How do I create a matrix that is only the frequencies within the COI of a wavelet transform coherence?

Prashant Kumar answered . 2024-12-21 02:49:04

% specific code (to remove)
load('f.mat')
load('coi.mat')
load('wtc.mat')
n = numel(coi);
t = (0:n - 1)*ts; % time vector

% define parameterts and signals
fs = 10; % frequency in Hz
ts = 1/fs; % time step
% t = (0:length(x) - 1)*ts; % time vector
% [wtc, wcs, f, coi] = wcoherence(x, y,fs); 

% create a mask (coi) so data below coi curve are zeroed
[m,n] = size(wtc);
mask = ones(m,n);
tmp = mask;
ind = round(m*coi/max(f));
for ci =1:n
     mask(1:ind(ci),ci) = 0; 
end
mask = flipud(mask); 

% apply Coi mask 
wtc = wtc.*mask;

% plot wtc within coi bounds
imagesc(t,f,abs(wtc));
set(gca,'YDir','normal');
title('X1');
xlabel('Time (samples)')
ylabel('Frequency (Hz)')
colormap('jet')
colorbar('vert')
hold on

plot(t,coi,'--w','linewidth',3);

% Finaly, I would take the average coherence within the frequency range 0.125-0.3 Hz
 freqRange = [0.125 0.3];
%     % Find indices corresponding to the frequency range
    freqIndices = find(f >= freqRange(1) & f <= freqRange(2));
    % Extract coherence values in the frequency range within the COI
    coherenceInRange = abs(wtc(freqIndices,:));
    % Calculate average coherence (ignoring NaNs)
    averageCoherence = mean(coherenceInRange,'all','omitnan');

on your side you simply have to remove these lines

% specific code (to remove)
load('f.mat')
load('coi.mat')
load('wtc.mat')
n = numel(coi);
t = (0:n - 1)*ts; % time vector

and uncomment this one

% t = (0:length(x) - 1)*ts; % time vector
% [wtc, wcs, f, coi] = wcoherence(x, y,fs); 

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