What is superresolution microscopy?

TL;DR

This paper clarifies the concept of superresolution microscopy, distinguishing between pseudo and true superresolution techniques, and discusses the underlying principles and limitations of optical resolution enhancement methods.

Contribution

It provides a comprehensive framework differentiating pseudo and true superresolution, based on resolution scaling with photon counts, applicable beyond optical imaging.

Findings

Pseudo superresolution improves images up to the diffraction limit.

True superresolution achieves significant resolution beyond the diffraction limit.

The framework applies to general measurement problems, not just optics.

Abstract

I explain what is, what is not, and what is only sort of superresolution microscopy. I discuss optical resolution, first in terms of diffraction theory, then in terms of linear systems theory, and finally in terms of techniques that use prior information, nonlinearity, and other tricks to improve performance. The discussion reveals two classes of superresolution: Pseudo superresolution techniques improve images up to the diffraction limit but not much beyond. True superresolution techniques allow substantial, useful improvements beyond the diffraction limit. The two classes are distinguished by their scaling of resolution with photon counts. Understanding the limits to imaging resolution involves concepts that pertain to almost any measurement problem, implying that the framework given here has broad application beyond optics.