Hi! I tried the codes form the link you gave. I was stuck at this lines:
  real_class = mask_test[20]
          net_out = model(img_test[20].view(-1, 3, 224, 224))
          print(net_out.shape)
          predicted_class = torch.argmax(net_out.squeeze(), dim = 0).detach().cpu().numpy()
          print(predicted_class.shape)
          print(np.unique(predicted_class))

in the line where I tried printing np.unique, I should be getting the prediction already. Because in the link when they printed this certain code, the result was [0 3] and when I checked their color map that corresponds to a bird. But mine always prints out [0], which give push me suspecting that maybe my network indeed is just predicting everything as background. What should I do?