Sound processing device, sound input / output system and sound processing method

Abstract

This invention provides a sound processing technology that can further clarify sound than before. It comprises: a sound signal generation unit (11) that generates a first sound signal (x1) and a second sound signal (x2) with identical spectra from a sound signal expressing sound; a filter (13) that removes at least a first frequency component below a specific first frequency from the first sound signal; a synthesis unit (14) that generates a synthesized sound signal by adding the first sound signal (with the first frequency component removed) to the second sound signal; and a correction signal generation unit (12) that generates a phase correction signal (p) based on the second sound signal; the filter includes an operational amplifier (132a) that amplifies the first sound signal; the operational amplifier is configured such that the first sound signal is input to an inverting input terminal; and by inputting the phase correction signal to a non-inverting input terminal, the first sound signal is output in a manner whose phase is corrected to approach the phase of the second sound signal.

Description

[Technical Field]

[0001] This invention relates to a sound processing device, a sound input / output system, and a sound processing method. [Previous Technology]

[0002] To receive inquiries or requests from users, most companies have contact points called call centers or support centers. The following is an example of using a call center as a contact point. A call center has one or more telephones. Each operator in the call center uses these telephones to communicate with users, understand their inquiries or requests, and provide responses. However, some users who call call centers are hard of hearing, and there are situations where hard of hearing users cannot fully understand what the operator is saying. As a result, poor communication may occur between the operator and the user. Therefore, various technologies have been proposed to solve this problem. For example, Patent Document 1 discloses a sound processing device for making it easy for people to clearly hear the sound emitted from speakers of audio devices, broadcasting equipment, etc.

[0003] [Prior Art Documents] [Patent Document 1] Japanese Patent Application Publication No. 2016-11005 [Summary of the Invention]

[0004] [Problem to be solved by the invention] However, in recent years there has been a demand for sound clarity technology that surpasses the previous sound processing technology described in Patent Document 1.

[0005] The present invention is made in view of this problem, and its object is to provide a sound processing technology that can make the sound clearer than before.

[0006] [Technical Means for Solving the Problem] The present invention provides a state-related sound processing apparatus with the following structure, comprising: a sound signal generation unit that generates a first sound signal and a second sound signal with identical spectra from a sound signal representing sound; a filter that removes at least a first frequency component below a specific first frequency from the first sound signal; a synthesis unit that generates a synthesized sound signal by adding the first sound signal (with the first frequency component removed) to the second sound signal; and a correction signal generation unit that generates a phase correction signal based on the second sound signal; the filter has an operational amplifier that amplifies the first sound signal; the operational amplifier is configured such that the first sound signal is input to an inverting input terminal; and by inputting the phase correction signal to a non-inverting input terminal, the first sound signal is output in a manner whose phase is corrected to be closer to the phase of the second sound signal.

[0007] Another sound processing method related to the present invention includes: a sound signal generation step, wherein a sound signal generator generates a first sound signal and a second sound signal with identical spectra from a sound signal expressing sound; a filtering step, wherein a filter removes at least a first frequency component below a specific first frequency from the first sound signal; and a sound synthesis step, wherein a sound synthesizer generates a synthesized sound signal by additively combining the first sound signal (with the first frequency component removed) with the second sound signal. The audio signal and the correction signal generation step involve generating a phase correction signal based on the second audio signal using a correction signal generator; the filter includes an operational amplifier that amplifies the first audio signal; the operational amplifier is configured such that the first audio signal is input to the inverting input terminal; in the filtering step, the first audio signal, corrected to a phase that is closer to the phase of the second audio signal, is output to the operational amplifier by inputting the phase correction signal to the non-inverting input terminal of the operational amplifier.

[0008] [Effects of the Invention] According to the present invention, sound can be made clearer than ever before.

Implementation Method

[0010] <Sound Processing Apparatus> Hereinafter, a sound processing apparatus relating to an embodiment of the present invention will be described with reference to the drawings.

[0011] [Structure of the Sound Processing Device] As shown in FIG1, the sound processing device 1 includes: a sound signal generation unit 11, a correction signal generation unit 12, a filter 13, and a synthesis unit 14. The sound processing device 1 of this embodiment further includes: a first port 15, an input buffer 16, an adjustment unit 17, and a second port 18. Furthermore, the sound processing device 1 may also include: a power supply unit, a detection unit, and a control unit (not shown).

[0012] (Port 1) Port 15 inputs a sound signal x representing the sound supplied from the machine connected to Port 15 to the input buffer 16. As shown in FIG2, the sound signal x contains: first formant component h1, second formant component h2, ..., nth formant component hn. Furthermore, although n varies slightly depending on the user at the transmitting end, it is at least a positive integer of 4. Furthermore, since Patent Document 1 describes the first formant component h1, second formant component h2, ..., nth formant component hn, this description is omitted in this embodiment.

[0013] (Input Buffer) As shown in FIG1, the input buffer 16 is disposed between the first port 15 and the sound signal generation unit 11. The input buffer 16, when used, can be configured as a microphone amplifier, a preamplifier to reduce output impedance, etc. In this embodiment, the input buffer 16, as shown in FIG3, applies adjustments to the sound signal x, reducing the upper limit of the frequency range and the fine-tuning space, and increasing the sound pressure level. Then, as shown in FIG1, the input buffer 16 outputs the sound signal x, which has undergone the necessary adjustments, to the sound signal generation unit 11. Furthermore, when it is not necessary to adjust the sound signal supplied from the first port (the machine connected to the first port is configured to output a sound signal that does not require adjustment), the sound processing device 1 may not include the input buffer 16.

