Call environment generation method, call environment generation device, computer program product

Abstract

A technique for generating a call environment is provided, such that when the call sound is broadcast through a speaker, the call content cannot be heard by anyone other than the caller. Herein, let SP<subgt;1< / subgt;, …, SP<subgt;N< / subgt> be speakers provided in a vehicle, let F<subgt;n< / subgt>(ω) be a first filter coefficient for generating an input signal of the speaker SP<subgt;n< / subgt>, and let <supgt;~< / supgt;F<subgt;n< / subgt>(ω) be a second filter coefficient different from the first filter coefficient for generating an input signal of the speaker SP<subgt;n< / subgt>. The technique includes: an audio signal generation step of generating a call-time audio signal obtained by adjusting the volume of an audio signal played in the call using a prescribed volume value when a start signal of the call is detected; a first partial signal generation step of generating a sound signal S<subgt;n< / subgt> that becomes an input signal of the speaker SP<subgt;n< / subgt> according to the voice signal of the call using the first filter coefficient F<subgt;n< / subgt>(ω); and a second partial signal generation step of generating an audio signal A<subgt;n< / subgt> that becomes an input signal of the speaker SP<subgt;n< / subgt> according to the call-time audio signal using the second filter coefficient <supgt;~< / supgt>F<subgt;n< / subgt>(ω).

Description

Technical Field

[0001] The present invention relates to a technique for generating a call environment for hands-free calls in, for example, an automobile. Background Art

[0002] In an audio system of an automobile, there is also a system capable of making hands-free calls. In the system of Non-Patent Document 1, when a call is started, music playback is temporarily stopped, and only the call voice is broadcast through a speaker in the vehicle.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Non-Patent Document 1: Instruction Manual for "Smartphone Cooperative Navigation" by SUZUKI, [online], [searched on May 12, 2020], Internet <URL:https: / / www.suzuki.co.jp / car / information / navi / pdf / navi.pdf> Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the system of Non-Patent Document 1, since music playback stops, for example, as Figure 1 shown, not only the driver's seat but also the passenger seat can hear the call voice, and there is a concern that the call content may be heard by the passenger in the passenger seat. Therefore, it becomes a problem when the call content is something that one does not want to be heard by anyone.

[0008] That is, in the existing system, when the call sound is broadcast through a speaker, it is impossible to prevent the call content from being heard by anyone other than the caller.

[0009] Therefore, an object of the present invention is to provide a technique for generating a call environment such that when the call sound is broadcast through a speaker, the call content is not heard by anyone other than the caller.

[0010] Means for Solving the Problems

[0011] One aspect of the present invention sets SP1,..., SP N as speakers provided in an acoustic space, and sets P1,..., P M as positions for determining a call location in the acoustic space, and includes: a position acquisition step in which when a call start signal is detected, a call environment generation device acquires the position P M_u (M u is a value satisfying 1 ≤ M u≤M integer); and playing step, for n = 1, ..., N, the conversation environment generating device uses the speaker SP n Playback based on sound signal S n and sound signal A n The sound signal S n The speaker SP is generated based on the voice signal of the call. n The input signal is the sound signal S n , the sound signal A n The speaker SP is generated based on the sound signal obtained by adjusting the volume of the sound signal played during the call (hereinafter referred to as the call sound signal). n The input signal is the audio signal A n , based on the sound signal S1, ..., sound signal S N The sound based on the audio signal of the call is set to be the sound based on the audio signal A1, ..., the audio signal A N The sound is set to be based on the sound signal during the call, and the sound based on the sound signal of the call is at position P M_u Middle position P M_u Positions other than P m (m=1,…,M u -1,M u +1, ..., M) is played louder, based on the sound of the audio signal during the call at position P M_u Positions other than P m (m=1,…,M u -1,M u +1,…,M) than the position P M_u Played bigger.

[0012] In one embodiment of the present invention, SP1, ..., SP N Assume that the speaker is installed in a car, P1 is the position of the driver's seat of the car, and P2, ..., P M Assume that the position of the seat other than the driver's seat of the car, and F n (ω) (n=1, ..., N, where ω represents frequency) is set to generate the loudspeaker SP n The filter coefficient of the input signal (hereinafter referred to as the first filter coefficient) is ～ F n (ω) (n=1, ..., N, where ω represents frequency) is set to generate the loudspeaker SP nfiltering coefficients different from the first filtering coefficient for the input signal (hereinafter referred to as the second filtering coefficient), including: an audio signal generation step, when the call environment generation device detects a start signal of a call, generating an audio signal obtained by adjusting the volume of the audio signal played in the call using a specified volume value (hereinafter referred to as the in-call audio signal); a first partial signal generation step, for n = 1…, N, the call environment generation device filters the voice signal of the call by using the first filtering coefficient F n (ω), thereby generating a voice signal S n that is an input signal to the speaker SP n ; and a second partial signal generation step, for n = 1…, N, the call environment generation device filters the in-call audio signal by using the second filtering coefficient ～ F n (ω), thereby generating an audio signal A n that is an input signal to the speaker SP n .

