1. An object tracking device, comprising: an input terminal configured to receive an input image; and at least one processor connected to the input terminal, wherein the at least one processor is configured to: store a past state of a target object in a past image, detect a first object which is moving in the input image, detect a second object which is resting in the input image, estimate a current state of the target object based on the past state of the target object, wherein the current state comprises a current moving state when the target object is currently moving in the input image, and wherein the current state comprises a current resting state when the target object is currently resting in the input image, determine whether to prioritize tracking the target object with information corresponding to the first object or with information corresponding to the second object based on the current state of the target object.