Sound output device and sound output method

Abstract

This sound output device is provided with a control unit. The control unit divides data of a sound into data of a plurality of sound portions, reproduces a first sound portion among the plurality of sound portions upon accepting a first operation, and, after the reproduction of the first sound portion, reproduces a second sound portion prior to the first sound portion.

Description

Sound output device and sound output method Cross-reference to related applications

[0001] This application claims priority to Japanese Patent Application No. 2023-117889, filed on July 19, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a sound output device and a sound output method.

[0003] There are known techniques for playing back recorded sounds. For example, Patent Document 1 discloses an audio playback device that rewinds audio in response to a rewind request from a driver.

[0004] JP 2016-119133 A

[0005] A sound output device according to one embodiment of the present disclosure includes a control unit that divides sound data into data of a plurality of sound parts, and upon receiving a first operation, plays a first sound part of the plurality of sound parts, and after playing the first sound part, plays a second sound part that precedes the first sound part.

[0006] A sound output method according to one embodiment of the present disclosure includes: dividing sound data into data of a plurality of sound parts; and, upon receiving a first operation, playing a first sound part of the plurality of sound parts, and, after playing the first sound part, playing a second sound part that precedes the first sound part.

[0007] A sound output device according to one embodiment of the present disclosure includes a control unit that, upon receiving a first operation, plays an Nth sound part (N is an integer satisfying 1≦N) from among a plurality of sound parts included in sound data, and, after playing the Nth sound part, plays an N+1th sound part that precedes the Nth sound part.

[0008] FIG. 1 is a diagram showing a schematic configuration of a sound output device according to an embodiment of the present disclosure; FIG. 2 is a block diagram of the sound output device shown in FIG. 1; FIG. 3 is a diagram showing an example of data of external sound; FIG. 4 is a diagram for explaining sound parts to be reproduced; FIG. 5 is a diagram for explaining sound parts to be reproduced; FIG. 6 is a flowchart showing an example procedure of sound output processing according to an embodiment of the present disclosure; FIG. 7 is a diagram showing an example of data of external sound according to another embodiment of the present embodiment; FIG. 8 is a diagram for explaining sound parts to be reproduced according to another embodiment of the present embodiment; and FIG. 9 is a diagram for explaining sound parts according to a comparative example.

[0009] Conventional techniques for playing back recorded sounds have room for improvement. For example, depending on a user's operation, the played back sound may be too long or too short. According to an embodiment of the present disclosure, the technique for playing back recorded sounds can be improved.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] As shown in FIG. 1 , the sound output device 1 according to this embodiment is a bone conduction earphone. However, the sound output device 1 is not limited to a bone conduction earphone. The sound output device 1 may be any device capable of reproducing sound data. As another example, the sound output device 1 may be an earphone, a neck speaker, an inner-ear earphone, an in-ear earphone, or a headphone. If the sound output device 1 is an inner-ear earphone or a headphone, it may have an external sound capture function. The external sound capture function is a function of collecting external sounds from the sound output device 1 and outputting them to the user. The external sounds are sounds generated outside the sound output device 1. For example, external sounds include sounds generated around the user. External sounds may include sounds generated by the user themselves.

[0012] The sound output device 1 includes a housing 1L, a housing 1R, and a fixing member 1F. The housing 1L is placed against the user's left temple. The housing 1R is placed against the user's right temple. The fixing member 1F fixes the housing 1L and the housing 1R to the user's left and right temples, respectively. The fixing member 1F includes a left ear hook that is placed over the user's left ear, a right ear hook that is placed over the user's right ear, and a band that connects these ear hooks.

[0013] The sound output device 1 is worn on the user's head. The user can hear external sounds while wearing the sound output device 1 on their head. However, if the user is paying attention to something else, they may miss external sounds containing necessary information. For example, if the user is creating a document on a computer or reading a book, they may miss external sounds containing necessary information. Even in such cases, the user can realize that they have missed external sounds containing necessary information by using selective attention. Selective attention refers to, for example, selectively paying attention to specific information in an environment where various external sounds are present. In this embodiment, if the user realizes that they have missed external sounds containing necessary information, they can have the sound output device 1 play the external sounds. By having the sound output device 1 play external sounds in this way, the user can confirm the necessary information.

[0014] 2, the sound output device 1 includes a speaker unit 10, a microphone unit 11, an input unit 12, a ring buffer 13, a storage unit 14, and a control unit 15. The ring buffer 13 may be a component of the storage unit 14. The ring buffer 13, the storage unit 14, and the control unit 15 may be housed in either a housing 1L or a housing 1R as shown in FIG. 1. Alternatively, when a housing is attached to the fixing member 1F, the ring buffer 13, the storage unit 14, and the control unit 15 may be housed in that housing.

