Living body recognizing device

A living body recognizing device, comprising:

• a captured image acquiring unit which acquires a captured image having a characteristics that a luminance of an image portion of a target object becomes higher as a temperature of the target object becomes higher than a background, and the luminance of the image portion of the target object becomes lower as the temperature of the target object becomes lower than the background, according to a temperature difference between the background and the target object, using an infrared camera;
• a living body image extracting unit which executes a first living body image extracting processing of extracting the image portion of the target object assumed to be a living body, from a region in the captured image in which the luminance is equal to or lower than a predetermined first threshold value, regardless of whether or not an area of the region in which the luminance is equal to lower than the predetermined first threshold value is larger than an area of a region in which the luminance is higher than the first threshold value;
• and
• a living body recognizing unit which recognizes an existence of the living body, based on the image portion of the target object extracted by the living body image extracting unit.