
Methodology  Process method of fragile bits  Results 

Hollingsworth et al. [5, 36]  Masking iris code bits corresponding to complex filter response near the axes of the complex plane  Improve the separation between the match and nonmatch Hamming distance distributions 

Hollingsworth et al. [8]  Consider the fragile bits provide beneficial information rather than ignoring fragile bits completely  Score fusion of fragile bit distance and Hamming distance works better than Hamming alone, and it improved the accuracy of matches 

Hollingsworth et al. [37]  Masks fragile bits  value is 8.2516 compared with 7.4825 for nonmask fragile bits 

Bolle et al. [7]  Theoretically proved the existence of fragile bits  — 

Dozier et al. [38]  Used genetic search to minimize the number of iris code bits  Approximately reduce 89% of iris code bits and discard the fragile bits 

Dozier et al. [39]  Only kept bits that were 90% or 100% consistent  Discard the fragile bits 

Proposed  Divided normalized iris into multitracks, and fused all tracks by local quality evaluation with PSO  value increase and EER decrease 
