Why does historical footage look faster

How artificial intelligence colors historical films

In order to flatter our eyes, the post-processors usually increase the resolution of the films they are treating. In many cases this would probably not even be necessary. "The image quality was darn good even in the first films by the Lumière brothers," says film expert Rüdel. If you digitize the original well with high digital resolution, the result is always better than an AI upscaled version of a bad digitization. Youtubers like Shiryaev or the people behind “Nineteenth century videos. Back to life. «Do not usually have access to the originals, but can find their films on the Internet or in the online offers of large libraries. The initial quality is correspondingly low.

But because upscaling is already used by default in video games and is accordingly widespread, it can be used by Youtubers with relatively little effort. And television manufacturers such as Samsung are already equipping their ultra-high-resolution 8K devices with AI chips that adapt the resolution of normal television signals in real time to the performance of the display.

"In the past, attempts were made to do this with simple interpolations between the pixels, for example by simply inserting a gray pixel between a black and a white pixel," explains Robert Sablatnig, head of the Computer Vision Lab at the Vienna University of Technology. However, the results were rather unsatisfactory. Today the algorithms are taught by means of examples of what images could look like in a higher resolution. Here, too, the quality of millions of images is first intentionally reduced in order to create training data. As a rule, the resolution of 4K images (with around 4000 pixels in width) is halved to 2K and the network learns to insert suitable additional pixels in order to restore the original state. Once the training is complete, the algorithm can then double the resolution from 4K images to 8K in order to operate the displays of modern televisions.

For reliable results, however, diversity is the key to success. "The network has to be prepared for anything that might appear on television or in the film," says Sablatnig. "Because if it is confronted with something that it has never seen, the result will not be nice either."