JP2010016483A - Sound signal correction apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct music data corresponding to hearing ability characteristics of an individual by simple processing. <P>SOLUTION: A measuring part 16 measures the frequency characteristics of the hearing ability of a user formed at a plurality of frequency points. A level shift part 18 level-shifts the frequency characteristic value of the hearing ability for a fixed amount in a prescribed band so that the measured frequency characteristic value of the hearing ability and an ideal frequency characteristic value get close at at least one frequency point in ideal frequency characteristics. A derivation part 20 derives a difference value between the level-shifted frequency characteristic value of the hearing ability and the ideal frequency characteristic value at each frequency point, then weighting the difference value at each frequency point by a weighting coefficient for each frequency point, and thus derives a correction coefficient for each frequency point. A filter part 22 corrects sound signals on the basis of the correction coefficient and a level shift amount when level-shifting the frequency characteristic value of the heating ability. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an audio signal correction technique, and more particularly to an audio signal correction apparatus that corrects an audio signal in accordance with the hearing ability of a user.

Conventionally, in a stereo or surround device, correction of a sound field such as gain, frequency characteristics, etc. has been made uniformly or according to the preference of the viewer. Further, the execution of correction takes time and the procedure is complicated (see, for example, Patent Document 1).
JP 2002-281599 A

  In recent years, portable digital audio players (hereinafter referred to as “playback apparatuses”) have become widespread, and the playback apparatuses play back data compressed by MP3 or the like. In such a reproducing apparatus, the reproduced music data may be difficult to hear due to background noise in the room or the surrounding environment. In addition, the way of hearing varies depending on individual differences such as the age of the user. Therefore, a function for correcting audio data is also required in the playback apparatus. On the other hand, since the playback device has few buttons and the like, improvement in operability for the user is required. Also, considering the processing capability of the playback device, it is required to simplify the processing when performing correction.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique that realizes correction of music data in accordance with individual hearing characteristics by simple processing.

  In order to solve the above problems, an audio signal correction apparatus according to an aspect of the present invention includes a measurement unit that measures frequency characteristics of a user's hearing formed at a plurality of frequency points over a predetermined band, and a measurement unit that performs measurement. The hearing ability is such that the measured frequency characteristic value of the hearing and the ideal frequency characteristic value are close to each other at at least one frequency point in the ideal frequency characteristic that is preset as an ideal hearing characteristic with respect to the frequency characteristic of the hearing ability. After deriving at each frequency point a difference value between the level shift unit that shifts the frequency characteristic value of the frequency level by a certain amount in a predetermined band, the frequency characteristic value of the hearing level shifted in the level shift unit, and the ideal frequency characteristic value, By weighting the difference value at each frequency point by the weighting factor for each frequency point Based on the derivation unit for deriving the correction coefficient for each frequency point, the correction coefficient for each frequency point derived in the derivation unit, and the level shift amount when level shifting the frequency characteristic value of hearing in the level shift unit, A correction unit that corrects the audio signal. The measurement unit measures the frequency characteristic of hearing in a sound pressure region having a level larger than the ideal frequency characteristic value, and the weighting factor for each frequency point in the derivation unit is specified to increase as the frequency increases. .

  According to this aspect, when the amplification factor is derived based on the difference between the ideal level and the measured hearing level, the hearing level is measured in a region worse than the ideal level, so that the measured hearing level is attenuated. Correction of music data according to individual hearing characteristics can be realized with a simple operation.

  Another aspect of the present invention is also an audio signal correction apparatus. This device has a measurement unit that measures frequency characteristics of a user's hearing formed at a plurality of frequency points over a predetermined band, and an ideal hearing characteristic for the frequency characteristics of the hearing that is measured in the measurement unit in advance. Level shift that shifts the frequency characteristic value of the hearing a certain amount in a predetermined band so that the measured frequency characteristic value of the hearing ability approaches the ideal frequency characteristic value at at least one frequency point in the set ideal frequency characteristic. And the difference between the frequency characteristic value of the hearing level shifted by the level shift unit and the ideal frequency characteristic value is derived at each frequency point, and the difference value at each frequency point is weighted by the weighting coefficient for each frequency point. To derive the correction coefficient for each frequency point A correction coefficient for each frequency point derived in the derivation unit, based on the level shift amount when shifting a level of the frequency characteristic values of the hearing in the level shift unit, and a correcting unit for correcting the audio signal. The derivation unit stores a plurality of types of weighting factors, and selects one of the plurality of types of weighting factors based on the type of audio signal to be corrected by the correction unit.