[0013] In one aspect of the present invention, let SP1,…, SP N be speakers provided in the sound space, let P1,…, P M be positions for determining the call location in the sound space, and let F n (ω) (n = 1,…, N, where ω represents frequency) be filtering coefficients (hereinafter referred to as the first filtering coefficient) for generating an input signal to the speaker SP n . Let ～ F n (ω) (n = 1,…, N, where ω represents frequency) be filtering coefficients different from the first filtering coefficient for generating an input signal to the speaker SP n (hereinafter referred to as the second filtering coefficient), including: a position acquisition step, when the call environment generation device detects a start signal of a call, acquiring the position P M u (M u is an integer satisfying 1 ≤ M u ≤ M); an audio signal generation step, when the call environment generation device detects the start signal, generating an audio signal obtained by adjusting the volume of the audio signal played in the call using a specified volume value (hereinafter referred to as the in-call audio signal); a first partial signal generation step, for n = 1…, N, the call environment generation device filters the voice signal of the call by using the first filtering coefficient F n (ω) to generate a voice signal S n that is an input signal to the speaker SP n; and a second partial signal generation step, for n = 1, ..., N, the call environment generation device generates an acoustic signal A that becomes an input signal to the speaker SP by filtering the acoustic signal during the call using a second filter coefficient ～ F n (ω). n of the speaker SP n .

[0014] Effect of the Invention

[0015] According to the present invention, in the case of playing a call sound through a speaker, it is possible to prevent the call content from being heard by anyone other than the caller. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a diagram showing a situation of playing sound during a hands-free call.

[0017] Figure 2 is a block diagram showing an example of the structure of the call environment generation device 100.

[0018] Figure 3 is a flowchart showing an example of the operation of the call environment generation device 100.

[0019] Figure 4 is a flowchart showing an example of the operation of the call environment generation device 100.

[0020] Figure 5 is a diagram showing a situation of playing sound during a hands-free call.

[0021] Figure 6 is a block diagram showing an example of the structure of the call environment generation device 200.

[0022] Figure 7 is a flowchart showing an example of the operation of the call environment generation device 200.

[0023] Figure 8 shows an example of the functional structure of a computer of each device in the embodiment for implementing the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail. In addition, the same reference numerals are assigned to structural parts having the same functions, and redundant descriptions are omitted.

[0025] Before describing each embodiment, the notation method in this specification will be described.

[0026] ^(caret) indicates a superscript. For example, x y^z indicates y z is a superscript for x, xy^z Indicates y z is the subscript for x. Additionally, _ (underscore) represents the subscript. For example, x y_z Indicates y z is the superscript for x, x y_z Indicates y z is the subscript for x.

[0027] For a certain character x, ^x or ～ For superscripts like ^ or ~ of x, it should originally be recorded directly above "x", but due to the constraints of the description marking in the specification, it is recorded as ^x or ～ x.

[0028] <First Embodiment>

[0029] The call environment generation device 100 generates a call environment for preventing the call sound from being heard by passengers other than the driver when the driver makes a hands-free call in the vehicle. Therefore, the call environment generation device 100 broadcasts the call sound and a masking sound (e.g., music) as playback sounds from N speakers installed in the vehicle, and the masking sound is used to prevent the call sound from being heard. Specifically, the call environment generation device 100 causes the call sound to be mainly heard at the driver's seat and the masking sound such as music to be mainly heard at seats other than the driver's seat. Hereinafter, SP1,..., SP N are set as the speakers installed in the vehicle, P1 is set as the position of the driver's seat, and P2,..., P M are set as the positions of seats other than the driver's seat. For example, P2 can be set as the position of the front passenger seat, and P3, P4, P5 can be set as the positions of the rear seats respectively.

[0030] Next, reference will be made to Figures 2 to 4 to explain the call environment generation device 100. Figure 2 is a block diagram showing the structure of the call environment generation device 100. Figure 3 and Figure 4 are flowcharts showing the operations of the call environment generation device 100. As Figure 2 shown, the call environment generation device 100 includes an audio signal generation unit 110, a first local signal generation unit 120, a second local signal generation unit 130, a large-scale signal generation unit 140, and a recording unit 190.

