internal Node Apply(Patch p)
{
var nd = Root;
while(!nd.IsLeaf) {
if (nd.Feature.ComputeFeature(p)) nd=nd.Right; else nd=nd.Left;
}
return nd;
}
public void AddPatches(List<Patch> patches,int offsetx, int offsety,int patchWidth,int patchHeight)
{
int w = Bitmap.PixelWidth;
int h = Bitmap.PixelHeight;
for (int y = 0; y <= h - patchHeight; y += offsety)
{
for (int x = 0; x <= w - patchWidth; x += offsetx)
{
var p = new Patch { Left = x, Top = y, Width = patchWidth, Height = patchHeight, Image = this };
patches.Add(p);
}
}
}
/// <summary>
/// Computes the feature.
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
public bool ComputeFeature(Patch p)
{
double angleInRads = 2 * Math.PI * p.Angle / 360.0;
var cos = Math.Cos(angleInRads);
var sin = Math.Sin(angleInRads);
double rotx = OffsetX * cos - OffsetY * sin;
double roty = OffsetX * sin + OffsetY * cos;
// todo: check that this doesn't go outside of the patch.
int tx = p.Left + p.NudgeX+ + p.Width / 2 + (int)Math.Round(rotx);
int ty = p.Top + p.NudgeY+ p.Height / 2 + (int)Math.Round(roty);
var px = p.Image.Pixels[ty, tx];
byte val = px.Red;
if (Channel == 1) val = px.Green; else if (Channel == 2) val=px.Blue;
return (LowerThreshold <= val) && (val<UpperThreshold);
}
public void Sample(Random rnd, Patch p)
{
bool inCircle = false;
int halfWidth = p.Width / 2;
do
{
// todo: work out about even vs odd size patches
OffsetX = rnd.Next(p.Width) - halfWidth;
OffsetY = rnd.Next(p.Height) - p.Height/2;
inCircle = (OffsetX * OffsetX + OffsetY * OffsetY)<=(halfWidth*halfWidth);
} while (!inCircle);
LowerThreshold = rnd.Next(256);
UpperThreshold = rnd.Next(256);
if (LowerThreshold > UpperThreshold)
{
var dummy = LowerThreshold;
LowerThreshold = UpperThreshold;
UpperThreshold = dummy;
}
UpperThreshold = 256;
Channel = (byte)rnd.Next(3);
}
private List<IFeature> GetFeatures(Patch p,int N)
{
var features = new List<IFeature>();
for (int i = 0; i < N; i++)
{
bool useHist = rnd.Next(3)>0;
var f = useHist ? (IFeature)new HistogramFeature() : (IFeature)new AbsoluteIntensityFeature();
f.Sample(rnd,p);
features.Add(f);
}
return features;
}
public void Sample(Random rnd, Patch p)
{
Bin = rnd.Next(p.Histogram[0].Length);
Threshold = rnd.Next(p.Width * p.Height);
Channel = (byte)rnd.Next(3);
}
public bool ComputeFeature(Patch p)
{
return p.Histogram[Channel][Bin] > Threshold;
}