Listening device and method for controlling the listening device

Abstract

To provide a listening device and a control method of the listening device in which a user can grasp an environmental sound, when the environmental sound is changed in a noise cancelled state.SOLUTION: A listening device 100 comprises: an environmental sound detection unit 101 which generates an environmental signal corresponding to a detected environmental sound; an environmental sound suppression signal generation unit 103 which generates an environmental sound suppression signal having a reverse phase against the environmental signal; a reproduction signal output unit 105 which outputs a reproduction signal in which the environmental sound suppression signal is superimposed on a sound source signal; and a monitoring unit 102 which monitors the magnitude of the environmental sound on the basis of the environmental signal. The environmental sound suppression signal generation unit 103, when the monitoring unit 102 determines that the magnitude of the environmental sound is equal to or more than a prescribed threshold value and a change amount per prescribed time of the magnitude of the environmental sound is equal to or more than a prescribed value, generates an environmental sound amplification signal having the same phase as that of the environmental signal instead of the environmental sound suppression signal. The reproduction signal output unit 105 outputs the reproduction signal in which the environmental sound amplification signal is superimposed on the sound source signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a listening device and a control method for a listening device.

Background Art

[0002] When walking while wearing a noise-canceling listening device such as headphones or earphones, it is difficult to recognize the surrounding situation due to the noise-canceling effect. For example, in Patent Document 1, a headset includes a sound output unit, a sound collection unit, a determination unit, and a notification unit. The sound collection unit collects ambient sound, and the determination unit determines whether or not the sound pressure change rate of a specific sound included in the ambient sound exceeds a threshold value. The notification unit performs a predetermined notification to the user based on the determination result of the determination unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology according to Patent Document 1, even in the noise-canceling state, at the time of danger, the user is notified of the surrounding situation using sounds such as guidance, warning sounds, and specific sounds. However, in the technology according to Patent Document 1, there is a problem that the user cannot grasp the surrounding sound, that is, the environmental sound. For example, if the user can grasp what kind of sound the environmental sound is, the options for the user to cope with danger increase.

[0005] In view of such problems, an object of the present disclosure is to provide a listening device and a control method for a listening device that allow a user to grasp environmental sound when there is a change in environmental sound in the noise-canceling state.

Means for Solving the Problems

[0006] The listening device of this disclosure is An ambient sound detection unit that generates an ambient signal corresponding to the detected ambient sound, An ambient sound suppression signal generation unit generates an ambient sound suppression signal that is in the opposite phase to the aforementioned ambient signal, A playback signal output unit that outputs a playback signal obtained by superimposing the ambient noise suppression signal onto the sound source signal, The system includes a monitoring unit that monitors the magnitude of the ambient sound based on the ambient signal, The aforementioned ambient noise suppression signal generation unit is If the monitoring unit determines that the magnitude of the ambient sound is above a predetermined threshold and the amount of change in the magnitude of the ambient sound per predetermined time is above a predetermined value, it generates an ambient sound amplification signal that is in phase with the ambient signal instead of the ambient sound suppression signal. The aforementioned playback signal output section is, A playback signal is output by superimposing the ambient sound amplification signal onto the aforementioned sound source signal.

[0007] The method for controlling the listening device in this disclosure is: It generates an environmental signal corresponding to the detected ambient sound, An ambient sound suppression signal is generated that is in the opposite phase to the aforementioned ambient signal. The system outputs a playback signal in which the ambient noise suppression signal is superimposed on the sound source signal. Based on the aforementioned environmental signal, the magnitude of the ambient sound is monitored, If it is determined that the magnitude of the ambient sound is above a predetermined threshold and the rate of change of the magnitude of the ambient sound per predetermined time is above a predetermined value, an ambient sound amplification signal in phase with the ambient signal is generated instead of the ambient sound suppression signal, and a playback signal is output in which the ambient sound amplification signal is superimposed on the sound source signal. [Effects of the Invention]

[0008] This disclosure provides a listening device and a control method for the listening device that allow the user to perceive changes in ambient sound when noise cancellation is enabled. [Brief explanation of the drawing]

