Signal processing system, signal processing method, and program

Abstract

This system provides a mechanism that makes binaural recording easier to implement. [Solution] A signal processing system comprising: a measuring device for acquiring measurement data relating to transmission characteristics; a first acquisition device for acquiring a first acoustic signal; and a control device connected to each of the measuring device and the first acquisition device via a network, wherein the control device corrects the first acoustic signal based on the measurement data acquired by the measuring device and generates a second acoustic signal.

Description

[Technical Field]

[0001] This disclosure relates to a signal processing system, a signal processing method, and a program. [Background technology]

[0002] In recent years, binaural recording has been attracting attention. Binaural recording is a technique that records sound as it is transmitted to the eardrums of both ears. For example, microphones placed inside the ear canals of both ears are used for binaural recording. Playing back binaurally recorded sound is also called binaural playback. By playing back binaural sound using earphones or headphones, it is possible to reproduce a sense of three-dimensionality and presence as if one were actually present at the recording location.

[0003] Various technologies related to binaural recording and binaural playback have been developed. For example, Patent Document 1 below proposes a binaural recording device that uses a noise-canceling microphone provided on the outside of an earphone that is held in the ear by inserting the earpiece into the ear canal. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-49947 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the technology described in Patent Document 1 above is still relatively new, and there is room for improvement in various aspects.

[0006] Therefore, this disclosure has been made in view of the above-mentioned issues, and the purpose of this disclosure is to provide a mechanism that makes it easier to perform binaural recording. [Means for solving the problem]

[0007] According to an aspect of the present invention, in order to solve the above problems, there is provided a signal processing system including a measuring device that acquires measurement data related to transmission characteristics, a first acquisition device that acquires a first acoustic signal, and a control device connected to each of the measuring device and the first acquisition device via a network. The control device corrects the first acoustic signal based on the measurement data acquired by the measuring device and generates a second acoustic signal.

[0008] The signal processing system may further include a reproducing device that reproduces an acoustic signal and a second acquisition device that acquires an acoustic signal. The measuring device may transmit, as the measurement data, a fourth acoustic signal corresponding to a third acoustic signal reproduced by the reproducing device and acquired by the second acquisition device to the control device.

[0009] The measuring device may transmit, as the measurement data, information indicating characteristics of the reproducing device or information indicating characteristics of the second acquisition device to the control device.

[0010] The measuring device may transmit, as the measurement data, information indicating a method by which the second acquisition device acquires the fourth acoustic signal to the control device.

[0011] The signal processing system may include two of the reproducing devices and two of the second acquisition devices. The two reproducing devices, the two second acquisition devices, and the measuring device may be wired-connected via a five-pole plug including two terminals for transmitting the third acoustic signal input to the two reproducing devices, two terminals for transmitting the fourth acoustic signal output from the two second acquisition devices, and one ground terminal.

[0012] The measuring device transmits, as the measurement data, a fifth acoustic signal acquired by the second acquisition device at a timing when acoustic signal reproduction by the reproducing device is not being performed to the control device, and the control device may further correct the first acoustic signal based on the fifth acoustic signal.

[0013] The measurement device may include a communication interface capable of cellular communication, and transmit the measurement data to the control device via the communication interface.

[0014] The measurement device may determine whether the acquired measurement data satisfies a predetermined condition, and transmit only the measurement data determined to satisfy the predetermined condition to the control device.

[0015] The signal processing system may further include a terminal device capable of receiving information input by a user and outputting information to the user. The terminal device inputs and outputs information related to the acquisition of the measurement data, and the measurement device may acquire the measurement data triggered by the input of information instructing to acquire the measurement data to the terminal device.

[0016] The terminal device may output information indicating an action to be performed by the user before acquiring the measurement data.

[0017] If the action to be performed by the user before acquiring the measurement data has not been performed, the terminal device may reject the input of information instructing to start the acquisition of the measurement data.

[0018] The control device may calculate the transmission characteristic based on the measurement data, and generate the second acoustic signal by convolving the inverse characteristic of the calculated transmission characteristic with the first acoustic signal.

[0019] Also, in order to solve the above problems, according to another aspect of the present invention, there is provided a signal processing method executed by a computer, including acquiring measurement data related to transmission characteristics via a network, acquiring a first acoustic signal acquired by a first acquisition device via the network, and correcting the first acoustic signal based on the measurement data to generate a second acoustic signal.

[0020] Furthermore, in order to solve the above problems, according to another aspect of the present invention, a program is provided for a computer to perform the following actions: acquire measurement data relating to transfer characteristics via a network; acquire a first acoustic signal acquired by a first acquisition device via the network; and correct the first acoustic signal based on the measurement data to generate a second acoustic signal. [Effects of the Invention]

[0021] As explained above, this disclosure provides a mechanism that makes it easier to perform binaural recording. [Brief explanation of the drawing]

[0022] [Figure 1] This figure shows an example of the configuration of a signal processing system according to one embodiment of the present disclosure. [Figure 2] This figure shows an example of the configuration of the measurement system according to this embodiment. [Figure 3] This figure shows an example of the configuration of the recording system according to this embodiment. [Figure 4] This figure shows an example of the configuration of the control device according to this embodiment. [Figure 5] This figure illustrates the measurement of transfer characteristics according to this embodiment. [Figure 6] This is a diagram illustrating the binaural recording according to this embodiment. [Figure 7] This is a diagram illustrating the binaural playback according to this embodiment. [Figure 8] This sequence diagram shows an example of the processing flow performed in the signal processing system according to this embodiment. [Figure 9] This diagram schematically shows an example of the hardware configuration of a measurement earphone and measurement microphone. [Figure 10] This diagram illustrates an example of a connection configuration between a measuring earphone and microphone and a measuring device. [Figure 11]This is a sequence diagram showing an example of the processing flow performed in the signal processing system according to the first modified example. [Figure 12] This is a sequence diagram showing an example of the processing flow performed in the signal processing system according to the second modified example. [Modes for carrying out the invention]

[0023] Preferred embodiments of this disclosure will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0024] <1. Example Configuration> (1) Configuration of signal processing system 1 Figure 1 is a diagram showing an example of the configuration of a signal processing system 1 according to one embodiment of the present disclosure. As shown in Figure 1, the signal processing system 1 includes a measurement system 2, a first terminal device 3, a recording system 4, a second terminal device 5, and a control device 6. The measurement system 2, the first terminal device 3, the recording system 4, the second terminal device 5, and the control device 6 are connected via a network 9 and can communicate with each other. The network 9 may include a local network or a public network. For example, the network 9 may be composed of telephone lines or the internet.

[0025] Measurement system 2 is a system for acquiring measurement data, which will be described later. Measurement system 2 will be explained in detail later.

[0026] The first terminal device 3 is a device that processes data acquired by the measurement system 2. The first terminal device 3 can accept information input from the user and output information to the user. For example, the first terminal device 3 displays a UI (User Interface) screen for operating the measurement system 2, notifies the user of information, and accepts operations from the user. As an example, the first terminal device 3 can be implemented using a smartphone or the like.

[0027] Recording System 4 is a system for performing binaural recording. Recording System 4 will be explained in detail later.

