public Vector SobelY(Vector L)
{
if (L.Dim != 3)
throw new Exception("sobel dim error");
Vector Ly = new Vector(3);
Ly[2] = L[0] + 2 * L[1] + L[2];
Ly[1] = 0;
Ly[0] = -Ly[2];
return Ly;
}
public Vector SobelX(Vector L)
{
if (L.Dim != 3)
throw new Exception("sobel dim error");
Vector Lx = new Vector(3);
Lx[0] = L[2] - L[0];
Lx[1] = 2 * Lx[0];
Lx[2] = Lx[0];
return Lx;
}
public static Vector operator -(Vector one, Vector other)
{
if (one.Dim != other.Dim)
throw new Exception("Vector lengths aren't the same");
Vector newV = new Vector(one);
for (int i = 0; i < other.Dim; i++)
newV[i] -= other[i];
return newV;
}
public static Vector operator /(Vector one, double param)
{
Vector newV = new Vector(one);
for (int i = 0; i < one.Dim; i++)
newV[i] /= param;
return newV;
}
public void SetRow(int position, Vector row)
{
if (Width != row.Dim)
throw new Exception("Dim Error");
for (int i = 0; i < Width; i++)
field[i, position] = row[i];
}
public Vector(Vector other)
{
field = new double[other.Dim];
for (int i = 0; i < other.Dim; i++)
field[i] = other[i];
}
public void SetColumn(int position, Vector column)
{
if (Height != column.Dim)
throw new Exception("Dim Error");
for (int i = 0; i < Height; i++)
field[position, i] = column[i];
}
public Vector Row(int position)
{
Vector newV = new Vector(Width);
for (int i = 0; i < Width; i++)
newV[i] = field[i, position];
return newV;
}
public Matrix GaussianElimination()
{
//if (Height != Width)
// throw new Exception();
Matrix newM = new Matrix(this);
int position = -1;
double param = 0;
int count = 0;
Vector positionV = new Vector(Width);
for (int i = 0; i < Width; i++)
{
if (position != -1)
{
newM.SwitchRow(position, count);
count++;
position = -1;
}
for (int j = count; j < Height; j++)
{
if (newM.field[i, j] != 0)
{
if (position != -1)
newM.SetRow(j, newM.Row(j) - positionV * newM[i, j] / param);
else
{
position = j;
param = newM[i, j];
newM.SetRow(j, newM.Row(j));
positionV = newM.Row(j);
}
}
}
}
return newM;
}
public Vector Column(int position)
{
Vector newV = new Vector(Height);
for (int i = 0; i < Height; i++)
newV[i] = field[position, i];
return newV;
}
public static Vector operator *(Matrix one, Vector other)
{
if (one.Width != other.Dim)
throw new Exception("Dim Error");
Vector newV = new Vector(one.Height);
for (int i = 0; i < newV.Dim; i++)
newV[i] = other * one.Row(i);
return newV;
}
public WriteableBitmap EdgeDetection(WriteableBitmap bmap, double bound)
{
int height = bmap.PixelHeight - 1;
int width = bmap.PixelWidth - 1;
Matrix thetaM = new Matrix(width, height);
Matrix greyM = new Matrix(width + 1, height + 1);
for (int i = 0; i < greyM.Width; i++)
for (int j = 0; j < greyM.Height; j++)
greyM[i, j] = Greyscale(bmap.GetPixel(i, j).R, bmap.GetPixel(i, j).G, bmap.GetPixel(i, j).B);
for (int i = 1; i < width; i++)
for (int j = 1; j < height; j++)
{
Vector lx = new Vector(3);
Vector ly = new Vector(3);
lx[0] = greyM[i - 1, j];
lx[1] = greyM[i, j];
lx[2] = greyM[i + 1, j];
ly[0] = greyM[i, j - 1];
ly[1] = greyM[i, j];
ly[2] = greyM[i, j + 1];
Vector slx = SobelX(lx);
Vector sly = SobelY(ly);
double gx = Math.Pow(slx * slx, 0.5);
double gy = Math.Pow(sly * sly, 0.5);
thetaM[i - 1, j - 1] = Math.Atan2(gy, gx);
}
WriteableBitmap plot = BitmapFactory.New(width, height);
for (int i = 0; i < width; i++)
for (int j = 0; j < height; j++)
{
if (thetaM[i, j] > bound)
plot.SetPixel(i, j, Colors.White);
else
plot.SetPixel(i, j, Colors.Black);
}
return plot;
}