  According to this aspect, a plurality of types of weighting factors to be used when generating correction coefficients are stored, and one weighting factor is selected according to the type of audio signal to be corrected, which is suitable for the type of audio signal. A correction factor can be generated.

  Yet another embodiment of the present invention is also an audio signal correction apparatus. This device has a measurement unit that measures frequency characteristics of a user's hearing formed at a plurality of frequency points over a predetermined band, and an ideal hearing characteristic for the frequency characteristics of the hearing that is measured in the measurement unit in advance. Level shift that shifts the frequency characteristic value of the hearing a certain amount in a predetermined band so that the measured frequency characteristic value of the hearing ability approaches the ideal frequency characteristic value at at least one frequency point in the set ideal frequency characteristic. And the difference between the frequency characteristic value of the hearing level shifted by the level shift unit and the ideal frequency characteristic value is derived at each frequency point, and the difference value at each frequency point is weighted by the weighting coefficient for each frequency point. To derive the correction coefficient for each frequency point A correction coefficient for each frequency point derived in the derivation unit, based on the level shift amount when shifting a level of the frequency characteristic values of the hearing in the level shift unit, and a correcting unit for correcting the audio signal. The deriving unit derives a weighting coefficient for each frequency point based on the audio signal to be corrected by the correcting unit.

  According to this aspect, since the weighting coefficient is generated based on the audio signal to be corrected and the correction coefficient is derived based on the generated weighting coefficient, a correction coefficient suitable for the audio signal can be generated.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to realize correction of music data in accordance with individual hearing characteristics by a simple process.

Example 1
Before describing the present invention specifically, an outline will be given first. The first embodiment of the present invention relates to a playback apparatus for playing back music data, like the above portable player. Here, the reproducing apparatus does not reproduce the stored music data as it is, but reproduces it after correcting it according to the user's preference. Considering the environment such as a portable player in which operability is limited and the processing capability, it is desirable that the operation for correcting the music data is simple. In order to cope with this, the reproducing apparatus according to the first embodiment executes the following processing. The playback device corrects the music data using a filter such as an equalizer. Prior to the correction, the playback device examines the user's hearing characteristics and determines the coefficient of the filter according to the examination result (hereinafter referred to as “testing process”). ).

  In such an inspection process, the playback apparatus sequentially plays back tone signals corresponding to a plurality of frequency values (hereinafter referred to as “frequency points”). At that time, the playback device plays back each tone signal so that the volume increases with time. The user depresses a button provided in the playback device at the timing when the played tone signal is heard. By repeating such processing for a plurality of tone signals, the playback apparatus acquires frequency characteristics of the hearing level over a plurality of frequency points (hereinafter referred to as “hearing characteristic data”). Further, the reproduction apparatus stores in advance a frequency characteristic (hereinafter referred to as “ideal characteristic data”) of an ideal hearing level (hereinafter referred to as “ideal level”) as an ideal hearing characteristic with respect to the hearing characteristic data.

  The playback device shifts the level of the audio characteristic data in the overall attenuation direction so that the audio characteristic data and the ideal characteristic data approach at least one frequency point (the value at that time is referred to as “level shift amount”). ). Further, the playback device determines a difference value at each frequency point for the level-shifted hearing characteristic data and ideal characteristic data. Further, the playback device stores a weighting coefficient for each frequency point based on the frequency characteristics of the music data, and derives a correction value for each frequency point based on the weighting coefficient and the difference value. Finally, the reproducing apparatus sets the correction value in the filter and sets the level shift amount in the amplifier.

  Here, a test is performed so that the hearing characteristic data is acquired in a sound pressure region having a level larger than that of the ideal characteristic data. Specifically, even if the user can hear when the tone signal is at the minimum volume, the hearing level is higher than the ideal level. As a result, the level shift amount is a positive value, that is, a value that attenuates at the time of level shift, and a value that amplifies when set in the amplifier, and combinations other than these are excluded. It becomes simple. In addition, for the user, the operation is simplified because the button is simply depressed at the timing when the tone signal is heard.

  FIG. 1 shows the configuration of a playback apparatus 100 according to Embodiment 1 of the present invention. The reproduction apparatus 100 includes a reception unit 10, a control unit 12, a storage unit 14, an inspection unit 32, a filter unit 22, a reproduction unit 24, a SW unit 26, a DAC unit 28, an output unit 30, and a display unit 34. The inspection unit 32 includes a measurement unit 16, a level shift unit 18, and a derivation unit 20, and the storage unit 14 includes inspection data 50, music data 52, ideal characteristic data 54, and a weight coefficient 56.

