What are non-machine-learning methods called? For my masters, I'm comparing different approaches to solve a problem (like image segmentation). 

I'm comparing machine learning and deep learning approaches to «classical» algorithms (like simple or adaptative threshold).

How would you call these «classical» or «standard » approaches? Like algorithms that don't rely on data but are «hand-designed».
I can't seem to find a correct term.
Machine learning models work on principle of probabilistic approach where you try to fit the function to map input with output. There are no hard bound rules that classify the output based on input.

Deterministic approach like if else are categorized as  non machine learning algorithms where every time it follows the same rules to evaluate the results.