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Quantifying Retroreflective Materials Using Digital Imagery
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 14, 2020 by SAE International in United States
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Retroreflection occurs when a light ray incident on a surface is reflected back towards the light source. The performance of a retroreflective material is of interest to accident reconstructionist, human factors professionals, lighting professionals, and roadway design professionals. The retroreflective effect of a material can be defined by the coefficient of retroreflection, which is a function of the light’s entrance angle and the viewer’s observation angle. The coefficient of retroreflection of a material is typically measured in a laboratory environment or in the field with a retroreflectometer. Often the material in question cannot be taken to a laboratory for testing and commercially available portable retroreflectometers are limited to entrance angles of 45 degrees or less and may be cost prohibitive in some cases. This paper presents a methodology to capture images of a retroreflective material at entrance angles between -4 degrees and 75 degrees and observations angles between 0.2 degrees and 1 degree. The process of calibrating the camera and the light source is presented and the coefficient of retroreflection and coefficient of retroreflected luminance are calculated from the images and presented as a function of entrance angle and observation angle.
CitationSuway, J. and Cornetto, A., "Quantifying Retroreflective Materials Using Digital Imagery," SAE Technical Paper 2020-01-0570, 2020, https://doi.org/10.4271/2020-01-0570.
- ASTM Standard E808-01 2009 10.1520/E0808-01R09 www.astm.org
- Suway , J. and Welcher , J. Quantifying Retroreflective DOT-C2 Tape Performance using a Retroreflectometer SAE Technical Paper 2015-01-1429 2015 https://doi.org/10.4271/2015-01-1429
- Suway , J. and Welcher , J. Retroreflective DOT-C2 Tape Performance in Relation to Observation and Entrance Angle - A Real World Study SAE Technical Paper 2015-01-1432 2015 https://doi.org/10.4271/2015-01-1432
- Muttart , J. , Dinakar , S. , Suway , J. , Kuzel , M. , Lohf , D. , Maloney , T. , and Whear , A.
- 3M Product Bulletin 963 June 2009 www.3M.com/tss
- Suway , J. and Suway , S. A Method for Digital Video Camera Calibration for Luminance Estimation SAE Technical Paper 2017-01-1368 2017 https://doi.org/10.4271/2017-01-1368