我发现Pooling会让CAM的分辨率降低，所以，为什么要用Pooling层或者stride>1的卷积层呢？

Answer:

1. Push the model to be invariant to small shift/rotation/scale/perturbations of the data。
2. Reduce network complexity, make training easier
3. Save time/computing
4. Increase reception field-,%E6%B1%A0%E5%8C%96%E5%B1%82%E5%8F%AF%E4%BB%A5%E5%A2%9E%E5%8A%A0%E6%84%9F%E5%8F%97%E9%87%8E.,-%E4%B8%8D%E8%BF%87%E5%8D%B7%E7%A7%AF)

I do not believe it. Or I think PFT regression net should be sensitive to smalll (organ) perturbation. Pooling will lose such information. I want to try if No-Pooling can lead to the same performance.