[0028] The second terminal device 5 is a device that acquires binaurally recorded content (i.e., acoustic signals) and performs various processing. The second terminal device 5 can output information to the user and accept information input from the user. For example, the second terminal device 5 acquires binaurally recorded content that has been corrected by the control device 6 and plays it back binaurally through playback earphones connected to the second terminal device 5. As an example, the second terminal device 5 can be implemented as a PC (Personal Computer).

[0029] The control device 6 is a device that performs correction processing to improve the quality of content recorded binaurally by the recording system 4. Specifically, the control device 6 corrects the content recorded binaurally by the recording system 4 based on measurement data acquired by the measurement system 2. Then, the control device 6 transmits the corrected content to the second terminal device 5.

[0030] (2) Configuration of Measurement System 2 Figure 2 shows an example of the configuration of the measurement system 2 according to this embodiment. As shown in Figure 2, the measurement system 2 includes measurement earphones 10 (10A and 10B), measurement microphones 20 (20A and 20B), and a measurement device 30. The measurement system 2 has two measurement earphones 10 and two measurement microphones 20 for both ears.

[0031] - Measurement earphones 10 The measurement earphone 10 is an audio output device that reproduces an acoustic signal. The measurement earphone 10 converts the input acoustic signal into sound and emits it into the surrounding space. The measurement earphone 10 can be connected to the measurement device 30 via various devices related to the reproduction of the acoustic signal, such as a DAC (Digital Analog Converter) and an amplifier. The measurement earphone 10 is used for measuring the transmission characteristics, which will be described later. Here, the measurement earphone 10 is an example of a playback device in this embodiment. The playback device may consist of any audio output device other than the earphone, such as a speaker.

[0032] - Measurement microphone 20 The measurement microphone 20 is an audio input device that acquires acoustic signals. The measurement microphone 20 converts sounds in the surrounding space into acoustic signals and outputs the converted acoustic signals. The measurement microphone 20 can be connected to the measurement device 30 via various devices related to the acquisition of acoustic signals, such as an ADC (Analog Digital Converter) and an amplifier. The measurement microphone 20 is used for measuring transfer characteristics. The measurement microphone 20 may be configured as any type of audio input device, such as a dynamic microphone, a MEMS (Micro Electro Mechanical Systems) microphone, a condenser microphone, or a laser microphone. In addition to microphones that apply an external DC voltage to the diaphragm, so-called electret condenser microphones that use electret elements in the diaphragm, back pole, or back chamber may also be used as condenser microphones. Here, the measurement microphone 20 is an example of the second acquisition device in this embodiment.

[0033] - Measuring device 30 The measuring device 30 is a device that performs processing related to the acquisition of measurement data. As shown in Figure 2, the measuring device 30 includes a communication unit 31, a storage unit 32, and a control unit 33.

[0034] The communication unit 31 is a communication interface that communicates with other devices via wired or wireless connection. The communication unit 31 performs communication in accordance with any communication standard. Examples of communication standards include LAN (Local Area Network), Wi-Fi (registered trademark), Bluetooth (registered trademark), cellular communication standards such as 4G or 5G, or USB (Universal Serial Bus).

[0035] In particular, the communication unit 31 functions as a first communication unit that communicates with the measurement earphone 10 and the measurement microphone 20. The communication unit 31 as the first communication unit is a wired or wireless audio interface. The communication unit 31 as the first communication unit transmits and receives acoustic signals to and from the measurement earphone 10 or the measurement microphone 20.

[0036] Furthermore, the communication unit 31 functions as a second communication unit that communicates with the first terminal device 3. The communication unit 31 as the second communication unit may also be a communication interface that can connect to a local network constructed with Wi-Fi or the like.

[0037] Furthermore, the communication unit 31 functions as a third communication unit that communicates with the control device 6. The communication unit 31 as the third communication unit may have a cellular communication-capable communication interface. That is, the measuring device 30 may have a SIM (Subscriber Identity Module) card for cellular communication.

[0038] The memory unit 32 stores various types of information. The memory unit 32 stores and reads data from a predetermined storage medium. An example of a predetermined storage medium is a non-volatile storage medium such as flash memory. For example, the memory unit 32 stores acquired measurement data.

[0039] The control unit 33 functions as an arithmetic processing unit and control unit, controlling the overall operation of the measuring device 30 according to various programs. The control unit 33 is implemented by electronic circuits such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The control unit 33 may also include a ROM (Read Only Memory) for storing the programs and calculation parameters to be used, and a RAM (Random Access Memory) for temporarily storing parameters that change as needed. The control unit 33 controls various processes for acquiring measurement data.

[0040] (3) Configuration of recording system 4 Figure 3 shows an example of the configuration of the recording system 4 according to this embodiment. As shown in Figure 3, the recording system 4 includes recording microphones 50 (50A and 50B) and a recording device 40. The recording system 4 has two recording microphones 50 for both ears.

[0041] - 50 microphones for recording The recording microphone 50 is an audio input device that acquires acoustic signals. The configuration of the recording microphone 50 is the same as that of the measurement microphone 20. The recording microphone 50 is used for binaural recording. Here, the recording microphone 50 is an example of the first acquisition device in this embodiment.

[0042] - Recording device 40 The recording device 40 is a device that processes data acquisition. The recorded data includes content recorded binaurally by the recording microphone 50. As shown in Figure 3, the recording device 40 includes a communication unit 41, an input unit 42, a storage unit 43, and a control unit 44.

[0043] The communication unit 41 is a communication interface that communicates with other devices via wired or wireless connection. The communication unit 41 performs communication in accordance with any communication standard. Examples of communication standards include LAN (Local Area Network), Wi-Fi (registered trademark), Bluetooth (registered trademark), cellular communication standards such as 4G or 5G, or USB (Universal Serial Bus).

[0044] In particular, the communication unit 41 functions as a first communication unit that communicates with the recording microphone 50. The communication unit 41 as the first communication unit is a wired or wireless audio interface. The communication unit 41 as the first communication unit transmits and receives audio signals to and from the recording microphone 50.

[0045] Furthermore, the communication unit 41 functions as a second communication unit that communicates with the second terminal device 5. The communication unit 41 as the second communication unit may also be a communication interface that can connect to a local network constructed with Wi-Fi or the like.

[0046] Furthermore, the communication unit 41 functions as a third communication unit that communicates with the control device 6. The communication unit 41 as the third communication unit may have a cellular communication-capable communication interface. That is, the recording device 40 may have a SIM (Subscriber Identity Module) card for cellular communication.

[0047] The input unit 42 receives various types of information from the user. The input unit 42 can be configured with any input device such as buttons, a touch panel, a keyboard, or switches.

[0048] The memory unit 43 stores various types of information. The memory unit 43 stores and reads data from a predetermined storage medium. An example of a predetermined storage medium is a non-volatile storage medium such as flash memory. For example, the memory unit 43 stores recorded data.

