stuck at 0% when excute python demo_large_image.py

[heheguoqushi]

My envirements are: Ubuntu18.0 GCC5.5.0
CUDA10.0 Python3.7 Pytorch==1.2.0 Torchvision==0.4 mmcv==0.4.3 I have Installed as the offical docs when I excute python demo_large_image.py it stuck at 0% for more than 10 mins， I think a 1M picture shoud not be slow as that.

(AerialDetection) txy@robot:~/AerialDetection$ python demo_large_image.py loading annotations into memory... Done (t=0.00s) creating index... index created! 0%| | 0/4 [00:00<?, ?it/s]

please help me. Thanks!