The scheme’s effectiveness is expected to be greatest when t1 = Q1 and t2 = Q2. However, the system must exercise caution here to ensure significant representation of both modalities in the fusion process; for example, if Q2 differs greatly from t2 while Q1 is close to t1, the authentication process is dominated by the face modality, thus reducing the process to an almost unimodal scheme based on the face biometric. A mandated benchmark is thus required for each quality score to ensure the fusion-based authentication procedure does not grant access for a user if the benchmark for each score is not met. Without such benchmarks, the whole authentication procedure could be exposed to the risk of potential fraudulent activity, including deliberate attempts to alter the quality score of a specific biometric modality. The system must thus ensure the weight of each modality does not fall below a certain threshold so the multimodal scheme remains viable.