1. A document type recognition apparatus comprising: an image region separation unit configured to output a signal indicative of each region obtained by separating an input image into a character region and a pattern region; a smoothing unit configured to perform smoothing processing to remove halftone dots of a particular number of lines or greater in the pattern region of the input image; an edge enhancement unit configured to output an image subjected to edge enhancement processing depending on an amount of edge on an edge portion of the character region in the input image on which the smoothing processing has been performed; a histogram creation unit configured to create a histogram of the image subjected to the edge enhancement processing; and a document type recognition unit configured to recognize a document type of the input image by utilizing the histogram.