High-Confident Block Diagonal Analysis for Multi-View Palmprint Recognition in Unrestrained Environment

Unrestrained palmprint recognition refers to a comprehensive identity authentication technology, that performs personal authentication based on the palmprint images captured in uncontrolled environments, i.e., smartphone cameras, surveillance footage, or near-infrared scenarios. However, unrestrained palmprint recognition faces significant challenges due to the variability in image quality, lighting conditions, and hand poses present in such settings. We observed that many existing methods utilize the subspace structure as a prior, where the block diagonal property of the data has been proved. In this paper, we consider a unified learning model to guarantee the consensus block diagonal property for all views, named high-confident block diagonal analysis for multi-view palmprint recognition (HCBDA_MPR). Particularly, this paper proposed a multi-view block diagonal regularizer to guide that all views learn a consensus block diagonal structure. In such a manner, the main discriminant features from each view can be preserved while the learning of the strict block diagonal structure across all views. Experimental results on a number of real-world unrestrained palmprint databases proved the superiority of the proposed method, where the highest recognition accuracies were obtained in comparison with the other state-of-the-art related methods.