/// <summary>
/// Creates a morphological structuring element of type
/// 'arbitrary'.
/// </summary>
/// <remarks>
/// <paramref name="nhood"/> is a matrix containing 1s and 0s.
/// The locations of 1s define the neighborhood for the
/// morphological operator. The origin of
/// <paramref name="nhood"/> is its center element.
/// </remarks>
/// <param name="nhood"></param>
/// <returns>
/// The created <see cref="StructuringElement"/>.
/// </returns>
public static StructuringElement CreateArbitrary(Matrix nhood)
{
StructuringElement se = new StructuringElement();
se.nhood = nhood;
/*int height = nhood.Height;
* int width = nhood.Width;
*
* if (neighborhood.All && height > 1 && width > 1)
* {
* // The structuring element has an all-ones neighborhood.
* // Decide if the SE should be decomposed.
*
* int advantage = (height * width) / (height + width);
*
* // Heuristic: if the theoretical computation advantage is
* // minimum a factor of 2, then we assume that the overhead cost
* // is worth to execute dilation or erosion twice.
* if (advantage >= 2) {
* Matrix sed1 = Matrix.Ones(height, 1);
* Matrix sed2 = Matrix.Ones(1, width);
*
* // TODO: add SEDs to queue
* }
* }*/
return(se);
}
/// <summary>
/// Creates a morphological structuring element of type
/// 'octagon'.
/// </summary>
/// <example>
/// StructuringElement.CreateOctagon(3);
/// Neighborhood =
/// |- 3 -|
/// 0,0,1,1,1,0,0 -
/// 0,1,1,1,1,1,0 3
/// 1,1,1,1,1,1,1 |
/// 1,1,1,1,1,1,1 -
/// 1,1,1,1,1,1,1
/// 0,1,1,1,1,1,0
/// 0,0,1,1,1,0,0
/// </example>
/// <param name="radius">
/// Specifies the distance from the origin to the border.
/// </param>
/// <returns>
/// The created <see cref="StructuringElement"/>.
/// </returns>
public static StructuringElement CreateOctagon(byte radius)
{
int length = 2 * radius + 1;
Matrix rr = new Matrix(length, length);
Matrix cc = new Matrix(length, length);
byte idx_off = 0;
//rr.BeginLoadData();
//cc.BeginLoadData();
for (int r = 0; r < length; r++)
{
idx_off = radius;
while (idx_off > 0)
{
rr[radius - idx_off, r] = idx_off;
rr[radius + idx_off, r] = idx_off;
cc[r, radius - idx_off] = idx_off;
cc[r, radius + idx_off] = idx_off;
idx_off--;
}
}
//rr.EndLoadData();
//cc.EndLoadData();
byte k = (byte)(radius / 3);
Matrix oct = rr + cc;
oct = (oct <= (radius + k));
Console.WriteLine(rr.ToString());
Console.WriteLine(cc.ToString());
Console.WriteLine(oct.ToString());
StructuringElement se = new StructuringElement();
se.nhood = oct;
return(se);
}
/// <summary>
/// Creates a morphological structuring element of type
/// 'diamond'.
/// </summary>
/// <example>
/// StructuringElement.CreateDiamond(4);
/// Neighborhood =
/// |-- 4 --|
/// 0,0,0,0,1,0,0,0,0 -
/// 0,0,0,1,1,1,0,0,0 |
/// 0,0,1,1,1,1,1,0,0 4
/// 0,1,1,1,1,1,1,1,0 |
/// 1,1,1,1,1,1,1,1,1 -
/// 0,1,1,1,1,1,1,1,0
/// 0,0,1,1,1,1,1,0,0
/// 0,0,0,1,1,1,0,0,0
/// 0,0,0,0,1,0,0,0,0
/// </example>
/// <param name="radius">
/// Specifies the distance from the origin to the border.
/// </param>
/// <returns>
/// The created <see cref="StructuringElement"/>.
