/// <summary>
/// Create a 2D filter kernel matrix populated in accordance with
/// filterKernelFun, with size (SX, SY) = (2 * radius + 1,
/// 2 * radius + 1) and anchor in the center at index (0, 0).
/// Functions to use as filterKernelFun are available in FilterKernelFun.
/// </summary>
/// <param name="radius"></param>
/// <param name="filterKernelFun">Function is evaluated at integer coordinates from (-radius,-radius) to (+radius,+radius).</param>
public static Matrix <float> Create2DKernel(
long radius, Func <float, float, float> filterKernelFun)
{
var kernel = new Matrix <float>(2 * radius + 1, 2 * radius + 1)
{
FX = -radius, FY = -radius
};
kernel.SetByCoord((long x, long y) => filterKernelFun((float)x, (float)y));
return(kernel);
}
/// <summary>
/// Computes an undistorted Grid with (count.X + 1, count.Y + 1) vertices
/// the coordinates are roughly in the range [0..imageSize.X, 0..imageSize.Y].
/// These can be used for a piecewise linear undistortion using the graphics
/// card. If count is not given, it is set to iamgeSize / 8, for one grid
/// point each 8 pixels.
/// </summary>
Matrix <V2f> ComputeUndistortedGrid(V2i imageSize, V2i count = default(V2i))
{
if (count == default(V2i))
{
count = imageSize / 8;
}
var grid = new Matrix <V2f>(count + V2i.II);
var delta = imageSize.ToV2d() / count.ToV2d();
var self = this;
grid.SetByCoord((x, y) => self.UndistortPixel(new V2d(x * delta.X, y * delta.Y), imageSize).ToV2f());
return(grid);
}