[0049] The control unit 44 functions as an arithmetic processing unit and control unit, and controls the overall operation of the recording device 40 according to various programs. The control unit 44 is implemented by electronic circuits such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The control unit 44 may also include a ROM (Read Only Memory) for storing the programs and calculation parameters to be used, and a RAM (Random Access Memory) for temporarily storing parameters that change as needed. The control unit 44 controls various processes for binaural recording.

[0050] (4) Configuration of the control device 6 Figure 4 shows an example of the configuration of the control device 6 according to this embodiment. As shown in Figure 4, the control device 6 includes a communication unit 61, a storage unit 62, and a control unit 63.

[0051] The communication unit 61 is a communication interface that communicates with other devices via wired or wireless connection. The communication unit 61 performs communication in accordance with any communication standard. Examples of communication standards include LAN (Local Area Network), Wi-Fi (registered trademark), Bluetooth (registered trademark), cellular communication standards such as 4G or 5G, or USB (Universal Serial Bus).

[0052] The storage unit 62 stores various types of information. The storage unit 62 stores and reads data from a predetermined storage medium. An example of a predetermined storage medium is a non-volatile storage medium such as flash memory. For example, the storage unit 62 stores various types of information such as measurement data, recorded data, correction coefficients, and corrected recorded data.

[0053] The control unit 63 functions as an arithmetic processing unit and control device, and controls the overall operation within the control device 6 according to various programs. The control unit 63 is implemented by electronic circuits such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The control unit 63 may also include a ROM (Read Only Memory) for storing the programs and calculation parameters to be used, and a RAM (Random Access Memory) for temporarily storing parameters that change as needed. The control unit 63 controls the calculation of transfer characteristics based on measurement data and the process of correcting the acoustic signal based on the calculated transfer characteristics.

[0054] <2. Technical Features> (1) Measurement of transfer characteristics The signal processing system 1 measures the transfer characteristics. Typically, the measurement of transfer characteristics is performed with a human user wearing a measurement earphone 10 and a measurement microphone 20. The transfer characteristics to be measured are the transfer characteristics from the sound source to the user's eardrum (i.e., the acoustic characteristics of the transmission path). However, the signal processing system 1 measures the transfer characteristics from the measurement earphone 10 to the measurement microphone 20 as an approximation of the transfer characteristics from the sound source to the user's eardrum. The acoustic characteristics may be frequency characteristics.

[0055] The measurement microphone 20 is positioned near the user's eardrum. On the other hand, the measurement earphone 10 is positioned on the user's auricle. This configuration makes it possible to measure the acoustic characteristics of the auricle, which greatly influence how sound is transmitted to the eardrum. As an example, the measurement microphone 20 may be positioned in the external auditory canal, and the measurement earphone 10 may be positioned in the concha. The user who wears the measurement earphone 10 and measurement microphone 20 for the measurement of transmission characteristics will be referred to as User A below.

[0056] The measuring device 30 reproduces the third acoustic signal through the measuring earphone 10. The measuring device 30 then transmits the fourth acoustic signal, which corresponds to the third acoustic signal reproduced by the measuring earphone 10 and acquired by the measuring microphone 20, to the control device 6 as measurement data related to the transfer characteristics. The third acoustic signal is an acoustic signal reproduced for the measurement of the transfer characteristics. The third acoustic signal may be, for example, a so-called sweep signal in which the frequency changes stepwise from a low frequency to a high frequency. The fourth acoustic signal can also be said to be the third acoustic signal influenced by the transmission path from the measuring earphone 10 to the measuring microphone 20.

[0057] More specifically, the measuring device 30 first outputs the stored third acoustic signal to the measuring earphone 10, causing the measuring earphone 10 to reproduce the third acoustic signal. The measuring microphone 20 acquires the fourth acoustic signal, which is the third acoustic signal reproduced from the measuring earphone 10 and is an acoustic signal originating from the sound that arrived via the transmission path from the measuring earphone 10 to the measuring microphone 20. The measuring device 30 then stores the fourth acoustic signal acquired by the measuring microphone 20. Subsequently, the measuring device 30 transmits the fourth acoustic signal as measurement data to the control device 6.

[0058] The control device 6 calculates the transfer characteristics based on the measurement data received from the measuring device 30. More specifically, the control device 6 calculates the transfer characteristics based on the third acoustic signal and the fourth acoustic signal. The calculated transfer characteristics correspond to the difference between the third acoustic signal and the fourth acoustic signal. It is assumed that the third acoustic signal is known to the control device 6.

[0059] The first terminal device 3 may input and output information related to the acquisition of measurement data. For example, the first terminal device 3 may send and receive control information to and from the measurement system 2, display a UI screen for operating the measurement system 2, and accept input of information instructing it to start acquiring measurement data. The measurement device 30 may acquire measurement data as a trigger when information instructing it to start acquiring measurement data is input to the first terminal device 3. With this configuration, the first terminal device 3 can function as the UI of the measurement system 2.

[0060] The specific process for measuring transfer characteristics will be explained with reference to Figure 5.

[0061] Figure 5 is a diagram illustrating the measurement of transmission characteristics according to this embodiment. As shown in Figure 5, the transmission path from the measurement earphone 10 to the measurement microphone 20 includes the measurement earphone 10 and the auricle 90 of user A wearing the measurement earphone 10 and the measurement microphone 20. Therefore, the transmission characteristics to be measured are expressed by the following equation.

[0062]

number

[0063] Here is the G m (ω) is the transfer characteristic. H a (ω) represents the acoustic characteristics of the measurement earphone 10. In this specification, acoustic characteristics refer to, for example, amplitude-frequency characteristics, but other characteristics such as phase-frequency characteristics, phase-delay characteristics, or group-delay characteristics may also be used. A (ω) represents the acoustic characteristics of User A's auricle (90). ω is the angular frequency.

[0064] (2) Binaural recording Recording system 4 performs binaural recording. Binaural recording is performed with the user wearing a recording microphone 50.

[0065] More specifically, the recording microphone 50 acquires a first acoustic signal originating from the sound source to be binaurally recorded. The recording device 40 then stores the first acoustic signal acquired by the recording microphone 50. Subsequently, the recording device 40 transmits the stored first acoustic signal as recording data to the control device 6.

[0066] The control device 6 generates corrected recording data by correcting the recording data received from the recording device 40. Specifically, the control device 6 corrects the first acoustic signal based on the measurement data acquired by the measurement device 30 and generates a second acoustic signal. For example, the control device 6 generates the second acoustic signal by applying a correction process based on the transfer characteristics calculated based on the measurement data to the first acoustic signal. Subsequently, the control device 6 stores the generated second acoustic signal as corrected recording data. The second terminal device 5 can receive the second acoustic signal, which is the corrected recording data, from the control device 6 and play it back binaurally using playback earphones. By playing back the second acoustic signal binaurally, it is possible to improve the quality of binaural playback compared to playing back the first acoustic signal binaurally. Thus, according to this embodiment, correction to improve the quality of binaural playback can be performed in advance during binaural recording.

