Classifying apparatus designed in particular for odor recognition

The present invention concerns pattern classification, notably in the field of the characterisation or the identification of odours and, more particularly, a pattern classification apparatus which selects, from a list, the appropriate classification rule dependent upon the application. A classification apparatus, notably for uses in recognition or characterisation of odors, comprises a plurality of sensors for generating raw data representing a plurality of instances of a plurality of different classes; and a processing unit for processing said raw data so as to determine an identification model. The identification model comprises definitions of the classes and a particular allocation rule selected dependent upon the application. The class definitions are established by analysing data obtained during a learning phase, the analysis being performed according to a particular information extraction method. During a later identification phase, the identification model enables an instance of unknown class to be allocated to an appropriate class amongst those defined during the learning phase. The information extraction method can be selected dependent upon the application. Preferably, a percentage of the data obtained during the learning phase is used to establish a plurality of candidate identification models, and the identification model which is selected for use is the one which gives the highest number of correct classifications when use to classify the other data obtained during the learning phase.