Research On Structured Light Parameters Determination And Image Apodization Method In SIM Image Reconstruction

In the field of life sciences,Structured Illumination Microscopy(SIM)is widely used due to its fast imaging speed and low fluorescence performance.The SIM needs to use an algorithm to reconstruct the super-resolution image.In this process,whether the spatial frequency and phase of the structured light can be accurately determined determines the reconstruction effect of the image.Some spatial frequency and phase measurement algorithms that have been proposed currently,which have errors in the low modulation depth,which affects the reconstruction quality of the image.After the image reconstruction is reconstructed,it is also necessary to perform apodization filtering on the reconstructed image to reduce the ringing effect caused by the image restoration.However,apodization filtering will inevitably reduce image resolution.There is currently less research on the nature of various apodization functions.To solve these problems,this paper studies the illumination pattern spatial frequency and phase measurement method and the apodization filtering method of reconstructed image in the two-dimensional SIM reconstruction algorithm.The main contents include the following aspects:(1)Study the structure illumination pattern frequency and phase measurement algorithm in SIM reconstruction algorithm,and propose an improved spectral component cross-correlation algorithm for determining spatial frequency and phase.The algorithm can simultaneously calculate the spatial frequency and phase,simplifying the algorithm and increasing the running speed.The result can be accurately calculated when the modulation depth of illumination pattern is low,and the spatial frequency error is close to 0,and the phase error is lower than 5 degrees.(2)Study the apodization filtering method in SIM reconstruction algorithm and propose a Gaussian apodization function.The filtering properties of the apodization function are studied by analyzing the point spread function.The filtering effect of the Gaussian apodized function and other apodization functions is analyzed and compared.At the same time,an evaluation method is introduced to quantitatively evaluate the filtered image.The results show that the Gaussian apodization function can maintain the image resolution and contrast while suppressing the ringing effect.(3)Experimentally,bovine pulmonary artery endothelial cells(BAPE),COS-7cells and Hela cells were imaged.The nine-frame reconstruction algorithm was used to verify the improved spectral component cross-correlation.Algorithm and Gaussian apodization function.The experimental results show that the improved spectral component cross-correlation algorithm can accurately reconstruct the image when the structural light modulation is low.The Gaussian apodization function is the best to maintain resolution and contrast of the image while suppressing the ringing effect.