[0031] In the recording unit 190, for example, the filter coefficients used in the filtering in the first local signal generation unit 120, the second local signal generation unit 130, and the large-scale signal generation unit 140 are recorded. These filter coefficients are used to generate the input signals for the speakers. Hereinafter, those used in the first local signal generation unit 120 to generate the speaker SPn The filtering coefficient of the input signal (hereinafter referred to as the first filtering coefficient) is expressed as F n (ω) (n = 1, …, N, where ω represents frequency), which will be used in the second local signal generation unit 130 to generate the speaker SP n The filtering coefficient of the input signal (hereinafter referred to as the second filtering coefficient) is expressed as ～ F n (ω) (n = 1, …, N, where ω represents frequency), which will be used in the large - range signal generation unit 140 to generate the speaker SP n The filtering coefficient of the input signal (hereinafter referred to as the third filtering coefficient) is expressed as ^F n (ω) (n = 1, …, N, where ω represents frequency). In addition, the first filtering coefficient F n (ω), the second filtering coefficient ～ F n (ω), and the third filtering coefficient ^F n (ω) are mutually different filtering coefficients.

[0032] In addition, the call environment generation device 100 is connected to N speakers 950 (i.e., speakers SP1, …, speakers SP N ).

[0033] It will be described according to Figure 3 the operation of the call environment generation device 100 at the start of a call.

[0034] In S110 - 1, when the audio signal generation unit 110 detects the start signal of a call, it generates and outputs an audio signal (hereinafter referred to as the in - call audio signal) obtained by adjusting the volume of the audio signal played during the call using a specified volume value. That is, the audio signal generation unit 110 broadcasts a masking sound during the call by generating the audio signal played during the call. For example, when the audio signal generation unit 110 is playing music at the start of a call, it generates an audio signal corresponding to the music being played, and in other cases, it can generate an audio signal corresponding to a sound prepared in advance for masking call sounds (for example, music suitable for BGM) as the audio signal played during the call.

[0035] In addition, the audio signal generation unit 110 adjusts the volume of the audio signal played during the call using a specified volume value to obtain the in - call audio signal. As the specified volume value, a volume value set in advance (for example, a volume value suitable for masking call sounds) can be used. Here, the volume value suitable for masking call sounds means that at seats other than the driver's seat (i.e., positions P other than position P1 m(where m = 2, …, M)) is a volume value such that the sound is of a magnitude that makes it difficult to hear the call sound, and at the driver's seat (i.e., position P1), it is of a magnitude that does not interfere with hearing the call sound.

[0036] The audio signal generation unit 110 may also use a volume value calculated based on the estimated volume of the audio signal played during the call and the estimated volume of the voice signal of the call as the specified volume value. Here, the estimated volume of the audio signal reproduced during the call refers to the volume estimated based on the level of the sound corresponding to the audio signal, and the estimated volume of the voice signal of the call refers to the volume estimated according to the level of the received voice during the call. The volume value V can be obtained, for example, by the following formula.

[0037] [Mathematical formula 1]

[0038]

[0039] Here, Q represents the estimated volume of the audio signal played during the call, R represents the estimated volume of the voice signal of the call, and β represents a specified constant.

[0040] That is, the volume value V is obtained by multiplying the ratio R / Q of the estimated volume R of the voice signal of the call to the estimated volume Q of the audio signal played during the call by a preset constant β. In addition, the constant β is a value such that the sound is of a magnitude that makes it difficult to hear the call sound at seats other than the driver's seat (i.e., positions P other than position P1) m (where m = 2, …, M)), and at the driver's seat (i.e., position P1), it is of a magnitude that does not interfere with hearing the call sound, and is a preset value.

[0041] By using the above volume value V, it is possible to make the ratio R / Q constant and always obtain the best masking effect.

[0042] In S120, the first partial signal generation unit 120 takes the voice signal of the call as input, and for n = 1, …, N, uses the first filter coefficient F n (ω) to filter the voice signal of the call, thereby generating and outputting a voice signal S that becomes the input signal of the speaker SP n . The first filter coefficient F n . (ω) is determined as a filter coefficient for filtering the voice signal of the call so that the call voice is of a magnitude that is easy to hear at the driver's seat (i.e., position P1), and at seats other than the driver's seat (i.e., positions P other than position P1) n (where m = 2, …, M)), the call voice is as small as possible. For example, G m (ω) can be used as the one from the speaker SP n,m (ω) as from the speaker SP nTo position P m For the transfer characteristics up to position P (n = 1, …, N, m = 1, …, M, where ω represents frequency), the first filter coefficient F n (ω) (n = 1, …, N) is determined as an approximate solution of the following equation.

