unit 102 is for performing predetermined signal processing such as FM modulation and amplification on the video signal that is a video captured by the camera 101.

  The handset microphone 103 and handset speaker 104 are for inputting and outputting analog voices (transmitted voice and received voice) for a visitor to establish a call with a resident. The handset audio codec 105 performs analog / digital conversion (A / D conversion) of an analog voice signal, which is a transmitted voice input to the handset microphone 103, into a digital voice signal, and will be described later of the room base unit 2. Digital / analog conversion (D / A conversion) of a digital voice signal, which is a received voice input to the base unit microphone 202 and transmitted via the wired transmission path L1a or the wireless transmission path L1b, into an analog voice signal. This is for outputting from the handset speaker 104.

  The slave unit I / F 106 is a signal transmission line from the slave unit operation unit 100 to the wired transmission path L1a or the wireless transmission path L1b, and from the slave unit video processing unit 102 to the wired transmission path L1a or the wireless transmission path L1b. And a signal transmission line between the cordless handset audio codec 105 and the wired transmission path L1a, or a signal transmission line between the cordless handset voice codec 105 and the wireless transmission path L1b, respectively. .

  Further, the living room master unit 2 includes a monitor 200, a master unit video processing unit 201, a master unit microphone 202, a master unit speaker 203, a master unit audio codec 204, an audio processing unit 205, a master unit operation unit 206, a CPU 207, and a master unit. An I / F 208 is provided.

  In this room master unit 2, the monitor 200 is controlled by the CPU 207 (in an image output state), and a call display indicating that there is a call from the entrance slave unit 1 by a visitor, and the camera 101 of the entrance slave unit 1. For example, the image display for displaying the picked-up image is performed by various image display media such as an LCD, a PDP, and an organic EL display. The master image processing unit 201 is controlled by the CPU 207, and for example, FM demodulation, amplification, etc., for video signals transmitted from the entrance unit 1 via the wired transmission path L1a or the wireless transmission path L1b. The predetermined signal processing is performed, and the image captured by the camera 101 of the front door 1 is displayed on the monitor 200.

  The base unit microphone 202 and the base unit speaker 203 are for inputting / outputting analog voices (transmitted voices, received voices) for a resident to establish a call with a visitor. In addition to the above-described call function, a call notification indicating that there is a call from the entrance cordless handset 1 by a visitor can be performed. The master unit audio codec 204 is controlled by the CPU 207 to convert an analog audio signal, which is a transmission voice input to the master unit microphone 202, into a digital audio signal, and to convert the analog unit into a digital audio signal. A digital audio signal, which is a received voice that is input to 103 and transmitted via a wired transmission path L1a or a wireless transmission path L1b, is converted from analog to digital into an analog audio signal and output from the master speaker 203. Is.

  The audio processing unit 205 is controlled by the CPU 207, and transmits a digital audio signal transmitted through the transmission line L2a from the master audio codec 204 to the wired transmission line L1a or the wireless transmission line L1b, and the wired transmission line L1a. Alternatively, transmission / reception control of the received digital audio signal transmitted through the reception line L2b from the wireless transmission line L1b to the master audio codec 204 is performed.

  The master unit operation unit 206 detects the operation by the CPU 207, and a resident who has confirmed that a visitor has called from the entrance slave unit 1 responds, and establishes a call using the master unit microphone 202 and the master unit speaker 203. For example, a response operation for making a call or an end call operation for ending a call that has been established, for example, is constituted by a call button. As the master unit operation unit 206, a push button provided on the casing surface (not shown) of the living room master unit 2, a touch panel (not shown) provided on the front surface of the monitor 200, and the like are suitable.

  The CPU 207 is for controlling each component of the living room base unit 2. Further, the base unit I / F 208 includes a signal transmission line from the wired transmission path L1a or the wireless transmission path L1b to the base unit video processing unit 201, and the wired transmission path L1a and (the transmission line L2a or the reception line L2b). (Via) signal transmission line between base unit processing unit 205 or wireless transmission path L1b and signal transmission line between voice processing unit 205 (via transmission line L2a or reception line L2b) and wired transmission This is for forming a signal transmission line between the path L1a and the CPU 207 or a signal transmission line between the wireless transmission path L1b and the CPU 207, respectively.

