Determining method, information processing apparatus, and recording medium

A determining method includes acquiring first direction information, when a first captured image captured by an imaging device is acquired, by referring to a storage storing a plurality of pieces of direction information indicating a plurality of directions associating with respective shapes of a plurality of contours of an object according to a plurality of directions of the object, the first direction information associated with a shape of a contour that corresponds to a shape of a contour of the subject included in the acquired first captured image among the shapes of the contours, and acquiring second direction information, when a second captured image newly captured by the imaging device is acquired, by referring to the storage to acquire second direction information associated with a shape of a contour that corresponds to a contour of the subject included in acquired second captured image among the shapes of contours.