| Laser imaging radar becomes more and more important in military because of the advantages of compact structure, well detective capability, small size, light weight, high resolution, and high-frame rate video. Compared with the way of the traditional floodlighting, laser imaging radar can more effectively enhance the light energy utilization by using Dammann grating array illuminator. Therefore, on the condition that the laser light emission power is limited, the use of Dammann grating array illuminator can greatly enlarger the laser imaging radar detection range and image quality. Improving the optimization speed of Dammann grating is the key technology for laser imaging radar illuminator that must be solved. This paper focused on study of improving the speed of Dammann grating feasibility by the parallel optimization method, meantime completed the optimum design of the splitting ratio for the 25×25 Dammann grating array.Based on study of the Dammann grating design principle, through the analysis of existing optimum algorithm, we used simulated annealing algorithm for optimal design of Dammann grating. Moreover combining the actual needs of this article, we studed the initial temperature, annealing strategy, the chain length of the simulated annealing cooling schedule, and completed three kinds of one-dimensional Dammann grating design when the splitting ratio was 1×100,1×120,1×150.On basis of the study of the traditional parallel simulated annealing algorithm, we used the temperature parallel simulated annealing algorithm, and made use of MPI+FORTRAN to optimize splitting ratio 25×25Dammann grating array, whose running time is 36 hours much better than the serial algorithm about 100 hours; Further, Dammann grating diffraction efficiency is as high as 93.78%, and non-uniformity is 0.02. This paper by changing the objective function of the size of the weight factor, got different combinations of optimization results and the simulation map of the Dammann grating surface structure . |
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