This is the website of the research project FREEDOM (2007-2010), supported by the French National Research Agency (Agence nationale de la recherche) under contract ANR-07-JCJC-004801.
This project deals with the restoration and the enhancement of moving pictures.
More precisely, it aims at:
Andrès Almansa, LTCI, Télécom ParisTech
Jean-François Aujol, CMLA, ENS Cachan
Julie Delon (coord.), LTCI, Télécom ParisTech
Yann Gousseau, LTCI, Télécom ParisTech
Saïd Ladjal, LTCI, Télécom ParisTech
Simon Masnou, lab. J-L Lions, Paris 6
Mila Nikolova, CMLA, ENS Cachan
With the rise of digital technology -- and, in particular, of digitalization techniques -- part of the motion-picture heritage has become easily and massively accessible. The digitalization process must however often be combined with the restoration of the various and numerous impairments that may notably alter films and videos, like flicker (unnatural temporal fluctuations of intensity, due to variations in exposure time or inhomogeneous ageing or degradation of the film support), unsteadiness, line scratches (bright, dark or colored lines due to film abrasion), video scratches (horizontal pulses due to scratches on the physical medium), color fading, tear damages, blotches, line-jitter or loss of line synchronization, moiré, vinegar syndrome, video dropouts, etc. Blotches are among the most frequent impairments; they can be due to the loss of pieces of gelatine constituting the film ( sparckle) or to the electrostatic adhesion of various particles on the film (dirt), e.g. dust or hair.
The quantity and diversity of impairments make the restoration process very difficult. But it is all the more necessary that new technologies -- high-quality screens, image freezing and the high-definition standards like 2K or 4K -- tend to accentuate every small defect. Another important fact is the amount of frames to restore. It may happen that almost every frame of a film be altered, which means nearly 130.000 frames for a 90mn sequence. This emphasizes the obvious need for fast and automatic restoration algorithms. In the same way, a certain amount of film archives needs to be converted to high definition standards for HDTV broadcasting, which motivates the development of new pertinent super-resolution techniques.
Various techniques for film restoration and enhancement have been developed, often integrated in a global restoration system. Many companies or institutions around the world have developed their own restoration architecture, sometimes with dedicated hardware components. Many restoration techniques still rely on human intervention and require a fastidious calibration of parameters, mainly:
A major issues of today's research in motion picture restoration is to attain for the previous impairments the full automation in both steps of digital restoration: the detection and the accurate correction. It is the main purpose of our research program. More precisely, the points we wish to develop in this project are the following ones: