A data processing apparatus which revises n-bit image data, includes a frame memory which stores therein n−m bit image data of a previous frame; a memory interface which outputs n-bit revision data including upper n−m bits having n−m bit image data of the previous frame outputted by the frame memory and lower m bits having fixed data corresponding to a decimal value 1; a first reviser which revises a color temperature of current frame image data by using n-bit image data of a current frame and the revision data; and a second reviser which revises a gray scale of the current frame image data by using the image data outputted by the first reviser and the revision data.