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Octocat-spinner-32 doc Replaced interpolation functions for better image quality. March 08, 2013
Octocat-spinner-32 tests tests: add tests for the --overwrite feature. June 24, 2012
Octocat-spinner-32 .gitignore Add ignore line for compile script (automake 1.14). June 24, 2013
Octocat-spinner-32 .mailmap git: add a mailmap to make Jens's commits look nicer. October 08, 2011
Octocat-spinner-32 AUTHORS Replaced interpolation functions for better image quality. March 08, 2013
Octocat-spinner-32 COPYING Rename files to follow autotools style more closely. August 15, 2011
Octocat-spinner-32 INSTALL build: update documentation. August 15, 2011
Octocat-spinner-32 Makefile.am Rename README so it displays as MarkDown on GitHub. June 30, 2013
Octocat-spinner-32 NEWS version: make the new version number 5 instead of 0.5. June 28, 2013
Octocat-spinner-32 README.md Rename README so it displays as MarkDown on GitHub. June 30, 2013
Octocat-spinner-32 TODO unpaper: rewrite options parsing, and update documentation October 11, 2011
Octocat-spinner-32 configure.ac Bump version for next release. June 28, 2013
Octocat-spinner-32 file.c Use errOutput when something is wrong in the input files, as we don't… July 08, 2013
Octocat-spinner-32 file.h Add missing license headers to files. October 11, 2011
Octocat-spinner-32 imageprocess.c Constantize a few more parameters and variables. June 29, 2013
Octocat-spinner-32 imageprocess.h Constantize a few more parameters and variables. June 29, 2013
Octocat-spinner-32 parse.c Add missing license headers to files. October 11, 2011
Octocat-spinner-32 parse.h Add missing license headers to files. October 11, 2011
Octocat-spinner-32 tools.c Constantize a few more parameters and variables. June 29, 2013
Octocat-spinner-32 tools.h Constantize a few more parameters and variables. June 29, 2013
Octocat-spinner-32 unpaper.1.xml Replaced interpolation functions for better image quality. March 08, 2013
Octocat-spinner-32 unpaper.c Improve version/usage text. March 08, 2013
Octocat-spinner-32 unpaper.h Replaced interpolation functions for better image quality. March 08, 2013
README.md

unpaper

Originally written by Jens Gulden — see [AUTHORS] for more information. Licensed under GNU GPL v2 — see [COPYING] for more information.

Overview

unpaper is a post-processing tool for scanned sheets of paper, especially for book pages that have been scanned from previously created photocopies. The main purpose is to make scanned book pages better readable on screen after conversion to PDF. Additionally, unpaper might be useful to enhance the quality of scanned pages before performing optical character recognition (OCR).

unpaper tries to clean scanned images by removing dark edges that appeared through scanning or copying on areas outside the actual page content (e.g. dark areas between the left-hand-side and the right-hand-side of a double- sided book-page scan).

The program also tries to detect misaligned centering and rotation of pages and will automatically straighten each page by rotating it to the correct angle. This process is called "deskewing".

Note that the automatic processing will sometimes fail. It is always a good idea to manually control the results of unpaper and adjust the parameter settings according to the requirements of the input. Each processing step can also be disabled individually for each sheet.

Input and output files can be in either .pbm, .pgm or .ppm format, thus generally in .pnm format, as also used by the Linux scanning tools scanimage and scanadf.

Conversion to PDF can e.g. be achieved with the Linux tools pgm2tiff, tiffcp and tiff2pdf.

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