[0015] The speaker unit 10 is capable of outputting sound. In this embodiment, the speaker unit 10 includes a left bone conduction speaker and a right bone conduction speaker. The bone conduction speakers output sound to the user by transmitting vibrations to the user's skull. The left bone conduction speaker is housed in a housing 1L. The right bone conduction speaker is housed in a housing 1R.

[0016] The microphone unit 11 is capable of collecting external sounds around the sound output device 1. The microphone unit 11 is configured to include a left microphone and a right microphone. The left microphone is housed in housing 1L. The right microphone is housed in housing 1R. The microphone unit 11 collects external sounds as stereo sounds using the left microphone and the right microphone. Of the two sounds contained in the stereo sounds, the sound collected by the left microphone is also referred to as "left sound." Furthermore, of the two sounds, the sound collected by the right microphone is also referred to as "right sound."

[0017] The input unit 12 is capable of receiving input from a user. The input unit 12 includes at least one input interface capable of receiving input from a user. The input interface is, for example, a physical key. The input unit 12 is located on the surface of the housing 1R as shown in FIG. 1 . However, the input unit 12 may be located on the surface of the housing 1R or on the fixed member 1F.

[0018] Data of the audio portion, which will be described later, is accumulated in chronological order in the ring buffer 13. The ring buffer 13 is configured to include components that are the same as or similar to components of a storage unit 14, which will be described later.

[0019] The storage unit 14 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The semiconductor memory is, for example, a random access memory (RAM) or a read-only memory (ROM). The RAM is, for example, a static random access memory (SRAM) or a dynamic random access memory (DRAM). The ROM is, for example, an electrically erasable programmable read-only memory (EEPROM). The storage unit 14 may function as a main storage device, an auxiliary storage device, or a cache memory. The storage unit 14 stores data used in the operation of the sound output device 1 and data obtained by the operation of the sound output device 1.

[0020] The control unit 15 is configured to include at least one processor, at least one dedicated circuit, or a combination of these. The processor is a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for specific processing. The dedicated circuit is, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The control unit 15 executes processing related to the operation of the sound output device 1 while controlling each part of the sound output device 1.

[0021] The control unit 15 collects external sounds around the sound output device 1, i.e., around the user, using the microphone unit 11. The control unit 15 divides data of the collected external sounds into data of a plurality of sound parts.

[0022] The control unit 15 divides the external sound data into data of multiple sound parts based on the meaning of the speech content included in the external sound. In this embodiment, the control unit 15 divides the external sound data into data of multiple sound parts by detecting speech sections from the external sound. A speech section is a section in which a speech state continues. The control unit 15 determines the detected speech section as a sound section. Generally, people pause in speech when they reach a breath, punctuation, or the like during speech. The positions where such people pause in speech may be determined as the boundaries of the speech section. By determining the positions where speech pauses are determined as the boundaries of the speech section, the speech section is divided in terms of the meaning of the speech content. In other words, by determining the positions where speech pauses are determined as the boundaries of the speech section, the external sound data can be divided into multiple sound parts based on the meaning of the speech content included in the external sound. Here, as described above, the external sound collected by the microphone unit 11 is stereo sound. Therefore, when silent data continues for a set time in both the left and right sound data included in the stereo sound, the control unit 15 may detect the position where the silent data continues for a set time as a position where a person pauses in speech, i.e., a boundary of a speech section. The control unit 15 may consider sound data to be silent if the volume of the sound data is equal to or less than a threshold. The threshold may be set based on the volume of sound data when no human voice is included. The set time may be set based on the language processed by the sound output device 1. When the processed language is Japanese, the set time may be, for example, 500 ms. Furthermore, after detecting a boundary of a speech section, when the control unit 15 detects voice data in either the left or right sound data, the control unit 15 may detect the time when the voice data is detected as the start of the next speech section.

[0023] For example, the control unit 15 collects external sound 2 as shown in FIG. 3 . External sound 2 includes the sound, "The boarding gate for the 12 o'clock flight of Airlines A to Narita has been changed to Gate 4." The control unit 15 detects speech segments from external sound 2 and divides the data of external sound 2 into data of sound portions 2a, 2b, 2c, 2d, and 2e. Sound portion 2a corresponds to the speech segment including the sound "departing at 12 o'clock." Sound portion 2b corresponds to the speech segment including the sound "Airlines A to Narita." Sound portion 2c corresponds to the speech segment including the sound "The boarding gate is." Sound portion 2d corresponds to the speech segment including the sound "to Gate 4." Sound portion 2e corresponds to the speech segment including the sound "It has been changed."