[0067] It is desirable that the user wearing the recording microphone 50 during binaural recording and the user wearing the measurement earphones 10 and measurement microphone 20 during the measurement of transmission characteristics are the same. Furthermore, it is desirable that the placement of the recording microphone 50 during binaural recording and the placement of the measurement microphone 20 during the measurement of transmission characteristics are the same. Furthermore, it is desirable that the acoustic characteristics of the measurement microphone 20 and the acoustic characteristics of the recording microphone 50 are the same. When all of these conditions are met, it is possible to maximize the effect of correction and improve the quality of binaural playback. Of course, even if at least one of these conditions is not met, it is still possible to improve the quality of binaural playback. In the following, it is assumed that binaural recording is performed with user A wearing the recording microphone 50, which has the same acoustic characteristics as the measurement microphone 20, in the same placement as during the measurement of transmission characteristics.

[0068] Binaural recording will be explained with reference to Figure 6.

[0069] Figure 6 is a diagram illustrating the binaural recording according to this embodiment. As shown in Figure 6, the transmission path from the sound source 80 to be binaurally recorded to the recording microphone 50, which has the same acoustic characteristics as the measurement microphone 20, includes the auricle 90 of user A wearing the recording microphone 50. Therefore, the first acoustic signal acquired by the recording microphone 50 is expressed by the following equation.

[0070]

number

[0071] Here, y rec (ω) is the first acoustic signal. x(ω) is an acoustic signal (hereinafter also referred to as the sound source signal) that originates from the sound source 80.

[0072] The control device 6 generates a second acoustic signal by correcting the first acoustic signal based on the transfer characteristics measured in advance. Specifically, the control device 6 uses the transfer characteristics G measured in advance. mBy convolving the inverse characteristic of (ω) with the first acoustic signal y rec a second acoustic signal is generated. The second acoustic signal is represented by the following equation.

[0073]

Equation

[0074] Here, y´(ω) is the second acoustic signal. G m -1 (ω) is the inverse characteristic of the transfer characteristic G m (ω). H a -1 (ω) is the inverse characteristic of the acoustic characteristic H a of the measurement earphone 10. The transfer characteristic G m The inverse characteristic G m -1 (ω) is also referred to as a correction coefficient hereinafter.

[0075] As shown in Equation (3), the second acoustic signal y´(ω) cancels the acoustic characteristic G A of the pinna 90 of user A, and the acoustic characteristic H a The inverse characteristic H a -1 (ω) of the measurement earphone 10 is pre-convolved with the sound source signal x(ω). Therefore, during binaural reproduction, it is possible to improve the quality of binaural reproduction without performing correction to cancel the acoustic characteristic G A of the pinna 90 of user A or to cancel the acoustic characteristic H a of the measurement earphone 10.

[0076] Since correction is not required during binaural playback, the overall processing load of the system can be significantly reduced in a system that distributes binaurally recorded content to a large number of second terminal devices 5 in real time. Furthermore, when correction is performed during binaural playback, it may be necessary to distribute metadata for correction along with the binaurally recorded content. In this respect, according to this embodiment, the distribution of metadata for correction is not required, so the communication load can also be significantly reduced. The metadata for correction includes the acoustic characteristics G of user A's auricle 90. A (ω), and the acoustic characteristics H of the measurement earphone 10 a Examples include (ω), etc.

[0077] Furthermore, according to this embodiment, binaural recording is performed with a recording microphone 50 attached to a human user A. Therefore, compared to performing binaural recording using a dummy head, it becomes possible to perform simple and high-quality binaural recording in a variety of use cases. For example, binaural recording can be performed by attaching the recording microphone 50 to a user who is shooting video while moving with a camera in their hand. In addition, the user can perform binaural recording and monitoring (i.e., checking the recorded sound) simultaneously.

[0078] (3) Binaural playback Binaural playback is performed with the user wearing playback earphones. The configuration of the playback earphones may be the same as that of the measurement earphones 10. The playback earphones are placed on the user's auricle. For example, the playback earphones may be placed in the concha. With the playback earphones placed on the user's auricle, a second acoustic signal is played. This allows the user wearing the playback earphones to listen to the binaurally recorded sound.

[0079] The user wearing the recording microphone 50 during binaural recording and the user wearing the playback earphones during binaural playback may be the same person. That is, binaural playback may be performed with user A wearing the playback earphones. On the other hand, the user wearing the recording microphone 50 during binaural recording and the user wearing the playback earphones during binaural playback may be different people. That is, binaural playback may be performed with user B, who is different from user A, wearing the playback earphones.

[0080] Furthermore, the acoustic characteristics of the measurement earphone 10 and the acoustic characteristics of the playback earphone may be the same or different.

[0081] The following describes the sounds a user will hear when binaurally recorded content is played back in three different playback environments.

[0082] -1st playback environment The first playback environment is one in which the acoustic characteristics of the measurement earphone 10 and the playback earphone are identical, and the playback earphone is worn by user A. Binaural playback in the first playback environment will be explained with reference to Figure 7.

[0083] Figure 7 is a diagram illustrating binaural playback according to this embodiment. As shown in Figure 7, the transmission path from the playback earphone 70, which has the same acoustic characteristics as the measurement earphone 10, to the eardrum of user A includes the auricle 90 of user A wearing the playback earphone 70. Therefore, the acoustic signal representing the sound heard by user A is expressed by the following equation.

[0084]

number

[0085] Here, y rep (ω) is an acoustic signal representing the sound heard by the user wearing the playback earphones 70, i.e., user A.a (ω) represents the acoustic characteristics of the playback earphone 70, which are identical to those of the measurement earphone 10.

[0086] As shown in equation (4), user A receives the first acoustic signal y rec (ω) can be heard. In other words, user A can hear the same sound as during binaural recording. In this way, it is possible to improve the quality of binaural playback.

[0087] -Second playback environment The second playback environment is one in which the acoustic characteristics of the measurement earphone 10 and the playback earphone 70 are identical, and the playback earphone 70 is worn by user B, who is different from user A.

[0088] In this playback environment, the transmission path from the playback earphone 70, which has the same acoustic characteristics as the measurement earphone 10, to user B's eardrum includes user B's auricle 90, which is wearing the playback earphone 70. Therefore, the acoustic signal representing the sound heard by user B is expressed by the following equation.

[0089]

number

[0090] Here, y rep (ω) is an acoustic signal representing the sound heard by the user wearing the playback earphones 70, i.e., user B. a (ω) represents the acoustic characteristics of the playback earphone 70, which are identical to those of the measurement earphone 10. B (ω) represents the acoustic characteristics of User B's auricle (90).

[0091] Referring to equation (2), the acoustic signal y represents the sound that user A hears during binaural recording. rec (ω) represents the acoustic characteristics G of user A's auricle 90 in the sound source signal x(ω). A(ω) is a convolved form. In contrast, referring to equation (5), the acoustic signal y represents the sound that user B hears during binaural playback. rep (ω) represents the acoustic characteristics G of user B's auricle 90 in the sound source signal x(ω). B (ω) is a folded form. In other words, user B can hear an acoustic signal in the binaural playback environment that represents the sound that user B would have heard if binaural recording had been performed with user B wearing the recording microphone 50 instead of user A. In this way, user B can hear sounds as if they were present at the binaural recording site, instead of user A. This makes it possible to improve the quality of binaural playback.

