Noise reduction techniques, fractional bi-spectrum and fractional cross-correlation, and applications
US10203195B2 · kind B2 · utility
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Key dates
| Filing date | Sep 13, 2017 |
| Grant date | Feb 12, 2019 |
| Priority date | — |
| Expiry date | Sep 21, 2037 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/2441
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A measurement method and system include illuminating an object to be measured with light at two different wavelengths and an incident angle; capturing an image of the object; detecting a frequency of an interference pattern from the image using Fractional Bi-Spectrum Analysis; and calculating a thickness of the object based on the Fractional Bi-Spectrum Analysis. The thickness is calculated based on a relationship between the thickness and the frequency of the interference pattern. The Fractional Bi-Spectrum Analysis is performed on a linear medium with the two different wavelengths being known.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.