Dictionary <int, List <Coordinate> > ExtractRawCoordinates(IBitGrid grid)
{
var labeling = new int[grid.Width, grid.Height];
var labelRelation = new EquivalenceRelation <int>();
var nextLabel = 1;
for (int y = 0; y < grid.Height; y++)
{
for (int x = 0; x < grid.Width; x++)
{
if (!grid.IsSet(x, y))
{
continue;
}
if (grid.IsSet(x, y - 1))
{
labeling[x, y] = labeling[x, y - 1];
}
else if (grid.IsSet(x - 1, y))
{
labeling[x, y] = labeling[x - 1, y];
if (grid.IsSet(x + 1, y - 1))
{
labelRelation.Relate(labeling[x - 1, y], labeling[x + 1, y - 1]);
}
}
else if (grid.IsSet(x - 1, y - 1))
{
labeling[x, y] = labeling[x - 1, y - 1];
if (grid.IsSet(x + 1, y - 1))
{
labelRelation.Relate(labeling[x - 1, y - 1], labeling[x + 1, y - 1]);
}
}
else if (grid.IsSet(x + 1, y - 1))
{
labeling[x, y] = labeling[x + 1, y - 1];
}
else
{
labeling[x, y] = nextLabel;
labelRelation.AddElement(nextLabel);
nextLabel++;
}
}
}
var coordinateLabeling = new Dictionary <int, List <Coordinate> >();
for (int y = 0; y < grid.Height; y++)
{
for (int x = 0; x < grid.Width; x++)
{
if (labeling[x, y] == 0)
{
continue;
}
var objectLabel = labelRelation.FindRepresentative(labeling[x, y]);
List <Coordinate> coordinates;
if (!coordinateLabeling.TryGetValue(objectLabel, out coordinates))
{
coordinates = new List <Coordinate>();
coordinateLabeling[objectLabel] = coordinates;
}
coordinates.Add(new Coordinate(x, y));
}
}
return(coordinateLabeling);
}
public IEnumerable <IObject> EnumerateObjects(IBitGrid grid)
{
return(ExtractRawCoordinates(grid).Select(kvp => Classifier.ClassifyAndCreate(kvp.Value)));
}