Patent ID: 9581546
Date: 2017-02-28
CPC Classifications: G01N

Claim:
1. A method of investigating optical properties of surfaces, wherein the surfaces include a surface provided with a layer of paint, wherein the layer of paint has effect pigments, the method comprising: irradiating radiation with an irradiation device at a first pre-set angle of incidence with respect to the surface onto the surface to be investigated; and receiving, at a radiation detector device, radiation scattered and/or reflected by the surface, wherein the radiation detector device is arranged at a pre-set detection angle with respect to the surface and has an image-recording unit which records black-and-white images, wherein this radiation detector device permits a spatially resolved detection of the radiation reaching it, wherein the irradiation device directs radiation in a first wavelength range onto the surface and the image-recording unit records a first spatially resolved image of this radiation scattered and/or reflected from the surface and the irradiation device directs radiation in a second wavelength range onto the surface and the image-recording unit records a second spatially resolved image of this radiation scattered and/ or reflected from the surface, wherein the radiation in the first wavelength range and the radiation in the second wavelength range, which differs from the first wavelength range at least in part, are directed staggered at least in part in terms of time onto the surface, and the radiation in the first wavelength range and the radiation in the second wavelength range are irradiated at the same angle of incidence onto the surface, wherein flake characteristics of the first spatially resolved image and the second spatially resolved image are calculated and as a result optical properties of the effect pigments at the respective illumination angle are determined, wherein radiation in a third wavelength range which differs from the first wavelength range and also from the second wavelength range is irradiated onto the surface at the first angle of incidence, and the image-recording unit records the radiation reflected and/or scattered by the surface, and in this way records a third spatially resolved image, wherein the irradiation directions of the irradiation devices and the irradiation direction of the radiation passed on from the surface to the image-recording unit are in one plane, wherein the first, second and third images are compared with each other, and the colours of the individual pigments or the colours at which the pigments reflect light back are determined from the comparison of the first, second and third images, wherein both the irradiation device and the radiation detector device are arranged in one housing, and wherein the housing has one opening in a region in which the radiation is to be discharged onto the surface.