Resolution Enhancement in Optical Microscopy Using Subpixel Shifts

Abstract

A new method of resolution enhancement in optical microscopy using the method of spatial subpixel shifts, i.e., shifts by some amount less than the resolution provided by the lens are considered. The resolution of optical microscopes is determined by the type of used lenses. Professional microscopes have a set of microlenses with different magnifications, which are mounted on turrets containing several lenses. Sometimes, it makes more sense to use one lens instead of a set of microlenses if it is possible to provide subpixel shifts. An increase in spatial resolution is carried out using the subpixel shift technique. In this case, the spectrum of the feature is supplemented by a multiplier, the type of which depends on the type of lens aperture. To obtain high-resolution features, it is necessary to divide the Fourier spectrum of an image obtained from several subpixel-shifted images by a factor depending on the selected aperture. This factor is called the aperture function. The aperture function is determined by the type of used lens and can be its nameplate value. An experimental method for calibrating a lens (obtaining its aperture function) with low resolution (\(8\times\)) based on images obtained with higher resolution lenses (\(40\times\)) is shown. Once the aperture function is defined, one low-resolution lens can be used to produce images at any resolution less than the resolution of the selected high-resolution lens (\(40\times\)).