A CPU of a console comprises a color image acquisition unit, a distance image acquisition unit, a specification unit, and an estimation unit. The color image acquisition unit acquires a color image, in which a patient and a periphery of the patient are captured, from a visible light camera. The distance image acquisition unit acquires a distance image indicating a distance between a radiation tube and an object, from a TOF camera. The specification unit specifies a kind of the object in the color image. The estimation unit estimates intensity of radiation in an environment captured in the color image based on reference information including the distance image and a specification image as a specification result of the kind of the object.