  The receiving unit 10 receives an instruction from the user and outputs the received instruction to the control unit 12. For example, the reception unit 10 is configured to include a button, and receives various instructions from the user by detecting that the button is pressed down by the user. The various instructions are, for example, (1) an instruction to start the inspection process, (2) a notification that the tone signal has been heard in the inspection process, and (3) an instruction to select music data to be reproduced and to reproduce the selected music data. is there. The control unit 12 controls the operation of the entire playback device 100. When the control unit 12 receives an instruction from the reception unit 10, the control unit 12 instructs the operations of the SW unit 26, the measurement unit 16, and the reproduction unit 24 according to the content of the instruction. Note that the contents of specific instructions will be described in the components. Further, the control unit 12 controls display on the display unit 34 in accordance with the contents of the received instruction. Hereinafter, after describing the operation of the inspection process, the operation of the process of reproducing music data (hereinafter referred to as “reproduction process”) will be described.

  The measurement unit 16 inputs an inspection process start instruction from the control unit 12. When the measurement unit 16 inputs an instruction to start the inspection process, the measurement unit 16 starts the inspection process. That is, the measurement unit 16 measures the frequency characteristics of the user's hearing level formed at a plurality of frequency points and the above-described hearing characteristic data. The storage unit 14 stores a plurality of types of digitized data. Specifically, test data 50, music data 52, ideal characteristic data 54, and weighting coefficient 56 are stored. The description of these data will be described together with the process in which the data is used. The inspection data 50 is formed by a plurality of tone signals, and each tone signal corresponds to each of a plurality of frequency points. Here, eight tone signals corresponding to each of the eight frequency points correspond to the inspection data 50.

  The measurement unit 16 acquires the inspection data 50 from the storage unit 14. The measurement unit 16 selects one of the plurality of tone signals, for example, the tone signal having the lowest frequency. The measurement unit 16 reproduces the selected tone signal. At that time, reproduction is performed so that the volume gradually increases. The measurement unit 16 outputs the reproduced tone signal to the SW unit 26. The SW unit 26 connects the measurement unit 16 and the DAC unit 28 when an instruction for an inspection process is input from the control unit 12. That is, the SW unit 26 outputs the tone signal input from the measurement unit 16 to the DAC unit 28. The DAC unit 28 receives a digital signal, converts the digital signal into an analog signal, and then outputs the analog signal to the output unit 30. In the inspection process, the DAC unit 28 inputs a tone signal as a digital signal and outputs a tone signal as an analog signal (hereinafter also referred to as “tone signal”) to the output unit 30.

  The output unit 30 is formed by a headphone or a speaker, and receives and outputs an analog signal from the DAC unit 28. In the inspection process, the output unit 30 outputs a tone signal. The display unit 34 is formed by a display or the like and displays various types of information. The display unit 34 inputs data related to display contents from the control unit 12. Here, display contents in the inspection process will be described. FIG. 2 shows a screen displayed on the display unit 34. A playback level bar 120 is displayed at the center of the screen. The left side of the playback level bar 120 corresponds to a state where the volume of the tone signal output from the output unit 30 is low, and the right side of the playback level bar 120 corresponds to a state where the volume of the tone signal output from the output unit 30 is high. To do.

  The current level pointer 122 corresponds to the current volume. As described above, since the volume of the tone signal output from the output unit 30 gradually increases, the current level pointer 122 is displayed so as to move from the left side to the right side of the playback level bar 120. The decision button 124 and the cancel button 126 are buttons for instructing “decision” and “cancel”. More specifically, when a user who is listening to a tone signal output from the output unit 30 hears a tone signal, the user moves the cursor to the decision button 124 and presses the button of the receiving unit 10. As a result, the control unit 12 recognizes that the user can hear the tone signal. Returning to FIG. The control unit 12 notifies the measurement unit 16 of the recognized timing (hereinafter referred to as “recognition timing”).

  The measurement unit 16 inputs the recognition timing from the control unit 12. The measurement unit 16 stores the relationship between the volume and timing when the tone signal is reproduced, and specifies the volume corresponding to the recognition timing based on the recognition timing from the control unit 12. The specified volume corresponds to the hearing level for one tone signal. This corresponds to the hearing level for one frequency point. When the hearing level is acquired, the measurement unit 16 changes the frequency point and performs the same process. Finally, the measurement unit 16 acquires hearing characteristic data.

