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Proposed standards for the NBS retroreflection MAP
Author(s) -
Eckerle Kenneth L.,
Hsia Jack J.
Publication year - 1982
Publication title -
color research and application
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.393
H-Index - 62
eISSN - 1520-6378
pISSN - 0361-2317
DOI - 10.1002/col.5080070304
Subject(s) - retroreflector , standard illuminant , optics , spectral power distribution , materials science , physics , laser
A proposed Measurement Assurance Program (MAP) service for retroreflectance is under development at the National Bureau of Standards. A package for the MAP consists of high‐ and low‐intensity bead‐sheeting retroreflectors, a prismatic retroreflector, and seven colored glass filters. The retroreflectors are being measured using the NBS reference retroreflectometer. The glass filter measurements are based on spectral data obtained using a high‐accuracy reference spectrophotometer. The luminous transmittances are calcúlated from the spectral transmittances using CIE Illuminant A and a CIE V(λ)‐type detector, and can be used to check the combined spectral distribution of source and responsivity of the receiver. Computations are mentioned which show that if a color‐correction filter is not chosen carefully, large errors may result. Preliminary results for pressure and temperature effects on two types of retroreflectors indicate small changes. Temperatures used were nominally 15, 25, and 32°C. Pressures used were nominally 0.85, 1.0, and 1.25 bars. Results showing the sensitivity of the coefficient of luminous intensity (C.I.L.) of the retroreflectors to various geometrical parameters are described. These parameters include the observation angle α, the entrance angles β 1 and β 2 , the source and receiver apertures δ, and the rotation angle ϵ.