Microwave Imaging Of 2-D Eletrical Conductor Based On Time-Domain Finite Element And Exploration Of Acceleration Using Graphics Processor Units (GPU)

In this project,the forward scattering problem is treated via.scalar Time-Domain Finite Element Method(TDFEM) and vector Time-Domain Finite Element Method,while inversion microwave imaging is implemented by global optimization algorithm,genetic algorithm and real differential evolution strategy. And completed reconstruction of the shape information of unknown scatterer is presented by the perfect union of scalar TDFEM,vector TDFEM and genetic algorithm(GA),real differential evolution strategy based on obtaining the ultra-band information through time-domain.Furthermore,we investigate Graphics Processor Unit(GPU) acceleration of TDFEM algorithm.And significant reduction of the computation time of TDFEM is obtained by GPU.Firstly,we introduce methods that characterize the shape of scatterer.Our focus is on discrete points method put forward by author and its merits.And then the method is used in this project.After this,we introduce time domain measured equation of invariance(MEI) into TDFEM,and bear out the analysis result by some examples. Finally,discuss some questions as we achieve microwave imaging through it.Secondly,focal point is obtaining the scattering information of near-field and far-field by scalar TDFEM and vector TDFEM.We can get the restrictions of optimization algorithm by extrapolating the approximate size of scatterer from the far-field scattering information,and upon that we can obtain the definite search coverage and find the globe optimum solution faster.We should first simply introduce and analysis the popular optimization algorithm in present-day.And then, GA and real differential evolution strategy are choosed to combine with scalar TDFEM and vector TDFEM respectively achieve imaging.And we will analysis the near-field and far-field next.There has big difference between them.As a result,the circumstances of far-firld solution space are more complicated than near-field solution space.For this reason,the far-field imaging is more difficult,and need more time to find optimum solution.In this paper,we will find the shape reconstructed agrees well with the shape of scatterer,so long as time is enough.But the question that can not skirt round is too much time is spent on imaging process.In addition,since the complicated computing of the time-domain finite element, GPU accelerated method is applied in the time-domain finite element calculation for prospective study.As the parallelism property of GPU,high-intensive computing capability and high accuracy,through full utilizing the excellent performance of GPU,the TD-FEM computational speed can multiplied.At last,we sum up and look forward to vistas of the project.And put forward the question should be solved in the future.