RESOLUTION ENHANCEMENT IN OPTICAL MICROSCOPY USING SUBPIXEL SHIFTS
V. I. Guzhov, S. P. Ilinykh, E. V. Andryushchenko, D. S. Khaidukov
Novosibirsk State Technical University, Novosibirsk, Russia
Keywords: super-resolution, subpixel shift, holography, Fourier transform, synthesized aperture, sampling
Abstract
The paper deals with a new method of resolution enhancement in optical microscopy by the method of spatial subpixel shifts, i.e., shifts by some value smaller than the resolution provided by the objective lens. The resolution of optical microscopes is determined by the type of objective lens used. Professional microscopes have a set of microlenses with different magnifications, which are mounted on a turret containing several lenses. It is shown that a single objective lens can be used instead of a set of microlenses if subpixel shifts can be provided. An increase in spatial resolution is provided using the subpixel shift technique. In this case, the spectrum of the feature is augmented by a multiplier, whose type depends on the type of the lens aperture. To obtain high-resolution features, it is necessary to divide the Fourier spectrum of an image formed from several subpixel shifted images by a multiplier depending on the aperture type. This multiplier is called the aperture function. The aperture function is determined by the type of the lens used and can be its passport value. The paper illustrates an experimental method of obtaining the aperture function of a low-resolution (8×) lens calibration based on images obtained with high-resolution (40×) lenses. After determining the aperture function, one low-resolution lens can be used to acquire images with a resolution smaller than that of the selected high-resolution (40×) lens.
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