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EP-4060656-B1 - AUDIO SIGNAL PROCESSING METHOD, AUDIO SIGNAL PROCESSING APPARATUS AND AUDIO SIGNAL PROCESSING PROGRAM

EP4060656B1EP 4060656 B1EP4060656 B1EP 4060656B1EP-4060656-B1

Inventors

  • WATANABE, TAKAYUKI
  • HASHIMOTO, DAI
  • SHIDOJI, HIROOMI

Dates

Publication Date
20260506
Application Date
20220318

Claims (13)

  1. An audio signal processing method comprising: dividing, by an area setter (30), a reproduction space into a plurality of areas (Areal, ..., Area8); detecting, by a sound source position detector (41), a position, in the reproduction space, of a sound source (OBJ1) that generates an audio signal; determining, by an area determiner (42), inside which area of the plurality of areas (Area 1, ..., Area8) the detected position of the sound source (OBJ1) is located; generating, by an initial reflected sound control signal generator (50), an initial reflected sound control signal (ER1, ..., ER64) by convolving (i) an impulse response of an initial reflected sound linked to the determined area corresponding to the detected position of the sound source (OBJ1) to (ii) the audio signal of the sound source (OBJ1) without (iii) convolving an impulse response of an initial reflected sound linked to any of the plurality of areas (Area1...Area8) of the reproduction space other than the determined area of the reproduction space corresponding to the detected position of the sound source (OBJ1) to (ii) the audio signal of the sound source (OBJ1); and using the generated initial reflected sound control signal (ER1, ... ER64) to generate a signal to be output to a corresponding one of a plurality of speakers (SP1, ..., SP64) in order to simulate an initial reflected sound in a virtual space, in the reproduction space, characterized in that the audio signal processing method further comprises setting a representative point (RP1...RP8) in each of the plurality of areas (Area1...Area8) in the reproduction space, wherein determining the area in which the detected position of the sound source (OBJ1) is located comprises selecting the area having a shortest distance between the representative point of that area and the detected position of the sound source (OBJ1).
  2. The audio signal processing method according to claim 1, wherein the determined area of the reproduction space includes the position of the detected sound source (OBJ1).
  3. The audio signal processing method according to any one of claims 1 to 2, further comprising detecting movement of the position of the sound source (OBJ1) from a first determined area of the reproduction space to a second determined area of the reproduction space, among the plurality of areas (Area1...Area8) of the reproduction space, different from the first determined area.
  4. The audio signal processing method according to claim 3, further comprising performing, in a case in which the position of the sound source (OBJ1) has been moved from the first determined area of the reproduction space to the second determined area of the reproduction space, crossfade processing on the initial reflected sound control signal generated before the movement and an initial reflected sound control signal generated after the movement.
  5. The audio signal processing method according to any one of claims 1 to 4, further comprising generating a reverberant sound control signal by convolving an impulse response of a reverberant sound to the audio signal of the sound source.
  6. The audio signal processing method according to claim 5, further comprising generating a speaker control signal by adding the initial reflected sound control signal and the reverberant sound control signal.
  7. An audio signal processing apparatus comprising: an area setter (30) configured to divide a reproduction space into a plurality of areas (Area1, ..., Area8); a sound source position detector (41) configured to detect a position, in the reproduction space, of a sound source (OBJ1) configured to generate an audio signal; an area determiner (42) configured to determine inside which area of the plurality of areas (Area1, ..., Area8) the detected position of the sound source (OBJ1) is located; and an initial reflected sound control signal generator (50) configured to generate an initial reflected sound control signal (ER1, ..., ER64) by convolving (i) an impulse response of an initial reflected sound linked to the determined area corresponding to a detected position of the sound source (OBJ1) to (ii) the audio signal of the sound source without convolving (iii) an impulse response of an initial reflected sound linked to any of the plurality of areas (Area1...Area8) of the reproduction space other than the determined area of the reproduction space corresponding to the detected position of the sound source (OBJ1) to (ii) the audio signal of the sound source (OBJ1), wherein the audio signal processing apparatus is further configured to use the generated initial reflected sound control signal (ER1, ..., ER64) to generate a signal to be output to a corresponding one of a plurality of speakers ( SP1 , ...,SP64) in order to simulate an initial reflected sound in a virtual space, in the reproduction space, characterized in that the initial reflected sound control signal generator (50) is further configured to set a representative point (RP1...RP8) in each of the plurality of areas (Area1...Area8) in the reproduction space, and to determine the area in which the detected position of the sound source (OBJ1) is located by selecting the area having a shortest distance between the representative point of that area and the detected position of the sound source (OBJ1).
  8. The audio signal processing apparatus according to claim 7, wherein the determined area of the reproduction space includes the detected position of the sound source (OBJ1).
  9. The audio signal processing apparatus according to any one of claims 7 to 8, further comprising a sound source position detector (41) that is configured to detect a movement of the position of the sound source (OBJ1) from a first determined area of the reproduction space to a second determined area of the reproduction space, among the plurality of areas of the reproduction space, different from the first determined area.
  10. The audio signal processing apparatus according to claim 9, wherein the initial reflected sound control signal generator (50) is configured to perform crossfade processing, in a case in which the position of the sound source has been moved from the first determined area of the reproduction space to the second determined area of the reproduction space, on an initial reflected sound control signal generated before the movement and an initial reflected sound control signal generated after the movement.
  11. The audio signal processing apparatus according to any one of claims 7 to 10, further comprising a reverberant sound control signal generator (70) that is configured to generate a reverberant sound control signal by convolving an impulse response of a reverberant sound to the audio signal of the sound source.
  12. The audio signal processing apparatus according to claim 11, further comprising an output signal generator (80,90) that is configured to generate a speaker control signal by adding the initial reflected sound control signal and the reverberant sound control signal.
  13. An audio signal processing program comprising instructions which, when the program is executed by an audio signal processing apparatus, cause the audio signal processing apparatus to carry out the following steps: dividing, by an area setter (30), a reproduction space into a plurality of areas (Area1, ..., Area8); detecting, by a sound source position detector (41), a position, in the reproduction space, of a sound source (OBJ1) that generates an audio signal; determining, by an area determiner (42), inside which area of the plurality of areas (Area 1, ..., Area8) the detected position of the sound source (OBJ1) is located; generating, by an initial reflected sound control signal generator (50), an initial reflected sound control signal (ER1, ..., ER64) by convolving (i) an impulse response of an initial reflected sound linked to the determined area corresponding to the detected position of the sound source (OBJ1) to (ii) the audio signal of the sound source (OBJ1) without (iii) convolving an impulse response of an initial reflected sound linked to any of the plurality of areas (Area1...Area8) of the reproduction space other than the determined area of the reproduction space corresponding to the detected position of the sound source (OBJ1) to (ii) the audio signal of the sound source (OBJ1); and using the generated initial reflected sound control signal (ER1, ... ER64) to generate a signal to be output to a corresponding one of a plurality of speakers (SP1, ..., SP64) in order to simulate an initial reflected sound in a virtual space, in the reproduction space, characterized in that the audio signal processing program further comprises instructions which cause the audio signal processing apparatus to carry out the step of setting a representative point (RP1...RP8) in each of the plurality of areas (Area1...Area8) in the reproduction space, wherein determining the area in which the detected position of the sound source (OBJ1) is located comprises selecting the area having a shortest distance between the representative point of that area and the detected position of the sound source (OBJ1).

