Optical flow sensor using a fast correlation algorithm
US6611319B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 29, 2002 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | Jan 29, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P5/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical flow sensor determines the velocity of a moving flow of air or other gas utilizing a plurality of photodetectors spaced apart in a direction parallel to the direction of gas flow. An optical beam is transmitted to the photodetectors across the flowing gas. Scintillations that occur in the flowing gas due to eddies and particulates in the gas are detected in the photodetectors at slightly different times. The output signals of the photodetectors are conditioned, amplified and transformed to digital form. Temporal cross correlation analysis is then performed on the digitized signals in a digital signal processor utilizing a fast correlation algorithm in which the total number of calculations is proportional to 2N, as contrasted with conventional systems in which the number of correlations is proportional to N2. A time differential between signals from the different photodetectors is then calculated electronically. The velocity of gas flow is then determined by dividing the spatial distance of separation between adjacent photodetectors by the time difference at which the same scintillation event is detected by each photodetector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.