public static double CalculateAngle(Descriptor first, Descriptor second)
{
return(Math.Acos(Math.Round(Descriptor.InnearMultiplication(first, second) / (first.Norm * second.Norm), 15)));
}
public void CreateDescriptors()
{
this.descriptors = new List <Descriptor>();
for (int k = this.keypoints.Count - 1; k >= 0; k--)
{
int t = this.keypoints[k].ExtermaIndex;
int scale = (int)extermas[t].ScaleLevel;
int blure = (int)extermas[t].BlureLevel;
int index = GetImageIndex(scale, blure);
int row = (int)extermas[t].Row;
int column = (int)extermas[t].Column;
double rotationAngle = keypoints[k].Orientation;
Matrix neighbour = GeometricEnhancement.GetImagePortion(this.scaleSpace[index], row, column, 9, rotationAngle);
//Matrix angle = new Matrix(17, 17);
List <double>[,] histogram = new List <double> [4, 4];
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
histogram[i, j] = new List <double>(new double[8]);
}
}
double sigma = 16 * 0.5;
double sigma2 = sigma * sigma;
//
for (int i = row - 8; i < row + 8; i++)
{
for (int j = column - 8; j < column + 8; j++)
{
int xPrime = j - column; int yPrime = i - row;
double magnitude = CalculateMagnitude(neighbour, j - (column - 8) + 1, (i - (row - 8)) + 1);
double tempAngle = CalculateAngle(neighbour, j - (column - 8) + 1, (i - (row - 8)) + 1) - rotationAngle;
double angle = tempAngle >= 0 ? tempAngle : 2 * Math.PI + tempAngle;
//
double angleD = angle * 180 / Math.PI;
double rotationD = rotationAngle * 180 / Math.PI;
int temp = (int)Math.Floor(angle / (Math.PI / 4)) % 8; //8 bin
int tempI = (int)(Math.Floor((i - row + 8) / 4.0));
int tempJ = (int)(Math.Floor((j - column + 8) / 4.0));
histogram[tempI, tempJ][temp] += magnitude * 1 / (2 * Math.PI * sigma2) * Math.Exp(-(xPrime * xPrime + yPrime * yPrime) / (2 * sigma2));
}
}
List <double> tempResult = new List <double>();
foreach (List <double> item in histogram)
{
tempResult.AddRange(item.ToArray());
}
Descriptor descriptor = new Descriptor(this.extermas[t], this.keypoints[k], tempResult.ToArray());
if (descriptor.Norm != 0)
{
this.descriptors.Add(descriptor);
}
else
{
this.keypoints.RemoveAt(k);
//this.extermas.Remove(k);
}
//this.descriptors.Add();
}
}