private static WatershedPixel[,] PixelMap(float[,] input)
{
var width = input.GetLength(0);
var height = input.GetLength(1);
var result = new WatershedPixel[width, height];
for (var x = 0; x < width; x++)
{
for (var y = 0; y < height; y++)
{
result[x, y] = new WatershedPixel(x, y, input[x, y]);
}
}
return(result);
}
public static float[,] Watershed(float[,] input, byte color = 255)
{
var width = input.GetLength(0);
var height = input.GetLength(1);
var queue = new Queue <WatershedPixel>();
var result = new float[width, height];// input.Clone() as float[,];
var map = PixelMap(input);
var histogram = PixelHistogram(map);
var distance = 0;
var end = new WatershedPixel(-1, -1, 0);
var count = 0;
var label = 0;
for (var h = 0; h < histogram.Count; h++)
{
foreach (var pixel in histogram[h])
{
pixel.Label = WatershedLabel.Mask;
foreach (var neighbour in Neighbours(map, pixel.X, pixel.Y, width, height))
{
if (neighbour == null)
{
continue;
}
if (neighbour.Label > 0 || neighbour.Label == WatershedLabel.Watershed)
{
pixel.Distance = 1;
queue.Enqueue(pixel);
break;
}
}
}
distance = 1;
queue.Enqueue(end);
while (true)
{
var pixel = queue.Dequeue();
if (pixel.Equals(end))
{
if (queue.Count == 0)
{
break;
}
else
{
queue.Enqueue(pixel);
distance++;
pixel = queue.Dequeue();
}
}
foreach (var neighbour in Neighbours(map, pixel.X, pixel.Y, width, height))
{
if (neighbour == null)
{
continue;
}
if (neighbour.Distance <= distance &&
(neighbour.Label > 0 || neighbour.Label == WatershedLabel.Watershed))
{
if (neighbour.Label > 0)
{
if (pixel.Label == WatershedLabel.Mask)
{
pixel.Label = neighbour.Label;
}
else if (pixel.Label != neighbour.Label)
{
pixel.Label = WatershedLabel.Watershed;
count++;
}
}
else if (pixel.Label == WatershedLabel.Mask)
{
pixel.Label = WatershedLabel.Mask;
count++;
}
}
else if (neighbour.Label == WatershedLabel.Mask && neighbour.Distance == 0)
{
neighbour.Distance = distance + 1;
queue.Enqueue(neighbour);
}
}
}
foreach (var pixel in histogram[h])
{
pixel.Distance = 0;
if (pixel.Label == WatershedLabel.Mask)
{
label++;
pixel.Label = label;
queue.Enqueue(pixel);
while (queue.Count > 0)
{
var n = queue.Dequeue();
foreach (var neighbour in Neighbours(map, n.X, n.Y, width, height))
{
if (neighbour == null)
{
continue;
}
if (neighbour.Label == WatershedLabel.Mask)
{
neighbour.Label = label;
queue.Enqueue(neighbour);
}
}
}
}
}
}
if (count > 0)
{
for (var x = 0; x < width; x++)
{
for (var y = 0; y < height; y++)
{
if (map[x, y].Label == WatershedLabel.Watershed)
{
result[x, y] = color;
}
}
}
}
return(result);
}
public override bool Equals(object obj)
{
WatershedPixel p = (WatershedPixel)obj;
return(X == p.X && X == p.Y);
}
