Solved by Nikronic in post #2 
              
              
                Hi, 
The only way to have a output such [batch, 1, 1, 1] is to have a filter with same_size as input when padding=0 and stride=1. 
The output have to be [batch, 1, 2, 2] for your example input and filters. And the reason is you can have four 2x2 squares in a 3x3 matrix. 
step one:
[[x, x, 0],
 [x, x…