[0014] (Audio Signal Generation Unit) The audio signal generation unit 11 generates a first audio signal x1 and a second audio signal x2 with identical spectra from the audio signal x supplied by the input buffer unit 16. "Equivalent spectra" means that the first audio signal x1 and the second audio signal x2 respectively contain a first formant component h1, a second formant component h2, ..., an nth formant component hn. Furthermore, the audio signal generation unit 11 in this embodiment further generates a third audio signal x3 with an identical spectrum to the second audio signal x2. In addition, the audio signal generation unit 11 supplies the first audio signal x1 to the high-pass filter 131, the second audio signal x2 to the synthesis unit 14, and the third audio signal to the correction signal generation unit 12. The sound signal generation unit 11 in this embodiment generates a first sound signal x1, a second sound signal x2, and a third sound signal x3 by splitting the sound signal. In this embodiment, the sound signal generation unit 11 is configured such that the intensity ratio of the first sound signal x1, the second sound signal x2, and the third sound signal x3 is 1:1:1, that is, the distribution ratio is 1:1:1. However, the distribution ratio of the sound signals is not limited to 1:1:1 and can be set appropriately. Furthermore, the sound signal generation unit 11 can also copy the sound signal supplied by the input buffer unit 16, and designate the source sound signal as the first sound signal x1, and the copied sound signal as the second sound signal x2 and the third sound signal x3.

[0015] (Correction Signal Generation Unit) The correction signal generation unit 12 generates a phase correction signal p based on the second audio signal x2 supplied from the audio signal generation unit 11. As described above, the audio signal generation unit 11 of this embodiment generates a third audio signal x3 with the same phase as the second audio signal x2. Therefore, the correction signal generation unit 12 of this embodiment generates the phase correction signal p based on the third audio signal x3. Thus, the correction signal generation unit 12 generates the phase correction signal p based on the dedicated third audio signal. In this way, by using the second audio signal when generating the phase correction signal p, phase shift of the second audio signal can be avoided. Furthermore, the correction signal generation unit 12 outputs the generated phase correction signal p to the operational amplifier 132a of the filter 13.

[0016] As shown in FIG. 4, the correction signal generation unit 12 of this embodiment includes a capacitor 121 and a resistor 122. One end of the capacitor 121 is connected to the audio signal generation unit 11, and the other end is connected to the non-inverting input terminal (+) of the operational amplifier 132a. One end of the resistor 122 is connected to the other end of the capacitor 121, and a bias voltage is applied to the other end. The correction signal generation unit 12 configured in this way outputs a phase correction signal p with frequency components of 1 / 2πCR (C: capacitance, R: resistance) or higher by means of the high-pass filter formed by the capacitor 121 and the resistor 122. Hereinafter, the lower limit value of the frequency components of the phase correction signal p is referred to as the "phase correction starting frequency fs". Furthermore, the correction signal generation unit 12 can adjust the phase correction starting frequency fs by changing at least one of the capacitor 121 and the resistor 122. Furthermore, as shown in Figure 5, the degree of phase correction by the operational amplifier 132a of filter 13 varies within the range of 0 to -180° based on the phase correction start frequency fs of the phase correction signal p input to the non-inverting input terminal (+). Details are described later. In this way, the phase correction start frequency fs will be adjusted to the most suitable value, that is, the phase difference between the corrected first audio signal x1 and the second audio signal x2 will be reduced to a minimum.

[0017] Furthermore, the impedance Z (internal resistance) of capacitor 121 changes according to the phase correction starting frequency fs. Specifically, the impedance Z of capacitor 121 is inversely proportional to the phase correction starting frequency fs, and its value is expressed as 1 / ωC ​​(ω=2πfs). In other words, the higher the phase correction starting frequency fs, the lower the impedance Z of capacitor 121. As a result, the higher the phase correction starting frequency fs, the higher the voltage of the phase correction signal generation unit 12 will output, and the lower the voltage of the phase correction signal generation unit 12 will output, and vice versa. In this way, by using capacitor 121, a correction signal generation unit 12 corresponding to various frequencies of sound signals can be constructed with a simple structure.

[0018] (Filter) Filter 13 removes at least a specific first frequency component below the first frequency from the first audio signal. The first frequency is the frequency between the upper limit frequency of the first formant component h1 and the lower limit frequency of the second formant component h2. In this embodiment, filter 13 is a bandpass filter that also removes second frequency components higher than the first frequency. In this embodiment, filter 13 is composed of a high-pass filter 131 and a low-pass filter 132.

[0019] The high-pass filter 131 removes the first frequency component from the first audio signal x1 supplied by the audio signal generation unit 11. In this embodiment, the high-pass filter 131 sets the first frequency to 400Hz. Furthermore, the high-pass filter 131 outputs the first audio signal x1' with the first frequency component removed to the low-pass filter 132. The first audio signal x1' is an audio signal that does not contain the first formant component h1, but contains the second formant component h2, the third formant component h3, ..., the nth formant component hn.

[0020] The high-pass filter 131 of this embodiment has an operational amplifier (not shown) that amplifies the first audio signal x1. Thus, the high-pass filter 131 of this embodiment outputs a first audio signal x1 after the first frequency component has been removed and amplified. The operational amplifier outputs a first audio signal x1 with increased intensity of the second formant component h2, the third formant component h3, ..., the nth formant component hn by amplifying the first audio signal x1 after the first frequency component has been removed. Furthermore, the high-pass filter 131 can also be configured such that, depending on the intended use, at least one of the operational amplifier's amplification rate and the frequency that forms the boundary between removal and non-removal can be arbitrarily set.

