/// <summary>
/// Calculates the perimeter of every object in a labeled image.
/// </summary>
/// <param name="image">A labeled image to process</param>
/// <returns>A Dictionary with perimeter per color label</returns>
public static Dictionary<Color, int> Perimeters(this Color[,] image)
{
return image.ChainCode().ToDictionary(x => x.Key, x => x.Value.Count());
}
public static Dictionary<Color, Rectangle> BoundingBox(this Color[,] image)
{
Dictionary<Color, Tuple<int, int>> firstPixels = image.FirstPixels();
Dictionary<Color, int[]> chainCode = image.ChainCode();
Dictionary<Color, List<Tuple<int,int>>> borders = new Dictionary<Color, List<Tuple<int, int>>>();
Dictionary<Color, double> thetas = image.AxisOfLeastMomentInertia();
Dictionary<Color, Tuple<double, double>> centroids = image.Centroids();
Dictionary<Color, Rectangle> result = new Dictionary<Color, Rectangle>();
foreach (Color key in chainCode.Keys) {
int[] value = chainCode[key];
Tuple<int, int> currentPixel = firstPixels[key];
List<Tuple<int, int>> listPixels = new List<Tuple<int, int>>();
listPixels.Add(currentPixel);
borders.Add(key, listPixels);
for (int i = 0; i < value.Length; i++) {
currentPixel = translate(currentPixel.Item1, currentPixel.Item2, value[i]);
borders[key].Add(currentPixel);
//borders.Add(key, listPixels);
}
foreach (Tuple<int,int> c in borders[key])
image[c.Item1, c.Item2] = Color.White;
double theta = thetas[key];
double centroidX = centroids[key].Item1;
double centroidY = centroids[key].Item2;
double sinTheta = Math.Sin(theta);
double cosTheta = Math.Cos(theta);
// Find min max for key
int minX= 512, minY= 512, maxX = 0, maxY = 0;
foreach ( Tuple<int,int> coord in borders[key] ) {
double x = coord.Item1 - centroidX;
double y = coord.Item2 - centroidY;
int newX = (int)((cosTheta * x) + ( sinTheta * y ));
int newY = (int)((-1 * sinTheta * x) + (cosTheta * y));
if ( newX < minX )
minX = newX;
if (newX > maxX)
maxX = newX;
if (newY < minY)
minY = newY;
if (newY > maxY)
maxY = newY;
}
if (new int[4] { minX, minY, maxX, maxY }.Any(x => x == int.MinValue || x == int.MaxValue))
continue;
Rectangle boundingBox = new Rectangle(minX + (int)centroidX, minY + (int)centroidY, Math.Abs(minX) + maxX, Math.Abs(minY) + maxY);
result.Add(key, boundingBox);
}
return result;
}
