Approximate Fast Foreground Colour Estimation

Compositing objects from one image or video onto another background is a classic computer vision problem. Compositing requires an estimate of the foreground object's transparency, a topic of study known as Alpha Matting. However, less studied is the requirement of an estimate for the foreground object's colours in transparent regions. Naively compositing without this leads to bleed-through of the original background. In this work, we propose an approximation for the multi-level foreground estimation technique from Germer et al. Our method can be implemented 11 lines of Python code and yields comparable results to state of the art approaches while also being faster. Our code is available at https://github.com/PhotoRoom/fast-foreground-estimation.