...pdfsandwich is a command line tool which is supposed to be useful to OCR scanned books or journals. It is able to recognize the page layout even for multicolumn text.
Essentially, pdfsandwich is a wrapper script which calls the following binaries: convert, unpaper, tesseract, gs, and hocr2pdf (if tesseract < 3.03). It is known to run on Unix systems and has been tested on Linux and MacOS X. It supports parallel processing on multiprocessor systems.
In contrast to most competing sandwich programs, it performs preprocessing of the scanned images, such as de-skewing or removal of dark edges etc.
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