anchor range in Anchor3DRangeGenerator

[mickeyouyou]

Simple question: why z axis of anchor range in Anchor3DRangeGenerator is same ? for code comment is z_min and z_max

anchor_range (torch.Tensor | list[float]): Range of anchors with
                shape [6]. The order is consistent with that of anchors, i.e.,
                (x_min, y_min, z_min, x_max, y_max, z_max).

like config below, they all use same value in z axis, Why?

                [0, -40.0, -0.6, 70.4, 40.0, -0.6],
                [0, -40.0, -0.6, 70.4, 40.0, -0.6],
                [0, -40.0, -1.78, 70.4, 40.0, -1.78],

and in my dataset there is a problem with this anchor z axis is higher than ground truth like :

Is there a way to adjust to this anchor range to feat my dataset ?

[Tai-Wang]

It's just because all the anchors are put on the same average ground (with their average centers' height) by default. You can make statistics on your customized dataset to make it fit your case.

[mickeyouyou]

Thank you so much for this issue, as you said this is the bbox buttom center we adjust bbox z axis with : z -= w/2, that works well

        if pred_bboxes is not None:
            # for horizon dataset
            pred_bboxes[..., 2] -= pred_bboxes[..., 5] / 2
            vis.add_bboxes(bbox3d=pred_bboxes)
        if gt_bboxes is not None:
            # for horizon dataset
            gt_bboxes[..., 2] -= gt_bboxes[..., 5] / 2
            vis.add_bboxes(bbox3d=gt_bboxes, bbox_color=(0, 0, 1))