[0021] The low-pass filter 132 removes the second frequency component from the first audio signal x1, from which the first frequency component supplied by the high-pass filter 131 has been removed. The second frequency component refers to frequency components above the second frequency. The second frequency (cutoff frequency) is the frequency between the upper limit frequency of the 5th formant component h5 and the lower limit frequency of the 6th formant component h6, or the frequency between the upper limit frequency of the 6th formant component h6 and the lower limit frequency of the 7th formant component h7. In this embodiment, the low-pass filter 132 sets the second frequency to 5kHz or 7kHz. Furthermore, the low-pass filter 132 outputs a first audio signal x1” with the higher frequency components after the 5th or 6th order removed. That is, it outputs an audio signal containing only the 2nd to 5th order formant components h2 to h5, or only the 2nd to 6th order formant components h2 to h6. The higher order formant components become noise that does not help in understanding speech. In this way, by removing the second frequency component through the low-pass filter 132, the signal-to-noise ratio in the synthesized audio signal x' described later can be improved.

[0022] Furthermore, for the first audio signal, removing frequency components inevitably results in a phase delay. Assuming the first audio signal x1, whose phase delay is only time T, is not corrected and is synthesized with the second audio signal x2, as shown in Figure 6, the voltage V1 of the first audio signal x1 will become -V1 due to the phase delay. Consequently, the voltage V of the synthesized audio signal will become V2 + (-V1) because the first audio signal x1 and the second audio signal x2 cancel each other out. The result is, as shown in Figure 7, a dead region (dip) is generated in a certain frequency range, causing the sound pressure of the first formant component h1 and the second formant component h2, which are particularly important for speech comprehension, to become extremely low, thus becoming a strong obstacle to improving clarity.

[0023] In this way, filter 13 will have the function of correcting phase delay. Specifically, as shown in FIG4, low-pass filter 132 includes operational amplifier 132a and other components 132b and 132c. Operational amplifier 132a amplifies the first audio signal x1. Furthermore, operational amplifier 132a is configured such that the first audio signal is input to the inverting input terminal (-). In addition, operational amplifier 132a outputs the first audio signal x1' corrected so that its phase is closer to the phase of the second audio signal by inputting a phase correction signal p to the non-inverting input terminal (+). Specifically, operational amplifier 132a compares the voltage of the first audio signal input to the inverting input terminal (-) and the voltage of the phase correction signal p input to the non-inverting input terminal (+). Then, if the voltage of the phase correction signal p is high, the first audio signal x1' with the phase ahead is output according to the voltage difference. On the other hand, if the voltage of the phase correction signal p is low, a first audio signal x1' with phase delay is output in response to the voltage difference. As described above, the voltage of the phase correction signal p varies according to the phase correction start frequency fs determined by the capacitor 121 and resistor 122 of the correction signal generation unit 12. In this way, for example, as shown in FIG5, the operational amplifier 132a will vary the degree of phase lead or delay according to the phase correction start frequency fs within the range of 0 to -180°. As described above, the phase correction start frequency fs is pre-adjusted. In this way, a phase correction signal p corresponding to the adjusted phase correction start frequency fs is input to the non-inverting input terminal (+) of the operational amplifier 132a. Then, the operational amplifier 132a will output the first audio signal x1' after correction in such a way that the phase difference with the second audio signal x2 becomes minimal.

[0024] Furthermore, filter 13 can also be configured such that low-pass filter 132 first removes the second frequency component from the first audio signal. Also, high-pass filter 131 can be configured such that it removes the first frequency component from the first audio signal after the second frequency component has been removed. In this case, the phase correction signal p is input to the non-inverting input terminal (+) of the operational amplifier provided by high-pass filter 131.

[0025] (Adjustment Unit) The adjustment unit 17 adjusts the sound pressure of the phase-corrected first sound signal x1'. Next, the adjustment unit 17 supplies the adjusted first sound signal x1' to the synthesis unit 14. The adjustment unit 17 adjusts the first sound signal based on the usage environment and the user's operating settings according to the degree of hearing loss. In this way, the adjustment unit 17 can adjust only the first to fifth formant components h1 to h5, which are important for speech comprehension, to a level exceeding the masking line MK' of the audible level. Furthermore, as shown in Figure 8, the adjustment unit 17 can freely select the output level curve of the synthesized sound signal x' to be "minimum," "maximum," or "intermediate."

[0026] (Synthesis Unit) The synthesis unit 14 adds the first sound signal x1' (after removing the first and second frequency components and correcting its phase) to the second sound signal x2 supplied from the sound signal generation unit 11 to generate a synthesized sound signal x'. As described above, the sound processing apparatus 1 of this embodiment includes an adjustment unit 17. In this way, the synthesis unit 14 of this embodiment adds the first sound signal x1 and the second sound signal x2 (after adjusting the sound pressure) to generate a synthesized sound signal x'. Then, the synthesis unit 14 supplies the generated synthesized sound signal x' to the second port 18. As shown in FIG9, since the phase of the corrected first sound signal x1' in the synthesis unit 14 is more advanced than the phase of the first sound signal x1 before T' correction, the corrected first sound signal x1' will be in phase with the second sound signal x2. The result is that the frequency characteristics of the synthesized sound signal x' output by the synthesis unit 14 are as shown in Figure 10.

