But the general scalar quantization (figure 3(a)) may cause great mistake because of the fixed interval of the quantizing template.
The adaptive quantization adjusts the center and length of the interval for each quantizing component.
The quantizing of the feature vector achieves the utilizing of Hash function in the protecting of biometric template.
Due the quantizing method, we present two schemes for the protection of biometric template--single-template scheme and multi-template scheme.
4) Quantizing the feature vector X via template [M.
3) Check the enrolled user's quantizing template MXi, if it contains the information of , process X' as follow:
4) Quantizing the feature vector Xi by the enrolled user's quantizing template MXi, get quantized feature vector ;
3) Quantizing the feature vector X' by the enrolled user's quantizing template array [M.
For single template scheme, suppose the quantizing template contains k intervals, and the number of components of the feature vector is n.