Has there been any work in applying models serially? I know we have the option in BI to run ALPR only on vehicle detections, but for the delivery model, I'd also only want it running if first there was a vehicle detection, and ideally, it would crop and only send the vehicle portion of the image to the model. This is especially useful if say you have a 4k camera and a vehicle at the end of the driveway. If the whole image is fed to a delivery model, and scaled to 640x640, then there might not be enough detail, but if just the vehicle is checked, then there will be plenty of detail.
I think about this for other models as well, like face detection only for confirmed people. If you detect a dog, then you can run a dog breed model, which may identify the dog as yours or someone else's.
There are any number of specialized models which one may want to run only after detecting something in a general model.