Abstract: Pattern recognition apparatus uses a recognition processor for processing an input signal to indicate its similarity to allowed sequences of reference patterns to be recognised. A speech recognition processor includes a classification arrangement to identify a sequence of patterns corresponding to said input signal and for repeatedly partitioning the input signal into a speech-containing portion and, preceding and/or following said speech-containing portion, noise or silence portions. A noise model generator is provided to generate a pattern of the noise or silence portion, for subsequent use by said classification means for pattern identification purposes. The noise model generator may generate a noise model for each noise portion of the input signal, which may be used to adapt the reference patterns.