[0092] However, the binaurally recorded sound source signal x(ω) may include the influence of acoustic characteristics specific to user A, in addition to the acoustic characteristics of user A's auricle 90. Such acoustic characteristics include those resulting from physical characteristics other than user A's auricle 90. The acoustic signal y represents the sound heard by user B. rep (ω) will include the influence of acoustic characteristics specific to user A, who is a different person, which may impair the naturalness of the sound.

[0093] However, when binaural recording is performed with the recording microphone 50 attached to a human ear, it is possible to improve the quality of binaural playback compared to when the recording microphone 50 is attached to a dummy head. When binaural recording is performed with the recording microphone 50 attached to a dummy head, the acoustic signal y representing the sound heard by user B is rep This is because (ω) would include the acoustic characteristics of the dummy head. In that case, the naturalness of the sound would be significantly impaired due to the difference in sound reflection coefficients compared to human skin and the difference in structure compared to the human body.

[0094] -Third playback environment The third playback environment is one in which the acoustic characteristics of the measurement earphone 10 and the playback earphone 70 are different, and the playback earphone 70 is worn by user B, who is different from user A.

[0095] In this playback environment, the transmission path from the playback earphone 70, which has different acoustic characteristics from the measurement earphone 10, to user B's eardrum includes user B's auricle 90, which is wearing the playback earphone 70. Therefore, the acoustic signal representing the sound heard by user B is expressed by the following equation.

[0096]

number

[0097] Here, y rep (ω) is an acoustic signal representing the sound heard by the user wearing the playback earphones 70, i.e., user B. n (ω) represents the acoustic characteristics of the playback earphone 70, which differ from the acoustic characteristics of the measurement earphone 10. B (ω) represents the acoustic characteristics of User B's auricle (90).

[0098] Referring to equation (6), User B uses the acoustic characteristics H corresponding to the difference between the measurement earphone 10 and the playback earphone 70 to represent the acoustic signal indicating the sound that User B hears in the second playback environment described above. n (ω) / H a The listener will hear a convoluted (ω) sound. In other words, user B will be able to hear a sound in the binaural playback environment that is similar to the sound that user B would have heard if binaural recording had been performed with user B wearing the recording microphone 50 instead of user A. Therefore, an improvement in the quality of binaural playback is expected.

[0099] (4) Processing flow The following describes an example of the processing flow related to the measurement of transfer characteristics and binaural recording, with reference to Figure 8. Figure 8 is a sequence diagram showing an example of the processing flow performed in the signal processing system 1 according to this embodiment. This sequence involves the measurement system 2, the first terminal device 3, the recording system 4, the second terminal device 5, and the control device 6.

[0100] As shown in Figure 8, first, the first terminal device 3 sends a signal to the measurement system 2 requesting the start of data acquisition (step S102). For example, the first terminal device 3 sends a signal requesting the start of data acquisition when a predetermined touch operation is input to the displayed UI screen.

[0101] Next, the measurement system 2 acquires measurement data (step S104). For example, the measurement device 30 plays a third acoustic signal using the measurement earphone 10 and acquires a fourth acoustic signal using the measurement microphone 20.

[0102] Next, the measurement system 2 transmits the measurement data to the control device 6 (step S106). For example, the measurement system 2 transmits the fourth acoustic signal to the control device 6 via cellular communication.

[0103] Next, the control device 6 calculates a correction coefficient (step S108). For example, the control device 6 calculates the transfer characteristics based on the known third acoustic signal and the fourth acoustic signal received from the measurement system 2. Then, the control device 6 calculates the inverse characteristics of the transfer characteristics as a correction coefficient. After that, the control device 6 stores the calculated correction coefficient.

[0104] Next, the recording system 4 acquires a first acoustic signal (step S110). For example, the recording device 40 acquires a first acoustic signal using the recording microphone 50 when a predetermined user operation, such as pressing a button, is input.

[0105] Next, the recording system 4 transmits the first acoustic signal to the control device 6 (step S112). For example, the recording system 4 transmits the first acoustic signal to the control device 6 via cellular communication.

[0106] Then, the control device 6 generates a second acoustic signal by correcting the first acoustic signal (step S114). For example, the control device 6 generates the second acoustic signal by convolving a correction coefficient (i.e., the inverse characteristic of the transfer characteristic measured in advance) into the first acoustic signal.

[0107] Next, the control device 6 transmits the generated second acoustic signal to the second terminal device 5 (step S116). The second terminal device 5 can then store the received second acoustic signal, distribute it to other devices, or perform binaural playback using the playback earphones 70.

[0108] (5) Effects According to the embodiment described above, the user can easily measure the transmission characteristics by wearing the measurement earphones 10 and measurement microphone 20 and playing a third acoustic signal. Furthermore, the user can easily perform high-quality binaural recording simply by wearing the recording microphone 50 and starting recording. As a result, the user can obtain high-quality content without having specialized knowledge of binaural recording. In this way, binaural recording can be performed more easily.

[0109] Furthermore, computationally intensive correction processes, such as calculating transfer characteristics, calculating correction coefficients, and convolution of correction coefficients, are performed by the control device 6. Therefore, compared to when the correction process is performed in the second terminal device 5, the processing load on the second terminal device 5 can be reduced. The effect of reducing the processing load is particularly significant when there are multiple users using binaurally recorded content, i.e., when there are multiple second terminal devices 5.

[0110] <3. Hardware Configuration Example> The measurement earphone 10 and measurement microphone 20 can be implemented using a variety of hardware. One example will be explained with reference to Figure 9.

[0111] Figure 9 is a schematic diagram showing an example of the hardware configuration of the measurement earphone 10 and the measurement microphone 20. As shown in Figure 9, the user's auricle 90 is fitted with headphones 100 as the measurement earphone 10 and a sound collection jig 200 including the measurement microphone 20.

[0112] (1) Headphones 100 The headphones 100 are an audio output device that reproduces acoustic signals. The headphones 100 are an example of a measurement earphone 10. The headphones 100 are configured as a so-called ear cuff type and are worn by the user so as to cover a part of the sound collection jig 200 worn by the user. The headphones 100 include a driver unit 110 and a frame 120.

[0113] The driver unit 110 is a device that converts the input acoustic signal into sound and emits it into the surrounding space.

[0114] The frame 120 is a component that holds the driver unit 110 to the auricle 90. When the headphones 100 are worn by the user, the frame 120 is curved so as to pass outside at least one of the helix 96 or earlobe 97 from the front to the back of the auricle 90. The driver unit 110 is connected to one end of the frame 120. The frame 120 then clamps the auricle 90 from the front and back of the auricle 90 between the driver unit 110 connected to one end of the frame 120 and the other end of the frame 120.

[0115] (2) Sound collection jig 200 The sound collection jig 200 has an insertion section 210 including a measuring microphone 20, a first frame 220, a second frame 230, and a third frame 240.

