/// <summary>
/// Implements a wavelet filter.
/// </summary>
/// <param name="data">Matrix</param>
public void Apply(float[,] data)
{
var B = WaveletDecomposition.Forward(data);
int n, m;
for (int i = 1; i < B.Length; i++)
{
var b = B[i];
n = b.GetLength(0);
m = b.GetLength(1);
if (!Maths.IsEven(n))
{
n--; // ?
}
if (!Maths.IsEven(m))
{
m--; // ?
}
// visu_shrink
var bb = Matrice.Reshape(b, b.Length).ToAbs();
Array.Sort(bb);
var median = Math.Sqrt(bb[bb.Length / 2]) * Math.Sqrt(Maths.Log2(n * m));
for (int y = 0; y < n; y++)
{
for (int x = 0; x < m; x++)
{
b[y, x] = Math.Abs(b[y, x]) > median ? b[y, x] : 0;
}
}
B[i] = b;
}
var output = WaveletDecomposition.Backward(B);
float factor = 1 + Factor;
n = data.GetLength(0);
m = data.GetLength(1);
for (int y = 0; y < n; y++)
{
for (int x = 0; x < m; x++)
{
// pass filtering
data[y, x] = output[y, x] + factor * (data[y, x] - output[y, x]);
}
}
}
/// <summary>
/// Implements a wavelet filter.
/// </summary>
/// <param name="data">Array</param>
public void Apply(Complex32[] data)
{
var B = WaveletDecomposition.Forward(data);
int n;
for (int i = 1; i < B.Length; i++)
{
var b = B[i];
n = b.GetLength(0);
if (!Maths.IsEven(n))
{
n--; // ?
}
// visu_shrink
var bb = b.ToAbs();
Array.Sort(bb);
var median = Math.Sqrt(bb[bb.Length / 2]) * Math.Sqrt(Maths.Log2(n));
for (int y = 0; y < n; y++)
{
b[y] = Maths.Abs(b[y]) > median ? b[y] : 0;
}
B[i] = b;
}
var output = WaveletDecomposition.Backward(B);
float factor = 1 + Factor;
n = data.GetLength(0);
for (int y = 0; y < n; y++)
{
// pass filtering
data[y] = output[y] + factor * (data[y] - output[y]);
}
}
/// <summary>
/// Initializes the wavelet filter.
/// </summary>
/// <param name="waveletDecomposition">Discrete wavelet decomposition</param>
/// <param name="factor">Factor [-1, 1]</param>
public WaveletFilter(WaveletDecomposition waveletDecomposition, float factor = -1.0f)
{
WaveletDecomposition = waveletDecomposition;
Factor = factor;
}
