Automated real-time particle characterization and three-dimensional velocimetry with holographic video microscopy

摘要

An in-line holographic microscope can be used to analyze on a frame-by-frame basis a video stream to track individual colloidal particles' three-dimensional motions. The system and method can provide real time nanometer resolution, and simultaneously measure particle sizes and refractive indexes. Through a combination of applying a combination of Lorenz-Mie analysis with selected hardware and software methods, this analysis can be carried out in near real time. An efficient particle identification methodology automates initial position estimation with sufficient accuracy to enable unattended holographic tracking and characterization.

主权项

1. A method of characterizing a parameter of a sample by holographic microscopy, comprising the steps of:
providing holographic image data of the sample from a storage medium; determining a first estimate of the number of objects in the holographic image data, each object associated with a set of concentric bright and dark rings; determining, for each set of concentric bright and dark rings, by a voting algorithm, a centroid defined by an approximate x, y position in a plane, with each pixel of the image data voting for pixels in a transformed image that may be centroids; determining an estimate of the axial position (z) of each of the objects; determining by Lorenz-Mie analysis an estimate of each of the objects' radius, refractive index; using holographic image data from the sample to characterize properties of the sample and generate information characteristic of the parameters of the sample; and analyzing the information characteristic of the sample parameters and determining in real time simultaneously size, position and refractive index of a particle of the sample.