Hi Pavan,
We don't support that yet, we were thinking about adding an additional bounding box datatype with an output decoder, but it's not quite there yet. There are a bunch a specific projects that do only that, so if that's your use case you have plenty of options.
You can really vaguely approximate it with a certai number of numeric outputs in Ludwig (for instance 4 if you are looking for just one bounding box), but as there is no specific decoder I doubt it's going to work well.
Check out the next releases of Ludwig to see when we'll add it!