Acoustic processing device and acoustic processing method

Abstract

To provide an acoustic processing device and an acoustic processing method capable of suppressing a reverberation added processing load.SOLUTION: In an acoustic processing device 1 having a controller 10, the controller 10 generates a first speech signal Sn1 downsampling an input speech signal Sin, generates a second speech signal Sn2 having reverberation added to the first speech signal Sn1, generates a third speech signal Sn3 having a harmonic added to the second speech signal Sn2, and combines the input speech signal Sin and the input third speech signal Sn3 to output the result as an output signal Sout to a speaker or the like.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The disclosed embodiments relate to an audio processing device and an audio processing method. [Background technology]

[0002] Conventionally, there is a sound processing device that adds reverberation (hereinafter, also referred to as reverb) to an audio signal. Patent Document 1 discloses a technology that adds reverberation by generating distortion in the harmonic band to an audio signal when the audio signal contains a small amount of harmonic band. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 06-110485 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional techniques have room for improvement in terms of reducing the processing load of adding reverberation. Specifically, there is a problem that the reverberation load increases as the length of reverberation added to a speech signal increases.

[0005] The present invention has been made in view of the above, and has an object to provide a sound processing device and a sound processing method that can reduce the processing load of adding reverberation. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the sound processing device of the present invention is a sound processing device having a controller, which generates a first sound signal by downsampling an input sound signal, generates a second sound signal by adding reverberation to the first sound signal, generates a third sound signal by adding harmonics to the second sound signal, and synthesizes the input sound signal and the third signal and outputs the synthesized signal. Effect of the Invention

[0007] According to the present invention, the processing load for adding reverberation can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a sound processing device. [Diagram 2] FIG. 2 is a flowchart showing a processing procedure executed by the sound processing device. [Diagram 3] FIG. 3 is a schematic diagram of a sound processing method according to a first modified example. [Figure 4] FIG. 4 is a schematic diagram of a sound processing method according to a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a detailed description will be given of an embodiment (hereinafter, referred to as an "embodiment") of a sound processing device and a sound processing method according to the present application with reference to the drawings. Note that the sound processing device and the sound processing method according to the present application are not limited to the embodiment.

[0010] First, a configuration example of a sound processing device according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing a configuration example of a sound processing device. As shown in Fig. 1, a sound processing device 1 includes a controller 10. Note that Fig. 1 illustrates a configuration for one channel, but if the surround system is a multi-channel system, controllers 10 are installed for the number of channels.

[0011] The controller 10 corresponds to a so-called processor. The controller 10 is realized by a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphical Processing Unit), or the like. The controller 10 executes a program according to an embodiment (not shown) stored in a storage unit (not shown) using a RAM as a working area. The controller 10 can also be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0012] The controller 10 executes reverberation processing for adding reverberation to the input audio signal Sin. As the reverberation processing, there is a technique called "convolution reverb" that uses a convolution operation.

[0013] Convolution reverb is a technique in which the impulse response measured in a room, concert hall, etc. is convolved with an FIR (Finite Impulse Response) filter, and can add a very natural reverberation.

[0014] On the other hand, convolution reverb has an issue in that the amount of calculation increases as the tap length of the FIR becomes longer. Specifically, the tap length of the FIR is determined by "sampling rate" x "reverb length" x "number of channels", and adding reverberation to a signal with a high sampling rate increases the processing load and leads to increased implementation costs.

[0015] That is, when convolution reverb is performed on a signal with a high sampling rate, the processing load increases. For this reason, in this embodiment, the controller 10 divides the input audio signal Sin into bands and performs reverb processing at a lower sampling rate.

[0016] Specifically, as shown in FIG. 1, the controller 10 removes high-frequency components from the audio signal Sin using a Low Pass Filter (LPF), and then performs downsampling to generate the first audio signal Sn1.

[0017] That is, the controller 10 downsamples the low-frequency band components whose frequencies are equal to or lower than the threshold value, extracted from the audio signal Sin, thereby enabling the controller 10 to remove noise from high-frequency components.

