Speech recognition begins when a person speaks into an electronic
device, such as a microphone. The microphone converts the speech
to an analog signal, which is then converted to a digital signal to
be stored on a computer. A
a program running on the
computer, attempts to decode the meaning of the speech signal.
of a person's speech are needed by the speech recognizer to decode
the signal. These features must be numerically measured and stored
in a form the recognizer can understand. The process of measuring
the features needed by a speech recognizer is called
for a theoretical overview of the feature extraction process.