When i train my data which like cocodataset,an error occurred,can someone help me fix it ?
The error information is :
libpng error: Read Error
Traceback (most recent call last):
File “tools/train.py”, line 142, in 
main()
File “tools/train.py”, line 138, in main
meta=meta)
File “/cache/user-job-dir/codes/mmdetection/mmdet/apis/train.py”, line 111, in train_detector
meta=meta)
File “/cache/user-job-dir/codes/mmdetection/mmdet/apis/train.py”, line 305, in _non_dist_train
runner.run(data_loaders, cfg.workflow, cfg.total_epochs)
File “/home/work/anaconda3/lib/python3.6/site-packages/mmcv/runner/runner.py”, line 371, in run
epoch_runner(data_loaders[i], **kwargs)
File “/home/work/anaconda3/lib/python3.6/site-packages/mmcv/runner/runner.py”, line 271, in train
for i, data_batch in enumerate(data_loader):
File “/home/work/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py”, line 582, in next
return self._process_next_batch(batch)
File “/home/work/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py”, line 608, in _process_next_batch
raise batch.exc_type(batch.exc_msg)
AttributeError: Traceback (most recent call last):
File “/home/work/anaconda3/lib/python3.6/site-packages/torch/utils/data/_utils/worker.py”, line 99, in _worker_loop
samples = collate_fn([dataset[i] for i in batch_indices])
File “/home/work/anaconda3/lib/python3.6/site-packages/torch/utils/data/_utils/worker.py”, line 99, in 
samples = collate_fn([dataset[i] for i in batch_indices])
File “/cache/user-job-dir/codes/mmdetection/mmdet/datasets/custom.py”, line 132, in getitem
data = self.prepare_train_img(idx)
File “/cache/user-job-dir/codes/mmdetection/mmdet/datasets/custom.py”, line 145, in prepare_train_img
return self.pipeline(results)
File “/cache/user-job-dir/codes/mmdetection/mmdet/datasets/pipelines/compose.py”, line 24, in call
data = t(data)
File “/cache/user-job-dir/codes/mmdetection/mmdet/datasets/pipelines/loading.py”, line 28, in call
results[‘img_shape’] = img.shape
AttributeError: ‘NoneType’ object has no attribute ‘shape’
Thanks,anyway!