Pattern Recognition Applications Alexandros Potamianos Dept of ECE, Tech. Univ. of Crete Fall
Applications Automatic Speech Recognition Optical Character Recognition
Automatic Speech Recognition Features: Mel Frequency Cepstrum Coefficients (MFCCs) Model: Hidden Markov Model Each phone is a 3-state HMM Parameter Estimation: EM (Baum-Welsh) Recognition (classification in time): Viterbi
Common tricks De-correlate features: MFCCs Overcome observation independence assumption: take derivatives of features in time
Optical Character Recognition Features: Pixel values or Wavelet transformations of pixel values Model: Multi-layered Neural Network Training: Back-propagation (Gradient descent) Recognition (classification): discriminant function maximization (Bayes rule)