[0018] Next, the controller 10 adds reverberation to the first audio signal Sn1 using an FIR filter to generate a second audio signal Sn2. As described above, the FIR filter adds reverberation using convolution reverb. In this case, the second audio signal Sn2 has a lower sampling rate than the audio signal Sin, and the tap length of the FIR can be shortened, so that the processing load can be reduced.

[0019] Next, the controller 10 performs upsampling on the second audio signal Sn2, and then adds harmonics by harmonizer processing to generate a third audio signal Sn3. That is, the controller 10 upsamples the second audio signal Sn2 and then adds harmonics.

[0020] Here, the upsampled second audio signal Sn2 is converted to have a sampling rate that is the same as that of the audio signal Sin, so that the controller 10 can add harmonics of an appropriate sampling rate.

[0021] Harmonizer processing is a process that adds harmonics to the input signal to interpolate high-frequency components, and artificially interpolates high-frequency components lost due to compression, etc.

[0022] The harmonizer process can be realized by a relatively simple process, so that it is possible to add harmonics while suppressing the processing load. Then, the controller 10 synthesizes the input audio signal Sin and the third audio signal Sn3 by an adder, and outputs the result as an output signal Sout to a speaker or the like.

[0023] In this manner, the sound processing device 1 adds reverberation to the first sound signal Sn1 from which the high-frequency components of the sound signal Sin have been removed by downsampling, while interpolating the reverberation of the high-frequency components by harmonizer processing.

[0024] Therefore, the sound processing device 1 according to the embodiment can avoid convolution reverb for signals of high frequency components, and can reduce the processing load of adding reverberation.

[0025] Next, a process procedure executed by the sound processing device 1 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a flowchart showing the process procedure executed by the sound processing device 1. Note that the process shown below is repeatedly executed by the controller 10 every time an audio signal Sin is input.

[0026] 2, the controller 10 performs downsampling on the audio signal Sin (step S101). That is, the controller 10 removes high-frequency components from the audio signal Sin using an LPF, and then performs downsampling to generate a first audio signal.

[0027] Next, the controller 10 adds reverberation to the first audio signal Sn1 (step S102). That is, the controller 10 adds reverberation to the first audio signal Sn1 using an FIR filter to generate a second audio signal Sn2.

[0028] Next, the controller 10 performs upsampling on the second audio signal Sn2 (step S103), and adds harmonics to the upsampled second audio signal Sn2 (step S104). That is, after upsampling, the controller 10 interpolates the reverberation of the high-frequency components of the second audio signal Sn2 by harmonizer processing, and generates a third audio signal Sn3.

[0029] Next, the controller 10 combines the third audio signal Sn3 with the audio signal Sin (step S105). That is, the controller 10 combines the third audio signal Sn3 with the audio signal Sin using an adder or the like to generate the output signal Sout, and ends the process.

[0030] Next, other examples of sound processing will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a schematic diagram of a sound processing method according to a first modified example. Fig. 4 is a schematic diagram of a sound processing method according to a second modified example. Note that in Fig. 3 and Fig. 4, the sound processing device 1, the controller 10, etc. are omitted.

[0031] As shown in FIG. 3, in the first modification, the controller 10 removes high frequency components from the audio signal Sin using an LPF, and then generates first audio signals Sn1a and Sn1b of multiple bands from the audio signal Sin by downsampling multiple times.

[0032] FIG. 3 shows a case where a first audio signal Sn1a in the mid-frequency range is generated by a first downsampling, and a first audio signal Sn1b in the low-frequency range is generated by a second downsampling.

[0033] That is, the first audio signal Sn1a generated by the first downsampling is a signal that is more suitable for reproducing high-frequency reverberation than the first audio signal Sn1b generated by the second downsampling.

[0034] The controller 10 adds reverberation to each of the first audio signals Sn1a and Sn1b using an FIR filter to generate a second audio signal Sn2a from the first audio signal Sn1a and a second audio signal Sn2b from the first audio signal Sn1b, respectively.

[0035] The controller 10 upsamples the second audio signal Sn2a and adds reverberation to the second audio signal Sn2a by harmonizer processing to generate a third audio signal Sn3a. The controller 10 also upsamples the second audio signal Sn2b, synthesizes it with the audio signal Sin and the third audio signal Sn3a, and outputs it as an output signal Sout.

