Archive notice: This article was originally published on July 31, 2006. Links and embedded videos are preserved as part of the historical record.
Even creating keys from blue-screen or green-screen recordings has its pitfalls, but the automated isolation of objects in front of a moving background has barely been solved so far. Only the commercial solution Mokey offers an approach here, by calculating a mask from the changes in the frames.
But the paper by Neel Joshi, Wojciech Matusik and Shai Avidan shows another way: With the help of a comparison of images from several cameras, the depth information can be reconstructed because the background differs more than the foreground in the different views. This makes it possible to generate a “synthetic exposure” with an alpha mask from the source images.
The algorithm used works linearly, meaning that the calculations also become only linearly slower as the number of cameras increases and, according to the researchers, can also be turned into a real-time application with further optimization. This would make it possible to record a high-resolution Z-buffer directly on the film set, which could offer entirely new possibilities for shooting and compositing.
More information and the paper can be found on the authors’ website (see link below).
Further links:
- Natural Video Matting
Mokey
