Patent ID: 7343023

Claim:
A hearing prosthesis comprising: a microphone adapted to generate an input signal in response to receiving an acoustic signal from a listening environment; an output transducer for converting a processed output signal into an electrical or an acoustic output signal; processing means adapted to process the input signal in accordance with a predetermined signal processing algorithm and related algorithm parameters to generate the processed output signal; a memory area storing values of the related algorithm parameters for the predetermined signal processing algorithm; the processing means being further adapted to: segment the input signal into consecutive signal frames of time duration, T frame , and generate respective feature vectors, O(t), representing predetermined signal features of the consecutive signal frames, compare each of the feature vectors, O(t), with a feature vector set to determine, for substantially each feature vector, an associated symbol value so as to generate an observation sequence of symbol values associated with the consecutive signal frames, wherein the feature vector set has been determined in an off-line training procedure which utilized real-life sound source recordings made through an input signal path of a target hearing prosthesis or by performing a substantially similar signal processing of an input signal to simulate characteristics of the input signal path, and stored in non-volatile memory locations of the hearing prosthesis, process the observation sequence of symbol values with at least one discrete Hidden Markov Model, λ source ={A source , B source , α 0 source }, associated with a predetermined sound source to determine element value(s) of a classification vector indicating a probability of the predetermined sound source being active in the listening environment, control one or several values of the related algorithm parameters in dependence of the element value(s) of the classification vector, thereby adapting characteristics of the predetermined signal processing algorithm to the current listening environment, wherein A source =A state transition probability matrix, B source =An observation symbol probability distribution matrix for an input observation O(t) for each state of the at least one Hidden Markov Model, and α 0 source =An initial state probability distribution vector.