  Next, a specific configuration of the voice processing unit 205 of the living room master unit 2 will be described with reference to the block diagram of FIG. The voice processing unit 205 includes a transmission side amplifier 250a, a transmission side band division processing circuit 251a, a transmission side noise level calculation circuit 252a, a transmission side signal determination circuit 253a, a transmission side attenuator 254a, and a transmission side waveform. Synthesis processing circuit 255a, reception side amplifier 250b, reception side band division processing circuit 251b, reception side noise level calculation circuit 252b, reception side signal discrimination circuit 253b, reception side attenuator 254b, reception side waveform synthesis processing circuit 255b, and attenuator control Circuit 256 is provided.

  In the voice processing unit 205, the transmission side amplifier 250a is provided on the transmission line L2a from the master unit audio codec 204 to the master unit I / F 208, and is a digital voice signal (send digital audio signal) that is a transmission voice. ). The receiver-side amplifier 250b is provided on the reception line L2b from the master unit I / F 208 to the master unit voice codec 204, and amplifies a digital voice signal (received digital voice signal) that is a received voice. .

  The transmission side band division processing circuit 251a is for dividing the transmission digital audio signal amplified via the transmission side amplifier 250a into a plurality of frequency bands. The reception side band division processing circuit 251b is for dividing the received digital audio signal amplified via the reception side amplifier 250b into a plurality of frequency bands.

  The transmission side noise level calculation circuit 252a is for calculating the noise level of the transmission digital voice signal divided into a plurality of frequency bands by the transmission side band division processing circuit 251a. Specifically, the first transmission for calculating the noise level by comparing the mean square sum derived in a plurality of different frequency bands of the input transmission digital audio signal with a preset noise determination threshold value. Detecting the presence or absence of periodicity from the correlation value of the autocorrelation derived in a plurality of different frequency bands of the transmitted digital audio signal and the correlation value and a preset noise judgment threshold And the second transmission side calculation means for calculating the noise level, and the correlation value of the cross-correlation between frames derived in a plurality of different frequency bands of the input transmission voice signal, the periodicity One of the transmission side calculation means is applied among the third transmission side calculation means for detecting the presence / absence and comparing the correlation value with a preset noise judgment threshold value to calculate the noise level. It is.

  The reception side noise level calculation circuit 252b is for calculating the noise level of the reception digital audio signal divided into a plurality of frequency bands by the reception side band division processing circuit 252b. Specifically, a first reception-side calculation for calculating a noise level by comparing a mean square sum derived in a plurality of different frequency bands of the received received digital audio signal with a preset noise determination threshold value And the presence / absence of periodicity are detected from autocorrelation correlation values derived in different frequency bands of the input received digital audio signal, and the correlation value is compared with a preset noise judgment threshold value. And detecting the presence / absence of periodicity from the correlation value of the cross-correlation between frames derived from a plurality of different frequency bands of the input received digital audio signal, Any one of the reception side calculation means is applied among the third reception side calculation means for comparing the correlation value with a preset noise judgment threshold value and calculating the noise level. It is.

  The first to third transmission side calculation means applied to the transmission side noise level calculation circuit 252a and the first to third reception side calculation means applied to the reception side noise level calculation circuit 252b. Specifically, the calculation means described in “Akihiro Yamaguchi, CQ Publisher,“ Daizen DSP Utilization ”published on October 15, 2006” is cited as the source.

