Robust Model-based Face Reconstruction through Weakly-Supervised Outlier Segmentation

TL;DR

This paper introduces FOCUS, a joint face autoencoder and outlier segmentation method that improves 3D face reconstruction by effectively localizing and excluding outliers like occluders and makeup, without requiring extensive annotations.

Contribution

The paper proposes a novel EM-type training strategy for joint face reconstruction and outlier segmentation, enhancing accuracy without needing 3D or segmentation annotations.

Findings

Achieves state-of-the-art 3D face reconstruction on NoW dataset.

Accurately localizes occluders without segmentation annotations.

Improves reconstruction quality by excluding outliers.

Abstract

In this work, we aim to enhance model-based face reconstruction by avoiding fitting the model to outliers, i.e. regions that cannot be well-expressed by the model such as occluders or make-up. The core challenge for localizing outliers is that they are highly variable and difficult to annotate. To overcome this challenging problem, we introduce a joint Face-autoencoder and outlier segmentation approach (FOCUS).In particular, we exploit the fact that the outliers cannot be fitted well by the face model and hence can be localized well given a high-quality model fitting. The main challenge is that the model fitting and the outlier segmentation are mutually dependent on each other, and need to be inferred jointly. We resolve this chicken-and-egg problem with an EM-type training strategy, where a face autoencoder is trained jointly with an outlier segmentation network. This leads to a synergistic effect, in which the segmentation network prevents the face encoder from fitting to the outliers, enhancing the reconstruction quality. The improved 3D face reconstruction, in turn, enables the segmentation network to better predict the outliers. To resolve the ambiguity between outliers and regions that are difficult to fit, such as eyebrows, we build a statistical prior from synthetic data that measures the systematic bias in model fitting. Experiments on the NoW testset demonstrate that FOCUS achieves SOTA 3D face reconstruction performance among all baselines that are trained without 3D annotation. Moreover, our results on CelebA-HQ and the AR database show that the segmentation network can localize occluders accurately despite being trained without any segmentation annotation.