[0024] The control unit 15 assigns an identifier (ID) to the divided sound portion data. The control unit 15 stores the sound portion data in the ring buffer 13 in association with the identifier. Here, the divided sound portion data includes left sound portion data and right sound portion data. The control unit 15 may store the left sound portion data and the right sound portion data in association with the same identifier in the ring buffer 13. Each time the control unit 15 divides the external sound data into new sound portion data, it stores the new sound portion data in association with the new identifier in the ring buffer 13. With this configuration, new sound portion data is sequentially accumulated in the ring buffer 13. When the sound portion data accumulated in the ring buffer 13 exceeds the capacity of the ring buffer 13, old sound portion data is deleted from the ring buffer 13. In this embodiment, recording external sound data means storing the external sound data in the ring buffer 13 as sound portion data.

[0025] The control unit 15 may accept a first operation via the input unit 12. The first operation is an operation that causes the sound output device 1 to execute a process of reproducing a plurality of sound portions accumulated in the ring buffer 13 going back in time. When the user feels that he or she has missed an external sound containing necessary information, the user performs the first operation on the input unit 12. The first operation on the input unit 12 may be any operation, such as pressing a physical key included in the input unit 12.

[0026] When the control unit 15 receives a first operation via the input unit 12, it plays a first sound portion among the multiple sound portions stored in the ring buffer 13. The first sound portion is data of the newest sound portion among the multiple sound portions stored in the ring buffer 13 at the time the first operation is received. After playing the first sound portion, the control unit 15 plays a second sound portion that precedes the first sound portion. In other words, when the control unit 15 receives a first operation, it plays an Nth sound portion among the multiple sound portions stored in the ring buffer 13, and after playing the Nth sound portion, it plays an N+1th sound portion that precedes the Nth sound portion. N is an integer that satisfies 1≦N≦M−1, where M is the number of sound portions stored in the ring buffer 13. A larger N for the Nth sound portion indicates that the sound portion is further back in the external sound data. The N+1th sound portion is the sound portion that precedes the Nth sound portion in time in the external sound data. The control unit 15 reproduces the sound portions by outputting the sound portions to the speaker unit 10. Here, the sound portions that are stereo sound include a left sound portion and a right sound portion. The control unit 15 may output the left sound portion to the left bone conduction speaker of the speaker unit 10, and output the right sound portion to the right bone conduction speaker of the speaker unit 10. With this configuration, the external sound data is reproduced for each sound portion in order, starting from the first sound portion and proceeding backward.

[0027] For example, in FIG. 3, it is assumed that the user feels that they have missed the sound "Gate 4" and performs a first operation on the input unit 12 at the time when sound portion 2e is accumulated in the ring buffer 13. That is, in FIG. 3, it is assumed that the first operation is accepted at the time when the control unit 15 accumulates sound portion 2e in the ring buffer 13. In this case, of the sound portions 2a to 2e accumulated in the ring buffer 13, sound portion 2e is the newest sound portion data at the time when the first operation is accepted. Therefore, the control unit 15 plays sound portion 2e as the first sound portion (N=1). After playing sound portion 2e, the control unit 15 plays sound portion 2d, which is older than sound portion 2e, as the second sound portion. With this configuration, as shown in FIG. 4, sound portions 2a to 2e accumulated in the ring buffer 13 are played in the following order: sound portion 2e, sound portion 2d, sound portion 2c, sound portion 2b, and sound portion 2a. In other words, the sound that will be played is, "There has been a change. The boarding gate is now Gate 4. Airlines A flight to Narita departs at 12 o'clock."

[0028] In this way, the external sound data is played back for each sound portion in order from the first sound portion back to the past, so that the user can listen to and check the external sound for each sound portion in order from the first sound portion.

[0029] The control unit 15 may play a sound effect before playing the first sound portion. For example, in Fig. 4, the control unit 15 may play a sound effect before playing sound portion 2e. By playing a sound effect, the user can be aware that external sound data is being played back retroactively for each sound portion.

[0030] After playing the Nth sound portion, the control unit 15 may play a sound effect and then play the N+1th sound portion. For example, in FIG. 4 , the control unit 15 may play sound effects between sound portion 2e and sound portion 2d, between sound portion 2d and sound portion 2c, between sound portion 2c and sound portion 2b, and between sound portion 2b and sound portion 2a. When external sound data is played back retroactively for each sound portion, the word order of the played sounds is reversed from the word order of the external sound. Therefore, some users may not be able to clearly grasp the boundaries of the speech sections. Even in such cases, by playing the Nth sound portion, a sound effect, and then the N+1th sound portion, the user can easily grasp the boundaries of the speech sections.

