public static List <Tuple <double, double> > FindPeaksAboveInitiationThreshold(List <double> v, double init_thresh)
{
List <Tuple <double, double> > peaks = new List <Tuple <double, double> >();
var binary_signal = v.Select(x => (x >= init_thresh) ? 1 : 0).ToList();
var diff_binary_signal = TxBDC_Math.DiffInt(binary_signal);
//Get all points where the signal rose above the initiation threshold and where it fell below
var rises = Enumerable.Range(0, diff_binary_signal.Count).Where(x => diff_binary_signal[x] == 1).ToList();
var falls = Enumerable.Range(0, diff_binary_signal.Count).Where(x => diff_binary_signal[x] == -1).ToList();
//If there is a fall before the first rise, then insert a rise at the very beginning
if (falls.Count > 0 && rises.Count > 0)
{
var first_rise = rises.FirstOrDefault();
var first_fall = falls.FirstOrDefault();
var last_rise = rises.LastOrDefault();
var last_fall = falls.LastOrDefault();
if (first_rise >= first_fall)
{
rises.Insert(0, 0);
}
if (last_rise >= last_fall)
{
falls.Add(diff_binary_signal.Count - 1);
}
}
else if (falls.Count > 0 && rises.Count == 0)
{
rises.Add(0);
}
else if (falls.Count == 0 && rises.Count > 0)
{
falls.Add(diff_binary_signal.Count - 1);
}
//Get elements of the signal between each rise and fall
for (int i = 0; i < rises.Count && i < falls.Count; i++)
{
var r = rises[i];
var f = falls[i];
var s = v.Where((y, x) => x >= r && x < f).Select(x => x).ToList();
var s_max = s.Max();
var s_max_idx = s.IndexOf(s_max);
var real_index = r + s_max_idx;
Tuple <double, double> new_peak = new Tuple <double, double>(s_max, real_index);
peaks.Add(new_peak);
}
return(peaks);
}
/// <summary>
/// Finds the "derivative" of a signal by calculating the difference between each element.
/// </summary>
/// <param name="a">The signal as a list of a doubles.</param>
/// <returns>The derivative of the input signal.</returns>
public static List <double> Diff(List <double> a)
{
return(TxBDC_Math.Diff(a, 0, a.Count));
}