Table 1 Pseudo-code of sub-database construction

Data: Raw fingerprint database

Result: sub-databases

1 c l u s t e r←A P_C l u s t e r(i n p u t);

2 for each c l u s t e r _i ∈c l u s t e r s do

3 for each p o i n t _j ∈c l u s t e r _i do

4 if r e l a t i v e_d e n s i t y(p o i n t _j ) >Threshold

5 Outliers are reassigned to the nearest neighbor;

6 back to Step 1;

7 end

8 end

9 Obtain the cluster center;

10 end

11 Construct each cluster as a sub-database;