[0009] [Figure 1]This is a block diagram showing an example of the configuration of a listening device according to the first and second embodiments. [Figure 2] This is a flowchart showing an example of the operation of the listening device according to the first embodiment. [Figure 3] This figure shows an example of an ambient sound suppression signal or ambient sound amplification signal generated from ambient sound in a listening device according to the first embodiment, and the noise cancellation effect therefrom. [Figure 4] This is a flowchart showing an example of the operation of the listening device according to the second embodiment. [Figure 5] This flowchart shows another example of the operation of the listening device according to the third embodiment. [Figure 6] This figure shows an example of an ambient sound suppression signal or ambient sound amplification signal generated from ambient sound in a listening device according to the second embodiment, and the noise cancellation effect achieved therefrom. [Figure 7] This figure shows an example of an ambient sound suppression signal or ambient sound amplification signal generated from ambient sound, and the noise cancellation effect thereof, in a listening device according to the second embodiment. [Figure 8] This block diagram shows an example of a computer configuration according to the first and second embodiments. [Modes for carrying out the invention]

[0010] In the following, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations will be omitted where necessary for clarity.

[0011] (First embodiment) First, the configuration of the listening device 100 according to the first embodiment will be explained using Figure 1. FIG. 1 is a block diagram showing an example of the configuration of a listening device 100 according to the first embodiment. The listening device 100 is, for example, a noise cancellation type earphone or headset. The listening device 100 includes an environmental sound detection unit 101, a monitoring unit 102, an environmental sound suppression signal generation unit 103, a sound source signal input unit 104, and a reproduction signal output unit 105.

[0012] The environmental sound detection unit 101 is a microphone or the like, and detects environmental sound around the user wearing the listening device 100, and generates an environmental signal corresponding to the detected environmental sound. The environmental sound is the sound of a vehicle, the sound of a person's conversation, or the like. The monitoring unit 102 monitors the magnitude of the environmental sound based on the environmental signal. Specifically, the monitoring unit 102 determines whether the magnitude of the environmental sound is equal to or greater than a predetermined threshold. Further, the monitoring unit 102 determines whether the amount of change per predetermined time of the magnitude of the environmental sound is equal to or greater than a predetermined value.

[0013] The environmental sound suppression signal generation unit 103 generates a signal for suppressing the environmental sound that the user listens to, that is, an environmental sound suppression signal having a reverse phase with respect to the environmental signal. Here, when the monitoring unit 102 determines that the magnitude of the environmental sound is equal to or greater than a predetermined threshold and the amount of change per predetermined time of the environmental sound is equal to or greater than a predetermined value, the environmental sound suppression signal generation unit 103 performs the following processing. The environmental sound suppression signal generation unit 103 generates a signal for amplifying the environmental sound that the user listens to, that is, an environmental sound amplification signal having the same phase as the environmental signal, instead of the environmental sound suppression signal. Then, after a predetermined time has elapsed since the generation of the environmental sound amplification signal, when the magnitude of the environmental sound does not continue to exceed the predetermined threshold, the environmental sound suppression signal generation unit 103 generates an environmental sound suppression signal instead of the environmental sound amplification signal.

[0014] Note that when the monitoring unit 102 determines that the magnitude of the environmental sound is equal to or greater than a predetermined threshold and the amount of change per predetermined time of the magnitude of the environmental sound is equal to or greater than a predetermined value, the environmental sound suppression signal generation unit 103 may stop the environmental sound suppression signal without generating the environmental sound amplification signal.

[0015] The sound source signal input unit 104 receives the sound source signal (hereinafter referred to as the sound source signal) to be played back by the listening device 100 from a sound source such as a music player. The playback signal output unit 105 is a speaker or the like, and it converts a playback signal, which is a sound source signal superimposed with an ambient sound suppression signal or an ambient sound amplification signal, into a playback sound and outputs it.

