Classifier (mathematics)

In mathematics, a classifier is a mapping from a (discrete or continuous) feature space X to a discrete set of labels Y.

Classifiers have practical applications in many branches of science and society. Built using a variety of mathematical techniques, classifiers viewed from afar can be seen as decision systems which accept values of some features or characteristics of a situation as input and produce as an output a discrete label related to the input values.

An example might be a clssifier which accepts a persons salary details, age, marital status, home address and credit history and classifies the person as acceptable/unacceptable to receive a new credit card or loan.

The application of classifiers is wideranging and often unseen. They find use in medicine( drug trial analysis, MRI data analysis), finance ( share analysis, Index prediction), mobile phones ( signal decoding, error correction), computer vision ( face recognition, target tracking ), voice recognition, datamining ( supermarket purchasing analysis, retail customer analysis ) and uncountable other areas.

Classifiers may either be fixed classifiers or learning classifiers, and learning classifiers may in turn be divided into supervised and unsupervised learning classifiers.

For a list of classifier applications and classifier technologies, please see statistical classification.

See also

• Artificial intelligence
• Artificial neural network
• Linear classifier
• Machine learning
• Pattern recognition
• Perceptron
• Support Vector Machine