Retro-reflectometer for measuring retro-reflectivity of objects in an outdoor environment comprising a lock-in amplifier coupled to an optical modulator and an optical detector
US11474037B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 2020 |
| Grant date | Oct 18, 2022 |
| Priority date | — |
| Expiry date | Jan 24, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0691
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for measuring retro-reflectivity of a target object in an outdoor environment includes a modulator to modulate a first optical signal based on a specified modulation value, an optical emitter, coupled to the modulator, to emit the first optical signal along an optical path towards the target object, and an optical detector positioned collinearly with respect to the optical emitter. The optical detector detects a second optical signal that is retro-reflected from the target object. The apparatus includes a lock-in amplifier coupled to the modulator and the optical detector. The lock-in amplifier receives a first electrical signal from the modulator and a second electrical signal from the optical detector, and generates, based on the first electrical signal and the second electrical signal, a third electrical signal indicative of the retro-reflectivity of the target object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.