[0016] Next, the operation of the listening device 100 according to the first embodiment will be explained using Figure 2. Figure 2 is a flowchart showing an example of the operation of the listening device 100 according to the first embodiment.

[0017] As shown in Figure 2, first, the ambient sound detection unit 101 of the listening device 100 detects ambient sounds around the user wearing the listening device 100 (step S101). Then, the ambient sound detection unit 101 generates an ambient signal corresponding to the detected ambient sounds.

[0018] Next, the ambient sound suppression signal generation unit 103 inverts the phase of the ambient signal and generates an ambient sound suppression signal that is in the opposite phase to the ambient signal (step S102). The playback signal output unit 105 converts the playback signal, which is the sound source signal superimposed with the ambient sound suppression signal, into playback sound and outputs it. In doing so, the listening device 100 cancels out ambient sounds in the playback sound that the user hears.

[0019] Next, the monitoring unit 102 determines whether the ambient noise level is above or below threshold A1 (step S103). Threshold A1 is set to a value for detecting danger to the user.

[0020] If it is determined that the ambient noise level is not above threshold A1 (NO in step S103), the listening device 100 returns to the process in step S101. On the other hand, if it is determined that the ambient noise level is above threshold A1 (YES in step S103), the monitoring unit 102 detects the amount of change in the ambient noise level per predetermined time S (step S104). The predetermined time S is, for example, 500 ms.

[0021] Next, the monitoring unit 102 determines whether the amount of change in the ambient noise level per predetermined time S is greater than or equal to a predetermined value A2 (step S105). The predetermined value A2 is set to a value for detecting danger to the user, similar to the threshold A1.

[0022] If it is determined that the amount of change in the ambient noise level per predetermined time S is not greater than or equal to a predetermined value A2 (NO in step S105), the listening device 100 returns to the process in step S101. On the other hand, if it is determined that the amount of change in the ambient noise level per predetermined time S is greater than or equal to a predetermined value A2 (YES in step S105), the ambient noise suppression signal generation unit 103 generates an ambient noise amplification signal that is in phase with the ambient noise signal instead of an ambient noise suppression signal (step S106). The amplitude of the ambient noise amplification signal can be set according to how much the user wants to amplify the ambient noise they hear. In this case, the playback signal output unit 105 outputs a playback signal in which the ambient noise amplification signal is superimposed on the sound source signal. By doing so, the listening device 100 performs a process to amplify the ambient noise in the playback sound that the user hears.

[0023] In step S106, the ambient sound suppression signal generation unit 103 may stop the ambient sound suppression signal without generating an ambient sound amplification signal.

[0024] Next, the monitoring unit 102 determines whether a predetermined time Z has elapsed since the processing in step S106 (step S107). If the monitoring unit 102 determines that the predetermined time Z has not elapsed (NO in step S107), it returns to the processing in step S107. On the other hand, if the monitoring unit 102 determines that the predetermined time Z has elapsed (YES in step S107), it determines whether the ambient noise level is equal to or greater than the threshold A1 (step S108). If the ambient noise level is determined to be equal to or greater than the threshold A1 (YES in step S108), the listening device 100 returns to the processing in step S108. On the other hand, if the ambient noise level is determined to be less than or equal to the threshold A1 (NO in step S108), the listening device 100 returns to the processing in step S101.

[0025] Next, using Figure 3, we will explain the ambient sound suppression signal or ambient sound amplification signal generated from ambient sound in the listening device 100 according to the first embodiment, and the noise cancellation effect therefrom. Figures 3(a) to 3(d) show the ambient sound suppression signal or ambient sound amplification signal generated from ambient sound in the listening device 100 according to the first embodiment, and the noise cancellation effect therefrom. Figure 3(a) is a graph showing the magnitude of ambient sound per unit time. The horizontal axis represents time (ms), and the vertical axis represents the magnitude of ambient sound (dB). Figure 3(b) is a graph showing the waveform of the ambient signal. The horizontal axis represents time (ms), and the vertical axis represents the amplitude of the ambient signal (dB). Figure 3(c) is a graph showing the waveform of the ambient sound suppression signal or ambient sound amplification signal. The horizontal axis represents time (ms), and the vertical axis represents the amplitude of the ambient signal (dB). Figure 3(d) is a graph showing the noise cancellation effect. The horizontal axis represents time (ms), and the vertical axis represents the noise cancellation effect (dB). A smaller value for the noise cancellation effect indicates that the noise in the playback sound heard by the user, i.e., ambient sound, is smaller.