[0043] [Mathematical formula 2]

[0044]

[0045] In addition, the above approximate solution can be obtained by using the least squares method.

[0046] In S130, the second local signal generation unit 130 uses the call-time sound signal output in S110-1 as an input, and for n = 1, …, N, uses the second filter coefficient ～ F n (ω) to filter the call-time sound signal, thereby generating and outputting the sound signal A that becomes the input signal of the speaker SP n . The second filter coefficient n F ～ F n (ω) is determined as a filter coefficient for filtering the call-time sound signal such that the masking sound becomes a large sound that makes it difficult to hear the call sound at seats other than the driver's seat (i.e., positions P other than position P1 m (m = 2, …, M)), and the masking sound becomes as small as possible at the driver's seat (i.e., position P1). For example, the second filter coefficient ～ F n (ω) (n = 1, …, N) can be determined as an approximate solution of the following equation.

[0047] [Mathematical formula 3]

[0048]

[0049] In addition, the above approximate solution can be obtained by using the least squares method.

[0050] Finally, in S950 (not shown), the speaker SP as the speaker 950 n (n = 1, …, N) uses the sound signal S output in S120 n and the sound signal A output in S130 n as inputs, and plays the sound based on the sound signal S n and the sound signal A n .

[0051] Therefore, if based on the sound signals S1, …, the sound signals S NSet the sound to the sound based on the voice signal of the call, and based on the audio signals A1, …, audio signal A N Set the sound to the sound based on the audio signal during the call, then the first filter coefficient F n (ω) (n = 1, …, N) and the second filter coefficient ～ F n (ω) (n = 1, …, N) are filter coefficients determined in the following manner, that is, at the driver's seat (i.e., position P1), the sound based on the voice signal of the call becomes easier to hear than the sound based on the audio signal during the call, and at seats other than the driver's seat (i.e., positions P m (m = 2…, M)), the sound based on the voice signal of the call becomes difficult to hear due to the sound based on the audio signal during the call. Therefore, for example, as Figure 5 shown, in such a way that the call sound is mainly heard at the driver's seat and the masking sound such as music is mainly heard at seats other than that, the sound based on the above signals is played from the speakers SP1, …, speakers SP N

[0052] In addition, as Figure 2 shown, the structural part including the first local signal generation unit 120 and the second local signal generation unit 130 is called the local signal generation unit 135. Therefore, the local signal generation unit 135 performs the following operations (refer to Figure 3 ).

[0053] In S135, the local signal generation unit 135 takes the voice signal of the call and the audio signal during the call output in S110 - 1 as inputs. For n = 1, …, N, it generates and outputs the voice signal S n that becomes the input signal for the speaker SP n , and generates and outputs the audio signal A n that becomes the input signal for the speaker SP n .

[0054] Then, for n = 1, …, N, the call environment generation device 100 uses the speaker SP n to play the sound based on the voice signal S n and the audio signal A n . In addition, this step is the step corresponding to the above S950.

[0055] Here, the sound based on the voice signal of the call is played louder at the driver's seat (i.e., position P1) than at seats other than the driver's seat (i.e., positions P m (m = 2, …, M)), and the sound based on the audio signal during the call is at seats other than the driver's seat (i.e., positions P1 other than the position P​m (for m = 2, …, M)) is played louder than the driver's seat (i.e., position P1). In other words, at the driver's seat (i.e., position P1), the sound based on the voice signal for the call is played in a way that it is easier to hear than the sound based on the audio signal during the call. At seats other than the driver's seat (i.e., positions other than P1 m (for m = 2, …, M)), the sound based on the voice signal for the call is played in a way that it is difficult to hear due to the sound based on the audio signal during the call.

[0056] It will be according to Figure 4 Describe the operation of the call environment generation device 100 at the end of a call.

[0057] In S110-2, when the audio signal generation unit 110 detects the end signal of the call, it generates and outputs an audio signal (hereinafter referred to as the normal-time audio signal) obtained by adjusting the volume of the audio signal reproduced after the call ends using the volume value before the call starts.

[0058] In S140, the wide-range signal generation unit 140 uses the normal-time audio signal output in S110-2 as an input, and for n = 1…, N, uses the third filter coefficient ^F n (ω) to filter the normal-time audio signal, thereby generating and outputting an audio signal A' n that becomes the input signal of the speaker SP n . The third filter coefficient ^F n (ω) can be determined as a filter coefficient for filtering the normal-time audio signal such that the sound can be heard evenly in all seats.