[0031] The control unit 15 may wait a predetermined time after playing the Nth sound portion before playing the N+1th sound portion. The predetermined time may be set taking into consideration user convenience. The predetermined time is, for example, one second. For example, in FIG. 4 , the control unit 15 leaves a predetermined time between sound portion 2e and sound portion 2d, between sound portion 2d and sound portion 2c, between sound portion 2c and sound portion 2b, and between sound portion 2b and sound portion 2a. By leaving a predetermined time after playing the Nth sound portion before playing the N+1th sound portion, the user can easily grasp the boundaries of the speech section.

[0032] The control unit 15 may slow down the playback speed of the Nth sound portion and the N+1th sound portion to a predetermined speed. The predetermined speed may be set taking into consideration the user's convenience. The predetermined speed may be slower than the normal playback speed. For example, in FIG. 4, the control unit 15 slows down the playback speed of sound portions 2a to 2e. By slowing down the playback speed of the sound portions in this manner, the user can easily understand the content of the played-back utterance, even if the word order of the played-back sounds is reversed from the word order of the external sounds.

[0033] The control unit 15 may accept a second operation via the input unit 12 before playback of all of the multiple sound portions accumulated in the ring buffer 13 is completed. The second operation is an operation that causes the sound output device 1 to execute a process of continuously playing back sound portions that are being played back or have finished being played back at the time the second operation is accepted, up to the first sound portion. In other words, if the control unit 15 accepts the second operation during playback of the N+1th sound portion or at the time playback of the N+1th sound portion is completed, the control unit 15 continuously plays back sound portions from the N+1th sound portion to the first sound portion. As long as the second operation and the first operation are distinguishable from each other, the second operation on the input unit 12 may be the same as the first operation on the input unit 12. For example, the second operation on the input unit 12 may be an operation such as pressing a physical key included in the input unit 12, like the first operation on the input unit 12. Even if the first operation on the input unit 12 and the second operation on the input unit 12 are the same, the second operation can be distinguished from the first operation by designating the operation received after the first operation as the second operation.

[0034] For example, in Fig. 4, it is assumed that the control unit 15 receives the second operation while playing back the sound portion 2b. In this case, the control unit 15 plays back the sound portions 2b through 2e, which is the first sound portion, in succession, as shown in Fig. 5. That is, the sound that is played back is, "The boarding gate for Airlines A bound for Narita has been changed to Gate 4."

[0035] 6 is a flowchart illustrating an example of a procedure for a sound output process according to an embodiment of the present disclosure. This sound output process corresponds to a sound output method according to the present embodiment. For example, when the sound output device 1 is powered on, the control unit 15 starts the process of step S1.

[0036] The control unit 15 collects external sounds around the sound output device 1 using the microphone unit 11 (step S1).

[0037] The control unit 15 determines whether or not a speech section is detected from the external sound collected in the processing of step S1 (step S2). If the control unit 15 does not determine that a speech section is detected from the collected external sound (step S2: NO), the control unit 15 returns to the processing of step S1. On the other hand, if the control unit 15 determines that a speech section is detected from the collected external sound (step S2: YES), the control unit 15 separates the speech section as a sound portion from the external sound and proceeds to the processing of step S3.

[0038] In the process of step S3, the control unit 15 assigns identifiers to the divided sound parts, and stores the sound parts in association with the identifiers in the ring buffer 13 (step S4).

[0039] The control unit 15 determines whether or not the first operation has been received by the input unit 12 (step S5). If the control unit 15 determines that the first operation has been received (step S5: YES), the control unit 15 proceeds to the process of step S6. On the other hand, if the control unit 15 does not determine that the first operation has been received (step S5: NO), the control unit 15 returns to the process of step S1.

[0040] In the process of step S6, the control unit 15 plays back the sound portion. In the first process of step S6, the control unit 15 plays back the first sound portion of the multiple sound portions stored in the ring buffer 13.

[0041] In the process of step S7, the control unit 15 determines whether or not the second operation has been received by the input unit 12. If the control unit 15 determines that the second operation has been received (step S7: YES), the control unit 15 proceeds to the process of step S8. On the other hand, if the control unit 15 does not determine that the second operation has been received (step S7: NO), the control unit 15 proceeds to the process of step S9.

[0042] In the process of step S8, the control unit 15 continuously plays back the sound portion that was being played or had finished playing at the time when the second operation was accepted in the process of step S7 through the first sound portion. After the process of step S8, the control unit 15 ends the sound output process. After the sound output process ends, the control unit 15 may execute the process from step S1 again.

[0043] In the process of step S9, the control unit 15 determines whether or not all of the plurality of sound parts stored in the ring buffer 13 have been reproduced in the process of step S6.

[0044] When the control unit 15 determines that all of the sound portions stored in the ring buffer 13 have been played (step S9: YES), the control unit 15 ends the sound output process. After the sound output process ends, the control unit 15 may execute the process from step S1 again.