[0026] As shown in Figure 3(a), at time P1, the monitoring unit 102 of the listening device 100 determines that the ambient noise level is equal to or greater than the threshold A1. At time P2, the monitoring unit 102 determines that the change in ambient noise level per predetermined time S is equal to or greater than the predetermined value A2.

[0027] As shown in Figures 3(b) and 3(c), until time P2, the ambient sound suppression signal generation unit 103 generates an ambient sound suppression signal that is out of phase with the ambient signal. Then, at time P2, the ambient sound suppression signal generation unit 103 generates an ambient sound amplification signal that is in phase with the ambient signal. Therefore, as shown in Figure 3(d), until time P2, the ambient sound heard by the user is canceled. From time P2 onward, the user can hear the ambient sound.

[0028] As described above, when the listening device 100 according to the first embodiment determines that danger is imminent to the user using threshold A1 and predetermined value A2, it generates a signal to amplify the ambient sound the user hears, that is, an ambient sound amplification signal in phase with the ambient signal, instead of an ambient sound suppression signal. Therefore, even in a noise-canceling state, the listening device 100 allows the user to perceive ambient sounds when danger arises. This enables the user to take various actions in response to the danger.

[0029] Furthermore, the technology described in Patent Document 1 could only notify the user when it detected an ambient sound that had been designated as a specific sound in advance. However, in the listening device 100, the ambient sounds detected when the user is in danger are not limited to specific sounds.

[0030] (Second embodiment) Next, the configuration of the listening device 200 according to the second embodiment will be described. The listening device 200 according to the second embodiment includes the ambient sound detection unit 101, monitoring unit 102, ambient sound suppression signal generation unit 103, sound source signal input unit 104, and playback signal output unit 105 of the listening device 100 according to the first embodiment.

[0031] The listening device 200 according to the second embodiment adds the following functions to the listening device 100 according to the first embodiment. In the listening device 100 according to the first embodiment, the ambient sound suppression signal generation unit 103 generates a signal for suppressing ambient sounds heard by the user, that is, an ambient sound suppression signal that is out of phase with the ambient signal corresponding to the ambient sound. Furthermore, if the monitoring unit 102 determines that the magnitude of the ambient sound is above a predetermined threshold and the amount of change of the ambient sound per predetermined time is above a predetermined value, the ambient sound suppression signal generation unit 103 generates a signal for amplifying the ambient sound heard by the user, that is, an ambient sound amplification signal that is in phase with the ambient signal, instead of the ambient sound suppression signal.

[0032] On the other hand, in the listening device 200 according to the second embodiment, when the monitoring unit 102 determines that the magnitude of the ambient noise is above a predetermined threshold and the amount of change of the magnitude of the ambient noise per predetermined time is above a predetermined value, the ambient noise suppression signal generation unit 103 reduces the amplitude of the ambient noise suppression signal over time, then generates an ambient noise amplification signal in place of the ambient noise suppression signal, and increases the amplitude of the ambient noise amplification signal over time. Furthermore, the ambient noise suppression signal generation unit 103 determines at least one of the amount of decrease of the ambient noise suppression signal over time and the amount of increase of the ambient noise amplification signal over time, based on the amount of change of the magnitude of the ambient noise per predetermined time.

