dataset数据加载异常

[Lyn3Mu]

问题确认 Search before asking

• 我已经查询历史issue(包括open与closed)，没有发现相似的bug。I have searched the open and closed issues and found no similar bug report.

Bug描述 Describe the Bug

在“paddleseg/transforms/transforms.py”文件的“Compose”的__call__() 方法中，当cv2.imread()读取的数据不存在时，会引发“AttributeError: 'NoneType' object has no attribute 'astype'”异常，而对于读取的数据的判空操作位于astype操作之后，后续判断无法捕获NoneType引发的异常。

复现环境 Environment

OS: Windows
PaddlePaddle: 2.2.2
PaddleSeg: release/2.8
Python: 3.9
CUDA: 11.3
CUDNN: 8.5.0

Bug描述确认 Bug description confirmation

• 我确认已经提供了Bug复现步骤、代码改动说明、以及环境信息，确认问题是可以复现的。I confirm that the bug replication steps, code change instructions, and environment information have been provided, and the problem can be reproduced.

是否愿意提交PR？ Are you willing to submit a PR?

• 我愿意提交PR！I'd like to help by submitting a PR!

[Lyn3Mu]

当数据集处理不规范时会引发此问题，即train/val_list.txt文件中路径索引所指向的图像被异常删除时会导致图像数据为空

[Asthestarsfalll]

感谢反馈，稍后会进行修复