[0027] (Port 2) Port 2 18 outputs the synthesized sound signal x' supplied by the synthesis unit 14 to the machine connected to Port 2 18.

[0028] (Power Supply Unit) The power supply unit provides power to the various parts of the sound processing device 1 that require power. The form of the power supply unit is not limited; it can be an AC / DC converter, such as an AC adapter, or a battery.

[0029] (Detection Section) The detection section is configured to detect whether power is being supplied from the power supply section to the sound processing section. If the power supply section functions normally, the detection section will display "Yes" detection information and provide it to the control section. On the other hand, if the power supply section does not function normally, the detection section will display "No" detection information and provide it to the control section. When the power supply section is an AC / DC converter, an example of a state where it does not function normally is a power outage. Furthermore, when the power supply section is a battery, an example of a state where it does not function normally is a dead battery.

[0030] (Selection Unit) The selection unit selects whether to apply sound processing to the sound signal x based on the control of the control unit. The selection unit is, for example, located between the low-pass filter 132 and the synthesis unit 14, and is configured as an ON / OFF switch of a switching circuit. When the selection unit is ON, the first sound signal x1, which has passed through the high-pass filter 131 and the low-pass filter 132, is supplied to the synthesis unit 14 and synthesized with the second sound signal x2 in the synthesis unit 14. On the other hand, when the selection unit is OFF, the first sound signal x1 is not supplied to the synthesis unit 14, and the second sound signal x2 is output from the synthesis unit 14. Alternatively, it can be located between the sound signal generation unit 11 and the high-pass filter 131, or between the high-pass filter 131 and the low-pass filter 132.

[0031] (Control Unit) The control unit controls the selection unit by applying sound processing to the sound signal x or by not applying sound processing to the sound signal x, depending on the detection result of the detection unit. When the detection result of the detection unit is "Yes", the control unit controls the selection unit by applying sound processing to the sound signal x (setting it to ON). On the other hand, when the detection result of the detection unit is "No", the control unit controls the selection unit by not applying sound processing to the sound signal x (setting it to OFF).

[0032] [Modification of the sound processing device] The sound processing device 1 associated with this embodiment is configured with analog circuits to form a high-pass filter 131, a low-pass filter 132, a correction signal generation unit 12, and a synthesis unit 14. However, at least any of these can also be configured with digital circuits.

[0033] Furthermore, the sound processing device 1 associated with this embodiment includes a high-pass filter 131 and a low-pass filter 132. However, alternatively, the sound processing device may also include a band-pass filter that simultaneously removes the first frequency component and the second frequency component.

[0034] Furthermore, the sound processing device 1 may also include a polarity switch and an amplifier disposed between the first port 15 and the sound signal generation unit 11.

[0035] Furthermore, the sound processing device 1 may also include a selection unit, an amplifier, a circuit splitter, a voice output adjuster, and a polarity switch disposed between the synthesis unit 14 and the second port 18.

[0036] Furthermore, the sound processing device 1 may also include an attenuator between the synthesis unit 14 and the second port 18. The attenuator adjusts the output arbitrarily according to the input audio source signal. By incorporating such an attenuator into the signal lines of existing devices that transmit sound via wired or wireless means, such as microphones, televisions, radios, and other entertainment playback devices, it is possible to provide a system that addresses hearing loss symptoms caused by hearing impairment.

[0037] [Effect of the sound processing device] The sound processing device 1 described above causes the low-pass filter 132 to correct the phase delay caused when the first and second frequency components are removed based on the phase correction signal p. In this way, the sound processing device 1 can make the sound clearer than before.

[0038] <Examples of Application of Sound Processing Device> Next, various devices incorporating the sound processing device 1 will be described. The sound processing device 1 can incorporate auxiliary devices 2, sound input / output systems 3 to 6, etc., as described below.

[0039] [Structure of the auxiliary device] As shown in Figure 11, the auxiliary device 2, in addition to the sound processing device 1, includes: a housing 21, an input terminal 22, and an output terminal 23.

[0040] The housing 21 is formed into a box shape to house the sound processing device 1. The housing 21 can be moved freely.

[0041] Input terminal 22 is provided on the surface of housing 21. Input terminal 22 is connected to a machine that outputs audio signals and receives audio signals from that machine. Input terminal 22 is connected to port 15 of audio processing device 1. In other words, input terminal 22 supplies audio signals input from the machine that outputs audio signals to port 15.

[0042] Output terminal 23 is provided on the surface of housing 21. Output terminal 23 is connected to the machine that inputs synthesized sound signal x' and outputs sound signal to that machine. Output terminal 23 is connected to port 18 of sound processing device 1. In other words, output terminal 23 outputs the synthesized sound signal x' supplied from sound processing device 1 to the machine that inputs synthesized sound signal x'.

[0043] [Effect of the auxiliary device] The auxiliary device 2 described above not only becomes easy to install or disassemble, but also can be easily applied to broadcasting equipment or other sound-producing devices in outdoor event venues because it can be easily transported or stored.

[0044] [Structure of the sound input / output system (1)] As shown in FIG12, the sound input / output system 3, in addition to the sound processing device 1, includes a sound input unit 31 and a sound output unit 32. The sound input / output system 3 of this embodiment also includes an amplification unit 33.

