Patent ID: 7633612

Claim:
An apparatus for determining surface properties, comprising at least a first radiation device which emits radiation onto a surface to be analysed, at least a first radiation detector device which receives at least part of the radiation emitted by the at least one radiation device and then scattered or reflected by the surface and outputs at least a first measurement signal which is characteristic of the reflected and/or scattered radiation, and at least one further radiation detector device which receives at least part of the radiation emitted by the at least one radiation device and then scattered or reflected by the surface and outputs at least a further measurement signal which is characteristic of the reflected or scattered radiation, wherein first radiation detector device is offset by a first predefined angle β 1 with respect to the direction of the radiation reflected by the surface, the further radiation detector device is offset by a further predefined angle γ 1 with respect to the direction of the radiation reflected by the surface, and the ratio between the value of the further predefined angle γ 1 and the value of the first predefined angle β 1 is at least 1.5:1 a movement device for moving the apparatus with respect to the surface, and a processor device which at least partially compares a first and a further measurement signal, wherein at least one signal is corrected by taking account of a geometric position of the radiation device with respect to the surface.