git-svn-id: https://svn.d4science.research-infrastructures.eu/gcube/trunk/data-analysis/EcologicalEngine@90868 82a268e6-3cf1-43bd-a215-b396298e98cf

src/main/java/org/gcube/dataanalysis/ecoengine/signals/SignalConversions.java

@@ -303,4 +303,91 @@ public class SignalConversions {
 		return (int) (time * sampleRate);
 	}
 
+	static double[] takeMaxFrequenciesInSpectrogram(double[][] spectrogram, int samplingRate,int windowSamples, float minfreq) {
+		double[] maxs = new double[spectrogram.length];
+		int j = 0;
+		for (double[] slice : spectrogram) {
+			int bestidx = 0;
+			double max = -Double.MAX_VALUE;
+			for (int k = 0; k < slice.length; k++) {
+				double ele = slice[k];
+				if (ele > max) {
+					max = ele;
+					bestidx = k;
+				}
+			}
+
+//			maxs[j] = spectrogram[j][bestidx];
+//			maxs[j]=bestidx;
+			int minFidx = SignalConversions.frequencyIndex(minfreq, windowSamples, samplingRate);
+//			System.out.println("min f idx: "+minFidx);
+			maxs[j] = spectrumIdx2Frequency(minFidx+bestidx,samplingRate,windowSamples);
+			j++;
+		}
+
+		return maxs;
+	}
+
+	static double[] takeLongestStableTract(double[] signal, double valuedifftoleranceperc) {
+		ArrayList<int[]> pairs = new ArrayList<int[]>();
+		int idx1 = -1;
+
+		int[] pair = null;
+		//analyze the signal
+		for (int i = 1; i < signal.length; i++) {
+			//if there is not current range create it
+			if (idx1 == -1) {
+				idx1 = 1;
+				pair = new int[2];
+				pair[0] = i - 1;
+				pair[1] = i - 1;
+			}
+			//if the current sample is similar to the previous, enlarge the range
+			if (Math.abs(signal[i] - signal[i - 1])/Math.max(signal[i],signal[i - 1]) <= valuedifftoleranceperc)
+				pair[1] = i;
+			//otherwise add the couple and reset
+			else {
+				idx1 = -1;
+				pairs.add(pair);
+			}
+		}
+		//if the last couple was reset, add the last interval
+		if (idx1 > -1)
+			pairs.add(pair);
+		
+		//find the longest pair
+		int best = 0;
+		int maxsize = 0;
+		int k = 0;
+		for (int[] setcouple : pairs) {
+			int diff = setcouple[1] - setcouple[0];
+			if (diff > maxsize) {
+				maxsize = diff;
+				best = k;
+			}
+			k++;
+		}
+		//take the longest range
+		int[] bestcouple = pairs.get(best);
+		//take the related slice of signal
+		double[] subsignal = new double[bestcouple[1] - bestcouple[0]];
+		System.out.println("Longest range: from "+bestcouple[0]+" to "+bestcouple[1]);
+		int l = 0;
+		for (int i = bestcouple[0]; i < bestcouple[1]; i++) {
+			subsignal[l] = signal[i];
+			l++;
+		}
+
+		return subsignal;
+	}
+
+	static float spectrumIdx2Frequency(int idx,int samplingRate,int windowsSizeSamples){
+		return ((float)idx*samplingRate)/(float)(windowsSizeSamples-1);
+	}
+	
+	static int spectrumFreq2Idx(float freq, int samplingRate,int windowsSizeSamples){
+		return Math.round((windowsSizeSamples-1)*freq/samplingRate);
+	}
+	
+	
 }