Watershed by accord

Bitmap input = ... 

// Apply the transform
var dt = new BinaryWatershed();
Bitmap output = dt.Apply(input);

// Show results on screen
ImageBox.Show("input", input);
ImageBox.Show("output", output);

// Mark points using PointsMarker
var marker = new PointsMarker(Color.Red, 5)
{
    Points = bw.MaxPoints
};

Bitmap marked = marker.Apply(result);
ImageBox.Show("markers", marked);