private static Complex2D DoScale(Complex2D channel, int dstWidth, int dstHeight)
{
var wFs = channel.Width;
var hFs = channel.Height;
var divX = dstWidth - wFs;
var divY = dstHeight - hFs;
Debug.Assert(divX != 0 || divY != 0, "No resize required.");
var xOffset = divX / 2;
var yOffset = divY / 2;
var xEnd = xOffset + wFs;
var yEnd = yOffset + hFs;
if (divX < 0 ||
divY < 0)
{
throw new Exception("New size is smaller than the input size");
}
var oldData = channel.Data;
// TODO: correct zero padding -> FFT shifted??
return(new Complex2D(
dstWidth,
dstHeight,
(i, j) => i >= xOffset && i < xEnd && j >= yOffset && j < yEnd
? oldData[(i - xOffset) + ((j - yOffset) * wFs)]
: Zero
));
}
public void Apply(Complex2D c)
{
var key = $"{_width}x{_height}";
double[] window;
if (!_winCache.TryGetValue(key, out window))
{
var hWin = CreateWindow1D(_width);
var vWin = _height == _width ? hWin : CreateWindow1D(_height);
window = new double[_width * _height];
for (int j = 0,
k = 0;
j < _height;
j++)
{
var fy = vWin[j];
for (var i = 0; i < _width; i++, k++)
{
window[k] = fy * hWin[i];
}
}
_winCache.Add(key, window);
}
var d = c.Data;
// elementwise multiply
if (c.Width == _width)
{
//non zero padded?
for (var i = 0; i < window.Length; i++)
{
d[i] *= window[i];
}
return;
}
//zero padded
var lf = c.Width - _width;
for (int i = 0,
j = 0;
i < window.Length;
j += lf)
{
for (var iLe = i + _width; i < iLe; i++, j++)
{
d[j] *= window[i];
}
}
}
/// <summary>
/// Creates a deblur filter from three channel in frequency domain.
/// </summary>
/// <param name="c0Freqz">channel 0 in frequency domain</param>
/// <param name="c1Freqz">channel 1 in frequency domain</param>
/// <param name="c2Freqz">channel 2 in frequency domain</param>
/// <param name="normalize">
/// if true, each pixel c_n with 0 < n < N-1 will be divided by 1/sum|c_n|, c_0 will be set
/// to 1+j0
/// </param>
/// <returns></returns>
public static DeblurFilter CreateFromFrequencies(Complex2D c0Freqz,
Complex2D c1Freqz,
Complex2D c2Freqz,
bool normalize = false)
{
var w = MathCV.Max(c0Freqz.Width, c1Freqz.Width, c2Freqz.Width);
var h = MathCV.Max(c0Freqz.Height, c1Freqz.Height, c2Freqz.Height);
var result = new DeblurFilter {
C0 = c0Freqz.Width != w || c0Freqz.Height != h?DoScale(c0Freqz, w, h) : new Complex2D(c0Freqz),
C1 = c1Freqz.Width != w || c1Freqz.Height != h?DoScale(c1Freqz, w, h) : new Complex2D(c1Freqz),
C2 = c2Freqz.Width != w || c2Freqz.Height != h?DoScale(c2Freqz, w, h) : new Complex2D(c2Freqz)
};
if (!normalize)
{
return(result);
}
var n = w * h;
var d0 = result.C0.Data;
var d1 = result.C1.Data;
var d2 = result.C2.Data;
var norm0 = (n - 1) / (d0.SumAbs() - d0[0].Magnitude);
var norm1 = (n - 1) / (d1.SumAbs() - d1[0].Magnitude);
var norm2 = (n - 1) / (d2.SumAbs() - d2[0].Magnitude);
d0[0] = d1[0] = d2[0] = Complex.One;
for (var i = 1; i < n; i++)
{
d0[i] *= norm0;
d1[i] *= norm1;
d2[i] *= norm2;
}
return(result);
}
public Complex2D[] Complex2DRoots()
{
double d = Math.Pow(B, 2) - 4 * A * C;
return(new Complex2D[] { (Complex2D.Sqrt(Math.Pow(B, 2) - 4 * A * C) - B) / (2 * A), (-Complex2D.Sqrt(Math.Pow(B, 2) - 4 * A * C) - B) / (2 * A) });
}
