“…Ensemble learning aims at combining multiple learners to obtain a more robust representation of the object and is successfully applied for vision tasks such as SAR image category (Zhao et al, 2016 ), fault diagnosis (Liu et al, 2021 ), image cluster (Tsai et al, 2014 ), and human activity recognition (Jethanandani et al, 2020 ). In addition, some researchers applied it to biometrics, e.g., classification tasks such as fingerprint classification (Zhang et al, 2011b ), palm-vein recognition (Joardar et al, 2017 ), and face recognition (Bhatt et al, 2014 ; Ding and Tao, 2018 ). As the features from different learners can achieve a complementary representation for the input image, their combination performs well for identification.…”