[0033] Furthermore, in the listening device 100 according to the first embodiment, the ambient sound suppression signal generation unit 103 generates an ambient sound suppression signal instead of the ambient sound amplification signal if the ambient sound level is not above a predetermined threshold after a predetermined time has elapsed since the generation of the ambient sound amplification signal. On the other hand, in the listening device 200 according to the second embodiment, the ambient sound suppression signal generation unit 103, after a predetermined time has elapsed since the generation of the ambient sound amplification signal, if the magnitude of the ambient sound is not above a predetermined threshold, reduces the amplitude of the ambient sound amplification signal over time. Subsequently, the ambient sound suppression signal generation unit 103 generates an ambient sound suppression signal instead of the ambient sound amplification signal and increases the amplitude of the ambient sound suppression signal over time.

[0034] Next, the operation of the listening device 200 according to the second embodiment will be explained using Figures 4 and 5. Figure 4 is a flowchart showing an example of the operation of the listening device 200 according to the second embodiment. First, the ambient sound detection unit 101 of the listening device 200 detects ambient sounds around the user wearing the listening device 200 (step S201). Then, the ambient sound detection unit 101 generates an ambient signal corresponding to the detected ambient sounds.

[0035] Next, the ambient sound suppression signal generation unit 103 inverts the phase of the ambient signal and generates an ambient sound suppression signal that is in the opposite phase to the ambient signal (step S202). The playback signal output unit 105 converts the playback signal, which is the sound source signal with the ambient sound suppression signal superimposed on it, into playback sound and outputs it to the user. In doing so, the listening device 200 cancels out ambient sounds in the playback sound that the user hears.

[0036] Next, the monitoring unit 102 determines whether the ambient noise level is above or below threshold A1 (step S203). Threshold A1 is set to a value for detecting danger to the user.

[0037] If it is determined that the ambient noise level is not above threshold A1 (NO in step S203), the listening device 100 returns to the process in step S101. On the other hand, if it is determined that the ambient noise level is above threshold A1 (YES in step S203), the monitoring unit 102 detects the amount of change in the ambient noise level per predetermined time S (step S204). The predetermined time S is, for example, 500 ms.

[0038] Next, the monitoring unit 102 determines whether the amount of change in the ambient noise level per predetermined time S is greater than or equal to a predetermined value A2 (step S205). The predetermined value A2 is set to a value for detecting danger to the user, similar to the threshold A1.

[0039] If it is determined that the amount of change in the ambient noise level per predetermined time S is not greater than or equal to a predetermined value A2 (NO in step S205), the listening device 200 returns to the process in step S201. On the other hand, if it is determined that the amount of change in the ambient noise level per predetermined time S is greater than or equal to a predetermined value A2 (YES in step S205), the ambient noise suppression signal generation unit 103 of the listening device 200 reduces the amplitude of the generated ambient noise suppression signal to zero over time (step S206). The amplitude of the ambient noise suppression signal that is ultimately reduced by the ambient noise suppression signal generation unit 103 is not limited to zero and can be set individually. The time taken to reduce the amplitude of the ambient noise suppression signal is, for example, approximately the same as the predetermined time S.

[0040] Next, the ambient sound suppression signal generation unit 103 generates an ambient sound amplification signal that is in phase with the ambient sound signal instead of an ambient sound suppression signal, and increases the amplitude of the ambient sound amplification signal from zero to a predetermined value over time (step S207). The amplitude of the ambient sound amplification signal initially generated by the ambient sound suppression signal generation unit 103 is not limited to zero, but can be set individually. This predetermined value can be set individually depending on how much the ambient sound is to be amplified. The time taken to increase the amplitude of the ambient sound suppression signal is, for example, approximately the same as a predetermined time S.

[0041] In step S207, the ambient sound suppression signal generation unit 103 may stop the ambient sound suppression signal without generating an ambient sound amplification signal.

[0042] Next, the monitoring unit 102 determines whether a predetermined time Z has elapsed since the processing in step S206 (step S208). If the monitoring unit 102 determines that the predetermined time Z has not elapsed (NO in step S208), it returns to the processing in step S208. On the other hand, if the monitoring unit 102 determines that the predetermined time Z has elapsed (YES in step S208), it determines whether the ambient noise level is equal to or greater than the threshold A1 (step S209). If the ambient noise level is determined to be equal to or greater than the threshold A1 (YES in step S209), the listening device 200 returns to the processing in step S209. On the other hand, if the ambient noise level is determined to be less than or equal to the threshold A1 (NO in step S209), the listening device 200 returns to the processing in step S201.