[0045] If the control unit 15 does not determine that all of the multiple sound parts stored in the ring buffer 13 have been played back (step S9: NO), the control unit 15 returns to the processing of step S6. If the control unit 15 played back the Nth sound part (N is an integer satisfying 1≦N) in the processing of the previous step S6, the control unit 15 plays back the N+1th sound part in the processing of the next step S6.

[0046] As described above, in the sound output device 1 according to the present embodiment, when the control unit 15 receives a first operation, it plays a first sound portion among the multiple sound portions stored in the ring buffer 13, and after playing the first sound portion, it plays a second sound portion that precedes the first sound portion. In other words, when the control unit 15 receives a first operation, it plays an Nth sound portion among the multiple sound portions stored in the ring buffer 13, and after playing the Nth sound portion, it plays an N+1th sound portion that precedes the Nth sound portion. When the first operation is received in this manner, the external sound data is played back in order, starting from the first sound portion and going back in time. This configuration prevents a situation in which the sound played back is too long or too short depending on the user operation. Furthermore, as described below, the user can easily check information they missed.

[0047] As a comparative example, assume that when the control unit 15 receives a predetermined operation via the input unit 12, the control unit 15 plays back all of the external sound data stored in the ring buffer 13. In this comparative example, when the control unit 15 receives a predetermined operation as shown in FIG. 3 , it plays back all of the data for external sound 2, which reads, "The boarding gate for the 12:00 departing A Airlines flight to Narita has been changed to Gate 4." In this case, if the user misses the sound "Gate 4," they must listen again for the sound "The boarding gate for the 12:00 departing A Airlines flight to Narita has been changed to Gate 4" before hearing the sound "Gate 4." In particular, if the capacity of the ring buffer 13 is large, the number of sounds the user must listen for increases. In this comparative example, it is possible to reduce the capacity of the ring buffer 13 to reduce the number of sounds the user must listen for. However, reducing the capacity of the ring buffer 13 may result in the ring buffer 13 being unable to store sounds the user missed, i.e., the user may not be able to record the sounds they missed.

[0048] In contrast to the comparative example, in this embodiment, when the control unit 15 receives a first operation, it plays the Nth sound portion. After playing the Nth sound portion, it plays the N+1th sound portion, which is older than the Nth sound portion. This configuration allows the user to listen back to each sound portion of the external sound data, starting with the most recent sound portion and moving backward. For example, for external sound 2 shown in FIG. 3, the user can listen back to the most recent sound portion 2e as shown in FIG. 4. This allows the user to quickly check the sound portion "to gate 4" even if the ring buffer 13 has a large capacity. Furthermore, the user can quickly check the sound portion "to gate 4" without reducing the capacity of the ring buffer 13 as in the comparative example. In this embodiment, the capacity of the ring buffer 13 does not need to be reduced, reducing the possibility of the user not being able to record the sound they missed, as in the comparative example.

[0049] As another comparative example, consider an example in which the control unit 15 plays back a previous audio portion each time it receives a predetermined operation from the input unit 12. In this comparative example, the user must perform a predetermined operation on the input unit 12 multiple times until the audio portion they missed is played back. For example, if the user misses the sound "To Gate 4" as shown in FIG. 3, the user must perform a predetermined operation on the input unit 12 four times before hearing the audio portion 2d as shown in FIG. 4. In addition, in this comparative example, an interface such as a seek bar is required to enable the user to visually check how many times they have performed the predetermined operation.

[0050] In contrast to the other comparative example, in this embodiment, when the control unit 15 receives a first operation, it plays the Nth sound portion, and after playing the Nth sound portion, it plays the N+1th sound portion that precedes the Nth sound portion. In other words, in this embodiment, if the user performs the first operation on the input unit 12 only once, external sound data is automatically played back for each sound portion, starting with the most recent sound portion and proceeding backward. This configuration can avoid a situation where the user has to perform a predetermined operation on the input unit 12 multiple times, as in the other comparative example. Furthermore, in this embodiment, because the user only needs to perform the first operation on the input unit 12 once, there is no need to provide a user interface such as a seek bar, as in the other comparative example. Therefore, in this embodiment, the configuration of the sound output device 1 can be further simplified.

[0051] Therefore, according to this embodiment, the technology for reproducing recorded sound can be improved.

[0052] Furthermore, in the sound output device 1 according to the present embodiment, when the control unit 15 receives a second operation during playback of the N+1th sound portion or at the point when playback of the N+1th sound portion has ended, the control unit 15 may continuously play back the N+1th sound portion through the first sound portion. By continuously playing back the N+1th sound portion through the first sound portion, the user can check the details of the information that he or she missed.

