1. Previous work on green screen keying required controlled illumination and manual guidance, which is not feasible for real-time applications.
2. Recent approaches have used deep learning models but these struggle to achieve both high robustness and pixel-wise accuracy.
3. The proposed method in the paper uses a deeply guided linear model that first performs segmentation using a robust CNN, then applies a linear model to refine the segmentation, achieving both high robustness and accuracy for real-time green screen keying without specialized lighting or manual input.