[0059] Finally, the speaker SP n (for n = 1, …, N) of the speaker 950 uses the audio signal A' output in S140 n as an input and plays the sound based on the audio signal A' n .

[0060] According to an embodiment of the present invention, when the call sound is broadcast through the speaker, it is possible to prevent the call content from being heard by people other than the caller. That is, when the driver in the car makes a hands-free call, it is possible to prevent the passengers from knowing the call content.

[0061] <Second Embodiment>

[0062] In the first embodiment, the generation of the call environment for the driver to make a hands-free call in the car is described. Here, for example, the generation of the call environment for making a hands-free call at a seat other than the driver's seat in the car or in a lounge with multiple seats is described.

[0063] When the call environment generation device 200 makes a hands-free call in an acoustic space where masking sounds such as reproduced music are present, such as in a car or a lounge, it generates a call environment that prevents the call sound from being heard by people other than the caller. Therefore, the call environment generation device 200 broadcasts the call sound and a masking sound (e.g., music) that prevents the call sound from being heard from N speakers installed in the acoustic space. Specifically, M positions (hereinafter referred to as P1, …, P M ) for determining the call location are set in advance in the acoustic space, and the call environment generation device 200 causes the call sound to be mainly heard at the position P M_u (M u is an integer satisfying 1 ≤ M u ≤ M) that is the call location, and causes the masking sound such as music to be mainly heard at positions other than the position P M_u , such as position P1, …, position P M_u-1 , position P M_u+1 , …, position P M . Hereinafter, SP1, …, SP N are the speakers installed in the acoustic space.

[0064] Hereinafter, the call environment generation device 200 will be described with reference to Figures 6 to 7 . Figure 6 is a block diagram showing the structure of the call environment generation device 200. Figure 7 is a flowchart showing the operation of the call environment generation device 200. As Figure 6 shown, the call environment generation device 200 includes a position acquisition unit 210, an audio signal generation unit 110, a first local signal generation unit 120, a second local signal generation unit 130, a large-range signal generation unit 140, and a recording unit 190.

[0065] In addition, the call environment generation device 200 is connected to N speakers 950 (i.e., speakers SP1, …, speakers SP N ).

[0066] The operation of the call environment generation device 200 at the start of a call will be described in accordance with Figure 7 .

[0067] In S210, when the position acquisition unit 210 detects a call start signal, it acquires and outputs the position P M_u (M u is an integer satisfying 1 ≤ M u ≤ M) that is the call location for the call.

[0068] In S110-1, when the audio signal generation unit 110 detects the start signal of a call, it generates and outputs an audio signal (hereinafter referred to as the in-call audio signal) obtained by adjusting the volume of the audio signal played during the call using a specified volume value.

[0069] In S120, the first partial signal generation unit 120 uses the voice signal of the call and the position P output in S210 M_u as inputs. For n = 1, …, N, it filters the voice signal of the call using the first filter coefficient F n (ω), thereby generating and outputting the voice signal S n that becomes the input signal of the speaker SP n . The first filter coefficient F n (ω) determines the filter coefficient for filtering the voice signal of the call such that the call voice becomes a relatively large and easily audible voice at the position P M_u , and the call voice becomes as small as possible at positions P M_u other than the position P m (m = 1, …, M u -1, M u +1, …, M). For example, if G n,m (ω) is set as the transfer characteristic from the speaker SP n to the position P m (where ω represents frequency, n = 1, …, N, m = 1, …, M), the first filter coefficient F n (ω) (n = 1, …, N) can be determined as the approximate solution of the following formula.

[0070] [Mathematical formula 4]

[0071]

[0072] In addition, the above approximate solution can be obtained by using the least squares method.

[0073] In S130, the second partial signal generation unit 130 uses the in-call audio signal output in S110-1 and the position P output in S210 M_u as inputs. For n = 1…, N, it filters the in-call audio signal using the second filter coefficient ～ F n (ω), thereby generating and outputting the audio signal A n that becomes the input signal of the speaker SP n . The second filter coefficient ～ F n (ω) determines the filter coefficient for filtering the in-call audio signal such that at the position P M_uPosition P other than m (m = 1, …, M u -1, M u +1, …, M), the masking sound becomes a relatively large sound that makes it difficult to hear the call sound. At position P M_u the masking sound should become as small as possible. For example, the second filter coefficient ～ F n (ω) (n = 1, …, N) can be determined as an approximate solution to the following equation.

[0074] [Mathematical formula 5]

[0075]

[0076] In addition, the above approximate solution can be obtained by using the least squares method.

