Needs camera and quite sophisticated software. The computer may take the most power and run hot. Hopefully it is general purpose enough so that it can be detached and used inside for gaming, 3D-design etc.

Identification of leafs may be more reliable with a multispectral camera, at least on daylight, but at night on LED-light may not help. Assuming there are other yellow things around.

EDIT:

Works more like a rake and could literally have a special version of a rake to pick 100 leaves in one movement. Or something else. Rake-head selection might depend on the tree species and type of lawn.

Before leaf blowers, rakes were deemed efficient enough.

Word about definitions:

Usually, the word "ground drone" implies that the robot has wheels or tracks and not in any way a helicopter or boat either. Might have 2, 4, 6 or 8 legs. Or skis+movers. Amphibious drone could be on ground or water. If a heli-drone has little wheels for taxiing to hangar, it does not make it a ground drone, not really.

The most common ground drone or UGV these days is robotic lawnmower that cuts grass. It is silent.