[0053] Furthermore, in the sound output device 1 according to this embodiment, the control unit 15 may divide the external sound data into multiple sound segments based on the meaning of the speech contained in the external sound. Here, dividing the external sound data into multiple sound segments by dividing the external sound data at fixed time intervals may result in the meaning of the speech in the divided sound segments being unclear. For example, dividing the data of external sound 2 shown in FIG. 3 at fixed time intervals may result in the sound "Gate 4 has been changed" being divided into the sound segments "Changed to Gate 4" and "Changed." The meaning of the speech "Changed to Gate 4" and "Changed" is unclear. In this embodiment, dividing the external sound data into multiple sound segments based on the meaning of the speech makes the speech in the divided sound segments clear. With this configuration, after the first operation is accepted, sound segments with clear meanings are sequentially played. For example, as described above with reference to FIG. 4, the sound "Changed to Gate 4. The boarding gate for A Airlines flight to Narita departs at 12:00" is played. With this configuration, the user can easily check the information that he or she missed.

[0054] (Other Embodiments) In a sound output device 1 according to another embodiment, when the Nth sound portion includes a particle, the control unit 15 does not reproduce the sound of the particle included in the Nth sound portion. In the same manner as or similar to the Nth sound portion, when the N+1th sound portion includes a particle, the control unit 15 does not reproduce the sound of the particle included in the N+1th sound portion. With this configuration, it is possible to reduce the possibility of the user making a mistake, as will be described below.

[0055] For example, FIG. 7 shows external sound 3. External sound 3 includes the sound "Men are on the right side, women are on the left side." The control unit 15 divides the data of external sound 3 into sound portions 3a, 3b, 3c, and 3d. Sound portion 3a corresponds to the speech section including the sound "Men are." Sound portion 3b corresponds to the speech section including the sound "right side." Sound portion 3c corresponds to the speech section including the sound "Women are." Sound portion 3d corresponds to the speech section including the sound "left side." Sound portions 3a and 3c include the particle "wa." Here, the control unit 15 considers that the first operation has been accepted at the time when sound portion 3d is stored in the ring buffer 13. In this case, the control unit 15 sets sound portion 3d as the first sound portion (N=1) and plays sound portion 3d, sound portion 3c, sound portion 3b, and sound portion 3a in this order, as shown in FIG. 8. However, the control unit 15 does not reproduce the particle sound "wa" included in the sound portion 3a and the sound portion 3c. With this configuration, the sound "Left side female, right side male" is reproduced.

[0056] As a comparative example, consider an example in which when a particle is included in the Nth sound portion, the sound of the particle included in the Nth sound portion is reproduced. In this comparative example, for sound portions 3a to 3d as shown in Fig. 7, the sound "Left side, women are on the right side, men are" is reproduced as shown in Fig. 9. This sound "Left side, women are on the right side, men are" includes the sound "women are on the right side." A user hearing this sound may mistakenly believe that women are on the right side.

[0057] In contrast to the comparative example, in another embodiment, when a particle is included in the Nth syllable portion, the control unit 15 does not reproduce the sound of the particle included in the Nth syllable portion. Similarly to or similar to the Nth syllable portion, when a particle is included in the N+1th syllable portion, the control unit 15 does not reproduce the sound of the particle included in the N+1th syllable portion. This configuration reduces the possibility that the user will mistakenly believe that the woman is on the right side, as in the comparative example. However, even if the user mistakenly believes that the woman is on the right side, as in the comparative example, if the user performs a second operation on the input unit 12, the sound "Men are on the right side, women are on the left side" as shown in FIG. 7 is reproduced. Therefore, the user can understand that the man is on the right side.

[0058] Other configurations and effects of the sound output device 1 according to the other embodiments are the same as or similar to the configurations and effects of the sound output device 1 according to the above-described embodiment.

[0059] While the present disclosure has been described based on various drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of the present disclosure. For example, the functions included in each functional unit can be rearranged so as not to cause logical inconsistencies. Multiple functional units may be combined into one or divided. The above-described embodiments of the present disclosure are not limited to faithful implementation of each of the described embodiments, but may be implemented by combining features or omitting some features as appropriate. In other words, those skilled in the art can make various modifications and alterations to the contents of the present disclosure based on the present disclosure. Therefore, these modifications and alterations are within the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, or each step can be added to other embodiments so as not to cause logical inconsistencies, or can be replaced with each functional unit, each means, or each step of other embodiments. Furthermore, in each embodiment, multiple functional units, each means, or each step can be combined into one or divided. Furthermore, each of the above-described embodiments of the present disclosure is not limited to being implemented faithfully according to each of the described embodiments, but can also be implemented by combining each feature or omitting some of them as appropriate.

