The development of automatic methods for the detection and removal of defects in film and video material is one of the core areas of DIGITAL. With these methods, historically valuable audiovisual documents can usually be fully restored and used for commercial purposes.
The Styrian company HS-Art Digital Service marketed methods developed by JOANNEUM RESEARCH in the form of several products for use in various areas of application, from high quality restoration for film archives to efficient removal of small defects in, for example, new DVD series editions.
UNESCO estimates that approximately 2.2 billion meters of nitrate-based film are stored in national and international film archives. Over time, these films are damanged for various (storage-related, mechanical) reasons and are constantly at risk of further decay. In light of the fact that these films represent evidence of our shared history, it is necessary to restore these contemporary historical documents in order to make them accessible to a broader audience.
Until recently, photochemical methods were used for restoration that prevented further deterioration, but were able to remove damages only to a very limited extent. Common defects include dust, scratches, graininess, shaking, and other image problems such as variations in brightness changes, effects from moisture damage and discoloration (e.g., fungus).
New methods for detection and correction of defects
JOANNEUM RESEARCH already began in the early 1990s to develop methods, which automatically detect defects in digitized film and video, and also automatically remove these defects. These methods are based on specialized image processing methods, such as motion detection and motion compensation or tracking the motion of pixels.
Due to steadily increasing processor power, it is possible to continually improve the methods and also to restore material with higher and higher resolution. In this way, the demands by the market for increasinly higher quality in the new digital television (e.g., HDTV) and film formats can be met.