  FIG. 3 shows a measurement result in the measurement unit 16. The horizontal axis corresponds to the frequency, and the vertical axis corresponds to the volume level output from the output unit 30. Each frequency point is shown as “f1” to “f8”. Also, the hearing level for each frequency point is shown as “A1” to “A8”. The hearing characteristic data corresponds to a combination of “A1” to “A8”, but may be a line connecting “A1” to “A8”. The audible area 200 is a part where the volume level is higher than the hearing characteristic data, and the inaudible area 202 is a part where the volume level is lower than the hearing characteristic data. In the audible area 200, the user can hear the tone signal, and in the inaudible area 202, the user cannot hear the tone signal. Returning to FIG.

  The ideal characteristic data 54 stored in the storage unit 14 is shown in FIG. 4 corresponding to FIG. FIG. 4 shows ideal characteristic data 54 stored in the storage unit 14. The horizontal and vertical axes in FIG. 4 are shown in the same manner as in FIG. The ideal level for each frequency point is shown as “B1” to “B8”. The ideal characteristic data 54 corresponds to a combination of “B1” to “B8”, but may be a line connecting “B1” to “B8”. The ideal characteristic data 54 can be said to be a minimum audible curve based on a frequency characteristic set in advance as an ideal minimum audible frequency characteristic in hearing.

  The level shift unit 18 inputs the hearing characteristic data from the measurement unit 16 and the ideal characteristic data 54 from the storage unit 14. The level shift unit 18 compares at least one hearing characteristic data with the ideal characteristic data 54 to identify at least one frequency point, for example, a frequency point having the smallest difference between the hearing level and the ideal level. The level shift unit 18 shifts the hearing characteristic data in the attenuation direction in all bands so that the hearing level and the ideal level match at the specified frequency point. The shift amount at this time corresponds to the “level shift amount”, and the above processing corresponds to attenuating the hearing characteristic data by the “level shift amount”.

  FIGS. 5A and 5B show an outline of processing in the level shift unit 18. FIG. 5A shows a state before the level shift in the level shift unit 18 and corresponds to a state in which FIGS. 3 and 4 are overlapped. FIG. 5B corresponds to a state where the hearing characteristic data is amplified. Also, the hearing levels “A1” to “A8” are indicated as “A1 ′” to “A8 ′”. Returning to FIG. Here, the volume level in the ideal characteristic data 54 in FIG. 4 is smaller than the volume level in the hearing characteristic data in FIG. That is, attenuation is performed by the level shift amount in the level shift unit 18, and amplification is not performed. This corresponds to the hearing characteristic data being measured in the region where the volume level is higher than the ideal characteristic data 54 in the measurement unit 16. Specifically, when the user presses the button when the volume level from the output unit 30 is the lowest and the control unit 12 recognizes the audible timing, the hearing level is higher than the ideal level in FIG. The tone signal is reproduced so that the signal becomes higher. Hereinafter, the level-shifted hearing characteristic data is also referred to as “hearing characteristic data”.

  The deriving unit 20 derives a difference value between the hearing characteristic data and the ideal characteristic data 54 at each frequency point. That is, the difference value between the hearing level “Ai ′ (i = 1 to 8)” and the ideal level “Bi (i = 1 to 8)” at each frequency point is calculated. Further, the weighting factor 56 of the storage unit 14 is determined so as to correspond to each frequency point. Hereinafter, a plurality of weighting factors 56 over a plurality of frequency points and one weighting factor 56 are referred to as “weighting factors 56” without distinction. The deriving unit 20 inputs the weighting coefficient 56 from the storage unit 14. The deriving unit 20 derives a correction value by multiplying the difference value and the weighting coefficient 56 while associating the frequency points. This is equivalent to deriving a correction value for each frequency point by weighting the difference value at each frequency point with a weighting factor 56 for each frequency point. Hereinafter, a plurality of correction values over a plurality of frequency points and one correction value are not distinguished from each other and are referred to as “correction values”.

  FIG. 6 shows an outline of processing in the derivation unit 20. FIG. 6 is shown in the same manner as FIG. At each frequency point, the difference value “D1” is derived from “D8”. A music waveform 204 is also shown. The music waveform 204 is a frequency characteristic for predetermined music data. In general, since the frequency characteristics of music data differ depending on the type of music data, the music waveform 204 corresponds to a frequency characteristic obtained by averaging the frequency characteristics of a plurality of types of music data. In addition, the reciprocal of the value corresponding to each frequency point of the music waveform 204 corresponds to the weighting factor 56 described above. When the weighting coefficient 56 is indicated by “E1” to “E8”, the value corresponding to each frequency point of the music waveform 204 is indicated by “1 / E1” to “1 / E8”. As described above, the weighting factor 56 is defined to increase as the frequency increases. Returning to FIG.

