The convention standard for object detection uses a bounding box to represent each individual object instance.
However, it is not practical in the industry-relevant applications in the context of warehouses due to severe occlusions among groups of instances of the same categories.
For example, as shown in Fig. 1(c), it is extremely difficult to annotate the stacked dinner plates even by a well-trained annotator.
Meanwhile, it is almost impossible for object detectors to detect all stacked dinner plates accurately, even for the state-of-the-art detectors.
Thus, it is necessary to rethink the definition of object detection in such scenarios.
