Abstract: A method for identifying timber surface properties using linearly polarized electromagnetic radiation containing various different wavelength components. Of the scattered radiation are measured by wavelength ranges the intensity components I.sub.min and I.sub.max that are mutually perpendicular as regards their polarization plane, wherein the polarization plane of the component I.sub.max is the same as that of the radiation directed to the surface. The identification of the surface types is made on the basis of the information about the color tone of the surface and the fiber structure achieved from the variables I.sub.min and P=(I.sub.max -I.sub.min)/(I.sub.max +I.sub.min).

Abstract: A method for identifying timber surface properties by using linearly polarized light. The polarization plane of the incident radiation is selected according to the object. The intensity components I.sub.min and I.sub.max having perpendicular polarization planes of the scattered radiation are measured, where the polarization plane of the component I.sub.max is the same as that of the incident radiation. On the basis of the quantities I.sub.min and ##EQU1## conclusions are drawn about the surface properties of the examined surface.