[0043] Subsequently, in step S202, when the ambient sound suppression signal generation unit 103 generates an ambient sound suppression signal instead of an ambient sound amplification signal, it may reduce the amplitude of the ambient sound amplification signal to zero over time, and increase the amplitude of the generated ambient sound suppression signal from zero to a predetermined value over time.

[0044] Figure 5 is a flowchart showing another example of the operation of the listening device 200 according to the second embodiment. In the example shown in Figure 5, the listening device 200 further performs an operation to determine at least one of the following based on the amount of change in the magnitude of the ambient sound per predetermined time S: an amount by which the amplitude of the ambient sound suppression signal decreases over time and an amount by which the amplitude of the ambient sound amplification signal increases over time.

[0045] First, the listening device 200 executes the processes from step S301 to step S305. The processes from step S301 to step S305 executed by the listening device 200 are the same as the processes from step S201 to step S205 described above, so their explanation is omitted.

[0046] Next, if it is determined that the amount of change in the ambient noise level per predetermined time S is greater than or equal to a predetermined value A2 (YES in step S305), the ambient noise suppression signal generation unit 103 of the listening device 200 reduces the amplitude of the ambient noise suppression signal to zero over time according to the amount of change in the ambient noise level per predetermined time S (step S306). Specifically, the ambient noise suppression signal generation unit 103 determines the amount of reduction per unit time to reduce the amplitude of the ambient noise suppression signal according to the amount of change in the ambient noise level per predetermined time S. Here, the greater the amount of change in the ambient noise level per predetermined time S, the greater the reduction per unit time. On the other hand, the smaller the amount of change in the ambient noise level per predetermined time S, the smaller the reduction per unit time. Then, the ambient noise suppression signal generation unit 103 reduces the amplitude of the ambient noise suppression signal to zero with the determined amount of reduction per unit time.

[0047] Next, the ambient sound suppression signal generation unit 103 generates an ambient sound amplification signal that is in phase with the ambient signal instead of an ambient sound suppression signal, and increases the amplitude of the ambient sound amplification signal from zero to a predetermined value over time according to the amount of change in the ambient sound level per predetermined time S (step S307). Specifically, the ambient sound suppression signal generation unit 103 generates an ambient sound amplification signal instead of an ambient sound suppression signal. Then, the ambient sound suppression signal generation unit 103 determines the amount of increase per unit time to increase the amplitude of the ambient sound amplification signal according to the amount of change in the ambient sound level per predetermined time S. Here, the ambient sound suppression signal generation unit 103 increases the amount of increase per unit time as the amount of change in the ambient sound level per predetermined time S increases. On the other hand, the ambient sound suppression signal generation unit 103 decreases the amount of increase per unit time as the amount of change in the ambient sound level per predetermined time S decreases. Furthermore, the ambient sound suppression signal generation unit 103 increases the amplitude of the ambient sound amplification signal from zero to a predetermined value by the determined amount of increase per unit time.

[0048] Next, the listening device 200 executes the processes from step S308 to step S309. The processes from step S308 to step S309 executed by the listening device 200 are the same as the processes from step S208 to step S209 described above, so their explanation is omitted.

[0049] Next, using Figures 6-7, we will explain the ambient sound suppression signal or ambient sound amplification signal generated from ambient sound in the listening device 200 according to the second embodiment, and the noise cancellation effect therefrom. Figures 6(a) to 6(d) and 7(a) to 7(d) show the ambient sound suppression signal or ambient sound amplification signal generated from ambient sound in the listening device 200 according to the second embodiment, and the noise cancellation effect therefrom. Figures 6(a) and 7(a) are graphs showing the loudness of ambient noise per unit time. The horizontal axis represents time (ms), and the vertical axis represents the loudness of ambient noise (dB). Figures 6(b) and 7(b) are graphs showing the waveform of an ambient signal. The horizontal axis represents time (ms), and the vertical axis represents the amplitude of the ambient signal (dB). Figures 6(c) and 7(c) are graphs showing the waveform of an ambient noise suppression signal or an ambient noise amplification signal. The horizontal axis represents time (ms), and the vertical axis represents the amplitude of the ambient signal (dB). Figures 6(d) and 7(d) are graphs showing the noise cancellation effect. The horizontal axis represents time (ms), and the vertical axis represents the noise cancellation effect (dB). A smaller value for the noise cancellation effect indicates that the noise in the playback audio heard by the user, i.e., ambient noise, is smaller.

