Added signal analysis basic functions

Signed-off-by: Nicola Vigano <nicola.vigano@esrf.fr>

initialise_gt.m

@@ -131,6 +131,7 @@ function initialise_gt(ignore_id19)
     addpath(fullfile(GT_MATLAB_HOME, 'zUtil_Imaging'));
     addpath(fullfile(GT_MATLAB_HOME, 'zUtil_Indexter'));
     addpath(fullfile(GT_MATLAB_HOME, 'zUtil_Maths'));
+    addpath(fullfile(GT_MATLAB_HOME, 'zUtil_NoiseAnalysis'));
     addpath(fullfile(GT_MATLAB_HOME, 'zUtil_OAR'));
     addpath(fullfile(GT_MATLAB_HOME, 'zUtil_Parameters'));
     addpath(fullfile(GT_MATLAB_HOME, 'zUtil_Python'));

zUtil_NoiseAnalysis/gtEvalSignalAutocorrelation.m

+function a = gtEvalSignalAutocorrelation(s, t)
+    a = gtImgMeanValue(s .* circshift(s, t));
+end
\ No newline at end of file

zUtil_NoiseAnalysis/gtGenerateAdditiveWhiteNoise.m

+function n = gtGenerateAdditiveWhiteNoise(dims, total_energy, data_type)
+    if (~exist('data_type', 'var'))
+        data_type = 'single';
+    end
+    if (iscell(dims))
+        n = cell(dims);
+        summed_energy = 0;
+        for ii = 1:numel(n)
+            n{ii} = rand(dims, data_type);
+            summed_energy = summed_energy + gtGetSignalEnergy(n{ii});
+        end
+        for ii = 1:numel(n)
+            n{ii} = n{ii} * (total_energy / summed_energy);
+        end
+    else
+        n = rand(dims, data_type);
+        n = n * (total_energy / gtGetSignalEnergy(n));
+    end
+end

zUtil_NoiseAnalysis/gtGetSignalAutocorrelation.m

+function s = gtGetSignalAutocorrelation(s)
+    s = convn(s, s, 'same') / numel(s);
+end
\ No newline at end of file

zUtil_NoiseAnalysis/gtGetSignalEnergy.m

+function e = gtGetSignalEnergy(s)
+    e = sum(sum(abs(s)));
+    e = sum(e(:)) / numel(s);
+end
\ No newline at end of file

zUtil_NoiseAnalysis/gtGetSignalNoiseRatio.m

+function r = gtGetSignalNoiseRatio(s, n, unit)
+    if (~exist('unit', 'var'))
+        unit = 'logaritmic';
+    end
+    r = gtGetSignalPower(s) / gtGetSignalPower(n);
+    switch(unit)
+        case 'decimal'
+            % Nothing
+        case 'logaritmic'
+            r = 10 * log10(r);
+    end
+end
\ No newline at end of file

zUtil_NoiseAnalysis/gtGetSignalPower.m

+function p = gtGetSignalPower(s)
+    p = gtImgMeanValue(s .* s);
+end
\ No newline at end of file

zUtil_NoiseAnalysis/gtGetSignalSpectralDensityPower.m

+function s = gtGetSignalSpectralDensityPower(s)
+    s = gtGetSignalAutocorrelation(s);
+    s = fftn(ifftshift(s));
+end
\ No newline at end of file