Research On Optical Vector Matrix Operation Method Based On Complex Media

Vector-matrix multiplication is the basic operation and building block in image processing technology and deep learning framework.With the significant advantages brought by the combination of optical computing technology and artificial intelligence vision and image processing algorithms,research on the optical implementation of vector-matrix operation has practical significance.In addition,the optical computing model based on conventional optical components is limited by its incompressible space volume in terms of scale expansion.Therefore,the design of many optical systems nowadays has turned to finding reasonable solutions in the research of irregular optical elements or the interaction of inhomogeneous materials with light,including but not limited to single-pixel imaging based on scattering layers or complex media and lensless imaging system,etc.This thesis focuses on the research and improvement of the principle and structure of the optical vector-matrix calculation model,aiming to study the construction method of a compact optical computing system in view of the limitations of the lens-based optical system model.On the basis of existing research,the optical transmission matrix(TM)and wavefront shaping method are applied to achieve controllable beam propagation and light field distribution through stochastic complex media,instead of standard optical components,and solve the optimization problem to determine an appropriate wavefront modulation scheme to complete the configuration of the matrix operator.Based on this,an implementation process and method of optical vector-matrix multiplication manipulation based on phase-only spatial light modulator is proposed.Specifically,the method of measuring TM is studied to deal with the problem of accurate characterization of optical transmission in complex media.A measurement method based on Double-phase coding is applied,which simplifies the setup of the optical path and supports complex amplitude modulation of the optical field.Through the TM and the complex amplitude modulation of the incident wavefront,the fixed linear transformation relationship of the optical field at the specified spatial position in front and behind the complex media is established.This principle is used to construct the optical calculation system in the experiment,the optical vector-matrix multiplication and the edge detection of the image are realized.Among them,the correlation coefficients of the real and imaginary parts between the experimental output value and the theoretical output value of the tested complex-valued matrix operator can reach more than 0.9.Finally,in view of the problem of the measurement efficiency of the TM,a designable random phase mask is proposed to replace the complex medium to construct the optical computing system.The optical propagation numerical calculation can replace the experimental data collection to optimize the measurement process of TM.The effectiveness of the scheme is verified by simulation,and its practical feasibility is analyzed.The work carried out in this thesis provides an implementation scheme for the design of a scalable and reconfigurable optical vector-matrix multiplier.In addition to the fundamental advantages of energy consumption and computing speed compared with conventional electronic components,the design can be applied to artificial intelligence image tasks and other analog optical computing technologies through extended scale,providing a certain idea and basis for the research of new methods of optical information processing.