An improved phase retrieval algorithm for optical anti-counterfeiting mask is proposed which combines the G-S
algorithm with the simulated annealing algorithm. The proposed algorithm takes full advantage of the respective
advantages of the G-S algorithm and the simulated annealing algorithm. In the scheme, the redesigned simulated
annealing algorithm is used to control the times of iterations to achieve global searching, which makes the G-S algorithm
to jump out automatically when the program is trapped in local optimal solution. The computer simulation results show
that the proposed algorithm improves the quality of decoded image obviously compared with the traditional G-S
algorithm, and reduces the running time of the program greatly.
A new fully distributed optical fiber sensing and location technology based on the Mach-Zehnder interferometers is
studied. In this security system, a new climbing point locating algorithm based on short-time average zero-crossing rate
is presented. By calculating the zero-crossing rates of the multiple grouped data separately, it not only utilizes the
advantages of the frequency analysis method to determine the most effective data group more accurately, but also meets
the requirement of the real-time monitoring system. Supplemented with short-term energy calculation group signal, the
most effective data group can be quickly picked out. Finally, the accurate location of the climbing point can be
effectively achieved through the cross-correlation localization algorithm. The experimental results show that the
proposed algorithm can realize the accurate location of the climbing point and meanwhile the outside interference noise
of the non-climbing behavior can be effectively filtered out.