Apparatus and method of particle geometry measurement by speckle pattern analysis
US5748311A · kind A · utility
Inventors
Key dates
| Filing date | Mar 11, 1996 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | Mar 11, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2015/1497
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention provides a method and a system for measuring geometric properties, such as diameter, shape and surface roughness of single rough particles by an optical method. The particle may be immersed in a gaseous or liquid fluid. A volume of the fluid, containing the particles to be measured, is illuminated by a beam of coherent electromagnetic radiation, resulting in a distribution of scattered radiation with a speckle structure. This distribution is detected with a one-dimensional or two-dimensional image detector. An autocorrelation function RI(r) of the detected intensity distribution is calculated, and from the position .delta.r of its first zero the diameter d.sub.P of the scattering particle is evaluated based on I, the wavelength of the electromagnetic radiation, and Z.sub.0, the distance from the particle to the detector. The system to perform this method comprises a radiation source, which is preferably a laser, to illuminate a measuring volume, and an array or matrix detector arranged to receive the backscattered light. The detected intensity distribution is converted to binary data and a signal processing unit calculates the autocorrelation function of the detected …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.