An occupant classification system utilizes a rules-based expert system to automatically classify the occupant of a seat for the purposes of airbag deployment. The invention provides users with the ability to create, test, and modify the image attributes or "features" used by the expert system to classify occupants into one of several predefined occupant-type categories. Users are also provided the ability to create, test, and modify the processes utilizing those chosen features. The user of the invention designs the features and the algorithms used by the expert system classifier. A feature extractor is used to extract features from an image of the occupant and surrounding seat area, and the values relating to those features are sent in a vector of features to the expert system classifier. The expert system classifier classifies the image of the occupant according to the internal rules for that classifier. The resulting occupant-type classification is sent to the confidence factor extractor, along with the vector of features. The confidence factor extractor generates a confidence factor indicating the probable accuracy of the occupant-type classification. The occupant-type classification and confidence factor are then sent to the airbag controller so the airbag deployment system can take the appropriate action. For embodiments involving multiple expert system classifiers, one weighted occupant-type classification and one weighted confidence factor are sent to the airbag controller.