  Next, the reproduction process will be described. The control unit 12 causes the display unit 34 to display a list of music data 52 stored in the storage unit 14. In addition, the control unit 12 inputs an instruction to select and play music data 52 (hereinafter collectively referred to as “playback instructions”) via the receiving unit 10. The reproduction unit 24 acquires the music data 52 from the storage unit 14 and reproduces it according to the reproduction instruction. The music data 52 is digitized music data, and a known technique may be used for reproduction of the music data 52, so that the description thereof is omitted here. The storage unit 14 may store a plurality of music data 52, but for the sake of clarity, only one music data 52 is shown here. Hereinafter, the reproduced music data 52 is also referred to as “music data 52”.

  The filter unit 22 receives the level shift amount from the level shift unit 18 and the correction value from the derivation unit 20. The filter unit 22 includes, for example, a plurality of IIR (Infinite Impulse Response) filters corresponding to each frequency point, and sets a correction value as a coefficient of each IIR filter. Furthermore, the filter unit 22 includes an amplifier at the subsequent stage of the IIR filter, and sets the level shift amount as the amplification factor of the amplifier. Note that a FIR (Finite Impulse Response) filter may be provided instead of the IIR filter, and at this time, a response characteristic to the correction value is set as a tap coefficient. The filter unit 22 receives the music data 52 and corrects the music data 52 using an IIR filter and an amplifier. In particular, the amplifier performs amplification by the level shift amount by the amount that the hearing characteristic data is attenuated in the level shift unit 18. Hereinafter, the corrected music data 52 is also referred to as “music data 52”. The filter unit 22 outputs the music data 52 to the SW unit 26.

  When the reproduction unit instruction is input from the control unit 12, the SW unit 26 connects the filter unit 22 and the DAC unit 28. That is, the SW unit 26 outputs the music data 52 input from the filter unit 22 to the DAC unit 28. In the reproduction process, the DAC unit 28 receives the music data 52 as a digital signal and outputs the music data 52 (hereinafter also referred to as “music data 52”) as an analog signal to the output unit 30. The output unit 30 outputs music data.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  The operation of the playback apparatus 100 configured as above will be described. FIG. 7 is a flowchart showing the procedure of correction processing in the playback apparatus 100. The level shift unit 18 substitutes 1 for the variable “i” (S10). Here, i corresponds to a frequency point. If i is smaller than 9 (Y in S12), the level shifter 18 derives the difference C [i] by subtracting the ideal level [i] from the hearing level A [i] (S14). Further, the level shifter 18 adds 1 to i (S16), and returns to Step 12. On the other hand, if i is not smaller than 9 (N in S12), the level shifter 18 substitutes 1 for i again (S18), and substitutes C [i], that is, C [1] for Cmin (S20). ).

  If i is smaller than 8 (Y in S22) and C [i + 1] is not larger than Cmin (N in S24), the level shifter 18 substitutes C [i + 1] for Cmin (S26). If C [i + 1] is larger than Cmin (Y in S24), step 26 is skipped. Further, the level shifter 18 adds 1 to i (S28), and returns to step 22. On the other hand, if i is not smaller than 8 (N in S22), the level shifter 18 stores Cmin (S30). Here, Cmin corresponds to the level shift amount described above.

  The deriving unit 20 substitutes 1 for i (S32). If i is smaller than 9 (Y in S34), the deriving unit 20 derives the above-described difference value D [i] by subtracting Cmin from C [i] (S36). In addition, the deriving unit 20 adds 1 to i (S38), and returns to Step 34. If i is not smaller than 9 (N in S34), the derivation unit 20 substitutes 1 for i again (S40). If i is smaller than 9 (Y in S42), the derivation unit 20 derives a correction value EQ [i] by multiplying D [i] and the weighting coefficient E [i] (S44). Further, the deriving unit 20 adds 1 to i (S46), and returns to Step 42. If i is not smaller than 9 (N in S42), the derivation unit 20 stores the correction value EQ [i] (S48).

  According to the embodiment of the present invention, since the user is requested to press the button when a tone signal is heard, the processing of the user can be simplified. Further, even with simple processing, it is possible to acquire hearing characteristic data. In addition, when the level shift amount is derived based on the difference between the ideal characteristic data and the audio characteristic data, the audio characteristic data is measured in a region where the volume level is larger than the ideal characteristic data, so that the audio characteristic data is attenuated. Only such a level shift amount can be derived. Further, since only the level shift amount that attenuates the hearing characteristic data is derived, it is possible to avoid derivation of the level shift amount that attenuates the signal. Further, since the level shift amount that attenuates the hearing characteristic data is derived, it is possible to set the level shift amount to be amplified in the amplifier. Moreover, since the level shift amount that is amplified by the amplifier is set, it is possible to suppress the deterioration of the sound quality. In addition, since only the level shift amount that is first attenuated and finally amplified is derived, it is not necessary to consider the opposite case, and the processing can be simplified.