  The transmission side signal discrimination circuit 253a discriminates whether the transmission digital audio signal is a silence signal or a sound signal according to a preset signal discrimination threshold based on the calculation result of the transmission side noise level calculation circuit 252a. Is to do. Specifically, the average sum of squares derived in a plurality of different frequency bands of the input transmitted digital audio signal is compared with a preset signal discrimination threshold to determine whether it is a silence signal or a sound signal. A first transmitting side discriminating means for discriminating; and detecting the presence or absence of periodicity from autocorrelation correlation values derived in a plurality of different frequency bands of the inputted transmitted digital audio signal; And a signal discrimination threshold set in advance to determine whether the signal is a silence signal or a sound signal, and a plurality of frequencies at which the input digital audio signal is different. The presence / absence of periodicity is detected from the correlation value of the cross-correlation between frames derived in the band, and the correlation value is compared with a preset signal discrimination threshold to determine whether the signal is a silence signal or a sound signal. Third transmitter to perform Among the different means, is any one of the transmitting end discrimination means is applied.

  The reception side signal discrimination circuit 253b is for discriminating whether the reception digital audio signal is a silence signal or a sound signal based on a preset signal discrimination threshold based on the calculation result of the reception side noise level calculation circuit 252b. Is. Specifically, the average sum of squares derived in a plurality of different frequency bands of the input received digital audio signal is compared with a preset signal discrimination threshold to determine whether it is a silence signal or a sound signal. Detecting the presence / absence of periodicity from the correlation value of the autocorrelation derived in a plurality of different frequency bands of the input received digital audio signal, and setting the correlation value and the preset value The received signal discrimination threshold is compared with the second receiving side discriminating means for discriminating whether the signal is a silent signal or a voiced signal, and is derived in a plurality of different frequency bands of the inputted received digital audio signal. A third receiver that detects the presence or absence of periodicity from the correlation value of the inter-correlation between frames and compares the correlation value with a preset signal discrimination threshold to determine whether the signal is a silence signal or a voice signal. ~ side Among the different means, is any one of the receiving-side determination unit is applied.

  Note that the first to third transmitting side determining means applied to the transmitting side signal determining circuit 253a and the first to third receiving side determining means applied to the receiving side signal determining circuit 253b. Specifically, the identification means described in “Akihiro Yamaguchi, CQ Publisher, published on October 15, 2006,“ The first complete DSP utilization ”” is cited as the source.

  The transmission side attenuator 254a is provided on the transmission line L2a from the transmission side band division processing circuit 251a to the master unit I / F 208, and divides the transmission digital voice signal by the transmission side band division processing circuit 251a. When the signal voltage is attenuated by the weighted amount for each of the plurality of frequency bands, it is controlled by the attenuator control circuit 256 based on the discrimination result of the transmission side signal discrimination circuit 253a. Also, the receiving side attenuator 254b is provided on the receiving line L2b from the receiving side band division processing circuit 251b to the base unit voice codec 204, and a plurality of received digital voice signals are divided by the receiving side band division processing circuit 251b. When the signal voltage is attenuated by an amount weighted for each frequency band, the attenuator control circuit 256 controls the signal voltage based on the discrimination result of the receiver side signal discrimination circuit 253b.

  The transmission side waveform synthesis processing circuit 255a synthesizes the transmission digital audio signals of the frequency bands of the plurality of frequency bands divided by the transmission side band division processing circuit 251a transmitted from the transmission side attenuator 254a. The waveform processing is performed as described above. In addition, the reception side waveform synthesis processing circuit 255b synthesizes the reception digital audio signals of the frequency bands of the plurality of frequency bands divided by the reception side band division processing circuit 251b transmitted from the reception side attenuator 254b. In this way, the waveform processing is performed.

  The attenuator control circuit 256 is for controlling the attenuation level (signal voltage) by inserting a loss into each of the transmitting side attenuator 254a and the receiving side attenuator 254b.

  In the intercom system according to the embodiment of the present invention configured as described above, a specific operation will be described below.

  In order to call a resident in the room where the room base unit 2 shown in FIG. 1 is installed, a visitor outside the house uses the handset operating unit 100 of the front door unit 1 to perform a predetermined call. When the operation is performed, the call signal generated by the slave unit operation unit 100 passes through the slave unit I / F 106, the wired transmission path L1a or the wireless transmission path L1b, and the master unit I / F 208 of the living room master unit 2. Are transmitted to the CPU 207, and the camera 101 and the slave image processing unit 102 are activated. In addition, the camera 101 starts capturing an image of a visitor who has performed a call operation (including an image near the outside of the dwelling unit) and generates a video signal. This video signal is subjected to predetermined signal processing such as FM modulation and amplification in the slave unit video processing unit 102, and then the slave unit I / F 106, a wired transmission path L1a or a wireless transmission path L1b, a living room The data is transmitted to the parent device video processing unit 201 via the parent device I / F 208 of the parent device 2.