[0077] Finally, in S950 (not shown), the speaker SP of the speaker 950 n (n = 1, …, N) takes the sound signal S output in S120 n and the audio signal A output in S130 n as inputs and plays the sound based on the sound signal S n and the audio signal A n .

[0078] Therefore, if the sound based on the sound signals S1, …, sound signal S N is set as the sound based on the call sound signal, and the sound based on the audio signals A1, …, audio signal A N is set as the sound based on the call-time audio signal, then the first filter coefficient F n (ω) (n = 1, …, N) and the second filter coefficient ～ F n (ω) (n = 1, …, N) are filter coefficients determined in the following manner, that is, at position P M_u the sound based on the call sound signal is more easily heard than the sound based on the call-time audio signal, and at positions P M_u other than position P m (m = 1, …, M u -1, M u +1, …, M), the sound based on the call sound signal is made difficult to hear by the sound based on the call-time audio signal. Therefore, at position P M_u the call sound is mainly heard, and at positions P M_u other than position P m (m = 1, …, M u -1, M uAt positions +1, …, M), the masking sound such as music being listened to mainly, from speaker SP1, …, speaker SP N Plays the sound based on the above signal.

[0079] In addition, as Figure 6 shown, the structural part including the first local signal generation unit 120 and the second local signal generation unit 130 is called the local signal generation unit 135. Therefore, the local signal generation unit 135 performs the following operations (refer to Figure 7 ).

[0080] In S135, the local signal generation unit 135 takes the voice signal of the call and the in-call sound signal output in S110-1 as inputs. For n = 1, …, N, based on the voice signal of the call, it generates and outputs the voice signal S n that becomes the input signal of speaker SP n , and based on the in-call sound signal, it generates and outputs the sound signal A n that becomes the input signal of speaker SP n .

[0081] Then, for n = 1, …, N, the call environment generation device 200 uses speaker SP n to play the sound based on the voice signal S n and the sound signal A n . In addition, this step is the step corresponding to the above S950.

[0082] Here, the sound based on the voice signal of the call is played louder at position P M_u than at positions P M_u other than position P m (m = 1, …, M u -1, M u +1, …, M). The sound based on the in-call sound signal is played louder at positions P M_u other than position P m (m = 1, …, M u -1, M u +1, …, M) than at position P M_u . In other words, at position P M_u , it is played in such a way that the sound based on the voice signal of the call is easier to hear than the sound based on the in-call sound signal. At positions P M_u other than position P m (m = 1, …, M u -1, M u +1, …, M), it is played in such a way that the sound based on the voice signal of the call is difficult to hear due to the sound based on the in-call sound signal.

[0083] In addition, the operation of the call environment generation device 200 at the end of a call is the same as that of the call environment generation device 100 at the end of a call (see Figure 4 ).

[0084] According to an embodiment of the present invention, in the case of playing a call sound through a speaker, it is possible to prevent the call content from being heard by anyone other than the caller. That is, when the caller makes a hands-free call in an acoustic space, it is possible to prevent anyone other than the caller from knowing the call content.

[0085] In the first and second embodiments, the generation of a call environment for hands-free calls has been described. However, the present invention can be applied to conversations in a specified space such as a vehicle represented by an automobile or a room. In this case, in the vehicle or the space, there are at least two people having a conversation (hereinafter simply referred to as conversationalists). For each conversationalist, the voice of the other conversationalist is played in a way that is enhanced and easy to hear, and for people other than the conversationalists, the masking sound is enhanced and played so that the voice of the conversation becomes difficult to hear. As an example of such a conversation, there is, for example, so-called in-car communication.

[0086] <Supplementary Note>

[0087] Figure 8 This is a diagram showing an example of the functional structure of a computer that implements each of the above devices. The processing in each of the above devices can be implemented by reading a program for causing the computer to function as each of the above devices into the recording unit 2020 and causing the control unit 2010, the input unit 2030, the output unit 2040, etc. to operate.

[0088] The device of the present invention, for example, as a single hardware entity, includes: an input unit connectable to a keyboard, etc., an output unit connectable to a liquid crystal display, etc., a communication unit connectable to a communication device (such as a communication cable) capable of communicating with the outside of the hardware entity, a CPU (which may also include a central processing unit (Central Processing Unit), a cache memory, or a register, etc.), a RAM or a ROM as a memory, an external storage device as a hard disk, and a bus connected in such a way that data exchange can be performed between these input unit, output unit, communication unit, CPU, RAM, ROM, and external storage device. In addition, if necessary, a device (driver) capable of reading and writing a recording medium such as a CD-ROM may be provided in the hardware entity. As a physical entity having such hardware resources, there is a general-purpose computer, etc.

