How to deal with gt_boxes zero sample?>

[lucasjinreal]

It will got error if image has no box inside it:

im_size: (800.0, 1066.0)
scale: 1.665624976158142
height, width: (50, 67)
rpn: gt_boxes.shape (0, 5, 1, 1)
rpn: gt_boxes []
total_anchors 40200
inds_inside 22400
anchors.shape (22400, 4)
Traceback (most recent call last):
  File "tools/train_net.py", line 112, in <module>
    max_iters=args.max_iters)