Method and apparatus for measuring color and/or composition
AssigneeMetso Paper Automation Oy
InventorsJohn Shakespeare, Tarja Shakespeare
Life of this patent
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Abstract
The invention relates to a method and apparatus for determining the color and/or composition of a material. A sample of the material is illuminated with at least three separate illumination bands singly or in combination, said illumination bands collectively substantially spanning at least the visible range. The light reflected or transmitted by the sample is measured with at least four light detector elements responsive to light in wavelength bands which substantially span the visible range when the sample is illuminated. The width of the illumination bands differs in such a manner that the illumination bands are narrowest near the expected fluorescence absorption bands.
Claims39
In a method for determining the color and/or composition of a material, the improvements comprising the steps of:
- illuminating a sample of the material with at least three separate illumination bands singly or in combination, said illumination bands collectively substantially spanning at least the visible range;
- and
- measuring the light reflected or transmitted by the sample in each of the states of illumination with at least four light detector elements responsive to light in wavelength bands which collectively substantially span at least the visible range as an apparent emissivity or transmissivity.
In an apparatus for determining the color and/or composition of a material, the improvements comprising:
- at least one arrangement producing at least three separate illumination bands which collectively substantially span at least the visible range, at least one arrangement containing at least four light detector elements responsive to light in wavelength bands which collectively substantially span at least the visible range, and means for coordinating the operation of the arrangement producing the illumination bands and containing the light detectors such that when a light source illuminates a sample of the material, the detectors measure the light reflected or transmitted by the sample as an apparent emissivity or transmissivity.
Dependencies are inferred from the claim text.