Automatic primary stabilization of sprocketless scanned film based on RAW image pin registration data processing

As reviewed in a previous article, working on RAW image sequences from digital scanned film offers undeniable advantages and a non-destructive access to critical image data such as exposure settings, white balance, and linear gamma, allowing for a greater control of shadows and highlights and overcoming some limitations usually associated with other image formats. However, handling this unprocessed information may also turn into a challenge if the acquired images do not include some basic improvements. One of them is image sequence stability.

In an attempt to make the ingestion of the digital scanned film sequences a more straightforward course for color grading and film restoration workflows, even working with footage that include damaged perforations and irregular splices, a new automated image stabilization process has been specifically developed to expand the NoGap 2D Film Scanner 8K RAW system toolset. But since this operation is carried out on content for long-term digital preservation not all types of steady results had been considered a valid target, because stabilizing scanned films in a preservation understanding way has some additional demands associated, beyond simply centering an image into a frame.

Stabilizing scanned films for long-term preservation

Designing from scratch an stabilization algorithm for digital preservation film footage involves think over possible undesirable side effects of this intervention. After a period of analysis and besides other technical aspects directly related to the color information, two requirements were maintained to limit the scope of the stabilization algorithm and not move away from essential restoration aspects like transparency and reversibility.

On one hand, stabilization processes that involved the loss of any pixel data present in the source image were discarded, since, stable or not, these can also be a perfect valid source of information for future research and future preservation protocols. On the other hand, it was considered mandatory that the stabilization process must respect a non-destructive way of working, so the resulting stabilized sequence must be open to revert, if necessary, to the genuine RAW capture information originally captured by the scanning system, now and in the future.

 

With the new developed algorythim, the 35mm scanned film is automatically analized and as a result a new sequence, in standard DNG format, is automatically generated containing the unprocessed RAW color information and a primary stabilization of the whole image. The stabilization process specially developed to analyze film footage does not require any external tracking software or user intervention other than just an initial reference frame setup.

Want to know more? Don’t hesitate to get in touch at: nogap2Dfilmscan@lasala1.com