Multi-angle colorimeter

Patent metadata

Field	Value
Publication number	US-9500525-B2
Application number	US-201214114117-A
Country	US
Kind code	B2
Filing date	Apr 9, 2012
Priority date	Apr 28, 2011
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

In a multi-angle colorimeter, a light detecting portion 40 includes a main light receiving window disposed in a predetermined position on a main geometry plane, and first and second auxiliary light receiving windows disposed on a secondary geometry plane, and a main photoelectric conversion element for converting a main component light received by the main light receiving window in a light reflected from a measurement point into an electrical main signal and first and second auxiliary photoelectric conversion elements for converting first and second auxiliary component lights received by the first and second auxiliary light receiving windows in the reflected light respectively into first and second electrical auxiliary signals. A calculating portion corrects the electrical main signal based on the first and second electrical auxiliary signals to obtain color information about the measurement point.

First claim

The invention claimed is:

1. A multi-angle colorimeter comprising:
(a) a plurality of illuminating means disposed on a virtual reference plane including a predetermined reference line and carrying out light irradiation at different angles from each other toward a predetermined measurement point on said reference line;
(b) a light detector comprising:
a main light receiving window disposed in a predetermined position on said reference plane;
a plurality of auxiliary light receiving windows disposed on a plane which includes said predetermined position and said predetermined measurement point and is orthogonal to said reference plane, and opposed to said measurement point respectively;
a main photoelectric conversion means for receiving a main component light received by said main light receiving window in a reflected light of said light irradiation from a measurement plane disposed on said measurement point and for converting said main component light into an electrical main signal; and
a plurality of auxiliary photoelectric conversion means for receiving a plurality of auxiliary component lights received by said plurality of auxiliary light receiving windows in the reflected light of said light irradiation and for converting said plurality of auxiliary component lights into a plurality of electrical auxiliary signals, and

(c) a calculating means for correcting a posture error, of said reference plane from the normal of said reference plane, of said electrical main signal based on said plurality of electrical auxiliary signals, thereby obtaining color information about said measurement plane which is present on said measurement point.

2. The multi-angle colorimeter according to claim 1 , wherein said calculating means comprises:
an approximation function estimating means for finding an approximation function which approximates to a directional dependency of said reflected light by using said electrical main signal and said plurality of electrical auxiliary signals;
a correction factor calculating means for calculating a correction factor based on said approximation function found by said approximation function estimating portion; and
a correcting means for carrying out a calculation for correcting said electrical main signal by using said correction factor obtained by said correction factor calculating means.

3. The multi-angle colorimeter according to claim 2 , wherein said correction factor calculating means calculates a ratio of measured values of said plurality of electrical auxiliary signals based on said approximation function found by said approximation function estimating means and storing said ratio of said measured values and said correction factor as a table, and
wherein said correcting means calculates a ratio of measured values of a plurality of electrical auxiliary signals obtained in each measurement, reads a correction factor for said ratio of said measured values by referring to said table, and furthermore, corrects a measured value of said electrical main signal by using said correction factor.

4. The multi-angle colorimeter according to claim 3 , further comprising a storing means for storing a predetermined threshold for defining an effective range for correction of said electrical main signal by said correcting means,
wherein said correcting means comprises an error processing means for comparing an index value corresponding to said ratio of said measured values of said plurality of electrical auxiliary signals with said predetermined threshold and for carrying out error processing if said index value departs from said effective range.

5. The multi-angle colorimeter according to claim 1 , wherein said main light receiving window includes a plurality of main light receiving windows disposed on said reference plane for receiving lights reflected at different angles from each other from said predetermined measurement point.

Assignees

• Teraoka Yoshitaka
• Tsurutani Katsutoshi
• Yamanoi Yuta
• Konica Minolta Inc

Inventors

• Teraoka Yoshitaka
• Tsurutani Katsutoshi
• Yamanoi Yuta

Classifications

• G01N2021/575

  Photogoniometering · CPC title

• G01N2021/4711

  Multiangle measurement · CPC title

• G01J3/502

  using a dispersive element, e.g. grating, prism · CPC title

• G01N2021/4735

  Solid samples, e.g. paper, glass · CPC title

• G01J3/504

  Goniometric colour measurements, for example measurements of metallic or flake based paints · CPC title