現在已經有許多人臉反欺騙方法來應對各種偽冒攻擊，並取得了不錯的性能。
儘管現有方法在數據集內場景上運行良好，但在處理看不見的場景時性能下降。
因此，在本篇論文中，我們專注在人臉反欺騙問題的域泛化，並提出了一種新的
圖片增強策略來增加數據多樣性。與幾種區域隨機遮擋的區域丟失策略不同，本
篇所提出的增強策略增加了激活值較低的補丁區域以生成更具挑戰性的圖像。此
外，我們將域對抗學習模塊與三元組挖掘相結合，以提取域不變的活性特徵，並
為看不見的域學習更好的類邊界。此外，還進一步結合了像素級監督，以輔助人
臉反欺騙模型通過估計像素因素來學習判別特徵。在幾個基準數據集上的廣泛實
驗結果證明了我們方法的有效性，並顯示出對最先進的競爭對手的顯著改進。

Many face anti-spoofing methods have been developed to counter diverse presentation
attacks and achieved promising performance. Despite existing methods
work well on the intra-dataset scenarios, the performance drops when dealing with
the unseen scenarios. In this paper, we focus on domain generalization for face antispoofing
(FAS) problem and propose a novel augmentation strategy to increase the
data diversity. Unlike several regional dropout strategies, where the region are
random occluded, the proposed augmentation strategy increase the patch area with
lower activation value to generate more challenging images. Moreover, we combine
Domain Adversarial Learning Module (DALM) with triplet mining to extract
domain-invariant liveness features and learn a better class boundary for unseen domains.
Additionally, the pixel-level supervision is further incorporated to guide the
face anti-spoofing model to learn discriminative features by estimating pixel-wise
factors. Extensive experimental results on several benchmark datasets prove that
our method show significant improvement over the state-of-the-art competitors.

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