Production face liveness with temporal consistency, behind billion-scale identity checks.
Frame-based liveness detectors at the time of this work (Xu et al., 2021) suffered from prediction inconsistency across time: a single frame might flip between live and spoof, producing flicker that broke the downstream face recognition system. The fix combined a temporal smoothing model with an adapter that turns short-clip predictions into a stable per-session decision.
This paper received the Best Paper Award at the 5th ChaLearn Face Anti-Spoofing Workshop @ ICCV 2021, and the methods were folded into Amazon Rekognition’s online liveness detection. The system has since handled billions of annual identity checks against presentation attacks, and its constraints (legitimate users must not be flagged while attackers shift from physical spoofs to GenAI deepfakes) are exactly what motivated the continuous lifelong-learning research direction that I work on now.
Several patents grew out of this program: liveness from motion, face, and context cues (Xu et al., 2025), gesture/facial-expression/concurrency validation (Zhang et al., 2025), and synthetic-image evaluation of biometric authorization (Xu et al., 2024).
The lifelong-update problem this program raises also motivated newer research on source-free adaptation (Li et al., 2025): an optimal-transport-guided adaptor lets a deployed anti-spoofing model adapt at the client side at test time, with only a small sample of target data and without touching the base model parameters or training set.
References
2025
Patent
Liveness Detection Based on Motion, Face, and Context Cues
Xiang Xu, Mingze Xu, Zheng Zhang, and 4 more authors
@misc{xu2025liveness,title={Liveness Detection Based on Motion, Face, and Context Cues},author={Xu, Xiang and Xu, Mingze and Zhang, Zheng and Xiong, Yuanjun and Xia, Wei and Wu, Jonathan and Tighe, Joseph},year={2025},note={US Patent 12,300,035 B1},}
Patent
Liveness Detection Based on Gesture Validation, Facial Expression Analysis, and Concurrency Validation
Zheng Zhang, Xiang Xu, Hao Chen, and 2 more authors
@misc{zhang2025liveness,title={Liveness Detection Based on Gesture Validation, Facial Expression Analysis, and Concurrency Validation},author={Zhang, Zheng and Xu, Xiang and Chen, Hao and Wu, Jonathan and Tighe, Joseph P.},year={2025},note={US Patent 12,333,863},}
@inproceedings{li2025optimal,title={Optimal Transport-Guided Source-Free Adaptation for Face Anti-Spoofing},author={Li, Zhuowei and Zhao, Tianchen and Xu, Xiang and Zhang, Zheng and Li, Zhihua and Chen, Xuanbai and Zhang, Qin and Bergamo, Alessandro and Jain, Anil K. and Xing, Yifan},booktitle={IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR)},year={2025},}
2024
Patent
Evaluating Biometric Authorization Systems with Synthesized Images
Xiang Xu, Hao Zhou, Jonathan Wu, and 1 more author
@misc{xu2024evaluating,title={Evaluating Biometric Authorization Systems with Synthesized Images},author={Xu, Xiang and Zhou, Hao and Wu, Jonathan and Tighe, Joseph P.},year={2024},note={US Patent 12,039,027},}
@inproceedings{xu2021liveness,title={On Improving Temporal Consistency for Online Face Liveness Detection System},author={Xu, Xiang and Xiong, Yuanjun and Xia, Wei},booktitle={IEEE/CVF International Conference on Computer Vision Workshops (ICCVW)},year={2021},note={Best Paper Award}}