[0045] (Voice Input Unit) The voice input unit 31 acquires the speaker's voice to generate a sound signal. In this embodiment, the voice input unit 31 is configured as a microphone. Furthermore, the voice input unit 31 is connected to the first port of the sound processing device 1. Then, the voice input unit 31 generates a sound signal x based on the input sound and supplies it to the first port 15. Alternatively, as shown in FIG13, the voice input unit 31 can also be a device that plays images, such as a television.

[0046] (Sound Output Unit) The sound output unit 32 outputs sound based on the sound signal x generated by the sound processing device 1. The sound input unit 31 in this embodiment is composed of a speaker, headphones, or earphones. Furthermore, the sound output unit 32 is connected to the second port 18 of the sound processing device 1. Then, the sound output unit 32 emits sound based on the synthesized sound signal supplied from the second port.

[0047] [Effects of the sound input / output system (1)] The sound input / output system 3 described above, except for the sound processing device 1, can be constructed from existing broadcasting equipment, sound propagation devices, etc. In this way, by incorporating existing broadcasting equipment, sound propagation devices, etc., the sound output by the sound input / output system 3 can be made clearer more easily.

[0048] [Structure of sound input / output system (2)] As shown in FIG14, the sound input / output system 4, in addition to the sound processing device 1, sound input unit 31, sound output unit 32 and amplification unit 33 which are the same as those in the sound input / output system 3, is equipped with a signal transmitter 41 and a receiver 42.

[0049] The signal transmitter 41 in this embodiment is composed of a wireless communication module. The signal transmitter 41 is connected to the second port 18 of the sound processing device 1. Then, the signal transmitter 41 converts the synthesized sound signal supplied from the second port into radio waves. Then, the signal transmitter 41 transmits the radio waves from the antenna 41a.

[0050] The receiver 42 in this embodiment is composed of a wireless communication module. The receiver 42 is connected to the amplifier 33. Then, the receiver 42 uses the antenna 42a to receive radio waves from the signal transmitter 41. Then, the receiver 42 converts the received radio waves into a synthesized audio signal and supplies it to the amplifier 33.

[0051] Furthermore, as shown in Figure 15, the voice input / output system 4 may consist of a voice input unit 31 and a voice output unit 32, which can be composed of a telephone microphone, and a signal transmitter 41 and a receiver 42, which can be composed of the telephone itself. In this case, the signal transmitter 41 will send a synthesized voice signal to the receiver 42 through a landline, network cable, etc.

[0052] [Effect of the sound input / output system (2)] According to the sound input / output system 4 described above, even if the speaker and the listener are far apart, the sound can still be clearly transmitted to the listener.

[0053] [Structure of the sound input / output system (3)] The sound input / output system 5 constitutes an audio device. As shown in FIG16, the sound input / output system 5 includes: a pair of input buffers 16 identical to those of the sound processing device 1, a pair of sound signal generating units 11, a correction signal generating unit 12, a filter 13, an adjustment unit 17, and a pair of synthesizers 14. Furthermore, the sound input / output system 5 includes a pair of sound output units 32 identical to those of the sound input / output system 3. Furthermore, the sound input / output system 5 includes a pair of sound input terminals 51, a second synthesizer 52, a second sound signal generating unit 53, and a third sound signal generating unit 54.

[0054] A pair of audio input terminals 51 are respectively connected to the input buffer 16. The right audio signal x(R) and the left audio signal x(L) are respectively input to the pair of audio input terminals 51. The input right audio signal x(R) and the left audio signal x(L) are respectively supplied to the input buffer 16.

[0055] The sound signal generation unit 11 in the sound input / output system 5 will not generate the third sound signal x3, but will generate the first sound signal x1(R), x1(L) and the second sound signal x2(R), x2(L).

[0056] The second synthesis unit 52 performs addition and synthesis on the right first audio signal x1(R) and the left first audio signal x1(L) generated by the pair of audio signal generation units 11 respectively. The synthesized first audio signal x1 is then supplied to the second audio signal generation unit 53.

[0057] The second sound signal generation unit 53 generates a third sound signal with the same spectrum as the first sound signal from the first sound signal x1.

[0058] The third sound signal generation unit 54 generates a right first sound signal x1'(R) and a left first sound signal x1'(L) from the phase-corrected first sound signal x1' supplied by the self-adjustment unit 17. Each first sound signal x1'(R) and x1'(L) is then supplied to a pair of synthesis units 14.

[0059] [Effect of the sound input / output system (3)] The sound input / output system 5 described above can make stereo (right sound signal and left sound signal) clearer than before.

[0060] [Structure of the audio input / output system (4)] The audio input / output system 6 constitutes a so-called remote conferencing system. As shown in FIG17, in addition to a pair of audio processing devices 1, a pair of audio input units 31, and a pair of audio output units 32 that are the same as those in the audio input / output system 3, the audio input / output system 6 is equipped with a pair of dedicated terminals 61 for the remote conferencing system. In addition, the audio input / output system 6 may also be equipped with a lens and a display (not shown).

[0061] The sound input unit 31 is connected to the first port of the sound processing device 1. The sound input unit 31 generates a sound signal x based on the input sound and supplies it to the first port 15. The second port 18 of the sound processing device 1 is connected to the dedicated terminal 61. Then, the sound processing device 1 generates a synthesized sound signal from the sound signal x supplied from the sound input unit 31 and supplies it to the dedicated terminal 61.

