An imaging fire detector is used to detect a fire from a recorded image sequence. Either a video camera or an infrared camera is used as an imaging device. Characterizing parameters of a fire are either analyzed individually or in combination. In order to detect changes, an object analysis, a pattern analysis or a spatial-frequency analysis of the recorded image sequences is conducted. Using a threshold value for the duration of the changes, short-term changes are detected and discarded. In a further embodiment, the fire detector may also be used as a burglar alarm. With the aid of communication means, the fire detector transmits a fire alert to a master station.