[0116] The insertion part 210 is a component that is inserted into the user's ear canal 98. The insertion part 210 is configured as a cylindrical body having a through-hole that penetrates in the insertion direction. The measuring microphone 20 is positioned inside the through-hole of the insertion part 210, with a gap between it and the inner wall of the through-hole. Therefore, when the insertion part 210 is inserted into the user's ear canal 98, the measuring microphone 20 is positioned near the user's eardrum. Furthermore, sounds arriving from the outside world pass through the through-hole and reach the user's eardrum. Consequently, the user can clearly hear ambient sounds while wearing the sound collection jig 200.

[0117] The first frame 220 is a ring-shaped component. The first frame 220 contacts the user's concha 92 when the sound collection jig 200 is attached to the user. The first frame 220 is connected to the insertion part 210.

[0118] The second frame 230 is a component configured in the shape of a shark fin with weight-reducing cutouts. The second frame 230 contacts the user's concha 91 when the sound-collecting jig 200 is attached to the user. The second frame 230 is connected to the first frame 220.

[0119] The third frame 240 is curved to pass outside the user's helix crus 93, from the front to the back of the user's auricle 90, when the sound-collecting jig 200 is attached to the user. The third frame 240 is connected to the first frame 220.

[0120] (3) Connection configuration with measuring device 30 Figure 10 is a diagram illustrating an example of a connection configuration between the measurement earphones 10 and measurement microphones 20 and the measurement device 30. As shown in Figure 10, the two measurement earphones 10 and two measurement microphones 20 and the measurement device 30 may be wired together via a 5-pole plug 35 consisting of five terminals (35A to 35E). Two terminals of the 5-pole plug 35 (e.g., terminals 35A and 35B) transmit the third acoustic signal input to the two measurement earphones 10. The other two terminals of the 5-pole plug 35 (e.g., terminals 35C and 35D) transmit the fourth acoustic signal output from the two measurement microphones 20. The remaining terminal of the 5-pole plug 35 (e.g., terminal 35E) is the ground terminal. With this configuration, the measurement earphones 10 and measurement microphones 20 and the measurement device 30 can be easily connected and disconnected.

[0121] Of course, at least one of the measuring earphones 10 or the measuring microphone 20 may be wirelessly connected to the measuring device 30.

[0122] (4) Supplement The above describes an example of the hardware configuration of the measurement earphone 10 and measurement microphone 20. According to the example described above, the measurement microphone 20 can be inserted into the user's ear canal 98 and positioned near the eardrum, while the measurement earphone 10 can be positioned on the user's auricle 90. Furthermore, it is possible to measure the transmission characteristics while keeping the user's ear canal 98 open.

[0123] The configuration of the recording microphone 50 may be the same as that of the measurement microphone 20. In that case, binaural recording can be performed while the user's ear canal 98 remains open.

[0124] The configuration of the playback earphone 70 may be the same as that of the measurement earphone 10.

[0125] Although the above describes an example in which the headphones 100 and the sound-collecting jig 200 are configured as separate devices, this disclosure is not limited to such an example. The headphones 100 and the sound-collecting jig 200 may be implemented as the same device. For example, a driver unit 110 may be provided on the first frame 220. In other words, the measurement earphone 10 and the measurement microphone 20 may be mounted on the same device.

[0126] <4. Supplement> While preferred embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the present disclosure is not limited to such examples. It is clear to any person with ordinary skill in the art to which the present disclosure pertains that various modifications or alterations may be conceived within the scope of the technical idea set forth in the claims, and these will naturally also be understood to fall within the technical scope of the present disclosure.

[0127] (1) First variation The measurement system 2 may communicate with the control device 6 via the first terminal device 3. For example, the measurement system 2 does not need to have the function of a third communication unit. Similarly, the recording system 4 may communicate with the control device 6 via the second terminal device 5. For example, the recording system 4 does not need to have the function of a third communication unit. An example of the processing flow in that case will be explained with reference to Figure 11.

[0128] Figure 11 is a sequence diagram showing an example of the processing flow performed in the signal processing system 1 according to the first modified example. This sequence involves the measurement system 2, the first terminal device 3, the recording system 4, the second terminal device 5, and the control device 6.

[0129] The processes related to steps S202 and S204 shown in Figure 9 are the same as the processes related to steps S102 and S104 described above with reference to Figure 8.

[0130] Next, the measurement system 2 transmits the measurement data to the first terminal device 3 (step S206-1). Then, the first terminal device 3 transmits the received measurement data to the control device 6 (step S206-2).

[0131] The processes in steps S208 and S210 are the same as those in steps S108 and S110 described above with reference to Figure 8.

[0132] Next, the recording system 4 transmits the first acoustic signal to the second terminal device 5 (step S212-1). Then, the second terminal device 5 transmits the received first acoustic signal to the control device 6 (step S212-2).

[0133] The subsequent processes in steps S214 and S216 are the same as those in steps S114 and S116 described above with reference to Figure 8.

[0134] (2) Second variation The recording system 4 may have playback earphones 70. More specifically, the recording device 40 may be connected to the playback earphones 70. In that case, the user can perform binaural recording while monitoring the binaurally recorded content by playing it back through the playback earphones 70. At that time, the recording device 40 may perform correction processing on the binaurally recorded content before playing the content back in binaural sound. An example of the processing flow in that case will be explained with reference to Figure 12.

[0135] Figure 12 is a sequence diagram showing an example of the processing flow performed in the signal processing system 1 according to the second modified example. This sequence involves the measurement system 2, the first terminal device 3, the recording system 4, the second terminal device 5, and the control device 6.

[0136] The processes related to steps S302 to S308 shown in Figure 12 are the same as the processes related to steps S102 to S108 described above with reference to Figure 8.

[0137] Next, the control device 6 transmits the correction coefficient to the recording system 4 (step S310).

[0138] Next, the recording system 4 acquires a first acoustic signal (step S312). For example, the recording device 40 activates the recording microphone 50 to acquire a first acoustic signal when a predetermined user operation, such as pressing a button, is input.

[0139] Next, the recording system 4 transmits the first acoustic signal to the control device 6 (step S314). The control device 6 may store the received first acoustic signal for backup purposes.

[0140] On the other hand, the recording system 4 generates a second acoustic signal by correcting the first acoustic signal (step S316). For example, the recording system 4 generates a second acoustic signal by convolving a correction coefficient received from the control device 6 (i.e., the inverse characteristic of the transfer characteristic measured in advance) into the first acoustic signal.

[0141] Next, the recording system 4 reproduces the second audio signal (step S318). For example, the recording device 40 reproduces the second audio signal using the playback earphone 70.

[0142] Next, the recording system 4 transmits the generated second acoustic signal to the second terminal device 5 (step S320).

[0143] The processes related to steps S312 to S320 may be executed sequentially or concurrently.

[0144] (3) Third variation The measuring device 30 may transmit information indicating the characteristics of the measuring earphone 10 as measurement data to the control device 6. Examples of information indicating the characteristics of the measuring earphone 10 include information indicating the acoustic characteristics of the measuring earphone 10 and the set value of the playback volume. The control device 6 calculates the transfer characteristics based on the characteristics of the measuring earphone 10. As a result, it becomes possible to further enhance the effect of correction and improve the quality of binaural playback.