[0062] Dedicated terminal 61 is connected to other dedicated terminals 61 via a network cable. Furthermore, one dedicated terminal 61 supplies synthesized audio signals from the audio processing device 1 to other dedicated terminals. Also, one dedicated terminal 61 supplies synthesized audio signals from other dedicated terminals 61 to the audio output unit 32.

[0063] The sound output unit 32 is connected to the dedicated terminal 61. Furthermore, the sound output unit 32 emits sound based on the synthesized sound signal supplied by the dedicated terminal 61.

[0064] [Effect of the sound input / output system (4)] According to the sound input / output system 6, the sound emitted by the speaker located on one (other) dedicated terminal side can be clearly transmitted to the listener located on another (one) dedicated terminal side. As a result, the person on one dedicated terminal side and the person on another dedicated terminal side can have a smooth conversation (dialogue).

[0065] <Sound Processing Method> Next, a sound processing method related to other embodiments of the present invention will be described.

[0066] As shown in Figure 18, the sound processing method includes: a sound signal generation step S1, a modified signal generation step S2, a filtering step S3, and a sound synthesis step S4.

[0067] (Sound Signal Generation Step) In the initial sound signal generation step S1, the sound signal generator generates a first sound signal x1 and a second sound signal x2 with identical spectra from the sound signal representing the sound. Additionally, in sound signal generation step S1, the sound signal generator can also generate a third sound signal that is in phase with the second sound signal. Furthermore, the sound signal generator can be the sound signal generation unit 11 constituting the sound processing device 1, or it can be any other device, or it can be an independent component.

[0068] (Correction Signal Generation Step) After generating the first sound signal x1 and the second sound signal x2, the process moves to the correction signal generation step S2. In the correction signal generation step S2, the correction signal generator generates a phase correction signal p based on the second sound signal x2. Furthermore, if a third sound signal is generated in the sound signal generation step S1, the correction signal generator can also generate the phase correction signal based on the third sound signal in the correction signal generation step S2. The correction signal generator used in the correction signal generation step S2 may also include a capacitor with one end connected to the sound signal generation unit and the other end connected to the non-inverting input terminal. The correction signal generator may be the correction signal generation unit 12 constituting the sound processing device 1, or it may be constituting other devices, or it may be an independent component.

[0069] (Filtering Step) After generating the first audio signal x1 and the second audio signal x2, a filtering step S3 is also performed. In filtering step S3, the filter removes a specific first frequency component below the first frequency from the first audio signal x1 (S31). Furthermore, in filtering step S3, by inputting a phase correction signal p to the non-inverting input terminal of the operational amplifier, the first audio signal, corrected to have a phase closer to the phase of the second audio signal, is output to the operational amplifier as x1 (S32). Additionally, in filtering step S3, a bandpass filter that removes second frequency components higher than the first frequency can also be used as the filter. Furthermore, in filtering step S3, a filter composed of a high-pass filter and a low-pass filter can also be used: the high-pass filter removes the first frequency component from the first audio signal; the low-pass filter removes the second frequency component from the first audio signal after the first frequency component has been removed. In this case, it is preferable to use a low-pass filter equipped with an operational amplifier. Alternatively, in filtering step S3, a high-pass filter comprising an operational amplifier amplifying the first audio signal can also be used. Furthermore, the filter can be part of the audio signal generation unit 11 of the audio processing device 1, or it can be part of other devices, or it can be a separate component. Furthermore, in filtering step S3, the removal of the second frequency component can be performed before the removal of the first frequency component. Alternatively, the removal of the first frequency component and the removal of the second frequency component can be performed simultaneously.

[0070] (Sound Synthesis Step) After the second frequency component is removed from the first sound signal x1, the process moves to the sound synthesis step S4. In the sound synthesis step S4, the sound synthesizer generates a synthesized sound signal x' by adding the phase-corrected first sound signal x1 to the second sound signal x2. The sound synthesizer may be the sound signal generation unit 11 constituting the sound processing device 1, or it may be a device or an independent component.

[0071] [Variation of the sound processing method] Furthermore, the sound processing method may further include an adjustment step. The adjustment step is preferably performed between the filtering step and the sound synthesis step. The adjustment step adjusts the sound pressure level of the phase-corrected first sound signal. When an adjustment step is included, in the sound synthesis step, the sound synthesizer adds and synthesizes the first sound signal with the second sound signal after the sound pressure level adjustment.

[0072] [Effects of the Sound Processing Method] As described above, in the filtering step S3 of the sound processing method, the filter corrects the phase delay caused by removing the first and second frequency components based on the phase correction signal p. In this way, according to the sound processing method, the sound can be made clearer than before.

[0073] <Notes> This invention is not limited to this embodiment. Various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments of the invention are also included in the technical scope of this invention.

[0074] <Summary> The sound processing apparatus related to aspect 1 of the present invention has the following structure, comprising: a sound signal generation unit that generates a first sound signal and a second sound signal with identical spectra from a sound signal expressing sound; a filter that removes at least a first frequency component below a specific first frequency from the first sound signal; a synthesis unit that generates a synthesized sound signal by adding the first sound signal with the first frequency component removed and the second sound signal; and a correction signal generation unit that generates a phase correction signal based on the second sound signal; the filter has an operational amplifier that amplifies the first sound signal; the operational amplifier is configured such that the first sound signal is input to an inverting input terminal; by inputting the phase correction signal to a non-inverting input terminal, the first sound signal is output in a manner whose phase is closer to the phase of the second sound signal.

[0075] The sound processing device can make the sound clearer than before.

