1. A method of classifying vehicle occupants comprising the steps of: generating a stereo image pair of the occupant from two cameras; inputting the image pair into an occupant classification controller; processing the stereo image pair into a differential edge density feature by the controller; inputting the differential edge density feature into a state machine of the controller; determining, by the state machine and using the differential edge density feature, if the occupant has changed; if the occupant has changed, applying a static classification process having a prior knowledge of the occupant category in memory of the controller; determining if prior occupant type has changed by the state machine and between an adult and a child; establishing whether the occupant is an adult or a child; switching on a corresponding adult or child dynamic classifier of the controller; switching off a static classifier of the static classification process; and utilizing the differential edge density features by the corresponding adult or child dynamic classifier to determine an occupant class output which signifies occupant position.