A method for measuring the optical quality of a given region of a glazing of a road or rail vehicle, the region being intended to be positioned in the optical path of an image-acquiring device, the measuring method being implemented by a measuring device including an emitter and a wavefront analyzer, the measuring method including emitting, with the emitter, a beam of light rays in the direction of the given region, analyzing, with the wavefront analyzer, the wavefront of the light rays transmitted by the given region, including generating a wavefront-error map, and determining, on the basis of the wavefront-error map, at least one optical-defect map, of any optical defects present in the region of the glazing.

A method, comprising: providing a light source, a high contrast providing object, and an image acquisition device; emitting a light beam from the light source through the high contrast providing object, a transparent object and a surface of the transparent object toward the image acquisition device; exposing the surface of the transparent object to icing conditions such that a layer of ice is formed by ice accretion on the surface, wherein the light beam traverses the layer of ice after having traversed the transparent object; acquiring a series of images over time of the high contrast providing object using the image acquisition device; determining blur occurring in the series of images over the time; and quantifying the loss of visibility over the time through the transparent object on the basis of the determined blur.