ExactScan is a versatile document capture application for home offices and workgroups. It is designed from the ground up for high-speed document scanners and can easily handle hundreds of images per minute, including duplex scans. Included functionality reaches from managing, sorting, and editing singles pages to writing multi- as well as single-page PDF files including JPEG compression and TIFF, JPEG, JPEG2000, and PNG bitmap files. ExactScan allows performing state of the art image processing including automatic cropping, deskewing, dynamic thresholding for perfect black and white documents, and descreening print rasters.
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.