(Example 2)
As in the first embodiment, the second embodiment of the present invention relates to a playback apparatus that derives a correction value and a level shift amount by examining a user's hearing and corrects music data based on the correction value and the level shift amount. In the first embodiment, one type of weighting factor is used to derive a correction value. On the other hand, the playback apparatus according to the second embodiment stores a plurality of types of weighting factors. For example, a plurality of types of weighting factors correspond to a plurality of types of music genres. When receiving a music data playback instruction, the playback device specifies the genre of the music data from information associated with the music data, and specifies a weighting factor corresponding to the specified genre. Also, the playback device derives a correction value using the identified weighting coefficient, and uses the correction value when playing back the music data.

  FIG. 8 shows the configuration of the playback apparatus 100 according to the second embodiment of the present invention. 8 is of the same type as the playback device 100 of FIG. 1, but the inspection unit 32 includes a measurement unit 16, a level shift unit 18, a derivation unit 20, and a selection unit 36, and the storage unit 14 includes , Inspection data 50, music data 52, ideal characteristic data 54, a first weighting factor 56a, a second weighting factor 56b, and an Nth weighting factor 56n. Below, it demonstrates focusing on the difference with Example 1. FIG.

  The measurement unit 16 and the level shift unit 18 derive the level shift amount in the inspection process, as in the first embodiment. Further, the derivation unit 20 derives a difference value in the inspection process as in the first embodiment. However, the deriving unit 20 does not derive a correction value in the inspection process. In the reproduction process, the control unit 12 inputs a reproduction instruction as described above. The control unit 12 outputs a reproduction instruction to the selection unit 36. Upon receiving the reproduction instruction, the selection unit 36 specifies the music data 52 to be reproduced. Here, the music data 52 stored in the storage unit 14 includes accompanying information. The accompanying information includes information regarding the music data 52. The information related to the music data 52 is, for example, information related to the data format, playback time, and type of the music data 52. Here, the information regarding the type is information regarding the genre of the music data 52.

  The selection unit 36 specifies the genre of the music data 52 while confirming accompanying information included in the specified music data 52. On the other hand, the storage unit 14 stores a first weighting coefficient 56 a to an Nth weighting coefficient 56 n as a plurality of weighting coefficients 56. Each of the plurality of weighting factors 56 is generated in advance so as to correspond to music data 52 of different genres. The selection unit 36 selects the weighting coefficient 56 corresponding to the specified genre. That is, the selection unit 36 selects one of a plurality of types of weighting factors 56 based on the type of music data 52 to be reproduced. The selection unit 36 outputs the selected weight coefficient 56 to the derivation unit 20. The deriving unit 20 derives a correction value using the weighting coefficient 56 selected by the selecting unit 36 as in the first embodiment. Further, the subsequent processing is the same as that in the first embodiment, and thus the description thereof is omitted here.

  The operation of the playback apparatus 100 configured as above will be described. FIG. 9 is a flowchart showing a selection procedure in the selection unit 36. The selection unit 36 receives an instruction to select music data 52 to be reproduced (S60). If there is information about the type of the music data 52 (Y in S62), the selection unit 36 selects the weighting coefficient 56 corresponding to the type (S64). On the other hand, if there is no information regarding the type of the music data 52 (N in S62), the selection unit 36 selects a predetermined weighting factor 56 (S66).

  According to the embodiment of the present invention, a plurality of types of weighting factors are stored, and one weighting factor is selected according to the genre of music data to be reproduced. Therefore, a weighting factor suitable for the genre of music data can be used. . In addition, since a weighting coefficient suitable for the genre of music data is used, a correction value suitable for the genre of music data can be generated. Moreover, since the correction value suitable for the genre of the music data is used, the correction suitable for the music data can be executed. In addition, since the weighting factor is automatically selected, the processing complexity can be suppressed.

(Example 3)
As in the first embodiment, the third embodiment of the present invention relates to a playback device that derives a correction value and a level shift amount by examining a user's hearing and corrects music data based on the correction value and the level shift amount. The playback device according to the first or second embodiment stores a weighting coefficient. On the other hand, the playback apparatus according to the third embodiment generates a weighting coefficient based on music data to be played back without storing the weighting coefficient. Also, the playback device derives a correction value using the generated weighting coefficient, and uses the correction value when playing back the music data.

