Shared Sampling for Real-Time Alpha Matting

基于传统方法的抠图算法，可望移动端实时。目前传统抠像算法中最好的。速度比closed form快。在alphpamatting网站的排名为28，36.4（实时版本）。

基本步骤为：

1. Expansion of Known Regions: extrapolates “known foreground" and “known background" regions of the trimap into the “unknown" regions;
2. Sample Selection and Matte Computation: tries to identify, for each pixel in the unknown regions, the best pair of foreground and background samples. It also com- putes an alpha matte from the obtained samples;
3. Local Smoothing: locally smooths the resulting matte while maintaining its distinct features.

• paper

• code