Signals can be in cell arrays

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

zUtil_NoiseAnalysis/gtGetSignalEnergy.m

 function e = gtGetSignalEnergy(s)
-    e = sum(sum(abs(s)));
-    e = sum(e(:)) / numel(s);
+    if (iscell(s))
+        e = sum(cellfun(@gtGetSignalEnergy, s));
+    else
+        e = sum(sum(abs(s)));
+        e = sum(e(:)) / numel(s);
+    end
 end
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zUtil_NoiseAnalysis/gtGetSignalPower.m

 function p = gtGetSignalPower(s)
-    p = gtImgMeanValue(s .* s);
+    if (iscell(s))
+        p = sum(cellfun(@gtGetSignalPower, s));
+    else
+        p = gtImgMeanValue(s .* s);
+    end
 end
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