  FIG. 10 shows the configuration of a playback apparatus 100 according to the third embodiment of the present invention. The playback device 100 in FIG. 10 is the same type as the playback device 100 in FIG. 1, but the inspection unit 32 includes a measurement unit 16, a level shift unit 18, a derivation unit 20, and a generation unit 38. , Inspection data 50, first music data 52a, second music data 52b, Nth music data 52n, and ideal characteristic data 54.

  The measurement unit 16 and the level shift unit 18 derive the level shift amount in the inspection process, as in the first embodiment. Further, the derivation unit 20 derives a difference value in the inspection process as in the first embodiment. However, as in the second embodiment, the deriving unit 20 does not derive a correction value in the inspection process. In the reproduction process, the control unit 12 inputs a reproduction instruction as described above. The control unit 12 outputs a reproduction instruction to the generation unit 38. When receiving the reproduction instruction, the generation unit 38 specifies the music data 52 to be reproduced. Here, the storage unit 14 stores first music data 52 a to N-th music data 52 n as music data 52.

  The generation unit 38 extracts the specified music data 52 from the storage unit 14. The generating unit 38 derives the music waveform 204 described above by performing Fourier transform on the extracted music data 52. Further, the generation unit 38 extracts a value corresponding to a desired frequency point from the music waveform 204, and calculates a reciprocal number of the extracted value, thereby deriving the weighting coefficient 56. The generation unit 38 outputs the generated weight coefficient 56 to the derivation unit 20. The deriving unit 20 derives a correction value using the weighting coefficient 56 generated by the generating unit 38 as in the first embodiment. Further, the subsequent processing is the same as that in the first embodiment, and thus the description thereof is omitted here.

  The operation of the playback apparatus 100 configured as above will be described. FIG. 11 is a flowchart showing the procedure of the reproduction process in the reproduction apparatus 100. If the generation unit 38 does not accept the reproduction instruction (N in S80), the generation unit 38 stands by. On the other hand, if the generation unit 38 receives the reproduction instruction (Y in S80), the generation unit 38 generates the weighting coefficient 56 (S82). The deriving unit 20 derives a correction value (S84).

  According to the embodiment of the present invention, since the weighting factor is generated based on the audio signal to be reproduced, the weighting factor suitable for the music data can be used. In addition, since a weighting factor suitable for music data is used, a correction value suitable for music data can be generated. In addition, since a correction value suitable for music data is used, correction suitable for music data can be executed. In addition, since the weighting factor is automatically generated, the processing complexity can be suppressed.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the first to third embodiments of the present invention, the hearing characteristic data is measured in the measurement unit 16 in a region where the volume level is higher than the ideal characteristic data 54. However, the present invention is not limited to this, and for example, the volume level of the tone signal in the measurement unit 16 may be set to an arbitrary value, or a volume level that is lower than the ideal characteristic data 54 may be used. At that time, the level shift unit 18 and the derivation unit 20 exclude the hearing level whose volume level is lower than the ideal level from the correction target. According to the present modification, correction that attenuates the music data 52 is not performed, and deterioration in sound quality can be suppressed while improving the degree of freedom in setting the volume level of the tone signal.

  In the first to third embodiments of the present invention, the measurement unit 16 causes the display unit 34 to display a screen as shown in FIG. However, the present invention is not limited to this. For example, the display unit 34 may display another screen in the inspection process. FIG. 12 shows a screen displayed in the modification of the present invention. As shown, the first reproduction level bar 130a to the eighth reproduction level bar 130h, which are collectively referred to as the reproduction level bar 130, are displayed. Each reproduction level bar 130 corresponds to a tone signal corresponding to each of the eight frequency points described above. In the inspection process, the measurement unit 16 outputs a first tone signal corresponding to the lowest frequency point. The user adjusts the volume level of the first tone signal by moving the first current level pointer 132 on the first reproduction level bar 130a up and down. When the tone signal reaches a volume level at which the tone signal can be heard at the minimum, the user presses the next button 134. Next, the measurement unit 16 outputs a second tone signal whose frequency point is higher than that of the first tone signal. The user performs the same processing as described above by moving the second current level pointer 132b on the second playback level bar 130b up and down. By repeating such processing, the measurement unit 16 acquires hearing characteristic data corresponding to the eight frequency points. According to the present embodiment, since the user adjusts the sound volume level by himself, the sound volume level at which the tone signal can be heard is minimized.