[0089] In the external storage device of the hardware entity, programs required to implement the above functions and data required in the processing of the programs are stored (not limited to the external storage device, for example, the program can also be read out and stored in a ROM as a dedicated storage device). In addition, data obtained through the processing of these programs is appropriately stored in a RAM, an external storage device, or the like.

[0090] In the hardware entity, as needed, each program stored in the external storage device (or ROM, etc.) and the data required for the processing of each program are read into the memory and appropriately interpreted and executed by the CPU for processing. As a result, the CPU implements the specified functions (each structural part represented as the above, … part, … unit, etc.).

[0091] The present invention is not limited to the above-described embodiments and can be appropriately modified without departing from the gist of the present invention. In addition, the processing described in the above embodiments can be executed not only in the order described in chronological order but also in parallel or individually according to the processing capabilities of the device executing the processing or as needed.

[0092] As described above, when the processing functions in the hardware entity (the device of the present invention) described in the above embodiments are implemented by a computer, the processing content of the functions that the hardware entity should have is described by a program. Then, by executing this program on the computer, the processing functions in the above hardware entity are implemented on the computer.

[0093] The program describing the processing content can be recorded on a computer-readable recording medium. As a computer-readable recording medium, for example, it can be a magnetic recording device, an optical disc, a magneto-optical recording medium, a semiconductor memory, or the like. Specifically, for example, as a magnetic recording device, a hard disk device, a floppy disk, a magnetic tape, etc. can be used. As an optical disc, a DVD (Digital Versatile Disc), a DVD-RAM (Random Access Memory), a CD-ROM (Compact Disc Read Only Memory), a CD-R (Recordable) / RW (ReWritable), etc. can be used. As a magneto-optical recording medium, an MO (Magneto-Optical disc) etc. can be used. As a semiconductor memory, an EEP-ROM (Electronically Erasable and Programmable-Read Only Memory), etc. can be used.

[0094] In addition, the distribution of the program is carried out, for example, by selling, transferring, or lending portable recording media such as DVDs and CD-ROMs that record the program. Furthermore, it can also be configured to store the program in the storage device of a server computer and forward the program from the server computer to other computers via a network, thereby distributing the program.

[0095] A computer that executes such a program, for example, first temporarily stores the program stored in a portable storage medium or the program forwarded from a server computer in its own storage device. Then, during the execution process, the computer reads the program stored in its own storage device and executes the process according to the read program. Additionally, as another execution mode of the program, the computer can also directly read the program from a portable storage medium, execute the process according to the program, and each time the program is forwarded from the server computer to the computer, it can also sequentially execute the process according to the received program. Furthermore, it can also be configured to achieve the processing function not by forwarding the program from the server computer to the computer, but only through the execution instruction and result acquisition, that is, to execute the above processing through a so-called ASP (Application Service Provider) type of service. Additionally, in the program of this mode, it is assumed to include information that complies with the program (data that is not a direct instruction to the computer but has the nature of specifying the processing of the computer) and is used as information for the processing of the electronic computer.

[0096] In addition, in this mode, it is assumed to constitute a hardware entity by executing a prescribed program on a computer, but it can also be assumed to implement at least a part of these processing contents only on the hardware.

[0097] The description of the above embodiments of the present invention is presented for the purpose of illustration and record. It is not meant to be exhaustive, nor is it meant to limit the invention to the exact form disclosed. Modifications and variations can be made according to the above teachings. The embodiments are selected and presented to provide the best illustration of the principles of the present invention and for those skilled in the art to utilize the present invention in various embodiments with various modifications to suit the considered practical use. All such modifications or variations are within the scope of the present invention determined by the appended claims, which are interpreted within the scope given in a fair, legal, and equitable manner.

