Delay estimation method and apparatus

Patent metadata

Field	Value
Publication number	US-11304019-B2
Application number	US-201916727652-A
Country	US
Kind code	B2
Filing date	Dec 26, 2019
Priority date	Jun 29, 2017
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A delay estimation method includes determining a cross-correlation coefficient of a multi-channel signal of a current frame, determining a delay track estimation value of the current frame based on buffered inter-channel time difference information of at least one past frame, determining an adaptive window function of the current frame, performing weighting on the cross-correlation coefficient based on the delay track estimation value of the current frame and the adaptive window function of the current frame, to obtain a weighted cross-correlation coefficient, and determining an inter-channel time difference of the current frame based on the weighted cross-correlation coefficient.

First claim

What is claimed is:

1. A delay estimation method, comprising:
obtaining a cross-correlation coefficient of a multi-channel signal of a current frame;
obtaining a delay track estimation value of the current frame based on buffered inter-channel time difference information of a past frame;
obtaining an adaptive window function of the current frame;
performing weighting on the cross-correlation coefficient to obtain a weighted cross-correlation coefficient based on the delay track estimation value of the current frame and the adaptive window function of the current frame; and
obtaining an inter-channel time difference of the current frame based on the weighted cross-correlation coefficient.

2. The delay estimation method of claim 1 , wherein obtaining the adaptive window function of the current frame comprises:
calculating a first raised cosine width parameter based on a smoothed inter-channel time difference estimation deviation of a previous frame of the current frame;
calculating a first raised cosine height bias based on the smoothed inter-channel time difference estimation deviation of the previous frame; and
obtaining the adaptive window function of the current frame based on the first raised cosine width parameter and the first raised cosine height bias.

3. The delay estimation method of claim 2 , comprising further calculating the first raised cosine width parameter using the following formulas:
win_width1=TRUNC(width_par1*( A*L _NCSHIFT_ DS+ 1)), and
width_par1= a _width1*smooth_dist_reg+ b _width1,
wherein a_width 1 =(xh_width 1 −xl_width 1 )/(yh_dist 1 −yl_dist 1 ) and b_width 1 =xh_width 1 −a_width 1 *yh_dist 1 , wherein win_width 1 is the first raised cosine width parameter, wherein TRUNC indicates rounding a value, wherein L_NCSHIFT_DS is a maximum value of an absolute value of the inter-channel time difference, wherein A is a preset constant and is greater than or equal to 4, wherein xh_width 1 is an upper limit value of the first raised cosine width parameter, wherein xl_width 1 is a lower limit value of the first raised cosine width parameter, wherein yh_dist 1 is a smoothed inter-channel time difference estimation deviation corresponding to the upper limit value of the first raised cosine width parameter, wherein yl_dist 1 is a smoothed inter-channel time difference estimation deviation corresponding to the lower limit value of the first raised cosine width parameter, wherein smooth_dist_reg is the smoothed inter-channel time difference estimation deviation of the previous frame, and wherein xh_width 1 , xl_width 1 , yh_dist 1 , and yl_dist 1 are all positive numbers.

4. The delay estimation method of claim 3 , comprising further calculating width earl using the following formulas:
width_par1=min(width_par1, xh _width1), and
width_par1=max(width_par1, xl _width1),
wherein min represents taking of a minimum value, and wherein max represents taking of a maximum value.

5. The delay estimation method of claim 3 , comprising further calculating win_bias 1 using the following formula:
win_bias1= a _bias1*smooth_dist_reg+ b _bias1,
wherein a_bias 1 =(xh_bias 1 −xl_bias 1 )/(yh_dist 2 −yl_dist 2 ) and b_bias 1 =xh_bias 1 −a_bias 1 *yh_dist 2 , wherein win_bias 1 is the first raised cosine height bias, wherein xh_bias 1 is an upper limit value of the first raised cosine height bias, wherein xl_bias 1 is a lower limit value of the first raised cosine height bias, wherein yh_dist 2 is a smoothed inter-channel time difference estimation deviation corresponding to the upper limit value of the first raised cosine height bias, wherein yl_dist 2 is a smoothed inter-channel time difference estimation deviation corresponding to the lower limit value of the first raised cosine height bias, wherein smooth_dist_reg is the smoothed inter-channel time difference estimation deviation of the previous frame, and wherein yh_dist 2 , yl_dist 2 , xh_bias 1 , and xl_bias 1 are all positive numbers.

