Research On Key Technology Of Snapshot Microlens Array Micro-hyperspectral Imaging System

With the continuous development of exogenous biosensor markers such as fluorescent proteins,quantum dots,and organic fluorophores in the field of biomedicine,the spectral information introduced through markers adds more observation dimensions to the time-series biochemical reactions of living cells.It plays an indispensable role in the research of immunology and molecular biology.In order to achieve non-single-point observation of living cells,the hyperspectral imaging technology that combines optical imaging and spectral analysis is applied to the microscopy field,and a data cube containing the image information and spectral information of the observation target is obtained through spatial scanning or wavelength scanning.However,the full-field spectral information collection of the target is realized by scanning,which cannot meet the demand for time-sensitive spectral collection of moving cells with high timeliness.The snapshot hyperspectral imager can obtain all the spatial spectrum information of the target through a single imaging of the detector.The integral field of view hyperspectral imager is one of the snapshot hyperspectral imagers,by introducing the "integral field of view unit",After the two-dimensional image information is divided and rearranged,it is dispersed by the hyperspectral imager,and the two-dimensional image information and one-dimensional spectral information of the observation target can be obtained at the same time,so as to realize non-scanning hyperspectral imaging data acquisition.The integral field of view snapshot hyperspectral imager has the advantages of high spectral reconstruction efficiency,wide working wavelength,high spectral resolution,etc.It has been widely used in the fields of astronomy and remote sensing and continue to expand the application to other fields,it is an effective technical means to realize the time series acquisition of moving cell spectrum.In view of this,this article has carried out in-depth research on the snapshot micro-hyperspectral system with the mature device and simple structure of the microlens array as the integral field of view unit.The goal is to develop a snapshot microlens array micro-hyperspectral imaging system that can realize the time-series observation of moving cells.Research has been carried out on a series of scientific issues in the design,processing,assembly and adjustment,spectrum reconstruction and calibration of the system,breakthrough the key technology in the development of the snapshot microlens array micro-hyperspectral imaging system.The main research contents of this paper are:1.Optical structure design.This paper proposes a snapshot micro-lens array microscopic hyperspectral imaging system structure that approximates the direct-view optical path structure.First,the mechanism of interference between spectral bands is analyzed by the principle of geometric optics,and based on this,the system microscopic imaging unit and surface are analyzed.The optical structure of the dispersive hyperspectral imaging unit is designed.After the design is completed,the tolerance analysis of the system is carried out,and the processing error of each component and the assembly and adjustment error of the system are formulated to ensure the engineering feasibility of the optical system;2.Research on reconstruction algorithm of 3D spectrogram.Aiming at the problem that the spectral strip array is interlaced on the surface of the detector and the data extraction is difficult,a precise spectrum reconstruction model based on optical tracing is proposed,the spatial dispersion equation of the prism and grating is deduced,and the microlens is established.The algorithm model of the corresponding relationship between the surface dispersion spectrum distribution of the array and its imaging position solves the problem of the interlacing of the spectral strip array on the surface of the detector and the difficulty of data extraction.Compared with the simulation results of optical design software,the error is better than 1/3 pixels,which proves the accuracy and reliability of the 3D spectrum reconstruction algorithm proposed in this paper;3.Research on system installation and adjustment technology.In order to realize the requirement of the project feasibility of the snapshot microlens array micro-hyperspectral imaging system,the modular design idea is adopted in the whole system design process.Among them,the independent module includes the tube lens in the microscopic imaging unit,the collimator lens group and imaging lens group in the surface dispersion hyperspectral imaging unit,and the prism-grating combined light splitting element.Each component can be independently assembled and inspected;at the same time,it can pass through the Polo The method of plate-assisted CCD detector focus adjustment ensures the accuracy of the focal plane of the CCD detector of the area dispersion type hyperspectral imaging unit.After completing the independent installation and adjustment of each part,the whole system is jointly adjusted to ensure that the performance of the instrument reaches the expected design effect;4.System calibration and testing technology research.An automatic online calibration algorithm through adaptive threshold selection and precise calculation of the position of the multi-spot array is proposed.The online spectral calibration algorithm and calibration software of the snapshot microlens array micro-hyperspectral imaging system are studied,and the system is designed and built.The required online spectral calibration and radiometric calibration system,by bringing the mercury lamp online calibration results into the 3D spectral image reconstruction algorithm model,the system can achieve 3D spectral calibration,and the spectral resolution of the calibrated instrument has been tested,And finally completed the three-dimensional spectrum calibration and radiation calibration of the entire working band of the instrument,and the calibration accuracy is better than0.2nm.In addition,this article also developed a three-dimensional spectral data playback software for the instrument,tested the performance indicators and functions of the snapshot microlens array microscopic hyperspectral imaging system,and verified the ability of the instrument to obtain snapshot microscopic hyperspectral data.