[0145] The control device 6 may store a combination of the identification information of the measurement earphone 10 and the acoustic characteristics of the measurement earphone 10. In this case, the measurement device 30 may transmit the identification information of the measurement earphone 10 as information indicating the acoustic characteristics of the measurement earphone 10. The control device 6 can use the identification information received from the measurement device 30 as a search key to retrieve the acoustic characteristics of the measurement earphone 10 and use it to calculate the transfer characteristics. With this configuration, the communication load can be reduced.

[0146] (4) Fourth variation The measuring device 30 may transmit information indicating the characteristics of the measuring microphone 20 as measurement data to the control device 6. Examples of information indicating the characteristics of the measuring microphone 20 include information indicating the acoustic characteristics of the measuring microphone 20 and the setting value of the microphone sensitivity. The control device 6 performs correction processing based on the characteristics of the measuring microphone 20. For example, the control device 6 adjusts the left-right balance based on the microphone sensitivity of the left and right measuring microphones 20 and then calculates the transmission characteristics. As a result, it becomes possible to further enhance the effect of the correction and improve the quality of binaural playback.

[0147] The control device 6 may store a combination of identification information for the measurement microphone 20 and the acoustic characteristics of the measurement microphone 20. In this case, the measurement device 30 may transmit the identification information of the measurement microphone 20 as information indicating the acoustic characteristics of the measurement microphone 20. The control device 6 can use the identification information received from the measurement device 30 as a search key to retrieve the acoustic characteristics of the measurement microphone 20 and use it to calculate the transfer characteristics. With this configuration, the communication load can be reduced.

[0148] (5) Fifth variation The recording device 40 may transmit information indicating the characteristics of the recording microphone 50 as recording data to the control device 6. Examples of information indicating the characteristics of the recording microphone 50 include information indicating the acoustic characteristics of the recording microphone 50 and the setting value of the microphone sensitivity. The control device 6 adjusts the correction coefficient based on the characteristics of the recording microphone 50. As a result, it becomes possible to further enhance the effect of the correction and improve the quality of binaural playback.

[0149] The control device 6 may store a combination of the identification information of the recording microphone 50 and the acoustic characteristics of the recording microphone 50. In this case, the recording device 40 may transmit the identification information of the recording microphone 50 as information indicating the acoustic characteristics of the recording microphone 50. The control device 6 can use the identification information received from the recording device 40 as a search key to search for the acoustic characteristics of the recording microphone 50 and use it for correction processing. With this configuration, the communication load can be reduced.

[0150] (6) Sixth variation The measuring device 30 may transmit information indicating how the measuring microphone 20 acquired the fourth acoustic signal to the control device 6 as measurement data. The control device 6 then calculates the transfer characteristics based on the information indicating how the measuring microphone 20 acquired the fourth acoustic signal. As a result, it becomes possible to further enhance the effect of correction and improve the quality of binaural playback.

[0151] For example, the measuring device 30 may transmit identification information of the third acoustic signal used to acquire measurement data to the control device 6 as information indicating how the measuring microphone 20 acquired the fourth acoustic signal. In this case, the control device 6 stores the combination of the identification information of the third acoustic signal and the third acoustic signal, searches for the third acoustic signal using the identification information received from the measuring device 30 as a search key, and uses it to calculate the transfer characteristics.

[0152] As another example, the measuring device 30 may acquire the fourth acoustic signal once and transmit it to the control device 6 as measurement data, or it may acquire the fourth acoustic signal multiple times and transmit the result of synchronous summation to the control device 6 as measurement data. In this case, the information indicating how the measuring microphone 20 acquired the fourth acoustic signal may include the number of times the fourth acoustic signal was synchronously summed.

[0153] (7) Seventh variation The measuring device 30 may transmit the fifth acoustic signal acquired by the measuring microphone 20 as measurement data to the control device 6 when the acoustic signal is not being played back by the measuring earphone 10. The control device 6 may then perform correction processing based on the fifth acoustic signal. Specifically, the measuring device 30 records ambient sound using the measuring microphone 20 and transmits the fifth acoustic signal corresponding to the ambient sound as measurement data to the control device 6. The control device 6 then cancels the component corresponding to the ambient sound indicated by the fifth acoustic signal from the fourth acoustic signal and calculates the transfer characteristics. With this configuration, the accuracy of the transfer characteristic calculation can be improved. As a result, the effect of correction can be further enhanced, and the quality of binaural playback can be improved.

[0154] (8) Eighth variation The measuring device 30 may determine whether the acquired measurement data satisfies predetermined conditions. The measuring device 30 determines that the predetermined conditions are met if it is assumed that the transfer characteristics can be appropriately calculated from the acquired measurement data, and determines that they are not met otherwise. As an example, the measuring device 30 determines whether the frequency characteristics of the fourth acoustic signal are within the range of appropriate frequency characteristics. As another example, the measuring device 30 determines whether the noise level of the fourth acoustic signal is below a predetermined threshold. As yet another example, the measuring device 30 determines whether the variation of the fourth acoustic signal acquired multiple times is below a predetermined threshold.

[0155] The measuring device 30 may transmit only the measurement data that it has determined to satisfy predetermined conditions to the control device 6. That is, the measuring device 30 transmits only the measurement data that is assumed to allow for the appropriate calculation of the transfer characteristics to the control device 6. Of course, the determination regarding the above predetermined conditions may be performed by the control device 6. However, when the measuring device 30 performs the determination regarding the above predetermined conditions, it is possible to reduce the communication load and the delay until the measurement data is reacquired, compared to when the control device 6 performs the determination regarding the above predetermined conditions.

[0156] The first terminal device 3 may prompt the user to reacquire measurement data if the measurement device 30 determines that the measurement data does not meet predetermined conditions. In this case, the first terminal device 3 may output information indicating the actions the user should take before acquiring the measurement data. For example, if the frequency characteristics of the fourth acoustic signal are determined to be outside the range of appropriate frequency characteristics, the first terminal device 3 may display information prompting the user to reinsert the 5-pole plug 35. As another example, if the noise level of the fourth acoustic signal is determined to be above a predetermined threshold, the first terminal device 3 may display information prompting the user to move to a quiet place. As yet another example, if the variation of the fourth acoustic signal acquired multiple times is determined to be above a predetermined threshold, the first terminal device 3 may display information prompting the user to remain still. With this configuration, it becomes easier to acquire measurement data for which the transfer characteristics can be appropriately calculated.

[0157] The first terminal device 3 may refuse to accept input of information instructing the user to start acquiring measurement data if the user has not yet performed the actions required before acquiring measurement data. For example, the first terminal device 3 determines the magnitude of the noise level based on the fifth acoustic signal acquired by the measurement microphone 20 when the measurement earphone 10 is not playing an acoustic signal. Then, if the noise level is above a predetermined threshold, the first terminal device 3 refuses to accept input of information instructing the user to start acquiring measurement data. For example, the first terminal device 3 may disable a button on the UI screen that instructs the user to start acquiring measurement data. With this configuration, it becomes possible to start acquiring measurement data only when it is possible to acquire measurement data that is expected to allow for appropriate calculation of transfer characteristics.

