Retroreflectivity measurement system
US10565459B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 18, 2018 |
| Grant date | Feb 18, 2020 |
| Priority date | — |
| Expiry date | Jun 18, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0216
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A retroreflectivity measurement system comprises a light source arranged to project light across a traffic lane during a measurement run, the light being limited to a particular portion of the visible light spectrum. A camera is selectively sensitive to this light to provide first filtered images and separately selectively sensitive to light at a portion of the spectrum not including the particular portion to provide second filtered images. A controller obtains sequences of first and second filtered images during the measurement run, and identifies within the sequences of images an illuminated road marking; determines a first intensity of the marking from a first filtered image, and a further intensity of the marking from the second filtered images; estimates an ambient intensity of the marking, by applying a scaling factor to the further intensity; and determines a retroreflectivity of the marking as a function of the first and estimated ambient intensities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.