Equal loudness contour based method for automatically recovering tone of voice signal according to volume adjustment

A technology of equal loudness curves and sound signals, applied in the field of digital signal processing, can solve problems such as active noise, timbre change, and sound quality deterioration

Inactive Publication Date: 2013-02-06
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, their object of study is active noise, which is different from music playback
All in all, the current volume control technology does not adapt to the subjective experience of the human ear, and it will cause problems such as poor sound quality and timbre change

Method used

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  • Equal loudness contour based method for automatically recovering tone of voice signal according to volume adjustment
  • Equal loudness contour based method for automatically recovering tone of voice signal according to volume adjustment
  • Equal loudness contour based method for automatically recovering tone of voice signal according to volume adjustment

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Experimental program
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Effect test

Embodiment 1

[0041] see figure 1 , the present embodiment is based on the method of automatically restoring the timbre of the sound signal according to the volume adjustment based on the equal loudness curve. Compensate to achieve the purpose of restoring the sound quality; the specific operation steps are as follows:

[0042] (1) When controlling the volume, the generated gain variation △S acts on the time-domain signal S of the sound file to obtain the time-domain signal S' after gain; perform Fourier transform on this time-domain signal S', Get the frequency domain signal S f ;

[0043] (2) Use a digital filter to the frequency domain signal S f Perform filtering and divide it into several frequency domain signals;

[0044] (3) Quantitatively analyze the equal loudness curve to obtain the compensation coefficient of each frequency segment under the condition of different gain variation △S;

[0045] (4) Combined with the compensation coefficient, the compensation signal of each frequ...

Embodiment 2

[0048] The present embodiment is basically the same as the first embodiment and the special features are as follows:

[0049] The gain variation ΔS is a coefficient for multiplying the original signal to amplify or reduce the original signal.

[0050] The digital filter is an FIR bandpass filter.

[0051] The compensation signal is the product of each frequency domain signal and its respective compensation coefficient.

[0052] The realization of the compensation is finally completed by adding the time domain signal of the compensation signal to the time domain signal S'.

[0053] The amount of compensation is obtained through quantitative analysis of equal loudness curves. Its analysis steps are as follows:

[0054] (1) Each point h on an equal loudness curve is determined by the frequency f and the sound pressure level S, and the relationship can be obtained: h = G ( f, S ), h represents a certain point on the equal loudness curve A point, f represents the frequency, S r...

Embodiment 3

[0069] see Figure 1~Figure 4 , the present embodiment is based on the method of automatically restoring the timbre of the sound signal according to the volume adjustment based on the equal loudness curve, and the specific operations are as follows:

[0070] Preferred embodiments of the present invention are described in detail as follows in conjunction with accompanying drawings:

[0071] Suppose the loudness of the sound is adjusted from 80 fang to 60 fang, then the gain change △S is -20dB, and the time domain signal S' after gain is obtained.

[0072] In order to simplify the processing, take 31.5Hz~500 Hz as an example, divide it into 4 sections for compensation. They are: 31.5Hz~62.5Hz; 62.5Hz~125Hz; 125Hz~250Hz; 250Hz~500Hz. The time-domain signal S' is filtered through the fir digital filter to obtain the frequency-domain signals of these four frequency bands.

[0073] Next, take points for the equal loudness curve in ISO226. Divide the abscissa into 100 grids. In ...

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Abstract

The invention relates to an equal loudness contour based method for automatically recovering tone of a voice signal according to volume adjustment. According to the method, the signal can be automatically compensated through the quantitative analysis of the equal loudness contour in combination with a gain coefficient delta S generated during the volume adjustment, thereby achieving the purpose of recovering the tone, so that the volume control can fit with the subjective feeling of human ears better, and better hearing can be provided to users.

Description

technical field [0001] The invention belongs to the field of digital signal processing, and relates to a method for frequency compensation of sound signals, in particular to a method for automatically restoring the timbre of sound signals based on volume adjustment based on equal loudness curves. Background technique [0002] The essence of volume control is to scale the amplitude of the audio signal waveform to change its sound pressure. Volume refers to the human ear's subjective perception of the strength of the sound it hears, which is different from sound pressure. When sound waves propagate, each part of the air medium produces periodic changes in compression and expansion, and the difference between the pressure of this changing part and the static pressure is called sound pressure. Sound pressure is an objective quantity. In today's electronic equipment, the essence of all volume adjustments is to adjust the magnitude of the current, and a change in the magnitude o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L21/003H03G7/00
Inventor 石复霖
Owner SHANGHAI UNIV
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