Patent ID: 9151710
Filing Date: 2015-10-06
Classification: G01N

Abstract:
1. An apparatus for measuring an object comprising cellulose material and at least one coloring substance including printing ink, wherein the apparatus comprising a detector and a measuring unit; the detector being configured to receive optical radiation transmitted through the measured object within the optical band ranging from 1.8 μm to 2.25 μm and being responsive to one or more predetermined optical absorption bands of water, one or more predetermined optical absorption bands of cellulose and two or more separate optical bands known to include spectral disturbance caused by the at least one coloring substance, the separate optical bands being apart from the predetermined optical bands associated with water and cellulose, at least two of the separate optical bands being on both sides of a predetermined optical band associated with water and at least two of the separate optical bands being on both sides of a predetermined optical band of cellulose; the measuring unit being configured to, on the basis of responses of the detector, measure at least one water dependent value on the basis of attenuation of the optical radiation in the one or more predetermined optical absorption bands of water, measure at least one cellulose dependent value on the basis of attenuation of the optical radiation in the one or more predetermined optical absorption bands of cellulose, determine general dependence of attenuation with respect to wavelength including spectral disturbance caused by the at least one coloring substance as a desired type of function by measuring attenuations at the measured wavelengths apart from the predetermined bands associated with water and cellulose; form each of at least one corrected water value on the basis of the desired type of function and a corresponding water dependent value, and form each of at least one corrected cellulose value on the basis of the desired type of function and a corresponding cellulose dependent value, and form a moisture value on the basis of at least one corrected moisture value and at least one corrected cellulose value, for compensating for the spectral disturbance of the at least one coloring substance.