/// <summary>
///
/// </summary>
/// <param name="img"></param>
/// <param name="configs"></param>
/// <returns></returns>
public override byte[,] ApplyFilter(byte[,] img, SortedDictionary<string, object> configs)
{
byte[,] ret = null; FourierTransform ft = new FourierTransform();
// Preprocess image.
int width = img.GetLength(0), height = img.GetLength(1), x, y;
double[,] imgProcessed = new double[width, height];
const double magic = 0.5;
//double min = double.MaxValue;
//// Find min.
//for (x = 0; x < width; ++x)
//{
// for (y = 0; y < height; ++y)
// {
// min = Math.Min(img[x, y], min);
// }
//}
// "normalize"
for (x = 0; x < width; ++x)
{
for (y = 0; y < height; ++y)
{
imgProcessed[x, y] = Math.Log(img[x, y] + magic, Math.E);
}
}
// Take fourier transform.
ComplexImage homomorph = ft.ApplyTransformBase(imgProcessed);
// (x)(a) Perform butterworth high pass to select reflectance;
// perform butterworth low pass to select illuminance.
// **** OR ****
// (b) Apply butterworth-generated weigth to select reflectance (1.0 in center)
// Apply (1.0 - butterworth-generated weigth) to select illuminance (0.0 in center)
// **** OR ****
// (c) Apply high pass buttwerworth. only.
SortedDictionary<string, object> hConfigs = reflectGetter.GetDefaultConfigs();
hConfigs["D0"] = configs["Butterworth-D0"];
hConfigs["n"] = configs["Butterworth-n"];
ComplexImage reflect = reflectGetter.ApplyFilter(homomorph, hConfigs);
ComplexImage illumin = illuminGetter.ApplyFilter(homomorph, hConfigs);
// (1, 1) = imagem original
// (1, 0) = high pass
// (0, 1) = low pass
double alpha = double.Parse(configs["Alpha"].ToString());
double beta = double.Parse(configs["Beta"].ToString());
// Generate new, Homomorphic-treated image
//(c)
//homomorph = illumin;
// Split into reflectance and illuminance
// - Sharp reflectance, smooth illuminance
// - sum
for (x = 0; x < homomorph.Width; ++x)
{
for (y = 0; y < homomorph.Height; ++y)
{
//(a)
homomorph[x, y] = new Complex(
reflect[x, y].real * beta + // Reflectance part
illumin[x, y].real * alpha // Illuminance part
,
reflect[x, y].imag * beta + // Reflectance part
illumin[x, y].imag * alpha // Illuminance part
);
}
}
// ... back to spatial domain.
imgProcessed = ft.ApplyReverseTransformBase(homomorph);
// Pos-process image.
ret = new byte[width, height];
for (x = 0; x < width; ++x)
{
for (y = 0; y < height; ++y)
{
ret[x, y] = (byte)Math.Max(byte.MinValue, Math.Min(byte.MaxValue, Math.Exp(imgProcessed[x, y]) - magic));
}
}
return ret;
}
