Last time I was doing image processing in C I was doing quantization of the colorspace using the technique out of a paper from 1982. Just because a source is old doesn't mean it is wrong.
It doesn't mean it's wrong. Like partial derivatives are centuries old. But we are moving on. Just recently I've seen a book on image recognition. While recent it was focused on math and not a word about NN. That looked so outdated. Someone spent the whole carer on this way. Another example would be linguistic approach to text translation. 'Stupid' LLM does it way better today. I can only guess how pro linguists feel about it.