1. A method for automatically adjusting a size of characters using a camera, comprising: receiving an image containing characters; detecting a region and a size of characters in the image; determining whether the size of the characters in the image falls within a recognizable character size range; if the size of the characters falls within the recognizable character size range, recognizing the characters in the image and displaying recognition results; and if the size of the characters does not fall within the recognizable character size range, automatically adjusting a zoom ratio of the image so that the size of the characters in the image falls within the recognizable character size range, and recognizing the characters in the resized image.