supdeq_calcITD

% SUpDEq - Spatial Upsampling by Directional Equalization

 function [itd_ms, itd_ys] = supdeq_calcITD( hrir, fs, th, us, fc )

 This function calculates the ITD (Interaural Time Delay) of a HRIR based
 on onset detection 

 Output:
 itd_ms            - ITD of the HRIR(s) in ms 
 itd_ys            - ITD of the HRIR(s) in micro seconds 

 Input:
 hrir              - [N x 2] HRIR with N samples and 2 channels    
 fs                - Sampling Rate
                     Default: 48000
 th                - Threshold (in dB) of the onset detection
                     Default: -20
 us                - Upsampling factor for onset detection
                     Default: 10
 fc                - Frequency in Hz at which an 8th order Butterworth 
                     lowpass is applied to the hrir before onset detection
                     Default: 3000

 Dependencies: AKTools

 Reference:
 A. Andreopoulou and B. F. G. Katz, ?Identification of perceptually relevant
 methods of inter-aural time difference estimation,? 
 J. Acoust. Soc. Am., vol. 142, no. 2, pp. 588?598, 2017.
   
 (C) 2020 by JMA, Johannes M. Arend  
             TH Köln - University of Applied Sciences
             Institute of Communications Engineering
             Department of Acoustics and Audio Signal Processing

0001 %% SUpDEq - Spatial Upsampling by Directional Equalization
0002 %
0003 % function [itd_ms, itd_ys] = supdeq_calcITD( hrir, fs, th, us, fc )
0004 %
0005 % This function calculates the ITD (Interaural Time Delay) of a HRIR based
0006 % on onset detection
0007 %
0008 % Output:
0009 % itd_ms            - ITD of the HRIR(s) in ms
0010 % itd_ys            - ITD of the HRIR(s) in micro seconds
0011 %
0012 % Input:
0013 % hrir              - [N x 2] HRIR with N samples and 2 channels
0014 % fs                - Sampling Rate
0015 %                     Default: 48000
0016 % th                - Threshold (in dB) of the onset detection
0017 %                     Default: -20
0018 % us                - Upsampling factor for onset detection
0019 %                     Default: 10
0020 % fc                - Frequency in Hz at which an 8th order Butterworth
0021 %                     lowpass is applied to the hrir before onset detection
0022 %                     Default: 3000
0023 %
0024 % Dependencies: AKTools
0025 %
0026 % Reference:
0027 % A. Andreopoulou and B. F. G. Katz, ?Identification of perceptually relevant
0028 % methods of inter-aural time difference estimation,?
0029 % J. Acoust. Soc. Am., vol. 142, no. 2, pp. 588?598, 2017.
0030 %
0031 % (C) 2020 by JMA, Johannes M. Arend
0032 %             TH Köln - University of Applied Sciences
0033 %             Institute of Communications Engineering
0034 %             Department of Acoustics and Audio Signal Processing
0035 
0036 function [itd_ms, itd_ys] = supdeq_calcITD( hrir, fs, th, us, fc )
0037 
0038 if nargin < 2 || isempty(fs)
0039     fs = 48000;
0040 end
0041 
0042 if nargin < 3 || isempty(th)
0043     th = -20;
0044 end
0045 
0046 if nargin < 4 || isempty(us)
0047     us = 10;
0048 end
0049 
0050 if nargin < 5 || isempty(fc)
0051     fc = 3000;
0052 end
0053 
0054 %Check type of array
0055 if size(hrir,2) > size(hrir,1)
0056     hrir = hrir';
0057 end
0058 
0059 %%
0060 
0061 onsetL = AKonsetDetect(hrir(:,1), us, th, 'rel', [fc fs]);
0062 onsetR = AKonsetDetect(hrir(:,2), us, th, 'rel', [fc fs]);
0063 
0064 itdSamples = onsetL-onsetR;
0065 itd_ms = itdSamples/fs*1000;
0066 itd_ys = itd_ms*1000;
0067     
0068 end
0069