[0158] (9) Others In the above embodiment, an example was described in which the measurement earphone 10 and measurement microphone 20 are worn by a human user, but this disclosure is not limited to such an example. The measurement earphone 10 and measurement microphone 20 may also be worn on a dummy head.

[0159] In the above embodiment, an example was described in which the recording microphone 50 is attached to a human user, but this disclosure is not limited to such an example. The recording microphone 50 may also be attached to a dummy head.

[0160] In the above embodiment, an example was described in which the acoustic characteristics of the measurement microphone 20 and the recording microphone 50 are identical, but this disclosure is not limited to such an example. The acoustic characteristics of the measurement microphone 20 and the recording microphone 50 may be different.

[0161] In the above embodiment, an example is shown in which the signal processing system 1 has two measurement earphones 10, two measurement microphones 20, and two recording microphones 50 for both ears; however, this disclosure is not limited to such an example. The signal processing system 1 may have one measurement earphone 10, one measurement microphone 20, and one recording microphone 50 for one ear. That is, this disclosure is applicable not only to binaural recording targeting both ears, but also to binaural recording targeting one ear.

[0162] In the above embodiment, an acoustic signal was given as an example of measurement data, but this disclosure is not limited to such an example. Another example of measurement data is an image. For example, the signal processing system 1 may estimate the transfer characteristics based on an image of the user's ear. Examples of ear images include images showing the external appearance of the ear, as well as images showing the internal structure of the ear, such as X-rays. The signal processing system 1 may also perform correction processing based on physical characteristics other than the user's ear. That is, the transfer characteristics estimated by the signal processing system 1 based on the measurement data are not limited to the transfer characteristics of the space from the sound source to the user's eardrum, but may also include the transfer characteristics of the user's body. The measurement data may also include, for example, images of the user's body other than their ear.

[0163] Each device described herein may be implemented as a standalone device, partially or entirely as separate devices, or combined into a single device. For example, some of the functions of the measurement system 2, the first terminal device 3, the recording system 4, or the second terminal device 5 may be provided on a device such as a server connected via a network 9. As another example, the control device 6 may be implemented as a standalone device or by multiple devices. Specifically, some of the functions of the control device 6 may be distributed and provided on multiple devices on a mesh network. As yet another example, the measurement device 30 and the first terminal device 3 may be configured as a single unit. The recording device 40 and the second terminal device 5 may also be configured as a single unit. Furthermore, the recording device 40 and the recording microphone 50 may also be configured as a single unit.

[0164] The series of processes performed by each device described herein may be implemented using software, hardware, or a combination of software and hardware. The programs constituting the software are pre-stored on a recording medium (more specifically, a non-temporary storage medium readable by a computer) located inside or outside each device. Each program is then loaded into RAM when executed by a computer controlling each device described herein, and executed by a processing circuit such as a CPU. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, or flash memory. The computer program may also be distributed via a network, for example, without using a recording medium. The computer may be an application-specific integrated circuit such as an ASIC, a general-purpose processor that performs functions by loading software programs, or a computer on a server used for cloud computing. Furthermore, the series of processes performed by each device described herein may be distributed and processed by multiple computers.

[0165] Furthermore, the processes described herein using flowcharts and sequence diagrams do not necessarily have to be executed in the order shown. Some processing steps may be executed in parallel. Additional processing steps may be adopted, and some processing steps may be omitted. [Explanation of symbols]

[0166] 1. Signal Processing System 2. Measurement System 3. First Terminal Device 4. Recording System 5. Second Terminal Device 6. Control device 9 Network 10 (10A, 10B) Measurement earphones 20 (20A, 20B) Measuring Microphone 30 Measuring devices 31 Communications Department 32 Storage section 33 Control Unit 40 Recording device 41 Communications Department 42 Input section 43 Storage section 44 Control Unit 50 (50A, 50B) Recording Microphone 61 Communications Department 62 Memory section 63 Control Unit 70 Playback earphones 80 sound sources 90 Auricle

Claims

1. A measuring device that acquires measurement data related to transfer characteristics, A first acquisition device for acquiring a first acoustic signal, A control device connected via a network to each of the aforementioned measuring device and the first acquisition device, Equipped with, The control device corrects the first acoustic signal based on the measurement data acquired by the measuring device and generates a second acoustic signal. Signal processing system.

2. The aforementioned signal processing system is A playback device that reproduces an audio signal, A second acquisition device for acquiring acoustic signals, Furthermore, The measuring device transmits the fourth acoustic signal, which corresponds to the third acoustic signal acquired by the second acquisition device and reproduced by the playback device, to the control device as measurement data. The signal processing system according to claim 1.

3. The measuring device transmits information indicating the characteristics of the regeneration device or information indicating the characteristics of the second acquisition device as measurement data to the control device. The signal processing system according to claim 2.

4. The measuring device transmits information indicating the method by which the second acquisition device acquired the fourth acoustic signal to the control device as measurement data. The signal processing system according to claim 2.

5. The signal processing system comprises two of the regeneration devices and two of the second acquisition devices, The two playback devices, the two second acquisition devices, and the measuring device are wired together via a five-pole plug consisting of two terminals for transmitting the third acoustic signal input to the two playback devices, two terminals for transmitting the fourth acoustic signal output from the two second acquisition devices, and one ground terminal. The signal processing system according to claim 2.

6. The measuring device transmits the fifth acoustic signal acquired by the second acquisition device as measurement data to the control device at a time when the playback device is not performing playback of the acoustic signal. The control device further corrects the first acoustic signal based on the fifth acoustic signal. The signal processing system according to claim 2.

7. The measuring device includes a cellular communication interface and transmits the measurement data to the control device via the communication interface. The signal processing system according to claim 1.

8. The measuring device determines whether the acquired measurement data satisfies predetermined conditions, and transmits only the measurement data that is determined to satisfy the predetermined conditions to the control device. The signal processing system according to claim 1.

9. The signal processing system further comprises a terminal device capable of receiving information input from a user and outputting information to the user. The terminal device inputs and outputs information related to the acquisition of the measurement data. The measuring device acquires the measurement data as a trigger when information instructing the terminal device to acquire the measurement data is input to the terminal device. The signal processing system according to any one of claims 1 to 8.

10. The terminal device outputs information indicating the actions the user should perform before acquiring the measurement data. The signal processing system according to claim 9.

11. The terminal device refuses to input information instructing it to start acquiring the measurement data if the user has not yet performed the action that should be performed before acquiring the measurement data. The signal processing system according to claim 9.

12. The control device calculates the transfer characteristics based on the measurement data, and generates the second acoustic signal by convolving the inverse characteristics of the calculated transfer characteristics into the first acoustic signal. The signal processing system according to claim 1.

13. Acquiring measurement data regarding transfer characteristics via a network, The first acoustic signal acquired by the first acquisition device is acquired via the network, Based on the measurement data, the first acoustic signal is corrected to generate a second acoustic signal. A signal processing method performed by a computer, including [the specified method].

14. On the computer, Acquiring measurement data regarding transfer characteristics via a network, The first acoustic signal acquired by the first acquisition device is acquired via the network, Based on the measurement data, the first acoustic signal is corrected to generate a second acoustic signal. A program to execute.

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