/// </returns>
public static StructuringElement CreateDiamond(byte radius)
{
int length = 2 * radius + 1;
Matrix rr = new Matrix(length, length);
Matrix cc = new Matrix(length, length);
byte idx_off = 0;
//rr.BeginLoadData();
//cc.BeginLoadData();
for (int r = 0; r < length; r++)
{
idx_off = radius;
while (idx_off > 0)
{
rr[radius - idx_off, r] = idx_off;
rr[radius + idx_off, r] = idx_off;
cc[r, radius - idx_off] = idx_off;
cc[r, radius + idx_off] = idx_off;
idx_off--;
}
}
//rr.EndLoadData();
//cc.EndLoadData();
Matrix diamond = rr + cc;
diamond = (diamond <= radius);
Console.WriteLine(rr.ToString());
Console.WriteLine(cc.ToString());
Console.WriteLine(diamond.ToString());
StructuringElement se = new StructuringElement();
se.nhood = diamond;
return(se);
}
/*public static StructuringElement CreateLine (ushort length,
* byte angle)
* {
* float theta = (float)((angle * System.Math.PI) / 180.0);
* double sin_theta = System.Math.Sin(theta);
* double cos_theta = System.Math.Cos(theta);
* int x2 = (int)System.Math.Round((length / 2) * cos_theta);
* int y2 = -(int)System.Math.Round((length / 2) * sin_theta);
*
* int x1 = -x2;
* int y1 = -y2;
*
* int dx = System.Math.Abs(x2 - x1);
* int dy = System.Math.Abs(y2 - y1);
*
* StructuringElement se = new StructuringElement();
* //se.nhood = pair;
* return se;
* }*/
/// <summary>
/// Creates a morphological structuring element of type
/// 'periodic line' with 2 * <paramref name="el"/> + 1 elements
/// which have a logical '1' value.
/// </summary>
/// <example>
/// StructuringElement.CreatePeriodicLine(2, 2, 1);
/// Neighborhood =
/// 1,0,0,0,0,0,0,0,0
/// 0,0,1,0,0,0,0,0,0
/// 0,0,0,0,1,0,0,0,0
/// 0,0,0,0,0,0,1,0,0
/// 0,0,0,0,0,0,0,0,1
/// </example>
/// <param name="el">
/// The SE will have 2 * el + 1 elements which have a logical
/// '1' value.
/// </param>
/// <param name="xOff">
/// The column offset between two '1' elements.
/// </param>
/// <param name="yOff">
/// The row offset between two '1' elements.
/// </param>
/// <returns>
/// The created <see cref="StructuringElement"/>.
/// </returns>
public static StructuringElement CreatePeriodicLine(ushort el,
short xOff,
short yOff)
{
int length = 2 * el + 1;
int colMax = 0;
int rowMax = 0;
Matrix idx = new Matrix(length, 2);
for (int i = 0; i < length; i++)
{
byte c = (byte)((i - el) * xOff);
byte r = (byte)((i - el) * yOff);
idx[0, i] = c;
idx[1, i] = r;
colMax = (c > colMax) ? c : colMax;
rowMax = (r > rowMax) ? r : rowMax;
}
int cols = 2 * colMax + 1;
int rows = 2 * rowMax + 1;
Matrix nhood = new Matrix(rows, cols);
for (int r = 0; r < length; r++)
{
int x = idx[0, r] + colMax;
int y = idx[1, r] + rowMax;
nhood[x, y] = 1;
}
Console.WriteLine(nhood.ToString());
StructuringElement se = new StructuringElement();
se.nhood = nhood;
return(se);
}
/// <summary>
/// Creates a morphological structuring element of type 'pair'
/// with 2 elements which have a logical '1' value. One of
/// these 2 elements is the origin in the center of the SE,
/// the other one is positioned with <paramref name="xOff"/>
/// and <paramref name="yOff"/> relatively to the origin.
/// </summary>
/// <example>
/// StructuringElement.CreatePair(-2, -3);
/// Neighborhood =
/// 1,0,0,0,0
/// 0,0,0,0,0
/// 0,0,0,0,0
/// 0,0,1,0,0
/// 0,0,0,0,0
/// 0,0,0,0,0
/// 0,0,0,0,0
/// </example>
/// <param name="xOff">
/// The column offset between the origin and the second element
/// </param>
/// <param name="yOff">
/// The row offset between the origin and the second element.
/// </param>
/// <returns></returns>
public static StructuringElement CreatePair(short xOff,
short yOff)
{
int xAbsOff = System.Math.Abs(xOff);
int yAbsOff = System.Math.Abs(yOff);
int width = xAbsOff * 2 + 1;
int height = yAbsOff * 2 + 1;
Matrix pair = new Matrix(height, width);
//pair.BeginLoadData ();
pair [xAbsOff, yAbsOff] = 1; //origin
pair [xAbsOff + xOff, yAbsOff + yOff] = 1;
//pair.EndLoadData ();
Console.WriteLine(pair.ToString());
StructuringElement se = new StructuringElement();
se.nhood = pair;
return(se);
}