Automated real-time particle characterization and three-dimensional velocimetry with holographic video microscopy
AssigneeNew York University
InventorsDavid G. Grier, Fook Chiong Cheong, Ke Xiao
Life of this patent
Estimating the term…
Abstract
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.
Claims18
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.
A method of characterizing parameters for holographic microscopy of objects comprising the steps of:
- receiving image data from a storage medium;
- transforming the image data using a Hough circular transform to determine by a voting algorithm a first estimate of the number of objects in the image data and the objects approximate x, y position in a plane;
- using the transformed data to determine a first estimate of the axial position (z) of each of the objects along with a first estimate of each of the object's size and composition;
- and
- applying Lorenz-Mie analysis of the image data for each of the objects to determine a second estimate of the resolution position, size and composition of each of the objects, wherein the second estimate has a higher accuracy than the first estimate with at least one step of updating the storage medium with the results and providing the results for display for interpretation by a user.
Dependencies are inferred from the claim text.