Research On Tomographic Reconstruction Based On Transport Of Intensity Equation

As a typical non-interfering 3D reconstruction method,tomographic reconstruction based on the transport of intensity equation has become a hotspot of a lot of research.In phase tomographic reconstruction,it is usually necessary to obtain phase information in multiple directions.Although the technology from light field moment imaging can give a reconstructed light field with perspective effect,it cannot directly obtain phase information,and the three-dimensional shape of the object cannot be obtained directly.On the other hand,solving phase information through the transport of intensity equation requires axial intensity differentiation,usually,the differentiation is obtained by finite differences between the two intensities,and its accuracy cannot be guaranteed.Therefore,how to improve the calculation accuracy of the axial differential,and then the accuracy of the recovered phase,is particularly important.Aiming at the problems mentioned above,this thesis has carried out corresponding research.The main research work and innovations are as follows:(1)A multiplication technique reconstruction method based on the transport of intensity equation is proposed.Firstly,by introducing the concept of light field moment,and based on the close relationship between the light field moment imaging and the transport of intensity equation under partially coherent light conditions,the first order of the light field moment is obtained by solving a Poisson equation similar to the transport of intensity equation.The moments,combined with the multiplication technique,are used to realize the phase tomography reconstruction at the scene.(2)A reconstruction method combining the transport of intensity equation based on high-order intensity differential and Fourier slice theorem is proposed.First,the multi-plane intensity measurement method is used to calculate the high-order intensity differential value to solve the transport of intensity equation.The accuracy of the phase recovery result is improved,and the Fourier slice theorem is used to back-project the phase projection in each direction to obtain each layer two-dimensional slices,and finally reconstruct the three-dimensional shape of the object.