Question for global_scaling_v2

[buaacyw]

Please see https://github.com/tianweiy/CenterPoint/blob/2145ada1f96b7b4b8f19f3b0012aab589962806f/det3d/core/sampler/preprocess.py#L838

def global_scaling_v2(gt_boxes, points, min_scale=0.95, max_scale=1.05):
    noise_scale = np.random.uniform(min_scale, max_scale)
    points[:, :3] *= noise_scale
    gt_boxes[:, :-1] *= noise_scale
    return gt_boxes, points

"gt_boxes" is [box_number,9]. 9 corresponds to x, y, z, w, h, l, vx, vy, r.
So why is the vx and vy of gt_boxes scaled? Is this a bug?
And by the way, where can I find the data format description of ground truth annotations (the definition of each dimension)? I can't find it in NuScenes' website and github. Thanks!

[tianweiy]

basically, the x and y for the current and previous frame Lidar point cloud are both scaled, so their differences (which is essentially the velocity) also need to be scaled.

xyz are defined according to this figure (from https://arxiv.org/pdf/1903.11027.pdf).

dimension is just width length height, corresponding to the xyz if i understand correctly

[buaacyw]

Thanks!