Evaluation device and recording medium storing evaluation program

Patent metadata

Field	Value
Publication number	US-10614563-B2
Application number	US-201815994168-A
Country	US
Kind code	B2
Filing date	May 31, 2018
Priority date	May 31, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

An evaluation device includes a projector to project a pattern having an edge component onto an object, an imaging device to capture an image of the object, a reflective-property correction unit to correct an amount of change in shape of a virtual image of the pattern reflected in the object, using reflective-property data of a surface of the object, and an evaluation-value calculator to evaluate image clarity of the surface of the object based on the corrected amount of change. A computer-readable non-transitory recording medium storing a program for causing a computer to execute a method. The method includes correcting an amount of change in shape of a virtual image of the pattern reflected in the object based on image data that is obtained by capturing an object onto which a pattern having an edge component is projected, using reflective-property data of a surface of the object.

First claim

What is claimed is:

1. An evaluation device, comprising:
a projector configured to project a pattern having an edge component onto an object;
an imaging device configured to capture an image of the object using a spectral camera; and
processing circuitry configured to
correct an amount of change in shape of a virtual image, of the pattern reflected in the object, using reflective-property data of a surface of the object;
evaluate an image clarity of the surface of the object based on the corrected amount of change;
convert the image of the object into spectral image data using first spectral data obtained by capturing the image of the object and second spectral data obtained by capturing an image of a reference whiteboard;
binarize lightness image data with a prescribed threshold based on the spectral image data to obtain a number for an amount of change in shape of an edge of the pattern;
calculate an approximate straight line for shape-changing positions of edges of the binarized lightness image data;
calculate changes in the edge with reference to the approximate straight line;
calculate frequency characteristics of the changes in the edge;
assign a weight to the frequency characteristics of the changes in the edge using data that reflects characteristics of human visual perception; and
integrate the weighted frequency characteristics, wherein

the processing circuitry corrects an integrated value of the object.

2. The evaluation device according to claim 1 , wherein the processing circuitry corrects the amount of change using color data of the surface of the object.

3. The evaluation device according to claim 2 , wherein the processing circuitry corrects the amount of change using lightness data of the color data of the surface of the object.

4. The evaluation device according to claim 1 , wherein the processing circuitry corrects the amount of change using reflectance data of the surface of the object.

5. The evaluation device according to claim 1 , wherein the processing circuitry evaluates the image clarity of the surface of the object based on subjective evaluation data that is obtained in advance.

6. The evaluation device according to claim 1 , wherein the imaging device focuses on and captures the image of the virtual image reflected in the object.

7. The evaluation device according to claim 1 , wherein the processing circuitry performs a conversion to obtain reflectance image data using the first spectral data and the second spectral data, and converts the obtained reflectance image data into the spectral image data according to the reflectance image data, third spectral data indicative of spectral data of illumination of the projector, and a color matching function.

8. The evaluation device according to claim 7 , wherein the processing circuitry uses the third spectral data that varies depending on a viewing condition of the object.

9. The evaluation device according to claim 1 , wherein
the spectral camera is a hyperspectral camera, and
the processing circuitry performs conversion to obtain the spectral image data that is L*a*b* image data.

10. The evaluation device according to claim 1 , wherein
the spectral camera is an RGB camera, and
the processing circuitry performs conversion to obtain the spectral image data that is XYZ image data.

11. The evaluation device according to claim 1 , wherein
the spectral camera is a monochrome camera,
in a case that reflectivity of the reference whiteboard is 100 percent, the processing circuitry performs conversion to obtain the spectral image data that is reflectance image data according to the reflectivity of the reference whiteboard and reflectivity of the object, and
the processing circuitry corrects the integrated value of the object using reflectance data of the surface of the object.

12. An evaluation device, comprising:
processing circuitry configured to
correct an amount of change in shape of a virtual image, of the pattern reflected in the object, based on image data that is obtained by capturing an object onto which a pattern having an edge component is projected, using reflective-property data of a surface of the object;
evaluate an image clarity of the surface of the object based on the corrected amount of change;
convert the image of the object into spectral image data using first spectral data obtained by capturing the image of the object and second spectral data obtained by capturing an image of a reference whiteboard;
binarize lightness image data with a prescribed threshold based on the spectral image data to obtain a number for an amount of change in shape of an edge of the pattern;
calculate an approximate straight line for shape-changing positions of edges of the binarized lightness image data;
calculate changes in the edge with reference to the approximate straight line;
calculate frequency characteristics of the changes in the edge;
assign a weight to the frequency characteristics of the changes in the edge using data that reflects characteristics of human visual perception; and
integrate the weighted frequency characteristics, wherein

the image of the object is captured using a spectral camera, and
the processing circuitry corrects an integrated value of the object.

13. A computer-readable non-transitory recording medium storing a program for causing a computer to execute a method, the method comprising:
correcting an amount of change in shape of a virtual image, of the pattern reflected in the object based on image data that is obtained by capturing an object onto which a pattern having an edge component is projected, using reflective-property data of a surface of the object;
evaluating an image clarity of the surface of the object based on the corrected amount of change;
converting the image of the object into spectral image data using first spectral data obtained by capturing the image of the object and second spectral data obtained by capturing an image of a reference whiteboard;
binarizing lightness image data with a prescribed threshold based on the spectral image data to obtain a number for an amount of change in shape of an edge of the pattern;
calculating an approximate straight line for shape-changing positions of edges of the binarized lightness image data;
calculating changes in the edge with reference to the approximate straight line;
calculating frequency characteristics of the changes in the edge;
assigning a weight to the frequency characteristics of the changes in the edge using data that reflects characteristics of human visual perception; and
integrating the weighted frequency characteristics, wherein
the image of the object is captured using a spectral camera, and
the computer corrects an integrated value of the object.

Assignees

• Ricoh Co Ltd

Inventors

• Watanabe Shuhei
• Sone Takuroh
• Kihara Hideyuki
• Gotoh Takayuki
• Soma Takashi
• Iwamatsu Akihiro

Classifications

• G01J2003/467

  Colour computing · CPC title

• G06T2207/30168

  Image quality inspection · CPC title

• G01N21/31

  Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} · CPC title

• G01N21/55

  Specular reflectivity · CPC title

• G06T7/13

  Edge detection · CPC title