} //ScanArrayForGridPattern()
/// <summary>
/// Steps through the passed array and and at each step cuts out a segment having length = numberOfCycles * cyclePeriod.
/// Each segment is then reduced to length = numberOfCycles * 2.
/// Then the reduced segment is passed to check for a grating pattern having period = 2 signal samples.
/// Use this method when the array to be scanned will be reduced on the fly.
/// </summary>
/// <param name="array"></param>
/// <param name="step"></param>
/// <param name="numberOfCycles"></param>
/// <param name="cyclePeriod">NB! MUST BE AN EVEN NUMBER!!!</param>
/// <returns></returns>
public static double[] ScanArrayForGratingPattern(double[] array, int step, int numberOfCycles, int cyclePeriod)
{
//noise reduce the array to get acoustic events
double Q, oneSD;
double[] noiseReducedArray = SNR.NoiseSubtractMode(array, out Q, out oneSD);
double threshold = 0.01;
int length = array.Length;
double[] gridScore = new double[length];
int segmentLength = numberOfCycles * cyclePeriod;
var output = new double[length];
for (int i = 0; i < length; i++)
{
if (noiseReducedArray[i] < threshold)
{
continue;
}
double[] extract = DataTools.Subarray(array, i, segmentLength);
if (extract == null)
{
return(output); // reached end of array
}
//now reduce the segment
double[] reducedSegment = null;
if (cyclePeriod == 2)
{
reducedSegment = extract;
}
else
{
int halfPeriod = cyclePeriod / 2;
int reducedLength = numberOfCycles * 2;
reducedSegment = new double[reducedLength];
for (int x = 0; x < reducedLength; x++)
{
///////two ways to reduce: (1) by average of the period or (2) by max of the period
double sum = 0;
for (int c = 0; c < halfPeriod; c++)
{
sum += extract[(x * halfPeriod) + c];
}
reducedSegment[x] = sum / (double)cyclePeriod;
///////(2)
//double max = -Double.MaxValue;
//for (int c = 0; c < halfPeriod; c++)
//{
// double value = extract[(x * halfPeriod) + c];
// if (max < value) max = value;
//}
//reducedSegment[x] = max;
}
}
//DataTools.writeBarGraph(reducedSegment);
double score = DetectPeriod2Grating(reducedSegment);
//write score to output array
for (int x = 0; x < segmentLength; x++)
{
if (output[i + x] < score)
{
output[i + x] = score;
}
}
i += (step - 1);
}
return(output);
} //ScanArrayForGridPattern()
