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US 6,643,022 B1Granted
Method and device for determining fibre orientation in a paper sample
AssigneeAmbertec Oy
InventorAntero Komppa
Life of this patent
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Abstract
The invention relates to a method and device for determining fiber orientation in a paper sample. The surface of the sample (1) is illuminated from an oblique angle (11) by means of more than one light source (2, 3). The illumination is rotated on the surface of the sample by electronically switching the light sources on and off in turn by means of a switch (12). The intensity of the light reflected from the surface of the sample is measured using at least one sensor (5) and, based on the measured light intensity and momentary direction of illumination, the fiber orientation in the sample is determined by means of a computing device (13)
Claims27
A method for determining fiber orientation in a paper sample comprising the steps of:
- providing a light sensor, the light sensor being spaced from the sample and facing a surface of the sample to receive light from an area on the surface of the sample viewed by the light sensor;
- arranging a plurality of light sources in circumferentially spaced positions at least partially around the light sensor, the light sources being radially spaced from the light sensor and being spaced from the sample;
- successively turning each of the light sources on and then off to cause each of the light sources, in turn, to sequentially and obliquely project a beam of light from the light source onto the area on the sample, the arcuate spacing of the light sources causing the light beam of each of the sources to illuminate the area from a different direction, the successive turning on and off of the light sources being at a common frequency in which a given light source is on while the other light sources are off and off while other light sources are on, the successive, repetitive turning on and off of the light sources at the common frequency creating a rotational effect in the illumination of the area of the sample;
- receiving, with the light sensor, a series of light signals comprising light obtained from the sample as a result of the sequential illumination of the area on the sample from different directions by the light projected from the light sources, the properties of the obtained light signals being dependent on the orientation of fibers in the sample and the direction of illumination of the sample by each of the light sources;
- measuring a property of each of the received light signals;
- using the properties of the received light signals and the associated directions of illumination to determine fiber orientation properties of the sample.
3 more elements
A device for determining fiber orientation in a paper sample comprising:
- a light sensor spaced from the sample and facing a surface of the sample to receive light from an area on the surface of the sample viewed by said light sensor;
- a plurality of light sources located in circumferentially spaced positions at least partially around said light sensor, said light sources being radially spaced from said light sensor and being spaced from the sample;
- means for electronically, successively switching each of said light sources on and then off to cause each of said light sources, in turn, to sequentially and obliquely project a beam of light from the light source onto the area on the sample, the arcuate spacing of said light sources causing the light beam of each of said sources to illuminate the area from a different direction, the successive switching on and off of said light sources being at a common frequency in which a given light source is on while the other light sources are off and off while other light sources are on, the successive, repetitive switching on and off of said light sources at the common frequency creating a rotational effect in the illumination of the area of the sample;
- said light sensor receiving a series of light signals comprising light obtained from the sample as a result of the sequential illumination of the area on the sample from different directions by the light projected from said light sources, the properties of the obtained light signals being dependent on the orientation of fibers in the sample and the direction of illumination of the sample by each of said light sources;
- and
- means coupled to said light sensor for determining fiber orientation properties of the sample from the properties of the received light signals and the associated directions of illumination.
3 more elements
Dependencies are inferred from the claim text.