MODNet: Real-Time Trimap-Free Portrait Matting via Objective Decomposition

24 Nov 2020  ·  Zhanghan Ke, Jiayu Sun, Kaican Li, Qiong Yan, Rynson W. H. Lau ·

Existing portrait matting methods either require auxiliary inputs that are costly to obtain or involve multiple stages that are computationally expensive, making them less suitable for real-time applications. In this work, we present a light-weight matting objective decomposition network (MODNet) for portrait matting in real-time with a single input image. The key idea behind our efficient design is by optimizing a series of sub-objectives simultaneously via explicit constraints. In addition, MODNet includes two novel techniques for improving model efficiency and robustness. First, an Efficient Atrous Spatial Pyramid Pooling (e-ASPP) module is introduced to fuse multi-scale features for semantic estimation. Second, a self-supervised sub-objectives consistency (SOC) strategy is proposed to adapt MODNet to real-world data to address the domain shift problem common to trimap-free methods. MODNet is easy to be trained in an end-to-end manner. It is much faster than contemporaneous methods and runs at 67 frames per second on a 1080Ti GPU. Experiments show that MODNet outperforms prior trimap-free methods by a large margin on both Adobe Matting Dataset and a carefully designed photographic portrait matting (PPM-100) benchmark proposed by us. Further, MODNet achieves remarkable results on daily photos and videos. Our code and models are available at, and the PPM-100 benchmark is released at

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Results from the Paper

Task Dataset Model Metric Name Metric Value Global Rank Result Benchmark
Image Matting AMD MODNet+ MSE 0.0024 # 1
MAD 0.81 # 1
Image Matting PPM-100 MODNet+ (Our) MSE 0.0046 # 1
MAD 0.97 # 1