A method for estimating spatial resolution of real image in the Fourier domain

TL;DR

This paper introduces a Fourier domain logarithmic intensity plot method to estimate the spatial resolution of real images, applicable across various imaging techniques, providing an alternative to traditional noise-based resolution measures.

Contribution

The paper presents a novel Fourier domain logarithmic intensity plot technique for estimating spatial resolution directly from real images, applicable to different imaging modalities.

Findings

Accurately estimated the point-spread function's FWHM from images.

Resolved 120-nm pitch square-wave patterns in microtomography.

Matched resolution estimates with traditional test object methods.

Abstract

Spatial resolution is a fundamental parameter in structural sciences. In crystallography, the resolution is determined from the detection limit of high-angle diffraction in reciprocal space. In electron microscopy, correlation in the Fourier domain is used for estimating the resolution. In this paper, we report a method for estimating the spatial resolution of real images from a logarithmic intensity plot in the Fourier domain. The logarithmic intensity plots of test images indicated that the full width at half maximum of a Gaussian point-spread function can be estimated from the images. The spatial resolution of imaging X-ray microtomography using Fresnel zone-plate optics was also estimated with this method. A cross section of a test object visualized with the imaging microtomography indicated that square-wave patterns up to 120-nm pitch were resolved. The logarithmic intensity plot was calculated from a tomographic cross section of brain tissue. The full width at half maximum of the point spread function estimated from the plot coincided with the resolution determined from the test object. These results indicated that the logarithmic intensity plot in the Fourier domain provides an alternative measure of the spatial resolution without explicitly defining a noise criterion.