1. A method of adjusting brightness of an image, the method comprising: detecting number distribution information of pixel brightness; adjusting the brightness of a specific area of the image using characteristic values according to a distribution characteristic of the detected number distribution information; determining whether contrast adjustment of the image is required; and adjusting contrast of the image in response to determining contrast adjustment of the image is required, wherein at least one of the steps of adjusting the brightness of a specific area of the image, determining whether contrast adjustment of an image is require, and adjusting contrast of the image is performed by a microprocessor.