[0050] As shown in Figure 6(a), at time P1, the monitoring unit 102 of the listening device 200 determines that the ambient noise level is equal to or greater than the threshold A1. At time P2, the monitoring unit 102 determines that the change in ambient noise level per predetermined time S is equal to or greater than the predetermined value A2.

[0051] As shown in Figures 6(b) and 6(c), until time P2, the ambient sound suppression signal generation unit 103 generates an ambient sound suppression signal that is out of phase with the ambient signal. From time P2 onward, the amplitude of the ambient sound suppression signal is gradually reduced to zero by the ambient sound suppression signal generation unit 103. Here, the amount of decrease R1 per unit time of the amplitude of the ambient sound suppression signal may be determined by the ambient sound suppression signal generation unit 103 according to the amount of change in the loudness of the ambient sound per predetermined time S. Subsequently, the ambient sound suppression signal generation unit 103 generates an ambient sound amplification signal that is in phase with the ambient signal instead of the ambient sound suppression signal, and the amplitude of the ambient sound amplification signal is gradually increased from zero to a predetermined value. Here, the amount of increase R2 per unit time of the ambient sound amplification signal may be determined by the ambient sound suppression signal generation unit 103 according to the amount of change in the loudness of the ambient sound per predetermined time S. Therefore, as shown in Figure 6(d), until time P2, the ambient sound heard by the user is canceled. From time P2 onward, the user can hear the ambient sound. Here, the user can gradually hear ambient sounds as time progresses from time P2.

[0052] Next, as shown in Figure 7(a), at time P3, the monitoring unit 102 of the listening device 200 determines that the ambient sound level is not above the threshold A1 after a predetermined time Z has elapsed since the generation of the ambient sound amplification signal. As shown in Figures 7(b) and 7(c), after time P3, the ambient sound suppression signal generation unit 103 reduces the amplitude of the ambient sound amplification signal over time. Subsequently, the ambient sound suppression signal generation unit 103 generates an ambient sound suppression signal in place of the ambient sound amplification signal, and the amplitude of the ambient sound suppression signal increases over time. Therefore, as shown in Figure 7(d), as time progresses from time P3, the user gradually becomes unable to hear ambient sounds.

[0053] As described above, the listening device 200 according to the second embodiment reduces the amplitude of the ambient sound suppression signal over time, then generates an ambient sound amplification signal in place of the ambient sound suppression signal, and increases the amplitude of the ambient sound amplification signal over time. Therefore, the listening device 200 can reduce the possibility that the user may suddenly hear ambient sounds and feel discomfort with the reproduced sound.

[0054] In addition, the listening device 200 determines at least one of the following based on the rate of change in the magnitude of ambient noise per predetermined time S: an amount by which the amplitude of the ambient noise suppression signal decreases over time and an amount by which the amplitude of the ambient noise amplification signal increases over time. For example, when a sudden danger approaches the user, such as when a vehicle suddenly approaches the user, the rate of change in the magnitude of ambient noise per predetermined time becomes large. With the listening device 200, the user can quickly hear ambient noise when a sudden danger approaches them.

