FLIP: Cross-domain Face Anti-spoofing with Language Guidance
Koushik Srivatsan Muzammal Naseer Karthik Nandakumar
Face anti-spoofing (FAS) or presentation attack detection is an essential
component of face recognition systems deployed in security-critical
applications. Existing FAS methods have poor generalizability to unseen spoof
types, camera sensors, and environmental conditions. Recently, vision
transformer (ViT) models have been shown to be effective for the FAS task due
to their ability to capture long-range dependencies among image patches.
However, adaptive modules or auxiliary loss functions are often required to
adapt pre-trained ViT weights learned on large-scale datasets such as ImageNet.
In this work, we first show that initializing ViTs with multimodal (e.g., CLIP)
pre-trained weights improves generalizability for the FAS task, which is in
line with the zero-shot transfer capabilities of vision-language pre-trained
(VLP) models. We then propose a novel approach for robust cross-domain FAS by
grounding visual representations with the help of natural language.
Specifically, we show that aligning the image representation with an ensemble
of class descriptions (based on natural language semantics) improves FAS
generalizability in low-data regimes. Finally, we propose a multimodal
contrastive learning strategy to boost feature generalization further and
bridge the gap between source and target domains. Extensive experiments on
three standard protocols demonstrate that our method significantly outperforms
the state-of-the-art methods, achieving better zero-shot transfer performance
than five-shot transfer of adaptive ViTs. Code:
https://github.com/koushiksrivats/FLIP