Method and apparatus for single-particle localization using wavelet analysis

Abstract

Accurate localization of isolated particles is important in single particle based super-resolution microscopy. It allows the imaging of biological samples with nanometer-scale resolution using a simple fluorescence microscopy setup. Nevertheless, conventional techniques for localizing single particles can take minutes to hours of computation time because they require up to a million localizations to form an image. In contrast, the present particle localization techniques use wavelet-based image decomposition and image segmentation to achieve nanometer-scale resolution in two dimensions within seconds to minutes. This two-dimensional localization can be augmented with localization in a third dimension based on a fit to the imaging system's point-spread function (PSF), which may be asymmetric along the optical axis. For an astigmatic imaging system, the PSF is an ellipse whose eccentricity and orientation varies along the optical axis. When implemented with a mix of CPU/GPU processing, the present techniques are fast enough to localize single particles while imaging (in real-time).