METHOD FOR SPECTROSCOPIC MEASUREMENT, SPECTROSCOPIC MEASUREMENT EQUIPMENT, AND GENERATING METHOD FOR TRANSFORMATION MATRIX

• US 20140052402A1
• Filed: 08/13/2013
• Published: 02/20/2014
• Est. Priority Date: 08/17/2012
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Arai, Yoshifumi
• Application Number:
  US13/965,321
• Publication Number:
  US 20140052402A1
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/506 measuring the colour produced by screens, monitors, displays or CRTs
• CPC Class Codes: G01J 3/524 Calibration of colorimeters

Abstract

In a method for spectroscopic measurement, a spectroscopic measurement equipment, and a generating method for a transformation matrix, a measured spectrum is converted into a spectrum by making a transformation matrix act on the measured spectrum. The transformation matrix is determined as follows. A known light measured spectrum is linearly projected to a linear space constituted by principal component vectors of the measured spectrum obtained by a reference measurement equipment to thereby convert the known light measured spectrum into a reference known light measured spectrum. The transformation matrix is determined so that an evaluation function, which is defined by a linear combination of a difference between an estimated spectrum obtained by making the transformation matrix act on the reference known light measured spectrum and a known light spectrum, and dispersions of respective components of the transformation matrix, takes an extreme value.

Claims

1. A method for spectroscopic measurement adapted to receive light and then measure a spectrum representing intensity of the light at a first number of predetermined wavelengths, the method comprising:

dispersing the light received into lights with measurement wavelengths, which are a second number of predetermined wavelengths;

generating a measured spectrum having the second number of light intensity values by detecting the light intensity at the second number of measurement wavelengths;

determining a transformation matrix adapted to convert the measured spectrum into the spectrum; and

converting the measured spectrum into the spectrum by making the transformation matrix act on the measured spectrum,

wherein the determining of a transformation matrix includes

performing principal component analysis on the measured spectrum obtained from predetermined reference measurement equipment to previously select a third number of principal component vectors, the third number being smaller than the second number,

obtaining a known light measured spectrum, which is the measured spectrum of known light as light having a known spectrum,

converting the known light measured spectrum into a reference known light measured spectrum by linearly projecting the known light measured spectrum to a linear space constituted by the third number of principal component vectors, and

determining the transformation matrix based on a condition in which an evaluation function, which is defined by a linear combination of a difference between an estimated spectrum as the spectrum obtained by making the transformation matrix act on the reference known light measured spectrum and a known light spectrum, and dispersions of respective components constituting the transformation matrix, takes an extreme value.

2. A generating method for a transformation matrix adapted to convert a measured spectrum representing light intensity measured at a second number of predetermined wavelengths into a spectrum representing light intensity at first number of predetermined wavelengths, the method comprising:

performing principal component analysis on the measured spectrum obtained from predetermined reference measurement equipment to previously select a third number of principal component vectors, the third number being smaller than the second number;

obtaining a known light measured spectrum, which is the measured spectrum of known light as light having a known spectrum;

converting the known light measured spectrum into a reference known light measured spectrum by linearly projecting the known light measured spectrum to a linear space constituted by the third number of principal component vectors;

obtaining a known light spectrum as the spectrum of the known light; and

determining the transformation matrix based on a condition in which an evaluation function, which is defined by a linear combination of a difference between an estimated spectrum as the spectrum obtained by making the transformation matrix act on the reference known light measured spectrum and the known light spectrum, and dispersions of respective components constituting the transformation matrix, takes an extreme value.

3. A spectroscopic measurement equipment adapted to output a spectrum representing intensity of light at a first number of predetermined wavelengths upon reception of the light, comprising:

a spectroscopic unit adapted to disperse the light received into lights with measurement wavelengths, which are a second number of predetermined wavelengths;

a measured spectrum generation unit adapted to generate a measured spectrum having the second number of light intensity values by detecting the light intensity at the second number of measurement wavelengths; and

a conversion unit adapted to convert the measured spectrum into the spectrum by making a predetermined transformation matrix act on the measured spectrum,

wherein the transformation matrix is determined

by obtaining a known light spectrum, which is the spectrum of known light as light having a known spectrum and a known light measured spectrum, which is the measured spectrum of the known light,

and converting the known light measured spectrum into a reference known light measured spectrum by linearly projecting the known light measured spectrum to a linear space constituted by a third number of principal component vectors of the measured spectrum obtained from a predetermined reference measurement equipment, the third number being smaller then the second number,

based on a condition in which an evaluation function, which is defined by a linear combination of a difference between an estimated spectrum as the spectrum obtained by making the transformation matrix act on the reference known light measured spectrum and a known light spectrum, and dispersions of respective components constituting the transformation matrix, takes an extreme value.