fix gt_masks type in maskiou_head._get_area_ratio

[tyomj]

Current version throws an exception bellow:

File "/home/user/mmdetection/mmdet/models/mask_heads/maskiou_head.py", line 160, in _get_area_ratio gt_instance_mask_area = gt_masks.sum((-1, -2)) AttributeError: 'list' object has no attribute 'sum'

gt_masks is a list of masks, so the simplest fix is to convert them into np.array.

(I'm actually surprised that no one faced with this bug before ¯_(ツ)_/¯)

[yhcao6]

Currently the Pad transform will convert gt_mask into ndarray, you can look up this line

mmdetection/mmdet/datasets/pipelines/transforms.py

Line 295 in e032ebb

results[key] = np.stack(padded_masks, axis=0)

mmdetection/configs/ms_rcnn/ms_rcnn_r50_caffe_fpn_1x.py

Line 136 in e032ebb

dict(type='Pad', size_divisor=32),

I tried to run this confighttps://github.com/open-mmlab/mmdetection/blob/master/configs/ms_rcnn/ms_rcnn_r50_caffe_fpn_1x.py with the latest mmdetection, but the program reported no error.

Have you modified something?

[tyomj]

Yes, you are right. Thanks for your help.
I was just confused by the docstring:

https://github.com/open-mmlab/mmdetection/blob/master/mmdet/models/mask_heads/maskiou_head.py#L115-L116

The problem I faced comes when applying albu transformation after Pad like this:

mmdetection/configs/albu_example/mask_rcnn_r50_fpn_1x.py

Lines 163 to 165 in e032ebb

	dict(type='Pad', size_divisor=32),
	dict(
	type='Albu',

So I caught my own bug in this transform which has to be fixed.
I have checked the same pipeline for both mask-rcnn and ms-rcnn. Everything is ok now.

But I see failure during CI building stage, which is not likely to be connected with my small fix. Could you please help with that?

[hellock]

#1818

[tyomj]

Thanks! Waiting #1818 to be merged.