1. An apparatus for processing an image, the apparatus comprising: a ghost information acquisitor, including at least one processor, configured to acquire, from an overlapping region of a left image and a right image of a panoramic image, ghost information related to a ghost pixel based on a threshold and a cost map; a tone correction map generator, including the at least one processor, configured to generate a tone correction map, based on a global tone correction function generated using pixels other than the ghost pixel in the overlapping region, and based on a local tone correction level generated using local information of a seam that connects the left image and the right image; and a bidirectional corrector, including the at least one processor, configured to generate a final tone correction map corresponding to the overlapping region by applying, to the tone correction map, a weighting based on the left image and a weighting based on the right image, and correct the left image and the right image using the final tone correction map.