A computer program causes a head-mounted display device including an camera and an image display section capable of being transparent at least against light from a scene to realize functions of: an image setting function of displaying, with the image display section, a marker image that is capable of being perceived to be at least partially aligned with a real marker; a detection function of detecting the real marker from an image captured with the camera; a parameter setting function of setting at least one parameter for allowing an AR object displayed with the display section to be perceived to correspond to an object in the scene; a determination function of determining whether a user's head is in a substantially static condition, and a collecting function of collecting, from the image or another image captured with the camera, calibration data that is to be used in the parameter setting function in response to an instruction, in the case where the user's head is determined to be in the substantially static condition by the determination function.