[0036] In this manner, in the first modified example, the sound processing device 1 adds reverberation to each of the first audio signals Sn1 of multiple bands, and adds harmonics to the second audio signal Sn2a in the higher frequency range among the second audio signals Sn2 of multiple bands.

[0037] As a result, in the first modified example, the sound processing device 1 can interpolate high-frequency reverberation without performing reverberation processing on the audio signal Sin with a high sampling rate, thereby reducing the processing load of adding reverberation.

[0038] Next, a second modified example will be described with reference to Fig. 4. As shown in Fig. 4, the controller 10 generates a first audio signal Sn1 by performing one downsampling from the audio signal Sin, similar to the procedure described in Fig. 1, and further generates a second audio signal Sn2 by adding reverberation to the first audio signal Sn1 using an FIR filter.

[0039] The controller 10 extracts the second audio signal Sn2 of the high frequency band components by an HPF (High Pass Filter) after upsampling the second audio signal Sn2. Next, the controller 10 adds harmonics to the second audio signal Sn2 of the high frequency band components by harmonizer processing to generate a third audio signal Sn3.

[0040] Then, the controller 10 synthesizes the second audio signal Sn2 that has not passed through the HPF, the third audio signal Sn3, and the audio signal Sin, and outputs the result as the output signal Sout.

[0041] In this way, in the second modified example, the sound processing device 1 extracts the second audio signal Sn2 of the high frequency band components by the HPF and adds harmonics. As a result, in the second modified example, the sound processing device 1 can interpolate high frequency reverberation without performing reverberation processing on the audio signal Sin with a high sampling rate, thereby reducing the processing load of adding reverberation.

[0042] As described above, the sound processing device 1 is a sound processing device having a controller 10, which generates a first sound signal Sn1 by downsampling an input sound signal Sin, generates a second sound signal Sn2 by adding reverberation to the first sound signal Sn1, generates a third sound signal Sn3 by adding harmonics to the second sound signal Sn2, and synthesizes and outputs the sound signal Sin and the third sound signal Sn3.

[0043] Therefore, according to the sound processing device 1 according to the embodiment, it is possible to add high-frequency reverberation without adding reverberation to a signal with a high sampling rate, thereby reducing the processing load for adding reverberation.

[0044] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0045] 1. Sound Processing Device 10 Controller Sin audio signal Sn1 First audio signal Sn2 Second audio signal Sn3 Third audio signal Sout Output signal

Claims

1. 1. A sound processing device having a controller, The controller: generating a first audio signal by downsampling the input audio signal; generating a second audio signal by adding reverberation to the first audio signal; generating a third audio signal by adding harmonics to the second audio signal; The input audio signal and the third audio signal are mixed and output. Sound processing equipment.

2. The controller: A low-frequency band component having a frequency equal to or lower than a threshold value extracted from the input audio signal is downsampled. The sound processing device according to claim 1 .

3. The controller: adding said harmonics after upsampling said second audio signal; The sound processing device according to claim 1 .

4. The controller: generating a first audio signal having a plurality of bands by downsampling a plurality of times; adding reverberation to each of the first audio signals of the plurality of bands to generate the second audio signals of the plurality of bands; adding harmonics to the second audio signal in a high frequency band among the second audio signals in the plurality of bands; The sound processing device according to claim 1 .

5. The controller: adding reverberation to the high frequency band components extracted from the second audio signal; The sound processing device according to claim 1 .

6. The controller: Adding reverberation to the first audio signal by a finite impulse response (FIR) filter The sound processing device according to claim 1 .

7. The controller: Adding harmonics to the second audio signal by harmonizer processing The sound processing device according to claim 1 .

8. A sound processing method executed by a controller, comprising: The controller: generating a first audio signal by downsampling an input audio signal; generating a second audio signal by adding reverberation to the first audio signal; generating a third audio signal by adding harmonics to the second audio signal; synthesizing the input audio signal and the third audio signal and outputting the result; An acoustic processing method comprising:

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