[0060] For example, in the above-described embodiment, the control unit 15 is described as detecting a speech section from external stereo sound data. However, the control unit 15 may convert the external stereo sound data into monaural sound data and detect a speech section from the converted monaural sound data.

[0061] For example, in the above-described embodiment, the control unit 15 is described as dividing the external sound data into multiple sound parts by detecting speech segments from the external sound. However, as long as the external sound data can be divided into multiple sound parts based on the meaning of the speech content included in the external sound, the control unit 15 may divide the external sound data into multiple sound parts by any process or method. As another example, the control unit 15 may divide the external sound data into multiple sound parts by dividing the external sound at positions where the sound becomes louder than a predetermined value or where the sound becomes higher than a predetermined pitch. The volume or pitch of a human sound (voice) generally increases or decreases where the speech content changes. Therefore, by dividing the external sound data at positions where the sound becomes louder than a predetermined value or where the sound becomes higher than a predetermined pitch, the external sound data can be divided into sound parts where the speech content changes. As yet another example, the control unit 15 may divide the external sound data into multiple sound parts at the positions where the speech content changes by using natural language processing such as sound recognition processing or morphological analysis. When the external sound includes many nouns or verbs, the external sound data is divided into data of multiple sound parts for each noun or verb, allowing the user to listen back to the sound parts for each noun or verb. As another example, the control unit 15 may estimate a scene from the external sound. The control unit 15 may divide the external sound data into data of different sound parts for each different scene. By dividing the external sound data into data of different external sound for each different scene, the user can listen back to the sound parts for each scene. For example, the user can listen back to sound parts for a greeting scene, a scene about recent topics, a business negotiation scene, etc.

[0062] In the above-described embodiment, the sound output device 1 has been described as dividing data of an external sound into a plurality of sound parts. However, the sound output device 1 may also divide data of any sound other than an external sound into a plurality of sound parts. That is, in the sound output device 1, the control unit 15 may divide data of any sound other than an external sound into a plurality of sound parts, and upon receiving a first operation, play an Nth sound part among the plurality of sound parts, and after playing the Nth sound part, play an N+1th sound part that precedes the Nth sound part.

[0063] For example, in the above-described embodiment, the control unit 15 is described as dividing external sound data into multiple sound portions. However, the control unit 15 does not have to divide the external sound data. When the external sound data is not divided, for example, when an utterance section is defined as a sound portion, the control unit 15 may store the delimitation positions of the utterance section in the storage unit 14. In this case, upon receiving the first operation, the control unit 15 may play the sound portion data based on the delimitation positions of the utterance section stored in the storage unit 14. That is, in the sound output device 1 according to the present embodiment, upon receiving the first operation, the control unit 15 may play the Nth sound portion (N is an integer satisfying 1≦N) of the multiple sound portions included in the sound data, and after playing the Nth sound portion, play the N+1th sound portion that precedes the Nth sound portion.

[0064] For example, in the above-described embodiment, the control unit 15 is described as reproducing sound portions going back in time from the first sound portion when receiving a first operation from the input unit 12. However, when receiving a predetermined operation from the input unit 12, the control unit 15 may reproduce the N-1th sound portion, which is immediately before the Nth sound portion, after reproducing the Nth sound portion.

[0065] In one embodiment, (1) the sound output device includes a control unit that divides sound data into data of a plurality of sound parts, and when a first operation is received, plays a first sound part of the plurality of sound parts, and after playing the first sound part, plays a second sound part that precedes the first sound part.

[0066] (2) In the sound output device described in (1) above, the data of the plurality of sound parts may be stored in a ring buffer, and the first sound part may be the newest sound part among the plurality of sound parts stored in the ring buffer at the time when the first operation is received.

[0067] (3) In the sound output device described in (1) or (2) above, the control unit may play a sound effect before playing the first sound portion.

[0068] (4) In the sound output device described in any one of (1) to (3) above, the control unit may play an Nth sound portion (N is an integer satisfying 1≦N), and after playing the Nth sound portion, play an N+1th sound portion that is earlier than the Nth sound portion.

[0069] (5) In the sound output device described in (4) above, the control unit may play back the Nth sound portion, then play back a sound effect, and then play back the N+1th sound portion.

[0070] (6) In the sound output device described in (4) or (5) above, the control unit may play the Nth sound portion after a predetermined time has elapsed since the Nth sound portion was played back, and then play the N+1th sound portion.

[0071] (7) In the sound output device according to any one of (4) to (6), the control unit may reduce the playback speed of the Nth sound portion and the N+1th sound portion to a predetermined speed.

[0072] (8) In the sound output device described in any one of (4) to (7) above, when a second operation is received during playback of the N+1 sound part or at the time when playback of the N+1 sound part has ended, the control unit may continuously play the N+1 sound part to the first sound part (N=1).

