gscan2pdf is a GUI to ease the process of producing PDFs from scanned documents. You scan in one or several pages and create a PDF of selected pages. Scanning is handled with SANE via scanimage. PDF conversion is done by PDF::API2. Perl is used for portability and ease of programming, with gtk2-perl for the GUI.
LibRaw is a library for reading RAW files obtained from digital photo cameras (CRW/CR2, NEF, RAF, DNG, and others). LibRaw is based on the source codes of the dcraw utility, though some of the drawbacks of dcraw have been eliminated. The users of the library are provided with an API to be used when writing their software programs.
SANE stands for "Scanner Access Now Easy" and is an application programming interface (API) that provides standardized access to any raster image scanner hardware (flatbed scanner, handheld scanner, video and still cameras, framegrabbers, etc.). The SANE standard is public domain and its discussion and development are open to everybody. The source code is written for UNIX (including Linux) and is available under the GPL, but commercial applications and backends are welcome. The package contains the libraries, net support, and scanimage. The X frontends xscanimage and xcam can be found in sane-frontends.