PROCESSING APPARATUS, PROCESSING METHOD, AND STORAGE MEDIUM

• US 20200132601A1
• Filed: 10/23/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Jinno, Takayuki
• Granted Patent: US 11,333,603 B2
• Time in Patent Office: Days
• CPC Class Codes: G01N 21/552 Attenuated total reflection
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 7/90 Determination of colour characteristics

Abstract

A processing apparatus includes an acquisition unit configured to acquire a plurality of pieces of color image data respectively representing a plurality of color images, a determining unit configured to determine a degree of correlation between at least two color values among a plurality of types of color values included in each of a plurality of pixel values corresponding to a pixel position in the plurality of color images, and a determination unit configured to determine, based on the determined degree of correlation, whether a feature related to a direction of light reflected from an object appears in the plurality of pixel values corresponding to the pixel position.

Claims

1. A processing apparatus that determines a feature of an object based on a plurality of color images obtained by capturing images of the object under a plurality of geometric conditions depending on a position of an imaging apparatus and a position of a light source that emits light to the object and in which a color of each pixel is represented by a plurality of types of color values, the processing apparatus comprising:

an acquisition unit configured to acquire a plurality of pieces of color image data respectively representing the plurality of color images;

a determining unit configured to determine a degree of correlation between at least two color values among the plurality of types of color values included in each of a plurality of pixel values corresponding to a pixel position in the plurality of color images; and

a determination unit configured to determine, based on the determined degree of correlation, whether a feature related to a direction of light reflected from the object appears in the plurality of pixel values corresponding to the pixel position.

2. The processing apparatus according to claim 1, wherein the determination unit determines whether a peak in change in the plurality of pixel values corresponding to the geometric conditions is a reflectance peak corresponding to a reflection characteristic of the object or a peak due to noise included in the color images.

3. The processing apparatus according to claim 1, wherein the determining unit determines a correlation coefficient between the at least two color values, and

wherein the determination unit makes the determination based on the determined correlation coefficient.

4. The processing apparatus according to claim 1, wherein the plurality of types of color values is a red (R) value, a green (G) value, and a blue (B) value.

5. The processing apparatus according to claim 3, wherein the determination unit determines at least one of a correlation coefficient between an R value and a G value, a correlation coefficient between the G value and a B value, and a correlation coefficient between the B and R values.

6. The processing apparatus according to claim 5, wherein, based on an average value of pixel values in the color images, the determination unit determines any one of the correlation coefficient between the R and G values, the correlation coefficient between the G and B values, and the correlation coefficient between the B and R values.

7. The processing apparatus according to claim 5, wherein in a case where at least one of the correlation coefficient between the R and G values, the correlation coefficient between the G and B values, and the correlation coefficient between the B and R values is larger than a predetermined threshold, the determination unit identifies that a peak in change in the plurality of pixel values corresponding to the geometric conditions is a reflectance peak corresponding to a reflection characteristic of the object.

8. The processing apparatus according to claim 5, wherein the correlation coefficient is a Pearson'"'"'s product-moment correlation coefficient.

9. The processing apparatus according to claim 5, wherein the correlation coefficient is a Spearman'"'"'s rank correlation coefficient.

10. The processing apparatus according to claim 5, wherein the correlation coefficient is a Kendall'"'"'s rank correlation coefficient.

11. The processing apparatus according to claim 1, wherein the determination unit approximates change in each of the plurality of types of color values corresponding to the geometric conditions to a function to calculate geometric conditions corresponding to peaks of the color values, and based on the geometric conditions corresponding to the peaks of the color values, determines whether the feature related to the direction of the light reflected from the object appears in the plurality of pixel values corresponding to the pixel position.

12. The processing apparatus according to claim 11, wherein the determination unit determines that the feature related to the direction of the light reflected from the object appears in the plurality of pixel values in a case where a difference between the geometric conditions corresponding to the peaks of the plurality of types of color values is smaller than a predetermined threshold.

13. The processing apparatus according to claim 1, wherein the determination unit determines whether each of the plurality of pixel values is larger than a predetermined threshold, and in a case where there are a large number of pixels having two or more color values among the plurality of types of color values that are larger than the predetermined threshold, the determination unit determines that a peak in change in the plurality of pixel values corresponding to the geometric conditions is a reflectance peak corresponding to a reflection characteristic of the object.

14. The processing apparatus according to claim 1, further comprising an estimation unit configured to estimate a reflection characteristic of the object based on the plurality of pieces of color image data and information regarding geometric conditions corresponding to each of the plurality of pieces of color image data when the images of the object are captured.

15. The processing apparatus according to claim 14, wherein the estimation unit selects a reflection model used to estimate the reflection characteristic based on a determination result of the determination unit.

16. The processing apparatus according to claim 14, wherein the estimation unit selects a neighboring pixel to be referenced to estimate the reflection characteristic of a pixel of interest based on a determination result of the determination unit.

17. The processing apparatus according to claim 1, wherein the feature related to the direction of the light reflected from the object is a feature of reflection from a flake included in the object.

18. The processing apparatus according to claim 1, wherein the feature related to the direction of the light reflected from the object is a feature of reflection due to surface unevenness of the object.

19. A processing method that determines a feature of an object based on a plurality of color images obtained by capturing images of the object under a plurality of geometric conditions depending on a position where the image is captured and a position of a light source that emits light to the object and in which a color of each pixel is represented by a plurality of types of color values, the processing method comprising:

acquiring a plurality of pieces of color image data respectively representing the plurality of color images;

determining a degree of correlation between at least two color values among the plurality of types of color values included in each of a plurality of pixel values corresponding to a pixel position in the plurality of color images; and

determining, based on the determined degree of correlation, whether a feature related to a direction of light reflected from the object appears in the plurality of pixel values corresponding to the pixel position.

20. A non-transitory computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a processing method that determines a feature of an object based on a plurality of color images obtained by capturing images of the object under a plurality of geometric conditions depending on a position where the image is captured and a position of a light source that emits light to the object and in which a color of each pixel is represented by a plurality of types of color values, the processing method comprising:

acquiring a plurality of pieces of color image data respectively representing the plurality of color images;

determining a degree of correlation between at least two color values among the plurality of types of color values included in each of a plurality of pixel values corresponding to a pixel position in the plurality of color images; and

determining, based on the determined degree of correlation, whether a feature related to a direction of light reflected from the object appears in the plurality of pixel values corresponding to the pixel position.