Color discrimination data input apparatus

• US 5,221,959 A
• Filed: 03/12/1991
• Issued: 06/22/1993
• Est. Priority Date: 03/16/1990
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Mori, Takeshi, Kikuchi, Susumu, Ohyama, Nagaaki
• Primary Examiner(s): Evans, F. L.
• Assistant Examiner(s): HANTIS, KAREN
• Application Number:
  US07/667,969
• Time in Patent Office: 833 Days
• Field of Search: 356/326-328, 356/402-411, 356/330-331, 356/310, 356/416, 356/419, 364/498, 364/526
• US Class Current: 356/326
• CPC Class Codes: G01J 2003/467 Colour computing
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/501 Colorimeters using spectrally-selective light sources, e.g. LEDs
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 2201/067 Electro-optic, magneto-optic, acousto-optic elements

Abstract

A color discrimination data input apparatus includes a light source for generating illumination light for illuminating a target object, a spectroscope for producing a spectrum having a plurality of spectral components, a color classification filter set to have a light-transmitting characteristic to pass only a light component having a wavelength range suitable for classification from the spectral components generated by the spectroscope in order to classify the spectral components reflected by the target object into predetermined classes, a photoelectric converting circuit for converting a reflected spectral component, upon radiation of the spectral component passing through the color classification filter on the target object, into an electrical signal, classifying circuit for classifying the reflected spectral components in accordance with the electrical signal output from the photoelectric converting circuit, the color estimating circuit of estimating a color of the target object from the reflected spectral component classified into any one of the classes by the classifying circuit on the basis of a preset absolute color estimation matrix, and an output unit for outputting a classification result obtained from the classifying circuit and an object color measurement result output from the color estimating circuit.

Claims

1. A color discrimination data input apparatus comprising:

light source means for emitting an illumination light;

spectroscope means for producing a spectrum including a plurality of spectral components from the illumination light emitted from said light source means;

color classification filter means having a spectrum characteristic that is usable for a classifying of objects and for an estimation of colors, said spectrum characteristic of said color classification filter means being set by means of a plurality of data samples of spectrums reflected from a plurality of objects to be classified into a plurality of classes, said color classification filter means including extracting means for extracting the plurality of spectral components from the spectrum generated by said spectroscope means;

illuminating means for illuminating a target object with said extracted spectral components extracted by said extracting means, such that reflected extracted spectral components are reflected by the target object, back to said color discrimination data input apparatus when the target object is illuminated by said illuminating means;

photoelectric converting means for converting the reflected extracted spectral components having a wavelength characteristic obtained by the spectrum passing through said color classification filter means, into an electrical signal;

computing means for color classifying the reflected extracted spectral components and for estimating a color of the target object, said computing means including;

color classifying means for classifying the reflected extracted spectral components into said plurality of classes in accordance with the electrical signal output from said photoelectric converting means; and

color estimating means for estimating the color of the target object from the reflected extracted spectral components classified into any one of said plurality of classes by said color classifying means, by means of a preset absolute color estimation matrix; and

output means for outputting a classification result obtained from said color classifying means and an object color measurement result output from said color estimating means.

2. An apparatus according to claim 1, wherein said color classification filter means has a light-transmitting characteristic which is determined by statistically constructing spectrum data from a training set prepared for each of the plurality of classes which include the reflected extracted spectral components.

3. An apparatus according to claim 1, wherein said color classification filter means comprises a liquid crystal filter whose transmittance is determined by liquid crystal alignment.

4. An apparatus according to claim 1, wherein said color estimating means includes means for estimating three primary color components of the reflected extracted spectral components according to a light-transmitting characteristic of said color classification filter means and color matching functions of three primary colors.

5. An apparatus according to claim 1, wherein said output means includes means for displaying the classification result in a pseudo color and displaying the object color measurement result as a color image.

