A Coarse-to-Fine Framework for Automatic Video Unscreen.

Video unscreen, a technique to extract foreground from given videos, has been playing an important role in today's video production pipeline. Existing systems developed for this purpose which mainly rely on video segmentation or video matting, either suffer from quality deficiencies or require tedious manual annotations. In this work, we aim to develop a fully automatic video unscreen framework that is able to obtain high-quality foreground extraction without the need of human intervention in a controlled environment. Our framework adopts a coarse-to-fine strategy, where the obtained background estimate given an initial mask prediction in turn helps the refinement of the mask by the alpha composition equation. We conducted experiments on two datasets, 1) the Adobe's Synthetic-Composite dataset, and 2) DramaStudio, our newly collected large-scale green screen video matting dataset, exhibiting the controlled environments. The results show that the proposed framework outperforms existing algorithms and commercial software, both quantitatively and qualitatively. We also demonstrate its utility in person replacement in videos, which can further support a variety of video editing applications.