Sheet measurement
First Claim
1. An apparatus for measuring a sheet comprising cellulose material and potentially lignin, the apparatus comprising:
- a detector configured to receive optical radiation transmitted through the measured sheet and being responsive to one or more predetermined optical absorption bands of lignin, and two or more separate optical bands apart from the one or more predetermined optical absorption bands of the lignin; and
a measuring unit configured to, on the basis of responses of the detector;
measure at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region in the one or more predetermined optical absorption bands of lignin,determine a general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands of lignin, the two or more separate optical bands apart from the one or more predetermined optical absorption bands of the lignin fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin, andform a value representing lignin content by removal of the general dependence of attenuation from the at least one lignin dependent value by forming each value of lignin content as a difference between corresponding values of the general dependence of attenuation and the lignin dependent value.
1 Assignment
0 Petitions
Accused Products
Abstract
A detector receives optical radiation interacted with the measured sheet and is responsive to a predetermined optical absorption band of lignin, a predetermined optical absorption band of dry matter and two or more separate optical bands. The measuring unit measures a lignin dependent value on the basis of attenuation in the absorption band of lignin, and a dry matter dependent value on the basis of attenuation in the absorption band of the dry matter, and determines a general dependence of attenuation with respect to wavelength by measuring attenuations in the separate optical bands. The measuring unit forms a value representing a dry matter content on the basis of the lignin dependent value, the dry matter dependent value and the general dependence of attenuation.
17 Citations
21 Claims
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1. An apparatus for measuring a sheet comprising cellulose material and potentially lignin, the apparatus comprising:
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a detector configured to receive optical radiation transmitted through the measured sheet and being responsive to one or more predetermined optical absorption bands of lignin, and two or more separate optical bands apart from the one or more predetermined optical absorption bands of the lignin; and a measuring unit configured to, on the basis of responses of the detector; measure at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region in the one or more predetermined optical absorption bands of lignin, determine a general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands of lignin, the two or more separate optical bands apart from the one or more predetermined optical absorption bands of the lignin fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin, andform a value representing lignin content by removal of the general dependence of attenuation from the at least one lignin dependent value by forming each value of lignin content as a difference between corresponding values of the general dependence of attenuation and the lignin dependent value. - View Dependent Claims (4, 5, 6, 8, 21)
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2. An apparatus for measuring a sheet comprising cellulose material and potentially lignin, the apparatus comprising:
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a detector configured to receive optical radiation transmitted through the measured sheet and being responsive to one or more predetermined optical absorption bands of lignin, one or more predetermined optical absorption bands of dry matter and two or more separate optical bands apart from the predetermined optical absorption bands of the lignin and the dry matter; and a measuring unit configured to, on the basis of responses of the detector; measure at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region in the one or more predetermined optical absorption bands of lignin, measure at least one dry matter dependent value on the basis of attenuation of the optical radiation in the one or more predetermined optical absorption bands of the dry matter, determine a general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands of lignin and the dry matter, two or more predetermined optical bands apart from the predetermined absorption bands of lignin and dry matter fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin and the dry matter, a band each wavelength of which being between one of the predetermined optical absorption bands of lignin and the dry matter, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin and the dry matter, andform a value representing a dry matter content on the basis of the at least one lignin dependent value, the at least one dry matter dependent value and the general dependence of attenuation. - View Dependent Claims (3, 7, 9)
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10. A method for measuring a sheet comprising cellulose material and potentially lignin, the method comprising:
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allowing optical radiation to interact with the measured sheet; measuring at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region transmitted through the measured sheet in one or more predetermined optical absorption bands of lignin; determining, by the measuring unit, a general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands associated with lignin, two or more separate optical bands apart from the one or more predetermined optical absorption bands of the lignin fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin; andforming a value representing lignin content by cancelling the determined general dependence of attenuation from the at least one lignin dependent value by forming each value of lignin content as a difference between corresponding values of the general dependence of attenuation and the lignin dependent value. - View Dependent Claims (13, 14, 15, 17, 18)
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11. A method for measuring a sheet comprising cellulose material and potentially lignin, the method comprising:
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allowing optical radiation to interact with the measured sheet; measuring at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region transmitted through the measured sheet in one or more predetermined optical absorption bands of lignin; measuring at least one dry matter dependent value on the basis of attenuation of the optical radiation interacted with the measured sheet in one or more predetermined optical absorption bands of dry matter; determining, by a measuring unit, the general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands associated with lignin and dry matter, two or more predetermined optical bands apart from the predetermined absorption bands of lignin and dry matter fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin and the dry matter, a band each wavelength of which being between one of the predetermined optical absorption bands of lignin and the dry matter, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin and the dry matter; andforming a value representing a dry matter content on the basis of the at least one lignin dependent value, the at least one dry matter dependent value and the general dependence of attenuation. - View Dependent Claims (12, 16)
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19. An apparatus for measuring a sheet comprising cellulose material and potentially lignin, the apparatus comprising:
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at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform; allowing optical radiation to interact with the measured sheet, measuring at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region transmitted through the measured sheet in one or more predetermined optical absorption bands of lignin, determining a general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands of lignin, two or more separate optical bands apart from the one or more predetermined optical absorption bands of the lignin fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin,forming a value representing lignin content by cancelling the determined general dependence of attenuation from the at least one lignin dependent value by forming each value of lignin content as a difference between corresponding values of the general dependence of attenuation and the lignin dependent value.
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20. An apparatus for measuring a sheet comprising cellulose material and potentially lignin, the apparatus comprising:
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at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to perform; allowing optical radiation to interact with the measured sheet, measuring at least one lignin dependent value on the basis of attenuation of the optical radiation of ultraviolet light or infrared region transmitted through the measured sheet in one or more predetermined optical absorption bands of lignin, measuring at least one dry matter dependent value on the basis of attenuation of the optical radiation interacted with the measured sheet at one or more predetermined optical absorption bands of dry matter, determining a general dependence of attenuation with respect to wavelength as a known type of function the parameters of which are based on the attenuation values at the measured wavelengths apart from the predetermined absorption bands of lignin and dry matter, two or more predetermined optical absorption bands fulfilling at least two of the following;
a band each wavelength of which being longer than any of the wavelengths of the predetermined optical absorption bands of lignin and the dry matter, a band each wavelength of which being between one of the predetermined optical absorption bands of lignin and the dry matter, and a band each wavelength of which being shorter than any of the wavelengths of predetermined optical absorption bands of lignin and the dry matter, andforming a value representing a dry matter content on the basis of the at least one lignin dependent value, the at least one dry matter dependent value and the general dependence of attenuation.
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Specification