private static void DFS(Vector2D START)
{
Stack<Vector2D> DFS_Stack = new Stack<Vector2D>();
DFS_Stack.Push(START);
while (DFS_Stack.Count > 0)
{
Vector2D Curr = DFS_Stack.Pop();
if(Helper.Vaild_Pixel((int)Curr.X, (int)Curr.Y, selected_image))
{
if(!selected_image[(int)Curr.Y, (int)Curr.X].block)
{
selected_image[(int)Curr.Y, (int)Curr.X].block = true;
//black or whiteen the pixel
selected_image[(int)Curr.Y, (int)Curr.X].blue = 240; //bgclor
selected_image[(int)Curr.Y, (int)Curr.X].green = 240;
selected_image[(int)Curr.Y, (int)Curr.X].red = 240;
DFS_Stack.Push(new Vector2D(Curr.X, Curr.Y + 1));
DFS_Stack.Push(new Vector2D(Curr.X, Curr.Y - 1));
DFS_Stack.Push(new Vector2D(Curr.X + 1, Curr.Y));
DFS_Stack.Push(new Vector2D(Curr.X - 1, Curr.Y));
}
}
}
}
/// <summary>
/// Calculate Gradient vector between the given pixel and its right and bottom ones
/// </summary>
/// <param name="x">pixel x-coordinate</param>
/// <param name="y">pixel y-coordinate</param>
/// <param name="ImageMatrix">colored image matrix</param>
/// <returns></returns>
private static Vector2D CalculateGradientAtPixel(int x, int y, RGBPixel[,] ImageMatrix)
{
Vector2D gradient = new Vector2D(0, 0);
RGBPixel mainPixel = ImageMatrix[y, x];
double pixelGrayVal = 0.21 * mainPixel.red + 0.72 * mainPixel.green + 0.07 * mainPixel.blue;
if (y == GetHeight(ImageMatrix) - 1)
{
//boundary pixel.
for (int i = 0; i < 3; i++)
{
gradient.Y = 0;
}
}
else
{
RGBPixel downPixel = ImageMatrix[y + 1, x];
double downPixelGrayVal = 0.21 * downPixel.red + 0.72 * downPixel.green + 0.07 * downPixel.blue;
gradient.Y = pixelGrayVal - downPixelGrayVal;
}
if (x == GetWidth(ImageMatrix) - 1)
{
//boundary pixel.
gradient.X = 0;
}
else
{
RGBPixel rightPixel = ImageMatrix[y, x + 1];
double rightPixelGrayVal = 0.21 * rightPixel.red + 0.72 * rightPixel.green + 0.07 * rightPixel.blue;
gradient.X = pixelGrayVal - rightPixelGrayVal;
}
return gradient;
}
/// <summary>
/// Calculate edge energy between
/// 1. the given pixel and its right one (X)
/// 2. the given pixel and its bottom one (Y)
/// </summary>
/// <param name="x">pixel x-coordinate</param>
/// <param name="y">pixel y-coordinate</param>
/// <param name="ImageMatrix">colored image matrix</param>
/// <returns>edge energy with the right pixel (X) and with the bottom pixel (Y)</returns>
public static Vector2D CalculatePixelEnergies(int x, int y, RGBPixel[,] ImageMatrix)
{
if (ImageMatrix == null)
throw new Exception("image is not set!");
Vector2D gradient = CalculateGradientAtPixel(x, y, ImageMatrix);
double gradientMagnitude = Math.Sqrt(gradient.X * gradient.X + gradient.Y * gradient.Y);
double edgeAngle = Math.Atan2(gradient.Y, gradient.X);
double rotatedEdgeAngle = edgeAngle + Math.PI / 2.0;
Vector2D energy = new Vector2D(
Math.Abs(gradientMagnitude * Math.Cos(rotatedEdgeAngle)),
Math.Abs(gradientMagnitude * Math.Sin(rotatedEdgeAngle)));
return energy;
}