What are common pitch detection algorithms?

Pitch detection estimates fundamental frequency of periodic signals (voice, music). Methods: Autocorrelation (peak in autocorrelation at period lag, robust but octave errors), AMDF (Average Magnitude Difference Function, dip at period lag, similar to autocorrelation), Cepstrum (log spectrum of spectrum reveals period as quefrency peak), YIN algorithm (modified autocorrelation with better accuracy), and PYIN (probabilistic YIN for polyphonic). Challenges: Noise, multiple harmonics, varying amplitude, and real-time requirements. Modern systems often combine methods with post-processing for robustness.