Italian Semester of Presidency of the European Union

International workshop
Rome, October, 29th 2003, Palazzo dei Congressi, Bibliocom 2003

Karl Magnus Drake
National Archives, Sweden

The management of image quality control and assurance as well as metadata in high volume digital imaging systems

Abstract

In obtaining the most adequate digital capture device for your digitization project/program and make it possible for you to objectively and numerically evaluate and compare the performance of such devices from various vendors they must deliver measurable digital results from their products offered. Issues of main concern in performance measurements of digitizing equipments (i.e. scanners and digital cameras) for image quality evaluation are:

• Spatial resolution
• Tonal/color reproduction
• Color fidelity
• Geometric accuracy

The software implemented in the digital imaging system should allow more or less automatic managing of production as well as other important types of metadata (i.e. administrative and context metadata) in order to mainly

• make the images usable for the users in all analog forms (i.e. on screen as well as for various print and film outputs) over a long time through production metadata
• identify and access the images as digital masters/webb-accessable surrogates in the "Digital Image Depository" (DID) through established paths/directory trees and filenaming principles by means of administrative metadata
• explain the origin/content of the digital reproductions of the originals by means of context metadata

Important digital imaging system software functions for image quality control/assurance as well as for monitoring and speeding up the various production processes are

• automatic calibration of the digital capture device
• automatic post-processing of images (i.e. rotating; deskewing; cropping; unsharp masking of images and image conversions from e.g. TIFF to JPEG2000) and subsequent (preferably automatic) quality control of the "enhanched"/converted images)
• automatic tracing/monitoring in log files who has run the digital imaging system and when as well as which above mentioned image post-processes the images have gone through (i.e. an audit-trail facility)
• possibility to save (in for example an INI-file) all image parameter settings in the digital image capturing software for later reuse of these parameter values

First main characteristics and common error types concerning digital capture devices will be presented.

Then practical procedures in objective/numeric evaluation of digital capture devices (i,e, scanners and digital cameras), currently in use at the National Archives of Sweden (NAS), will be demonstrated.

Digital imaging applications developed at NAS and now employed at various digitization projects/programs within NAS, implementing some of the above mention required software functions, will also be delineated during the workshop.