SEAPAVAA Newsletter
Jan-Sept 1999

Editorial: Copyright in the AV industry

Country Updates

Features

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Film studios, national archives, and news libraries around the world have a large number of old films awaiting a new lease on life. These old movies are recorded on material which are susceptible to gouges, scratches, and the accumulation of dirt. The result is a variety of artifacts that make old movies look their age.

vAdopting digital film archiving technology can stop the deterioration in old movies, but defects that are already present in the films will be inherited into the digital storage. Restoration of degraded motion pictures is a labor-intensive and costly undertaking.

A much publicized event is the restoration work of Disney's 1937 masterpiece - Snow White and the Seven Dwarfs, which was re-released in 1993. It would be rewarding to reproduce the old movies with as much fidelity to the original negatives as possible so that these movies can be re-released on other media such as DVD, cable TV, TV broadcast stations, and video-on-demand.

A motion picture restoration software, Revival has been successfully developed at Nanyang Technological University of Singapore. Revival restores old, noise-corrupted motion pictures and transfers the restored pictures to new storage media with little human guidance. The marked difference between Revival and the other existing filtering approaches is Revival's ability to accurately remove only the unwanted elements without disturbing undamaged areas of the film. This is akin to restoring a work of art without disturbing the artist's original brush strokes. This is a significant breakthrough, as the resulting pictures will not suffer from the loss of some detail after restoration.

Users can safely use Revival to restore clips of a movie without worrying that the restored pictures will not blend into the remaining untouched frames. The ability of Revival to identify and restore the blemished areas in a picture is demonstrated by the restoration of films with subtitling. Traditional techniques readily identify the edges of the subtitling and soften these edges, losing the fine lines and crispness thereby severely reducing the legibility of the words. Revival models the subtitling text as part of the image and has no apparent effect on this part of the image.

Revival Streamlined Workflow

Revival is a high-precision, resolution independent restoration software package that focuses on restoring old movies having scratches, film-grain, and dirt-and-sparkle noise. The first release of Revival is implemented on silicon graphics UNIX workstations running IRIX 6.3 and above.

Revival is designed for use by broadcasters, movie producers, media preservationists, and post-production specialists, emphasizing on an intuitive graphical user-interface and streamlined workflow that takes both the novice and the expert into account. The workflow is designed to provide the user with the flexibility to restore any specified sets of segments of a motion picture. A movie typically consists of a few batches (clips) that require restoration work that can be specified in terms of the start-and-end frame or in-and-out time code.

Three main architectural components combine to make Revival a powerful motion picture restoration system. The first is the blotch (dirt-and-sparkle) removal algorithm, which allows users to automatically restore the motion picture that are corrupted by commonly found artifacts such as fungus, and dirt-and-sparkle noise. The user has the flexibility to fine-tune two key parameters to optimize performance.

The first parameter reflects the amount of motion that is exhibited in the particular segment. The second parameter allows the user to select the degree of noise that the sequence exhibits. Although the default values of these two parameters are provided, the fine-tuning will allow for more efficient processing to be carried out on resource-limited workstations.

The second main architectural component is the persistent-scratch removal algorithm. Vertical scratches require special treatment due to the repetition of the scratches at the same or nearby location in adjacent frames. An adaptive scratch-removal algorithm has been developed in Revival that efficiently and effectively conceals vertical scratches in old motion pictures. The adaptive process also ensures that only areas of the image that are suffering from scratches are processed, leaving the rest of the image as before. Most common types of vertical scratches, including positive and negative scratches, are effectively handled. The user can fine-tune parameters to enable the best possible concealment. A major advantage of the persistent-scratch removal in Revival is that vertical scratches are semi-automatically detected; the user only needs to graphically specify the position of the scratches in one (key) frame, leaving Revival to restore a clip of the motion picture automatically.

The third architectural component is the handling of film-grain noise in which various film-grain noise can be effectively attenuated to various degrees.

Being image-resolution independent allows restoration work to be carried out on various types of formats such as D1 PAL/NTSC, HDTV and film resolution. The first release of Revival will only support D1 resolution although some film and HDTV motion pictures have been successfully treated in our laboratory. The other features of Revival are its ability to automatically handle scene-change and 3:2 pull-down pictures. Revival also allows the seamless connection of the restoration system to the Digital VTR (such as D1) or Betacam VTR via a third party DDR, thus providing a total solution to motion picture restoration.

The restoration software has been four years in the making at Singapore's Nanyang Technological University. Revival was first unveiled as a crude algorithmic model in 1996 when it scooped a US$100,000 grand prize in Texas Instruments' Worldwide Digital Signal Processing Solutions Challenge held in Atlanta.

Although Revival has been designed to restore old noise-corrupted motion pictures, it can also be used in the telecine-transfer to enhance the quality of the process since the original clarity of the pictures will not be compromised in the noise-removing process. Besides, Revival can also be used as a pre-processor in the VCD and DVD encoding process to improve the compression rate and video quality of the encoded images.