/// <summary>
/// Initializes the Laplace pyramid filter.
/// </summary>
/// <param name="lap">Laplacian pyramid</param>
/// <param name="factor">Factor [-1, 1]</param>
public LaplacianPyramidFilter(LaplacianPyramidTransform lap, float factor = -1.0f)
{
this.lap = lap;
this.factor = factor;
}
/// <summary>
/// Local laplacian filter.
/// </summary>
/// <param name="input">Input data</param>
/// <param name="radius">Radius</param>
/// <param name="sigma">Sigma</param>
/// <param name="factor">Factor</param>
/// <param name="n">Number of steps</param>
/// <param name="levels">Levels</param>
/// <returns>Output data</returns>
internal static void llfilter(float[] input, int radius, float sigma, float factor, int n, int levels)
{
// exception
if (factor == 0)
{
return;
}
// data
int height = input.GetLength(0);
int y, level, length = 256;
float step = 1.0f / n;
float min = 0.0f, max = 1.0f;
// pyramids
int n_levels = (int)Math.Min((Math.Log(height) / Math.Log(2)), levels);
LaplacianPyramidTransform lpt = new LaplacianPyramidTransform(n_levels, radius);
GaussianPyramidTransform gpt = new GaussianPyramidTransform(n_levels, radius);
float[][] input_gaussian_pyr = gpt.Forward(input);
float[][] output_laplace_pyr = lpt.Forward(input_gaussian_pyr);
float[][] temp_laplace_pyr;
float[] I_temp, I_gaus, I_outp;
float[] T;
// do job
for (float i = min; i <= max; i += step)
{
height = input.GetLength(0);
I_temp = new float[height];
T = Rem(sigma, factor, i, length);
// remapping function
for (y = 0; y < height; y++)
{
I_temp[y] = T[Maths.Byte(input[y] * (length - 1))];
}
temp_laplace_pyr = lpt.Forward(I_temp);
T = Rec(i, step, length);
// pyramid reconstruction
for (level = 0; level < n_levels; level++)
{
I_gaus = input_gaussian_pyr[level];
I_temp = temp_laplace_pyr[level];
I_outp = output_laplace_pyr[level];
height = I_outp.GetLength(0);
for (y = 0; y < height; y++)
{
I_outp[y] += T[Maths.Byte(I_gaus[y] * (length - 1))] * I_temp[y];
}
output_laplace_pyr[level] = I_outp;
}
}
// backward transform
I_outp = lpt.Backward(output_laplace_pyr);
height = input.GetLength(0);
for (y = 0; y < height; y++)
{
input[y] = I_outp[y];
}
return;
}