[0076] The sound processing device related to the state 2 of the present invention may also be configured as follows: in the state 1, the filter is a bandpass filter that removes the second frequency component that is higher than the first frequency.

[0077] Based on this structure, the signal-to-noise ratio can be improved.

[0078] The sound processing apparatus related to the state 3 of the present invention may also be configured as follows: In the state 2, the filter is composed of the following high-pass filter and the following low-pass filter: The high-pass filter removes the first frequency component from the first sound signal; The low-pass filter removes the second frequency component from the first sound signal after the first frequency component has been removed; The low-pass filter is equipped with the operational amplifier.

[0079] According to this structure, since the phase delay is corrected more accurately because the operational amplifier is only passed after all frequency components have been removed (becoming a state where the phase will no longer be delayed).

[0080] The sound processing apparatus related to the state 4 of the present invention may also be configured as follows: in the state 1, the sound signal generation unit generates a third sound signal with the same spectrum as the second sound signal, and the correction signal generation unit generates the phase correction signal based on the third sound signal.

[0081] According to this structure, the correction signal generation unit generates the correction signal based on the dedicated third audio signal. In this way, the phase shift of the second audio signal can be avoided when using the second audio signal to generate the correction signal.

[0082] The sound processing device related to the state 5 of the present invention may also be configured as follows: In the state 1, the correction signal generation unit is equipped with a capacitor with one end connected to the sound signal generation unit and the other end connected to the non-inverting input terminal.

[0083] According to this structure, the higher the frequency of the signal passing through the filter, the greater the phase delay. On the other hand, the higher the frequency of the signal input to the capacitor, the greater the output, and the larger the input to the non-inverting input terminal of the low-pass filter becomes, which will cause the phase of the output signal to lead. In this way, a correction signal generation unit corresponding to various frequencies of audio signals can be constructed with a simple structure.

[0084] The sound processing device related to the state sample 6 of the present invention may also be configured as follows: in the state sample 1, the first frequency is the frequency between the upper limit frequency of the first formant component and the lower limit frequency of the second formant component.

[0085] According to this structure, since the first formant component is omitted from the first sound signal, and only the second formant component, the third formant component, etc. are left, only the second formant component and the third formant component can be amplified.

[0086] The sound processing apparatus related to the state 7 of the present invention may also be configured as follows: in the state 6, the second frequency is the frequency between the upper limit frequency of the 5th formant component and the lower limit frequency of the 6th formant component, or the frequency between the upper limit frequency of the 6th formant component and the lower limit frequency of the 7th formant component.

[0087] Based on this structure, the signal-to-noise ratio can be further improved.

[0088] The sound processing device related to the state 8 of the present invention may also be configured as follows: In the state 3, the high-pass filter is configured to include an operational amplifier that amplifies the first sound signal, and outputs the first sound signal after removing the first frequency component and amplifying it.

[0089] According to this structure, the clarity of the sound can be improved.

[0090] The sound processing apparatus related to the state 9 of the present invention may also be configured as follows: in the state 1, there is an adjustment unit that adjusts the sound pressure of the first sound signal after the phase correction; the synthesis unit adds the first sound signal after the sound pressure correction and the second sound signal together.

[0091] Based on this structure, it is possible to output sound that is appropriate for the usage environment and the degree of hearing loss.

[0092] The sound input / output system related to the state 10 of the present invention may also be configured as follows: in any one of the states 1 to 6, it includes: a sound input unit that acquires the speaker's voice to generate a sound signal; a sound processing device; and a sound output unit that outputs sound based on the synthesized sound signal generated by the sound processing device.

[0093] Based on this structure, the sound can be made clearer than ever before.

[0094] The sound processing method related to the state 11 of the present invention is a method comprising: a sound signal generation step, wherein a sound signal generator generates a first sound signal and a second sound signal with identical spectra from a sound signal expressing sound; a filtering step, wherein a filter removes at least a first frequency component below a specific first frequency from the first sound signal; and a sound synthesis step, wherein a sound synthesizer generates a synthesized sound signal by adding the first sound signal (with the first frequency component removed) to the second sound signal. The sound signal generation and correction signal generation steps involve generating a phase correction signal based on the second sound signal by a correction signal generator; the filter has an operational amplifier that amplifies the first sound signal; the operational amplifier is configured such that the first sound signal is input to the inverting input terminal; in the filtering step, the first sound signal, corrected to have its phase closer to the phase of the second sound signal, is output to the operational amplifier by inputting the phase correction signal to the non-inverting input terminal of the operational amplifier.

[0095] According to this sound processing method, the sound can be made clearer than before. 1: Sound processing device 11: Sound signal generation unit 12: Correction signal generation unit 121: Capacitor 122: Resistor 13: Filter 131: High-pass filter 132: Low-pass filter 132a: Operational amplifier 132b, 132c: Component 14: Synthesis unit 15: Port 1 16: Input buffer unit 17: Adjustment unit 18: Port 2 2: Auxiliary device 21: Housing 22: Input terminal 23: Output terminal 3, 4, 5, 6: Sound Audio Input / Output System 31: Audio Input Unit 32: Audio Output Unit 33: Amplifier Unit 41: Signal Transmitter 41a, 42a: Antenna 42: Receiver 51: Audio Input Terminal 52: Second Synthesizer 53: Second Audio Signal Generation Unit 54: Third Audio Signal Generation Unit 61: Dedicated Terminal p: Phase Correction Signal t: Synthesized Audio Signal x: Audio Signal x1, x1': First Audio Signal x2: Second Audio Signal x3: Third Audio Signal [Simplified Explanation of the Diagram]