  When the CPU 207 of the living room master unit 2 shown in FIG. 1 receives the call signal transmitted from the entrance slave unit 1 connected via the wired transmission line L1a or the wireless transmission line L1b, the entrance child by the visitor. A ringing tone or a voice message indicating that there is a call from the machine 1 is output from the parent machine speaker 203 to make a call notification, and the monitor 200 and the parent machine video processing unit 201 are controlled to be active. By this control, the monitor 200 is imaged by the base unit video processing unit 201, for example, a video signal subjected to predetermined signal processing such as FM demodulation and amplification, that is, captured by the camera 101 of the entrance unit 1. Visitors' images (including images near the outside of the dwelling unit) will be displayed. Note that the monitor 200 displays not only the image of the visitor captured by the camera 101 of the entrance cordless handset 1 (including the image of the vicinity in the vicinity of the outside of the dwelling unit) but also from the entrance cordless handset 1 by the visitor. A call message indicating that there is a call, picture data, and the like can be displayed under the control of the CPU 207.

  Thereafter, in FIG. 1, a resident who has confirmed that the visitor has called from the entrance cordless handset 1 together with the visitor discrimination is determined using the base unit operating unit 206 of the room base unit 2. When the response operation is performed, the CPU 207 that detects this operation controls the base unit voice codec 204 and the voice processing unit 205 and the slave unit voice codec 105 of the front door unit 1 to be active.

  Here, in the voice processing unit 205 of the living room master unit 2 shown in FIG. 2, the transmitting side amplifier 250a is an analog voice signal of the sent voice inputted by the resident to the base unit microphone 202 shown in FIG. After the transmission digital audio signal subjected to the analog / digital conversion is amplified via the machine audio codec 204, it is transmitted to the transmission side band division processing circuit 251a on the transmission line L2a. Further, the transmission side band division processing circuit 251a converts the transmission digital audio signal amplified via the transmission side amplifier 250a into a plurality of frequency bands, here, 250 Hz to 500 Hz, 500 Hz to 1 kHz, 1 kHz to 2 kHz, After being divided into five different frequency bands such as 2 kHz to 4 kHz and 4 kHz to 8 kHz, they are transmitted to the transmission side noise level calculation circuit 252a, the transmission side signal determination circuit 253a, and the transmission side attenuator 254a, respectively. In addition, the division | segmentation process to the several frequency band performed in the transmission side band division | segmentation processing circuit 251a is not limited to the aspect of the division | segmentation into five different frequency bands as mentioned above, Two or more types Can be arbitrarily divided into a plurality of frequency bands.

  Further, the transmission side noise level calculation circuit 252a constituting the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 transmits transmissions of five different frequency bands transmitted from the transmission side band division processing circuit 251a. Based on the digital audio signal, the noise level of each transmitted digital audio signal in each frequency band is calculated. As specific means, any one of the first to third transmission side calculation means described above can be applied, and the calculation result is sent to the transmission side signal determination circuit 253a. .

  Furthermore, the transmission side signal discrimination circuit 253a that constitutes the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 is set in advance within a predetermined time based on the calculation result of the transmission side noise level calculation circuit 252a. Based on the signal discrimination threshold, it is discriminated whether each of the transmitted digital audio signals of five different frequency bands is a silence signal or a sound signal. As specific means, any one of the first to third transmission side determination means described above can be applied, so that the transmission digital voice of the voice transmitted by the resident is used. It is possible to accurately determine not only the signal but also the transmitted digital audio signal such as a frictional sound having a low frequency in a high frequency band having a high frequency component as a sound signal, and the determination result is sent to the attenuator control circuit 256. Send it out.

