How to ensure that the 2D query corresponds to the same target in different perspective images?

[xifen523]

From Fig. 2 of the paper, it is given that object 4 corresponds to two queries, corresponding to the left-front image and the frontal image of two perspectives respectively. How do you know that this query will correspond to the same target?

[InchSoup]

We use the camera parameters to project the 3D anchor onto the image plane. If it is a cross-camera target, it will be projected onto multiple cameras (as in object 4 in Figure 2).
This guides the generation of 2D queries so that 2D queries in different perspectives are sharing (or allocated by) the same 3D query, which means these 2D queries correspond to the same target.