Filtering and interpolation of microscopy data in frequency domain.

Contents

• Read raw image.
• Setup microscope parameters.
• Filter and interpolate by factors of 1,2, or 3.
• Compare results.
• Zoom in on a region.

Read raw image.

clear all;

rawfile='/images/shalin/2012_07_13_EcoliFM/SM4_100x1.4Mag1.5EcoliFMdye3_good/img_000000000_VariLC - State0 - Acquired Image_000.tif';
raw=imread(rawfile);

Setup microscope parameters.

inpix=7.4/(100*1.5); %100x objective, 1.5x optovar, 7.4um pixel of Qimaging Camera.
emlambda=0.598; % FM dye when bound to phospholipid membrane emits at 598nm.
NA=1.4; % Numerical aperture of the imaging lens.
fcut=2*NA/emlambda; % The spatial frequency cutoff of the imaging system.

Filter and interpolate by factors of 1,2, or 3.

FilteredNoInterpolation=opticalLowpassInterpolation(raw,inpix,fcut,1);
FilteredInterpolationx2=opticalLowpassInterpolation(raw,inpix,fcut,2);
FilteredInterpolationx3=opticalLowpassInterpolation(raw,inpix,fcut,3);

Compare results.

xaxis=inpix*[0 size(raw,2)-1];
yaxis=inpix*[0 size(raw,1)-1];
figure(1); clf;
set(1,'Position',[10 10 1200 800],'Color','white','defaultaxesfontsize',16); colormap gray;

imagecat(xaxis,yaxis,raw,...
   FilteredNoInterpolation,FilteredInterpolationx2,FilteredInterpolationx3,'equal','link');

Zoom in on a region.

ylim([0 20]); xlim([30 50]);
snapnow;

Published with MATLAB® R2012b