Abstract: An apparatus for measuring the retroreflectivity of a surface. The apparatus comprises a light source for illuminating an area of said surface at an incident angle relative to the surface; a detector for detecting light reflected back from the surface at an observation angle relative to the surface; a signal processing unit adapted to receive a detector signal from the detector and to determine, from at least the received detector signal, a measure of retro reflectivity of the surface; a range finder for measuring a distance between the apparatus and the illuminated area. The signal processing unit is further adapted to adjust the measure of retroreflectivity responsive to the measured distance.

Abstract: An apparatus for measuring the retroreflectivity of a surface. The apparatus comprises a light source for illuminating an area of said surface at an incident angle relative to the surface; a detector for detecting light reflected back from the surface at an observation angle relative to the surface; a signal processing unit adapted to receive a detector signal from the detector and to determine, from at least the received detector signal, a measure of retro reflectivity of the surface; a range finder for measuring a distance between the apparatus and the illuminated area. The signal processing unit is further adapted to adjust the measure of retroreflectivity responsive to the measured distance.

Abstract: A method and apparatus for measuring light reflections of an object, comprising a light-source illumination-observation assembly, the assembly comprising: (A) an illumination unit comprising an illumination light source and illumination aperture stop being arranged to provide a confined luminous field, an illumination field stop (307) adapted to provide an illumination beam (305) of light from said confined luminous field, an collimating optical element (309) adapted to collimate said illumination beam and to provide an illumination field (313) on an object; (B) an observation unit comprising: at least one observation field stop adapted to provide an observation beam (306) comprising a ray boundary, at least one focusing optical element (309) adapted to focus said observation beam, an observation light receiver; and (C) at least one common optical element (309) arranged so that said illumination beam and said observation beam form an overlap therein; and (D) a unit separation stop (310) adapted to stop light