[0073] (9) In the sound output device described in any one of (1) to (8) above, the control unit may divide the sound data into data of a plurality of sound parts based on the meaning of the speech content contained in the sound.

[0074] (10) In the sound output device described in (9) above, the control unit may divide the sound data into the data of the plurality of sound parts by detecting a speech section from the sound.

[0075] (11) In the sound output device described in any one of (4) to (10) above, the control unit may, when the Nth sound portion includes a particle, not reproduce the sound of the particle included in the Nth sound portion, and when the N+1th sound portion includes a particle, not reproduce the sound of the particle included in the N+1th sound portion.

[0076] In one embodiment, (12) a sound output method includes: dividing sound data into data of a plurality of sound parts; and, upon receiving a first operation, playing a first sound part of the plurality of sound parts, and, after playing the first sound part, playing a second sound part that precedes the first sound part.

[0077] In one embodiment, (13) the sound output device includes a control unit that, upon receiving a first operation, plays an Nth sound part (N is an integer satisfying 1≦N) from among a plurality of sound parts included in the sound data, and, after playing the Nth sound part, plays an N+1th sound part that precedes the Nth sound part.

[0078] In this disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In the configurations distinguished by descriptions such as "first" and "second" in this disclosure, the numbers in the configurations can be exchanged. For example, the first sound portion can exchange the identifiers "first" and "second" with the second sound portion. The exchange of identifiers is performed simultaneously. The configurations remain distinguished even after the identifier exchange. The identifiers may be deleted. A configuration from which the identifiers have been deleted is distinguished by a symbol. The descriptions of identifiers such as "first" and "second" in this disclosure should not be used solely to interpret the order of the configurations or to justify the existence of identifiers with smaller numbers.

[0079] REFERENCE SIGNS LIST 1 Sound output device 1F Fixed member 1L, 1R Housing 2, 3 External sound 2a, 2b, 2c, 2d, 2e, 3a, 3b, 3c, 3d Sound part 10 Speaker unit 11 Microphone unit 12 Input unit 13 Ring buffer 14 Storage unit 15 Control unit

Claims

1. A sound output device comprising a control unit that divides sound data into multiple sound part data, and when a first operation is received, plays a first sound part of the multiple sound parts, and after playing the first sound part, plays a second sound part that is earlier than the first sound part.

2. The sound output device according to claim 1, wherein data of the multiple sound parts is stored in a ring buffer, and the first sound part is the newest sound part among the multiple sound parts stored in the ring buffer at the time when the first operation is received.

3. The sound output device according to claim 1 or 2, wherein the control unit reproduces a sound effect before reproducing the first sound portion.

4. A sound output device as described in any one of claims 1 to 3, wherein the control unit plays an Nth sound portion (N is an integer satisfying 1≦N) and, after playing the Nth sound portion, plays an N+1th sound portion that is earlier than the Nth sound portion.

5. The sound output device according to claim 4, wherein the control unit plays back the Nth sound portion, then plays a sound effect, and then plays back the N+1th sound portion.

6. The sound output device according to claim 4 or 5, wherein the control unit plays back the Nth sound portion after a predetermined time has elapsed since the Nth sound portion was played back, and then plays back the N+1th sound portion.

7. The sound output device according to claim 4, wherein the control unit reduces the playback speed of the Nth sound portion and the N+1th sound portion to a predetermined speed.

8. A sound output device as described in any one of claims 4 to 7, wherein when the control unit accepts a second operation during playback of the N+1 sound portion or at the point when playback of the N+1 sound portion has ended, the control unit continuously plays the N+1 sound portion through the first sound portion (N=1).

9. A sound output device according to any one of claims 1 to 8, wherein the control unit divides the sound data into data of a plurality of sound parts based on the meaning of the speech content contained in the sound.

10. The sound output device according to claim 9, wherein the control unit divides the sound data into data of the plurality of sound parts by detecting speech segments from the sound.

11. A sound output device as described in claim 4 or any one of claims 5 to 10 dependent on claim 4, wherein the control unit, when a particle is included in the N sound portion, does not play the sound of the particle included in the N sound portion, and when a particle is included in the N+1 sound portion, does not play the sound of the particle included in the N+1 sound portion.

12. A sound output method comprising: dividing sound data into a plurality of sound portion data; and, when a first operation is accepted, playing a first sound portion among the plurality of sound portions, and, after playing the first sound portion, playing a second sound portion that precedes the first sound portion.

13. A sound output device having a control unit that, when a first operation is received, plays an Nth sound part (N is an integer satisfying 1≦N) out of multiple sound parts included in sound data, and, after playing the Nth sound part, plays an N+1th sound part that is earlier than the Nth sound part.

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