SF2Net: Sequence Feature Fusion Network for Palmprint Verification

Currently global features are usually extracted directly from local patterns in palmprint verification. Furthermore, sequence features for palmprint verification are only used as local features, but the properties of sequence features are not fully utilized. To solve this issue, this paper introduces Sequence Feature Fusion Network (SF2Net) for palmprint verification. SF2Net proposes a new paradigm: using stable and spatially correlated sequence features as an intermediate bridge to generate robust global representations. SF2Net’s core mechanism is to first extract fine-grained local features that are then converted into sequence features by a Sequence Feature Extractor (SFE). Finally, the sequence features are used as a superior input to capture high-quality global features. By fusing multi-order texture-based local features with globally extracted sequence features, SF2Net achieves superior discrimination. To ensure high accuracy even with limited training data, a hybrid loss function is proposed, which integrate a cross-entropy loss and a triplet loss. Triplet loss effectively optimizes feature separation by explicitly considering negative samples. Extensive experiments on multiple publicly available palmprint datasets demonstrate that SF2Net achieves state-of-the-art (SOTA) performance. Remarkably, even with a small training-to-testing ratio (1:9), SF2Net achieves 100% accuracy, surpassing SOTA methods under several benchmark datasets. The code is released at https://github.com/20201422/SF2Net