1. An X-ray imaging apparatus comprising: an X-ray source configured to irradiate X-rays toward a subject; a filter configured to control a dosage amount of X-rays being irradiated toward the subject; and a processor configured to distinguish and set up an uninterested region in an X-ray image obtained based on the irradiated X-rays, and to control the filter to set the dosage amount of X-rays to be irradiated into the uninterested region.