A system and method for reliably detecting singulated parcels traveling on a conveyor belt by comparing parcel characteristics before and after parcel agitation. First, parcel characteristics are evaluated. Then parcels are agitated to promote a change in characteristics, for example volume or dimensions, of the unsingulated parcels. Next, parcel characteristics are again evaluated and compared to the previously-evaluated characteristics. If there is no appreciable difference in characteristics, the parcel is deemed singulated.