Description

BACKGROUND Technical Field An embodiment of the present disclosure relates to an audio signal processing method and an audio signal processing apparatus that perform predetermined processing on a sound to be inputted from a sound source. Background Information In an acoustic system for a hall or the like, various technologies to control a reflected sound and a reverberant sound have been put to practical use. For example, a reverberation adding apparatus disclosed in Japanese Unexamined Patent Application Publication No. H7-334182 generates an initial reflected sound signal of two channels from an inputted audio signal. This reverberation adding apparatus generates a reverberant sound signal from the initial reflected sound signal of two channels. Then, this reverberation adding apparatus outputs the initial reflected sound signal and the reverberant sound signal from a speaker or the like, and obtains a desired reflected sound and reverberant sound. However, the initial reflected sound is changed into a different sound when the position of the sound source being an origin of the initial reflected sound changes even while a shape of a reproduction space in which the initial reflected sound is emitted does not change. Attention is drawn to document EP 3 0188 918 A1 which relates to an apparatus for generating a first multitude of output signals based on at least one audio source signal comprising a delay network and a feedback processor. The delay network comprises a second multitude of delay paths, each delay path having a delay line and an attenuation filter. Each delay line is configured for delaying delay line input signals and for combining the at least one audio source signal and a reverberated audio signal to obtain a combined signal, wherein the attenuation filter of a delay path is configured for filtering the combined signal from the delay line of the delay path to obtain an output signal. The first multitude of output signals comprises the output signal. The feedback processor is configured for reverberating the first multitude of output signals to obtain a third multitude of the reverberated audio signals comprising the reverberated audio signal. Further attention is drawn to document US 2003/007648 A1 which relates to a sound processing apparatus for creating virtual sound sources in a three dimensional space including a number of modules. These include an aural exciter module; an automated panning module; a distance control module; a delay module; an occlusion and air absorption module; a Doppler module for pitch shifting; a location processor module; and an output. SUMMARY The invention is defined by the appended independent claims. Further embodiments of the invention are defined by the appended dependent claims. In view of the foregoing, an object of an embodiment of the present disclosure is to obtain a clearer initial reflected sound in accordance with a position of a sound source. An audio signal processing method divides, by an area setter, a reproduction space into a plurality of areas; detects, by a sound source position detector, a position, in the reproduction space, of a sound source that generates an audio signal; determines, by an area determiner, inside which area of the plurality of areas the detected position of the sound source is located; generates, by an initial reflected sound control signal generator, an initial reflected sound control signal by convolving (i) an impulse response of an initial reflected sound linked to the determined area corresponding to the detected position of the sound source to (ii) the audio signal of the sound source without (iii) convolving an impulse response of an initial reflected sound linked to any of the plurality of areas of the reproduction space other than the determined area of the reproduction space corresponding to the detected position of the sound source to (ii) the audio signal of the sound source; and uses the generated initial reflected sound control signal to generate a signal to be output to a corresponding one of a plurality of speakers in order to simulate an initial reflected sound in a virtual space, in the reproduction space. The audio signal processing method further comprises setting a representative point in each of the plurality of areas in the reproduction space, wherein determining the area in which the detected position of the sound source is located comprises selecting the area having a shortest distance between the representative point of that area and the detected position of the sound source An audio signal processing method is able to obtain a clearer initial reflected sound in accordance with a position of a sound source. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a functional block diagram showing a configuration of an acoustic system including an audio signal processing apparatus according to an embodiment of the present disclosure.FIG. 2 is a flow chart of an audio signal processing method according to an em