Unable to understand unet architecture
I was trying to replicate UNET architecture but was having problems understanding why there is 16 written in the encoder part here:

Is this part of the architecture or should we need to choose it randomly? I understood it is the number of output channels of the conv layers but why 16, not any other number?

That's a design decision, so you won't find a clear reason for your question.
Other than that, the numbers in architecture are usually kept as multiple of 2, here 2**4. This is for practical reasons. It is usually the go-to method when testing variable-sized networks: they will try varying the numbers of layers, and numbers of channels as well as other network layouts and figure out which one is best for the task by experimenting.

By your first question,

should we need to choose it randomly [...]?

Why would you not stick to the network's specification if you're looking to replicate it in the first place? If you ever find an advantage to putting 8 instead of 16, or even 32 if you have the capacity to do so, then go right ahead!