6. An apparatus according to claim 2, further comprising a data generator including:

means for constructing the training set comprising the plurality of classes from the reflected extracted spectral components, obtained by illuminating a plurality of samples, the classes of each of the reflected extracted spectral components of which is known;

means for transforming the training set into a training set having lower dimensional degrees in unit of classes, by projecting the training set of each of the classes into a space constituted by r eigenvectors obtained by a major component analysis, the space being a space U complementarily orthogonal to a first major component vector, and the major component analysis operating a calculation of interclass covariance matrix from the training set of a reference class in the classes which correspond to a reference color;

means for calculating a vector for maximizing a Fisher ratio representing a degree of separation between the classes from the training sets having the lower dimensional degrees;

setting means for setting the light-transmitting characteristic of said color classification filter means on the basis of the vector; and

means for calculating the absolute color estimation matrix corresponding to the light-transmitting characteristic set by said setting means and color matching functions of three primary colors.

7. An apparatus according to claim 1, wherein said color classification filter means includes a plurality of filters by which light-transmitting characteristics are obtained, and said color estimating means includes a matrix operation circuit means for operating the absolute color estimation matrix.

8. An apparatus according to claim 7, wherein said photoelectric converting means comprises an image detector, and said apparatus further includes:

A/D converting means for converting the electrical signal output from said photoelectric converting means into reflected extracted spectral component data constituted by a digital signal; and

a plurality of frame memories, arranged in correspondence with said plurality of filters, each of said frame memories storing reflected extracted spectral component data input through the corresponding one of said filters, and the reflected extracted spectral component data read out from said plurality of frame memories being input to said matrix operation circuit means and said color classifying means.

9. An apparatus according to claim 1, wherein said photoelectric converting means includes image pickup means for converting the reflected spectral components from the target object into an image signal.

10. A color discrimination data input apparatus comprising:

light source means for emitting an illumination light;

spectroscope means for producing a spectrum including a plurality of spectral components from the illumination light emitted from said light source means;

color classification filter means having a spectrum characteristic that is usable for a classifying of objects and for an estimation of colors, said spectrum characteristic of said color classification filter means being set by means of a plurality of data samples of spectrums reflected from a plurality of objects to be classified into a plurality of classes, said color classification filter means including extracting means for extracting the spectral components from the spectrum generated by said spectroscope means;

illuminating means for illuminating a target object with said extracted spectral components extracted by said extracting means, such that reflected extracted spectral components are reflected by the target object, back to said color discrimination data input apparatus when the target object is illuminated by said illuminating means;

a color filter having a light-transmitting characteristic suitable for input of a color image of three primary colors thereto;

image pickup means for converting the reflected extracted spectral components from the target object, into an image signal;

photoelectric converting means for converting the reflected extracted spectral components having a wavelength characteristic obtained by the spectrum passing through said color classification filter means, into an electrical signal; and

filter control means for selectively locating said color classification filter means and said color filter in an optical path between said light source means and said photoelectric converting means as needed.

11. An apparatus according to claim 10, further comprising image forming means for encoding the image signal from said image pickup means, upon insertion of at least said color classification filter means in the optical path, into three primary colors on the basis of a light-transmitting characteristic of said color classification filter means to form an image as visualized color discrimination information contained in the image signal.

12. An apparatus according to claim 11, wherein said image forming means includes means for forming a color image from the image signal from said image pickup means and a color image obtained by superposing the color discrimination information on the color image upon insertion of said color filter in the optical path.

13. An apparatus according to claim 10, wherein said color classification filter means comprises a liquid crystal filter whose transmittance is determined by liquid crystal alignment.

14. An apparatus according to claim 11, wherein said color classification filter means includes a plurality of filters by which the light-transmitting characteristics are obtained.

15. An apparatus according to claim 14, wherein said image forming means includes:

A/D converting means for converting an image signal output from said image pickup means into reflected spectral component data including a digital signal;

a plurality of frame memories arranged in correspondence with said plurality of filters and said color filter, each of said frame memories storing reflected spectral component data input through the corresponding one of said filters;

a coding circuit for coding the reflected spectral component data read out from said plurality of frame memories into signals corresponding to R, G and B signals in accordance with the light-transmitting characteristic of the color classification filter means; and

an adder means for adding the reflected spectral component data read out from said plurality of frame memories corresponding to said color filter to coded signal output from said coding circuit in unit of color components, and for generating an image signal containing the color discrimination information.