A method of operating an air conditioner, including: obtaining an image acquired by a camera; determining a distance and a direction of an occupant relative to the air conditioner, based on the image; using at least one machine-learning network to classify an air-blowable space of the air conditioner into an intensive air blowing area and a non-intensive air blowing area, based on the distance and the direction of the occupant; controlling the air conditioner to operate in an intensive operation mode with respect to the intensive air blowing area; and controlling the air conditioner to operate in a non-intensive operation mode with respect to the intensive air blowing area and the non-intensive air blowing area based on completion of the intensive operation mode. A time duration of the intensive operation mode is smaller than a time duration of the non-intensive operation mode.