[0009] Figure 1 is a block diagram showing an example of the structure of a sound processing apparatus related to an embodiment of the present invention. Figure 2 is a diagram illustrating the formant components of a sound signal. Figure 3 is a diagram showing the adjustment characteristics of the input buffer section of the sound processing apparatus of Figure 1. Figure 4 is a circuit diagram showing an example of the specific structure of the filter and the correction signal generation section of the sound processing apparatus of Figure 1. Figure 5 is a diagram showing the phase correction characteristics of the filter of the sound processing apparatus of Figure 1. Figure 6 is a diagram illustrating the case where a first sound signal and a second sound signal are synthesized without phase correction. Figure 7 is a diagram showing the frequency characteristics of the synthesized sound signal without phase correction. Figure 8 is a diagram showing an example of the adjustment of the sound signal from the adjustment section of the sound processing apparatus of Figure 1. Figure 9 is a diagram showing the phase and output timing changes of the sound signal, the first sound signal before and after correction, and the synthesized sound signal. Figure 10 is a diagram showing the overall output characteristics of the synthesis section. Figure 11 is a schematic diagram showing an example of the specific structure of an auxiliary device incorporated into the sound processing apparatus of Figure 1. Figure 12 is a schematic diagram showing an example of the specific structure of a sound input / output system incorporated into the sound processing apparatus of Figure 1. Figure 13 is a schematic diagram showing another example of the specific structure of a sound input / output system. Figure 14 is a schematic diagram showing another example of the specific structure of a sound input / output system. Figure 15 is a schematic diagram showing another example of the specific structure of a sound input / output system. Figure 16 is a schematic diagram showing another example of the specific structure of a sound input / output system. Figure 17 is a schematic diagram showing another example of the specific structure of a sound input / output system. Figure 18 is a flowchart showing an example of the flow of a sound processing method related to another embodiment of the present invention.

Claims

1. A sound processing apparatus comprising: a sound signal generation unit that generates a first sound signal and a second sound signal with identical spectra from a sound signal expressing sound; a filter that removes at least a first frequency component below a specific first frequency from the first sound signal; a synthesis unit that generates a synthesized sound signal by adding the first sound signal (with the first frequency component removed) to the second sound signal; and a correction signal generation unit that generates a phase correction signal based on the second sound signal; the filter having an operational amplifier that amplifies the first sound signal; the operational amplifier being configured such that the first sound signal is input to an inverting input terminal; and outputting the first sound signal corrected such that its phase approaches the phase of the second sound signal by inputting the phase correction signal to a non-inverting input terminal.

2. The sound processing apparatus as described in claim 1, wherein, This filter is a bandpass filter that removes second frequency components that are higher than the first frequency.

3. The sound processing apparatus as described in claim 2, wherein, The filter is composed of a high-pass filter and a low-pass filter: the high-pass filter removes the first frequency component from the first audio signal; the low-pass filter removes the second frequency component from the first audio signal after the first frequency component has been removed; the low-pass filter includes the operational amplifier.

4. The sound processing apparatus as described in claim 1, wherein, The sound signal generation unit generates a third sound signal with the same spectrum as the second sound signal, and the correction signal generation unit generates the phase correction signal based on the third sound signal.

5. The sound processing apparatus of claim 1, wherein the correction signal generating unit includes a capacitor having one end connected to the sound signal generating unit and the other end connected to the non-inverting input terminal.

6. The sound processing apparatus as described in claim 1, wherein, The first frequency is the frequency between the upper limit frequency of the first resonance component and the lower limit frequency of the second resonance component.

7. The sound processing apparatus as described in claim 2, wherein, The second frequency is the frequency between the upper limit frequency of the 5th resonant component and the lower limit frequency of the 6th resonant component, or the frequency between the upper limit frequency of the 6th resonant component and the lower limit frequency of the 7th resonant component.

8. The sound processing apparatus as described in claim 3, wherein, The high-pass filter is constructed by an operational amplifier that amplifies the first audio signal, and outputs the first audio signal after removing the first frequency component and amplifying it.

9. The sound processing apparatus of claim 1 further comprises: an adjustment unit for adjusting the sound pressure of the first sound signal after phase correction; and a synthesis unit for additively synthesizing the first sound signal after sound pressure adjustment with the second sound signal.

10. A sound input / output system comprising: a sound input unit that acquires a speaker's voice to generate a sound signal; a sound processing device according to any one of claims 1 to 6; and a sound output unit that outputs sound based on the synthesized sound signal generated by the sound processing device.

11. A sound processing method comprising: a sound signal generation step, wherein a sound signal generator generates a first sound signal and a second sound signal with identical spectra from a sound signal representing sound; a filtering step, wherein a filter removes at least a first frequency component below a specific first frequency from the first sound signal; a sound synthesis step, wherein a sound synthesizer generates a synthesized sound signal by adding the first sound signal (with the first frequency component removed) to the second sound signal; and a correction signal generation step, wherein a correction signal generator generates a phase correction signal based on the second sound signal; the filter having an operational amplifier amplifying the first sound signal; the operational amplifier being configured such that the first sound signal is input to an inverting input terminal; in the filtering step, the first sound signal, corrected to a phase closer to the phase of the second sound signal, is output to the operational amplifier by inputting the phase correction signal to a non-inverting input terminal of the operational amplifier.

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