Investigation Of Reconstruction Algorithms For Lensless Microscopic Imaging And Its Application

Lensless Microscopic Imaging(LMI)is a technique that directly records cell projections onto a sensor without any optical components.The LMI technology has broad application prospects in biomedical applications due to its advantages of low cost,portability,and large field of view(FOV).At present,the research on LMI technology mainly focuses on the improvement of resolution and the expansion of applications.The research content of this paper is mainly aimed at these two aspects.The specific research contents are as follows:(1)Set up a Single-Frame LMI platform,adapt the Lucy-Richardson(LR)algorithm,and use it together with the Angle Spectrum Method(ASM)and Convolution Method(CM)algorithms.One of the Single-Frame LMI reconstruction algorithms,and the resolution of the three reconstruction results are compared to select the best Single-Frame LMI reconstruction algorithm.The results show that ASM is the best single lensless lens reconstruction algorithm,and the resolution of the reconstructed image is the highest,which is 3.10 μm,which is 3 times higher than the original image.(2)Design a matrix light source to obtain multi-angle images,and calibrate multiple LMI systems,respectively.Using the Fourier Ptychographic Microscopic(FPM)and Extended Ptychographic Iterative Engine(e PIE)algorithm reconstruct the captured multi-angle images.The results show that the FPM algorithm may not be applicable to LMI,and the reconstructed image will have ghosting.The resolution of the reconstructed image of the e PIE algorithm is 3.10 μm,and it may be necessary to reduce the displacement between adjacent images to achieve further improvement in resolution.(3)Since the resolution of Single-Frame LMI images in this paper has met the imaging requirements of most cells,and because cells are a special transparent substance,the ASM,CM,and LR algorithms are used to weight individual J2-3T3 cell images.The results showed that the ASM-reconstructed cell diameter was closest to the microscopically measured J2-3T3 cell diameter,14 μm.In terms of cell counting,the edge of the cell cluster was blurred when the image was taken,which caused errors in the counting results.The AMM,CM,and L-R algorithms were used to reconstruct the J2-3T3 cell mass.Only the reconstruction result of the ASM algorithm can separate the cells in the cell cluster one by one,and the counting result of the reconstructed cell cluster is more consistent with the number of true cells in the cell cluster.In summary,the ASM algorithm reconstruction results are most beneficial for cell observation/counting.In addition,this paper proposes a new polarized light observation device based on lensless microscopic imaging.The phospholipase can be detected by the lensless polarizing analyzer by using the liquid crystal to change the brightness of the liquid crystal in the field of view after adding the TBS buffer,the phospholipid and the phospholipase solution.In the same time,the device can overcome the shortcomings of the polarizing microscope,has the advantages of low cost,portability,small size,large field of view,and can realize fast and real-time imaging.