1. A document processing apparatus comprising: an acquisition unit that acquires document data containing plural pieces of page image data corresponding to respective pages of a plurality of documents, each document being formed by stacking and half-folding sheets; a detection unit that detects, based on characteristics of the plural pieces of page image data, pieces of page image data corresponding to pages to be printed on a same side of a same sheet in the documents, from the plural pieces of page image data contained in the document data; a specifying unit that specifies, based on positions of the detected pieces of page image data in the document data, pieces of page image data corresponding to respective pages of each document, from the plural pieces of page image data contained in the document data; and an output unit that outputs data, which is based on pieces of page image data corresponding to respective pages of at least one of the documents, based on a specifying result of the specifying unit, wherein the detection unit includes a first detection unit that detects page image data having an image drawn in a first area corresponding to a first end, and a second detection unit that detects page image data having an image drawn in a second area corresponding to a second end opposed to the first end, and the detection unit detects the pieces of page image data corresponding to the pages to be printed on the same side of the same sheet in the documents, based on a detection result of the first detection unit and a detection result of the second detection unit.
1. A document processing apparatus comprising: an acquisition unit that acquires document data containing plural pieces of page image data corresponding to respective pages of a plurality of documents, each document being formed by stacking and half-folding sheets; a detection unit that detects, based on characteristics of the plural pieces of page image data, pieces of page image data corresponding to pages to be printed on a same side of a same sheet in the documents, from the plural pieces of page image data contained in the document data; a specifying unit that specifies, based on positions of the detected pieces of page image data in the document data, pieces of page image data corresponding to respective pages of each document, from the plural pieces of page image data contained in the document data; and an output unit that outputs data, which is based on pieces of page image data corresponding to respective pages of at least one of the documents, based on a specifying result of the specifying unit, wherein the detection unit includes a first detection unit that detects page image data having an image drawn in a first area corresponding to a first end, and a second detection unit that detects page image data having an image drawn in a second area corresponding to a second end opposed to the first end, and the detection unit detects the pieces of page image data corresponding to the pages to be printed on the same side of the same sheet in the documents, based on a detection result of the first detection unit and a detection result of the second detection unit. 3. The document processing apparatus according to claim 1 , wherein the detection unit detects the pieces of page image data corresponding to the pages to be printed on the same side of the same sheet in the documents, based on sizes of the page images indicated by the plural pieces of page image data contained in the document data.