Hi Vincenzo!



 vicio:

the input is a 3-channels image and my output is a one channel image.
…
The output contains the probability that a given pixel is active.


If I understand your description, you wish to perform binary (that is to say
two-class) semantic segmentation.
U-Net is a well-established semantic-segmentation architecture.
Pytorch’s torchvision includes some pre-built semantic-segmentation
models (but not U-Net), such as fcn_resnet50.
Best.
K. Frank