Claims

1. A method for generating a call environment, wherein, Let SP1, …, SP N be speakers installed in an automobile, let P1 be the position of the driver's seat of the automobile, and let P2, …, P M be the positions of seats other than the driver's seat of the automobile. Let F n (ω) be the filter coefficient, i.e., the first filter coefficient, for generating the input signal of the speaker SP n . Let ～ F n (ω) be the filter coefficient different from the first filter coefficient, i.e., the second filter coefficient, for generating the input signal of the speaker SP n . Here, n = 1, …, N, and ω represents frequency. the method for generating a call environment includes: a sound signal generation step, when the call environment generation device detects a start signal of a call, generating a sound signal obtained by adjusting the volume of the sound signal played during the call using a specified volume value, that is, a sound signal during a call; The first partial signal generation step, for n = 1, …, N, the call environment generation device filters the voice signal of the call by using the first filter coefficient F n (ω), thereby generating a voice signal S n that becomes the input signal of the speaker SP n ; and Second local signal generation step, for n = 1, …, N, the call environment generation device uses the second filter coefficient ～ F n (ω) to filter the sound signal during the call, thereby generating the sound signal A n that becomes the input signal of the speaker SP n , Set G n,m (ω) as the transfer characteristic from the speaker SP n to the position P m up to, where m = 1, …, M The first filter coefficient F n (ω) is the filter coefficient determined as an approximate solution of the following formula, [Mathematical formula 6] Second filtering coefficient ～ F n (ω) is the filtering coefficient determined as the approximate solution of the following formula: [Mathematical formula 7] 2. The method for generating a call environment according to claim 1, characterized in that, the specified volume value is a volume value set in advance, or a volume value calculated based on the estimated volume of the sound signal played during the call and the estimated volume of the voice signal of the call.

3. A method for generating a call environment, wherein, Let SP1, …, SP N be speakers arranged in the acoustic space, and let P1, …, P M be positions for determining a call location in the acoustic space. Let F n (ω) be the filtering coefficient, i.e., the first filtering coefficient, for generating an input signal of the speaker SP n , and let ～ F n (ω) be a filtering coefficient different from the first filtering coefficient, i.e., the second filtering coefficient, for generating an input signal of the speaker SP n . Here, n = 1, …, N, and ω represents frequency. the method for generating a call environment includes: Position acquisition step: When the call environment generation device detects a start signal of a call, it acquires the position P of the call location of the call M_u , M u where M u is an integer satisfying 1 ≤ M a sound signal generation step, when the call environment generation device detects the start signal, generating a sound signal obtained by adjusting the volume of the sound signal played during the call using a specified volume value, that is, a sound signal during a call; The first partial signal generation step, for n = 1, …, N, the call environment generation device filters the voice signal of the call by using the first filter coefficient F n (ω), thereby generating a voice signal S n that becomes the input signal of the speaker SP n ; and Second partial signal generation step, for n = 1, …, N, the call environment generation device filters the sound signal during the call by using the second filter coefficient ～ F n (ω) to generate the sound signal A that becomes the input signal of the speaker SP n n ,​ Set G n,m (ω) as the transfer characteristic from the speaker SP n to the position P m up to, where m = 1, …, M The first filter coefficient F n (ω) is the filter coefficient determined as an approximate solution of the following formula, [Mathematical formula 8] Second filtering coefficient ～ F n (ω) is the filtering coefficient determined as an approximate solution of the following formula: [Mathematical formula 9] 4. The method for generating a call environment according to claim 3, characterized in that, the specified volume value is a volume value set in advance, or a volume value calculated based on the estimated volume of the sound signal played during the call and the estimated volume of the voice signal of the call.

5. A call environment generation device, wherein, Let SP1, …, SP N be speakers installed in the vehicle, let P1 be the position of the driver's seat of the vehicle, and let P2, …, P M be the positions of seats other than the driver's seat of the vehicle. Let F n (ω) be the filtering coefficient, i.e., the first filtering coefficient, for generating the input signal of speaker SP n . Let ～ F n (ω) be the filtering coefficient different from the first filtering coefficient, i.e., the second filtering coefficient, for generating the input signal of speaker SP n . Here, n = 1, …, N, and ω represents frequency. the call environment generation device includes: a sound signal generation unit, when detecting a start signal of a call, generating a sound signal obtained by adjusting the volume of the sound signal played during the call using a specified volume value, that is, a sound signal during a call; The first partial signal generation unit, for n = 1, …, N, filters the voice signal of the call by using the first filter coefficient F n (ω) to thereby generate a voice signal S n that becomes the input signal to the speaker SP n ; and Second local signal generation unit, for n = 1, …, N, uses the second filter coefficient ～ F n (ω) to filter the sound signal during a call, thereby generating a sound signal A that becomes an input signal to the speaker SP n n ,​ Set G n,m (ω) as the transfer characteristic from the speaker SP n to the position P m up to, where m = 1, …, M The first filter coefficient F n (ω) is a filter coefficient determined as an approximate solution to the following equation: [Mathematical formula 10] Second filtering coefficient ～ F n (ω) is the filtering coefficient determined as the approximate solution of the following formula: [Mathematical formula 11] 6. A computer program product, including a program for causing a computer to execute the method for generating a call environment according to any one of claims 1 to 4.

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