The architecture of OWLv2 is identical to OWL-ViT, however the object detection head now also includes an objectness classifier, which predicts the (query-agnostic) likelihood that a predicted box contains an object (as opposed to background). The objectness score can be used to rank or filter predictions independently of text queries.
Usage of OWLv2 is identical to OWL-ViT with a new, updated image processor ([Owlv2ImageProcessor]).