“…The exploitation of the complementarity between biometric modalities increases the overall accuracy, improves the performance, reduces the vulnerability and therefore, results in more robust biometric systems which offer enhanced security against forgeries [52]. Due to different biometric traits can be extracted from hand images such as hand geometry [47,35], palmprint [97] or hand veins [208,191], hand can be considered multimodal itself and, thus, it is possible to improve the system performance by exploiting the information provided by its different traits. In this manner, some hand multimodal systems have been developed during the last years combining hand 202,98,95,43,22,174,96,190,101,81,68,121,62,149,69,209,206,193,108,85,148,152,139,66 [189,65,51,72,11,195,194,5,200,58,55,54,128,3,…”