It is a figure which shows the structure of the reproducing | regenerating apparatus which concerns on Example 1 of this invention. It is a figure which shows the screen displayed in the display part of FIG. It is a figure which shows the measurement result in the measurement part of FIG. It is a figure which shows the ideal characteristic data memorize | stored in the memory | storage part of FIG. FIGS. 5A to 5B are diagrams illustrating an outline of processing in the amplification unit of FIG. It is a figure which shows the process outline | summary in the derivation | leading-out part of FIG. 3 is a flowchart showing a procedure of correction processing in the playback apparatus of FIG. 1. It is a figure which shows the structure of the reproducing | regenerating apparatus based on Example 2 of this invention. It is a flowchart which shows the selection procedure in the selection part of FIG. It is a figure which shows the structure of the reproducing | regenerating apparatus based on Example 3 of this invention. FIG. 11 is a flowchart showing a procedure of reproduction processing in the reproduction apparatus of FIG. 10. FIG. It is a figure which shows the screen displayed in the modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Reception part, 12 Control part, 14 Storage part, 16 Measurement part, 18 Level shift part, 20 Derivation part, 22 Filter part, 24 Playback part, 26 SW part, 28 DAC part, 30 Output part, 32 Inspection part, 34 Display unit, 50 inspection data, 52 music data, 54 ideal characteristic data, 56 weighting factor, 100 playback device.

Claims (3)

A measurement unit that measures frequency characteristics of the user's hearing formed at a plurality of frequency points over a predetermined band;
The frequency characteristic value of the measured hearing and the ideal frequency characteristic value are close to each other at at least one frequency point in the ideal frequency characteristic preset as an ideal hearing characteristic with respect to the frequency characteristic of the hearing measured by the measurement unit. A level shift unit that shifts the frequency characteristic value of the hearing ability by a certain amount in the predetermined band;
After the difference value between the frequency characteristic value of the hearing level shifted in the level shift unit and the ideal frequency characteristic value is derived at each frequency point, the difference value at each frequency point is weighted by a weighting factor for each frequency point. A derivation unit for deriving a correction coefficient for each frequency point;
A correction unit that corrects an audio signal based on a correction coefficient for each frequency point derived in the deriving unit and a level shift amount when level-shifting the frequency characteristic value of hearing in the level shift unit;
The measurement unit measures a frequency characteristic of hearing in a sound pressure region having a level larger than the ideal frequency characteristic value,
The audio signal correction apparatus according to claim 1, wherein a weighting factor for each frequency point in the deriving unit is defined to increase as the frequency increases. A measurement unit that measures frequency characteristics of the user's hearing formed at a plurality of frequency points over a predetermined band;
The frequency characteristic value of the measured hearing and the ideal frequency characteristic value are close to each other at at least one frequency point in the ideal frequency characteristic preset as an ideal hearing characteristic with respect to the frequency characteristic of the hearing measured by the measurement unit. A level shift unit that shifts the frequency characteristic value of the hearing ability by a certain amount in the predetermined band;
After the difference value between the frequency characteristic value of the hearing level shifted in the level shift unit and the ideal frequency characteristic value is derived at each frequency point, the difference value at each frequency point is weighted by a weighting factor for each frequency point. A derivation unit for deriving a correction coefficient for each frequency point;
A correction unit that corrects an audio signal based on a correction coefficient for each frequency point derived in the deriving unit and a level shift amount when level-shifting the frequency characteristic value of hearing in the level shift unit;
The derivation unit stores a plurality of types of weighting coefficients, and selects one of the plurality of types of weighting factors based on the type of the audio signal to be corrected by the correction unit. Signal correction device. A measurement unit that measures frequency characteristics of the user's hearing formed at a plurality of frequency points over a predetermined band;
The frequency characteristic value of the measured hearing and the ideal frequency characteristic value are close to each other at at least one frequency point in the ideal frequency characteristic preset as an ideal hearing characteristic with respect to the frequency characteristic of the hearing measured by the measurement unit. A level shift unit that shifts the frequency characteristic value of the hearing ability by a certain amount in the predetermined band;
After the difference value between the frequency characteristic value of the hearing level shifted in the level shift unit and the ideal frequency characteristic value is derived at each frequency point, the difference value at each frequency point is weighted by a weighting factor for each frequency point. A derivation unit for deriving a correction coefficient for each frequency point;
A correction unit that corrects an audio signal based on a correction coefficient for each frequency point derived in the deriving unit and a level shift amount when level-shifting the frequency characteristic value of hearing in the level shift unit;
The derivation unit derives a weighting coefficient for each frequency point based on the audio signal to be corrected by the correction unit.

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