private static Signal RescaleSignal(Signal decomposition, Signal signal, DecompositionLevel level)
{
var rescaled = WaveMath.InterpolateCubic(decomposition, (uint)Math.Pow(2, level.Index + 1));
if (rescaled.SamplesCount < signal.SamplesCount)
{
var extensionSize = signal.SamplesCount - rescaled.SamplesCount;
int right;
var left = right = extensionSize / 2;
if (left + right != extensionSize)
{
left++;
}
SignalExtension.Extend(ref rescaled, SignalExtension.ExtensionMode.SmoothPadding0, left, right);
}
else
{
rescaled.Samples = SignalExtension.Deextend(rescaled.Samples, signal.SamplesCount);
}
rescaled.CustomPlot = null;
rescaled.Finish = signal.Finish;
rescaled.SamplingRate = signal.SamplingRate;
rescaled.SamplingInterval = signal.SamplingInterval;
return(rescaled);
}
public void TestDeextend()
{
var points = new double[] { 2, 6, 1, 6, 5, 0, 4, 5, 3, 4 };
var extended = SignalExtension.Extend(points, SignalExtension.ExtensionMode.SymmetricHalfPoint, 100);
var deextended = SignalExtension.Deextend(extended, points.Length);
Assert.IsTrue(deextended.SequenceEqual(points));
points = new double[] { 1, 2 };
deextended = SignalExtension.Deextend(points, 1);
Assert.IsTrue(deextended.SequenceEqual(points));
}
/// <summary>
/// Multilevel inverse discrete 1-D wavelet transform
/// </summary>
/// <param name="decompositionLevels">The decomposition levels of the DWT</param>
/// <param name="motherWavelet">The mother wavelet to be used. Example: CommonMotherWavelets.GetWaveletFromName("DB4") </param>
/// <param name="level">The depth-level to perform the DWT</param>
/// <param name="convolutionMode">Defines what convolution function should be used</param>
/// <returns></returns>
public static double[] ExecuteIDWT(List <DecompositionLevel> decompositionLevels, MotherWavelet motherWavelet, int level = 0, ConvolutionModeEnum convolutionMode = ConvolutionModeEnum.ManagedFFT)
{
if (level == 0 || level > decompositionLevels.Count)
{
level = decompositionLevels.Count;
}
if (level <= 0)
{
return(null);
}
var approximation = (double[])decompositionLevels[level - 1].Approximation.Clone();
var details = (double[])decompositionLevels[level - 1].Details.Clone();
for (var i = level - 1; i >= 0; i--)
{
approximation = WaveMath.UpSample(approximation);
approximation = WaveMath.Convolve(convolutionMode, approximation, motherWavelet.Filters.ReconstructionLowPassFilter, true, -1);
details = WaveMath.UpSample(details);
details = WaveMath.Convolve(convolutionMode, details, motherWavelet.Filters.ReconstructionHighPassFilter, true, -1);
//sum approximation with details
approximation = WaveMath.Add(approximation, details);
if (i <= 0)
{
continue;
}
if (approximation.Length > decompositionLevels[i - 1].Details.Length)
{
approximation = SignalExtension.Deextend(approximation, decompositionLevels[i - 1].Details.Length);
}
details = (double[])decompositionLevels[i - 1].Details.Clone();
}
return(approximation);
}