  In the voice processing unit 205 of the room master 2 shown in FIG. 2, the signal discrimination threshold set in the transmission side signal discrimination circuit 253a is a plurality of frequency bands divided by the transmission side band division processing circuit 251a. Here, it has the property of being dynamically updated based on the average intensity for each of the five different frequency bands. This property makes it easy to cope with various conditions such as the surrounding environment in the dwelling unit and the gender of the resident.

  On the other hand, it is an analog audio signal of a transmission voice inputted by the visitor to the slave microphone 103 of the entrance cordless handset 1 shown in FIG. The signal is transmitted to the receiver amplifier 250b of the voice processing unit 205 shown in FIG. 2 via the slave unit I / F 106, the wired transmission path L1a or the wireless transmission path L1b, and the master unit I / F 208 of the living room master unit 2. Is done. The receiver-side amplifier 250b amplifies the received transmission digital voice signal as a received digital voice signal, and then sends it to the receiver-side band division processing circuit 251b on the reception line L2b. Here, the reception side band division processing circuit 251b converts the received digital audio signal amplified via the reception side amplifier 250b into a plurality of frequency bands, here, 250 Hz to 500 Hz, 500 Hz to 1 kHz, 1 kHz to 2 kHz, 2 kHz to After being divided into five different frequency bands such as 4 kHz and 4 kHz to 8 kHz, they are transmitted to the receiving side noise level calculation circuit 252b, the receiving side signal discrimination circuit 253b, and the receiving side attenuator 254b, respectively. The division processing into a plurality of frequency bands performed by the reception side band division processing circuit 251b is not limited to the above-described division into five different frequency bands, but two or more types Different frequency bands can be arbitrarily divided into a plurality of frequency bands.

  Further, the reception side noise level calculation circuit 252b constituting the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 receives received digital voice signals of five different frequency bands transmitted from the reception side band division processing circuit 251b. Based on the above, the noise level of each received digital audio signal in each frequency band is calculated. As specific means, any one of the first to third receiving side calculating means described above can be applied, and the calculation result is sent to the receiving side signal discriminating circuit 253b.

  Further, the reception side signal determination circuit 253b that constitutes the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 is a signal set in advance within a predetermined time based on the calculation result of the reception side noise level calculation circuit 252b. It is determined whether the received digital audio signals in five different frequency bands are silence signals or voice signals, respectively, according to the determination threshold. As specific means, any one of the first to third receiving side determination means described above can be applied, so that only the reception digital audio signal of the reception voice of the call by the visitor can be used. In addition, a received digital voice signal such as a frictional sound with a low frequency in a high frequency band with a high frequency component can also be accurately discriminated as a voiced signal, and this judgment result is sent to the attenuator control circuit 256.

  The signal discrimination threshold set in the receiver side signal discrimination circuit 253b is based on the average intensity for each of a plurality of frequency bands divided by the receiver side band division processing circuit 251b, here, for each of five different frequency bands. It has the property of being dynamically updated. This property makes it easy to cope with various conditions such as the surrounding environment outside the dwelling unit and the sex of visitors.

  Next, as an example of the control, the attenuator control circuit 256 that constitutes the voice processing unit 205 of the living room master unit 2 shown in FIG. When the determination result of the circuit 253b is silence, the attenuation level of the transmitting side attenuator 254a is suppressed to a low level by an amount weighted for each of five different frequency bands, while the attenuation level of the receiving side attenuator 254b is increased. Loss can be inserted into the received digital voice signal to suppress the noise component. By this control, the signal voltage of the transmission digital audio signal, which is determined to be sound by the transmission side signal determination circuit 253a and amplified via the transmission side amplifier 250a on the transmission line L2a, is the transmission side. Attenuation level is kept low by the attenuator 254a and a plurality of frequency bands divided by the transmission side band division processing circuit 251a, here, transmitted digital audio signals of the frequency bands of five different frequency bands are transmitted. After the waveform processing is performed by the transmitting side waveform synthesis processing circuit 255a so as to synthesize, the master unit I / F 208, the wired transmission path L1a or the wireless transmission path L1b shown in FIG. The data is transmitted to the handset audio codec 105 via / F106. Here, the handset audio codec 104 performs digital / analog conversion on the received voice transmission digital audio signal, and has a high frequency band in which the above frequency components are high as well as a normal voice transmission by a resident. A small frictional sound can also be output from the handset speaker 104 as a voice signal reception voice. As a result, it is possible to prevent the head of the call voice output from the handset speaker 104 from being cut off and to improve the call quality.

