Abstract: In a method and a device for determining the optical transmission factor of a glass panel by identification transmits an incident electromagnetic radiation towards the glass panel and the intensity of the reflected radiation is detected and measured. The reflection coefficient of the panel is compared with reflection coefficient reference values representing the transmission factor of tinted glass reference panels to determine the optical transmission factor of the panel examined.

Abstract: The invention relates to a device for detecting the presence of extraneous substances in a medium in the vicinity of a wall separating two mediums.The device provides in the medium I illumination of a wall under a radiation corresponding to the transparency of the semi-transparency of the material of the wall on a reference illumination zone. Directional detectors permit covering of the reference illumination zone, the mean direction of the reception cone having with respect to the mean direction of the beam an inclination such that the intersection volume of the beam and of the reception cone is a minimum.Application to the aid of driving of automobiles or airplanes and the control of industrial chemical processes is disclosed.