public override ulong Create(BitmapData image)
{
var data = new DenseMatrix(32, 32);
using (var unmanaged = new UnmanagedImage(image))
{
using (var filtered = ExtractChannel.Apply(unmanaged))
{
Filter.ApplyInPlace(filtered);
using (var imgdata = Resize.Apply(filtered))
{
unsafe
{
var src = (byte *)imgdata.ImageData.ToPointer();
var offset = imgdata.Stride - imgdata.Width;
var width = imgdata.Width;
var height = imgdata.Height;
for (var y = 0; y < height; y++)
{
for (var x = 0; x < width; x++, src++)
{
data.At(y, x, (float)*src / 255);
}
src += offset;
}
}
}
}
}
var dct = DctMatrix.FastDCT(data);
var vals = new double[dctsize * dctsize];
var valscount = 0;
for (var r = 1; r <= dctsize; r++)
{
for (var c = 1; c <= dctsize; c++)
{
vals[valscount] = dct.At(r, c);
++valscount;
}
}
var sorted = new double[dctsize * dctsize];
Array.Copy(vals, sorted, vals.Length);
Array.Sort(sorted);
var mid = dctsize * dctsize / 2;
var median = (sorted[mid - 1] + sorted[mid]) / 2d;
ulong index = 1;
ulong result = 0;
for (var i = 0; i < dctsize * dctsize; i++)
{
if (vals[i] > median)
{
result |= index;
}
index = index << 1;
}
return(result);
}
public override ulong Create(BitmapData image)
{
var data = new DenseMatrix(32, 32);
using (var unmanaged = UnmanagedImage.FromManagedImage(image))
using (var filtered = ExtractChannel.Apply(unmanaged))
{
new Convolution(Filter, 9).ApplyInPlace(filtered);
using (var imgdata = new ResizeNearestNeighbor(32, 32).Apply(filtered))
{
unsafe
{
byte *src = (byte *)imgdata.ImageData.ToPointer();
int offset = imgdata.Stride - imgdata.Width;
int width = imgdata.Width;
int height = imgdata.Height;
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++, src++)
{
data.At(y, x, (float)*src / 255);
}
src += offset;
}
}
}
}
var dct = DctMatrix.FastDCT(data);
int dctsize = 8;
var vals = new List <double>();
for (int r = 1; r <= dctsize; r++)
{
for (int c = 1; c <= dctsize; c++)
{
vals.Add(dct[r, c]);
}
}
var sorted = new List <double>(vals);
sorted.Sort();
var mid = dctsize * dctsize / 2;
double median = (sorted[mid - 1] + sorted[mid]) / 2d;
ulong index = 1;
ulong result = 0;
for (int i = 0; i < dctsize * dctsize; i++)
{
if (vals[i] > median)
{
result |= index;
}
index = index << 1;
}
return(result);
}