tool to perform OCR on DjVu documents

 Ocrodjvu is a wrapper around the Optical Character Recognition (OCR)
 systems Cuneiform, Gocr, Ocrad, OCRopus and (standalone) Tesseract. It
 is designed for OCR on documents in DjVu format, which is especially
 suited for high-quality archiving of books.
 .
 After processing, the DjVu document embeds a text layer. Other programs can
 then be used to read the document, search it for specific terms, print it out,
 or use the information in the OCR layer as a way to improve the document's
 accessibility.