MOTION DETERMINING APPARATUS, METHOD FOR MOTION DETERMINATION, AND NON-TRANSITORY COMPUTER-READABLE STORAGE MEDIUM FOR STORING PROGRAM

An apparatus for motion determination includes: a memory; and a processor coupled to the memory, the processor being configured to (a) execute a specifying process that includes specifying an orientation of a head portion of a subject, (b) execute a calculation process that includes calculating a trajectory of a position of the head portion of the subject in a vertical direction and a trajectory of the position of the head portion of the subject in a transverse direction in a predetermined time range, and (c) execute a determination process that includes when the calculated trajectory in the vertical direction and the calculated trajectory in the transverse direction satisfy a determination condition for the specified orientation of the head portion, determining that there is a predetermined motion mapped to a motion of the head portion of the subject in the vertical direction.