  Further, as another example of the control, the attenuator control circuit 256 that constitutes the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 is that the discrimination result of the transmitting side signal discriminating circuit 253a is silent and the receiving side signal discriminating circuit. If the determination result of 253b is sound, a loss is inserted so that the attenuation level of the transmission side attenuator 254a is increased by an amount weighted for each of the five different frequency bands, and the transmission digital audio signal While the noise component can be suppressed, the attenuation level of the receiving side attenuator 254b is set low. By this control, the signal voltage of the received digital audio signal, which is determined to be sound by the receiving side signal determining circuit 253b and amplified via the receiving side amplifier 250b on the receiving line L2b, is attenuated by the receiving side attenuator 254b. The reception side waveform synthesis is performed so that the received digital voice signals of the frequency bands of the frequency bands divided in the reception side band division processing circuit 251b, in this case, the five frequency bands are synthesized. After being subjected to waveform processing by the processing circuit 255b, it is transmitted to the base unit audio codec 204 shown in FIG. Here, the main unit audio codec 204 performs digital / analog conversion on the received voice-received digital audio signal, and has a low power in a high frequency band in which not only a normal transmission voice by a visitor but also the above-described frequency component is high. The friction sound can also be output from the main unit speaker 203 as a voice signal reception voice. As a result, it is possible to prevent the head of the call voice output from the main unit speaker 203 from being cut off and to improve the call quality.

  Although the interphone system of the present invention has been described with a specific embodiment, the present invention is not limited to this embodiment, and any intercom system known so far, for example, as long as the effects of the present invention are obtained, for example, Even an intercom system having the entrance cordless handset incapable of image capturing / processing functions (101, 102) and the living room base unit incapable of image output / processing functions (200, 201). It goes without saying that it can be adopted.

The block diagram which shows the structure of the intercom system by the Example of this invention. The block diagram which shows the specific structure of the audio | voice processing part of a living room main | base station in the intercom system by the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Entrance cordless handset 103 …… Slave unit microphone 104 …… Slave unit speaker 2 …… Home base unit 202 …… Base unit microphone 203 …… Base unit speaker 204 …… Base unit audio codec 205 …… Sound processing unit 251a ...... Sending-side band division processing circuit 251b ....... Receiving-side band division processing circuit 252a ....... Sending-side noise level calculation circuit 252b ....... Receiving-side noise level calculation circuit 253a .... Sending-side signal discrimination circuit 253b. Side signal discriminating circuit 254a …… Sending side attenuator 254b …… Receiving side attenuator 255a …… Sending side waveform synthesis processing circuit 255b …… Receiving side waveform synthesis processing circuit 256 …… Attenuator control circuit L1a …… Wired transmission line L1b …… Wireless transmission line L2a …… Transmission line L2b …… Reception line

Claims (9)

