OCCUPANT TEMPERATURE ESTIMATING DEVICE, OCCUPANT STATE DETECTION DEVICE, OCCUPANT TEMPERATURE ESTIMATING METHOD, AND OCCUPANT TEMPERATURE ESTIMATING SYSTEM

Included are: a temperature image acquiring unit that acquires a temperature image; a binarization processing unit that sets at least one temperature candidate region in a target region included in a region of the temperature image, by binarizing pixels in the target region on the basis of temperature information possessed by the pixels in the target region; a candidate region temperature calculating unit that calculates a region temperature for the temperature candidate region in the target region on the basis of temperature information possessed by a pixel in the temperature candidate region; and a temperature estimating unit that determines a temperature region from among the at least one temperature candidate region on the basis of a separation degree calculated for the temperature candidate region in the target region, and estimates that a temperature of a body part of an occupant is the region temperature for the temperature region.