3D position_embeding in frustrume

[BingyuZhou]

PETR/projects/mmdet3d_plugin/models/dense_heads/petrv2_head.py

Line 384 in f7525f9

coords3d = inverse_sigmoid(coords3d)

is it problematic here? the coord3d can be negative value, which makes inverse_sigmoid useless. Meanwhile, inverse_sigmoid gets value in [-inf, inf]. Isn't this position embedding value too large since it will add img feature later in attention?

BTW, what is usage of coords_mask? Seems not used.

Thanks!