Connected to the entrance slave unit (1) having the slave unit microphone (103) and the slave unit speaker (104) via a wired transmission path (L1a) or a wireless transmission path (L1b), A master unit microphone (202) for inputting and outputting a voice signal for establishing a call between the slave unit microphone and the slave unit speaker, and a room master unit (2) having a master unit speaker (203);
The living room master unit performs analog / digital conversion of a transmission analog voice signal input to the base unit microphone into a transmission digital voice signal, and is also input to the slave unit microphone of the entrance slave unit. A base unit voice codec (204) for digitally / analog converting a received digital voice signal transmitted via the digital signal into a received analog voice signal and outputting it from the base unit speaker; and the transmission path from the base unit voice codec To control transmission / reception of the transmitted digital voice signal transmitted through the transmission line (L2a) to the receiver and the received digital voice signal transmitted through the transmission line (L2b) from the transmission path to the base unit voice codec. Voice processing unit (205),
The voice processing unit includes a transmission side band division processing circuit (251a) for dividing the transmitted digital audio signal into a plurality of frequency bands, and a function for dividing the received digital audio signal into a plurality of frequency bands. A reception side band division processing circuit (251b) and a transmission side noise level calculation for calculating a noise level of the transmitted digital voice signal divided into the plurality of frequency bands by the transmission side band division processing circuit. A circuit (252a), a reception-side noise level calculation circuit (252b) for calculating a noise level of the received digital audio signal divided into the plurality of frequency bands by the reception-side band division processing circuit, and the transmission side Whether the transmitted digital audio signal is a silence signal or a sound signal based on a signal discrimination threshold set in advance based on the calculation result of the talk side noise level calculation circuit. The received digital voice signal is a silent signal or a voiced signal according to a signal discrimination threshold set in advance based on the computation result of the transmitter side signal discrimination circuit (253a) and the reception side noise level calculation circuit. Based on the discrimination results of the receiver side signal discriminating circuit (253b), the transmitter side signal discriminating circuit, and the receiver side signal discriminating circuit for discriminating whether or not there is the divided digital audio signal transmitted. Losses are inserted into the transmitting side attenuator (254a) for attenuating the weighted amount for each band and the receiving side attenuator (254b) for attenuating the received digital voice signal by the weighted amount for each divided band. An attenuator control circuit (256) for controlling the attenuation level and the transmitted digital voice signal of each frequency band from the transmitting attenuator are synthesized. Transmitting side waveform synthesis processing circuit (255a) for processing the waveform so as to be received, and receiving side waveform synthesis for processing the waveform so that the received digital voice signal of each frequency band from the receiving side attenuator is synthesized. An intercom system comprising a processing circuit (255b).   The transmission side noise level calculation circuit and the reception side noise level calculation circuit respectively compare a mean square sum derived in a plurality of different frequency bands of the input digital audio signal with a preset noise determination threshold value. The intercom system according to claim 1, wherein the noise level is calculated.   The transmission side noise level calculation circuit and the reception side noise level calculation circuit each have an autocorrelation correlation value derived in a plurality of different frequency bands of the input digital audio signal and a preset noise determination threshold value. The intercom system according to claim 1, wherein the noise level is calculated.   The transmission side noise level calculation circuit and the reception side noise level calculation circuit each have a correlation value of cross-correlation between frames derived in a plurality of different frequency bands of the input digital audio signal and a preset noise determination The intercom system according to claim 1, wherein the noise level is calculated by comparing with a threshold value.   The transmitting side signal discriminating circuit and the receiving side signal discriminating circuit each compare a mean square sum derived in a plurality of different frequency bands of the input digital audio signal with a preset signal discrimination threshold, The intercom system according to claim 1, wherein it is determined whether the sound signal is the silent signal or the sound signal.   The transmitting side signal discriminating circuit and the receiving side signal discriminating circuit respectively compare autocorrelation correlation values derived in different frequency bands of the input digital audio signal with preset signal discrimination thresholds. The intercom system according to claim 1, wherein the interphone system determines whether the sound signal is the silent signal or the sound signal.   The transmitting side signal discriminating circuit and the receiving side signal discriminating circuit each have a correlation value of inter-correlation between frames derived in a plurality of different frequency bands of the input digital audio signal and a preset signal discrimination threshold value. The intercom system according to claim 1, wherein a determination is made as to whether the signal is the silence signal or the sound signal.   8. The comparison operation performed in each of the transmission side signal determination circuit and the reception side signal determination circuit is performed based on a comparison with a signal determination threshold value within a predetermined time. The intercom system according to any one of the above.   The signal discrimination threshold is dynamically updated based on an average intensity for each of a plurality of frequency bands divided by the transmission side band division processing circuit and the reception side band division processing circuit. The intercom system according to any one of claims 5 to 8.

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