[0055] Next, using Figure 8, an example of the hardware configuration of the computer 500 of the listening device 100 according to the first embodiment and the listening device 200 according to the second embodiment will be described. Figure 8 is a block diagram showing an example of the hardware configuration of the computer 500. As shown in Figure 8, the computer 500 has a processor 501 and a memory 502. The processor 501 may be, for example, a microprocessor, an MPU (Micro Processing Unit), or a CPU (Central Processing Unit). The processor 501 may include multiple processors. The memory 502 is composed of a combination of volatile memory and non-volatile memory. The memory 502 may include storage located away from the processor 501. In this case, the processor 501 may access the memory 502 via an I / O interface that is not shown.

[0056] Furthermore, each configuration in the above-described embodiment may consist of hardware, software, or both, and may consist of one piece of hardware or software, or multiple pieces of hardware or software. The functions (processes) of each configuration in the above-described embodiment may be implemented by a computer. For example, a program for performing the method in the embodiment may be stored in memory 502, and each function may be implemented by executing the program stored in memory 502 with a processor 501.

[0057] These programs, when loaded into a computer, include a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiments. The programs may be stored on non-temporary computer-readable media or tangible storage media. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drives (SSDs), or other memory technologies, CD-ROMs, digital versatile discs (DVDs), Blu-ray® discs, or other optical disc storage, magnetic cassettes, magnetic tapes, magnetic disk storage, or other magnetic storage devices. The programs may be transmitted over temporary computer-readable media or communication media. Examples, but not limited to, include electrical, optical, acoustic, or other forms of propagating signals.

[0058] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0059] 100, 200 listening devices 101 Ambient sound detection unit 102 Monitoring Department 103 Environmental sound suppression signal generation unit 104 Audio signal input section 105 Playback signal output section 500 Computers 501 Processor 502 memory

Claims

1. An ambient sound detection unit that generates an ambient signal corresponding to the detected ambient sound, An ambient sound suppression signal generation unit generates an ambient sound suppression signal that is in the opposite phase to the aforementioned ambient signal, A playback signal output unit that outputs a playback signal obtained by superimposing the ambient noise suppression signal onto the sound source signal, The system includes a monitoring unit that monitors the magnitude of the ambient sound based on the ambient signal, The aforementioned ambient noise suppression signal generation unit is If the monitoring unit determines that the magnitude of the ambient sound is above a predetermined threshold and the amount of change in the magnitude of the ambient sound per predetermined time is above a predetermined value, it generates an ambient sound amplification signal that is in phase with the ambient signal instead of the ambient sound suppression signal. The aforementioned playback signal output section is, A playback signal is output by superimposing the ambient sound amplification signal onto the aforementioned sound source signal. Listening device.

2. The aforementioned ambient noise suppression signal generation unit is If the monitoring unit determines that the ambient noise level is above a predetermined threshold and that the change in ambient noise level per predetermined time is above a predetermined value, the amplitude of the ambient noise suppression signal is reduced over time, and then the amplitude of the ambient noise amplification signal is increased over time. The listening device according to claim 1.

3. Based on the amount of change per predetermined time in the magnitude of the ambient sound, at least one of the amount of decrease over time in the ambient sound suppression signal and the amount of increase over time in the ambient sound amplification signal is determined. The listening device according to claim 2.

4. The aforementioned ambient noise suppression signal generation unit is If the monitoring unit determines that the ambient noise level is above a predetermined threshold and that the change in the ambient noise level per predetermined time is above a predetermined value, the ambient noise suppression signal is stopped without generating the ambient noise amplification signal. The listening device according to claim 1.

5. It generates an environmental signal corresponding to the detected ambient sound, An ambient sound suppression signal is generated that is in the opposite phase to the aforementioned ambient signal. The system outputs a playback signal in which the ambient noise suppression signal is superimposed on the sound source signal. Based on the aforementioned environmental signal, the magnitude of the ambient sound is monitored, If it is determined that the magnitude of the ambient sound is above a predetermined threshold and the rate of change of the magnitude of the ambient sound per predetermined time is above a predetermined value, an ambient sound amplification signal in phase with the ambient signal is generated instead of the ambient sound suppression signal, and a playback signal is output in which the ambient sound amplification signal is superimposed on the sound source signal. A method for controlling a listening device.

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