You have special fingerprint algorithms that are suited for sound modifications like pitch https://biblio.ugent.be/publication/5754913 but it's not going to work with humming or live audio. I don't know if such a thing exists.

If you want to do some research, here is a short review paper on the topic http://www.cs.toronto.edu/~dross/ChandrasekharSharifiRoss_IS...

As for 2d array spectrogram, it is not needed in my lib (expect when plotting is activated). I only care about maxima in the spectrum of each data window. In other words, 1d spectra are enough.