运行代码,网络是MAP-Net,结果IOU一直是0

Reading checkpoints...
Checkpoint not find 
train from scratch...
Total train image:3106
Total validate image:152
Total epoch:3
Batch size:4
Learning rate:0.001
Data Argument:
h_flip: True
v_flip: True
rotate: True
clip size: 450

除此之外,每一个epoch后,loss都是负的,没经过一次epoch 负号后面的值也越来越大....