1. A vehicle including an apparatus for determining an object characteristic of an object that may be located on a seat of a vehicle, comprising: at least one transmitter/receiver assembly arranged to transmit electromagnetic waves into a space above the seat in which the object is expected to be present and receive electromagnetic waves modified by presence of an object in the space above the seat and at least partly occupying the space above the seat, said at least one transmitter/receiver assembly generating image signals from received electromagnetic waves at a first instance when said at least one transmitter/receiver assembly transmits electromagnetic waves into the space above the seat and at a second instance when said at least one transmitter/receiver assembly is not transmitting electromagnetic waves into the space above the seat; and a processor coupled to said transmitter/receiver assembly and determining a characteristic of the object based on analysis of the generated image signals at the first and second instances.