6. The delay estimation method of claim 5 , comprising further calculating win_bias 1 using the following formulas:
win_bias1=min(win_bias1, xh _bias1), and
win_bias1=max(win_bias1, xl _bias1),

wherein min represents taking of a minimum value, and wherein max represents taking of a maximum value.

7. The delay estimation method of claim 1 , comprising further calculating loc_weight_win using the following formulas:
loc_weight_win( k )=win_bias1 when 0≤ k ≤TRUNC( A*L _NCSHIFT_ DS/ 2)−2*win_width1−1,

loc_weight_win( k )=0.5*(1+win_bias1)+0.5*(1−win_bias1)*cos(π*( k −TRUNC( A*L _NCSHIFT_ DS/ 2))/(2*win_width1)) when TRUNC( A*L _NCSHIFT_ DS/ 2)−2*win_width1≤ k ≤TRUNC( A*L _NCSHIFT_ DS/ 2)+2*win_width1−1; and

loc_weight_win( k )=win_bias1 when TRUNC( A*L _NCSHIFT_ DS/ 2)+2*win_width1≤ k≤A*L _NCSHIFT_ DS,

wherein loc_weight_win(k) represents the adaptive window function, wherein k=0, 1, . . . , A*L_NCSHIFT_DS, wherein A is a preset constant and is greater than or equal to 4, wherein L_NCSHIFT_DS is a maximum value of an absolute value of the inter-channel time difference, wherein win_width 1 is a first raised cosine width parameter, and wherein win_bias 1 is a first raised cosine height bias.

8. The delay estimation method of claim 2 , wherein after obtaining the inter-channel time difference of the current frame based on the weighted cross-correlation coefficient, the delay estimation method further comprises:
calculating a smoothed inter-channel time difference estimation deviation of the current frame based on the smoothed inter-channel time difference estimation deviation of the previous frame, the delay track estimation value of the current frame, and the inter-channel time difference of the current frame,
calculating the smoothed inter-channel time difference estimation deviation of the current frame using the following formulas:
smooth_dist_reg_update=(1−γ)*smooth_dist_reg+γ*dist_reg′, and

dist_reg′=|reg_prv_corr−cur_itd|,

wherein smooth_dist_reg_update is the smoothed inter-channel time difference estimation deviation of the current frame, wherein γ is a first smoothing factor and 0<γ<1, wherein smooth_dist_reg is the smoothed inter-channel time difference estimation deviation of the previous frame, wherein reg_prv_corr is the delay track estimation value of the current frame, and wherein cur_itd is the inter-channel time difference of the current frame.

9. The delay estimation method of claim 1 , wherein obtaining the adaptive window function of the current frame comprises:
obtaining an initial value of the inter-channel time difference of the current frame based on the cross-correlation coefficient;
calculating an inter-channel time difference estimation deviation of the current frame based on the delay track estimation value of the current frame and the initial value of the inter-channel time difference of the current frame using the following formula:
dist_reg=|reg_prv_corr−cur_itd|,

wherein dist_reg is the inter-channel time difference estimation deviation of the current frame, wherein reg_prv_corr is the delay track estimation value of the current frame, and wherein cur_itd_init is the initial value of the inter-channel time difference of the current frame; and
obtaining the adaptive window function of the current frame based on the inter-channel time difference estimation deviation of the current frame.

10. The delay estimation method of claim 9 , wherein obtaining the adaptive window function of the current frame based on the inter-channel time difference estimation deviation of the current frame comprises:
calculating a second raised cosine width parameter based on the inter-channel time difference estimation deviat

Assignees

• Huawei Tech Co Ltd

Inventors

• Shlomot Eyal
• Li Halting
• Miao Lei

Classifications

• G10L25/03

  characterised by the type of extracted parameters · CPC title

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• H04S2400/03

  Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 (H04S2400/01 takes precedence) · CPC title

• H04S1/007 Primary

  in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02) · CPC title

• H04S5/00

  Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation · CPC title