Digital ICE Scratch Correction Using Infrared-enabled Scanners

Published on website: November 18, 2009
Categories: Digital ICE , Gabriel Fielding , Lab and Post Production , The StoryBoard Blog

A huge number of movies and television shows are held in studio vaults and in television archives.  With high-definition television and high-bandwidth connections to the home, there has never been more demand for bringing content out of storage and making it available to consumers.  Old films have very high resolution and can be easily scanned and compressed for digital distribution.  But before this can happen, minor imperfections such as scratches and dust need to be removed to meet rigorous image quality standards set by the studios and networks.

Film scanners equipped with infrared (IR) illumination and Kodak’s Digital ICE software can automatically detect and correct scratches and dust so they are invisible to even the most critical viewers. The Kodak Digital Ice software operates by analyzing the familiar red, green, and blue channels along with the extra IR channel to provide an accurate per-pixel defect matte.  The defect matte is used to identify which pixels to adjust so that scratched pixels can be restored nearly to their original values.

The power of the Kodak Digital ICE algorithm is most easily demonstrated with some examples. Figure 1 shows a “before” and “after” pair of images.  These samples, from color negative film, were intentionally scratched to simulate the effects of improperly handled color negative film rolls.  The images below have had their color and contrast adjusted for display on computer screens; hence, defects appear lighter in the images.  It can be seen in the “after” image on the right that the scratches are virtually gone and that all image details have been preserved.

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Figure 1: A scan of a 5218 film frame showing (a) scan without using Digital ICE processing, and (b) scan with Digital ICE processing.

Figure 2 shows another “before” and “after” pair of images.  Clearly, Digital ICE has corrected a significant amount of light loss caused by scratches and dust on the film.  As before, these films were intentionally scratched and allowed to accumulate dirt and dust for testing purposes.

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Figure 2: A scan of a film frame showing (a) scan without using Digital ICE processing, and (b) scan with Digital ICE processing.

Many of the real images encountered in the restoration of older films have less obvious defects.  In fact, some images appear to have no defects at all when the movie is stopped.  But when the movie or video is playing, the scratches and dust become more visible.  Figure 3 shows an original frame of film on the left and the defect matte on the right revealing the dust and scratches detected by Digital ICE.  Digital ICE automatically corrects these seemingly “invisible” defects, resulting in far superior image quality.

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Figure 3: A scanned film frame showing (a) scan without using Digital ICE processing, and (b) the defects detected by Digital ICE processing.

Summary: Scratches and dust have never been easier and faster to find and fix when you scan your film with a scanner using Kodak’s Digital ICE software.  The combination of infrared illumination and high-speed image processing offer a powerful tool for traditional “dustbusting” applications as well as for more intensive film restoration projects.