Multi-angle colorimeter
First Claim
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1. A multi-angle colorimeter comprising:
- one or plural illuminators for illuminating a surface of an object to be measured from one or plural directions and for measuring a colorimetric value of the surface of the object;
one or plural light receivers for receiving reflected light from the surface illuminated by said one or plural illuminators respectively, and for measuring a colorimetric value of the surface of the object;
a reflection characteristics calculator for calculating a reflectance characteristics of the surface for plural directions of illumination or light receiving;
an angular error detector for detecting an angular error of the illuminators and the light receivers with respect to the surface, and comprising a measurement system different from the illuminators and the light receivers;
an approximation function setter for determining an approximation function that approximates a directional dependence of the reflectance characteristics of the surface based on the detected angular error and the reflection characteristics obtained by said reflection characteristics calculator;
a reflection characteristics error estimator for estimating an error of the reflection characteristics in each measurement direction based on the determined approximation function and the detected angular error; and
a corrector for correcting the obtained reflection characteristics in each measurement direction based on the estimated reflection characteristics error.
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Abstract
In a multi-angle colorimeter having an illumination system that illuminates a sample surface and a plurality of light receiving systems that receive reflected light therefrom, an illumination system for orientation error detection is provided that illuminates the sample surface from substantially close direction to the normal of the sample surface. Actual measured reflectance factor is corrected based on the specific approximation function obtained from the measured reflectance factor and detected orientation error.
23 Citations
15 Claims
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1. A multi-angle colorimeter comprising:
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one or plural illuminators for illuminating a surface of an object to be measured from one or plural directions and for measuring a colorimetric value of the surface of the object; one or plural light receivers for receiving reflected light from the surface illuminated by said one or plural illuminators respectively, and for measuring a colorimetric value of the surface of the object; a reflection characteristics calculator for calculating a reflectance characteristics of the surface for plural directions of illumination or light receiving; an angular error detector for detecting an angular error of the illuminators and the light receivers with respect to the surface, and comprising a measurement system different from the illuminators and the light receivers; an approximation function setter for determining an approximation function that approximates a directional dependence of the reflectance characteristics of the surface based on the detected angular error and the reflection characteristics obtained by said reflection characteristics calculator; a reflection characteristics error estimator for estimating an error of the reflection characteristics in each measurement direction based on the determined approximation function and the detected angular error; and a corrector for correcting the obtained reflection characteristics in each measurement direction based on the estimated reflection characteristics error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of measuring characteristics of a material containing special effect flake pigments using a multi-angle colorimeter, comprising the steps of:
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illuminating a surface of an object to be measured from one or plural directions by at least one of illuminator; receiving reflected light from the surface illuminated in one or plural directions by at least one of light receiver;
calculating reflectance characteristics of the surface in plural directions;detecting an angular error of the illuminator and the light receiver with respect to the surface by a measurement system different from the illuminator and the light receiver; determining an approximation function that approximates a directional dependence of the reflectance characteristics based on the detected angular error and the calculated reflection characteristics; estimating an error of the reflection characteristics in each measurement direction based on the determined approximation function and the detected angular error; correcting the calculated reflection characteristic in each measurement direction based on the estimated error of the reflection characteristic; and
,outputting said corrected reflection characteristic in each measurement direction.
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Specification