The HP OfficeJet Linux driver provides printing, scanning, and photo-card access support for most Hewlett-Packard multi-function peripherals connected to a parallel port, USB port, or LAN via selected HP JetDirect print servers. Additional applications are provided to view the contents of the front-panel LCD and to access other control and status features of the device.
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.
The metric implemented in the Image::Density Perl Module estimates the density of data where there is data, and has a reasonable correlation with goodness as judged by humans. That is, if you let a human look at a set of images and judge quality, the density values for those images as calculated here tend to correlate well with the human judgement (densities that are too high or too low represent "bad'' images). It is intended for use on bitonal TIFF images, such as those from scanning paper documents.