JPH116765A - Pearl color sorter - Google Patents

Abstract

(57) [Summary] [Object] To provide a pearl color classification device capable of subtle classification in accordance with human visual perception that senses a subtle and complicated color tone. An illuminating means (3) for illuminating a pearl (S) placed as appropriate, an imaging means (1) for imaging a pearl (S) to obtain RGB analog image data, and converting the obtained analog image data into digital image data. A / D conversion means 5, storage means 6 for storing the converted digital image data, processing data extraction means 7 for removing the background part and the halation part from the stored digital image data and extracting the processing data, HS for converting the obtained processing data into HSI data including hue data, saturation data, and brightness data
It comprises an I data conversion means 8, a histogram calculation means 9 for calculating a hue histogram based on the obtained hue data, and a color classification means 10 for classifying a pearl color based on the obtained histogram. Since the classification is performed based on the hue data, the pearl having a subtle hue can be classified reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color classification apparatus capable of automatically classifying pearl colors having subtle colors.

[0002]

2. Description of the Related Art A pearl grown in nature is provided with a pearl layer formed by laminating 1000 or more translucent thin films having a thickness of only about 0.3 μm around an artificial nucleus. Its color, luster, size, etc. are different depending on the natural environment such as the type of shellfish and seawater conditions. In particular, the color of each pearl is slightly different due to optical phenomena such as surface reflection, multiple reflection, and interference caused by the multilayered nacre layer. Therefore, in the case of ornaments such as necklaces, it is necessary to unify the color of each pearl in terms of its commercial value, and since the commercial value differs individually in the market according to the color, some It is necessary to classify crab.

Conventionally, white pearls are classified into six categories shown in FIG. 7 as classification criteria. This classification is based on the human visual perception of a subtle and complicated color tone. WN is strong reddish and weak yellowish, WG is strong greenish and weak yellowish, and MN is reddish. Are strong and medium yellowish, MG is greenish and medium yellowish, LN is reddish and strong yellowish, LG is greenish and yellowish strong Means things.

[0004] Conventionally, in consideration of the so-called color rendering properties of light, in which the pearl color looks different from the original color due to the effect of lighting, pearls are placed under natural light, which is a more common light source,
A skilled inspector visually observes this and classifies the colors as described above.

[0005]

However, in the above-described classification by a skilled inspector using natural light, since the pearl color is slightly different depending on the intensity of natural light, the irradiation angle, and the like, the inspector can feel a certain level of pearl color. In order to obtain the classification result of the accuracy of the inspection, it is necessary to specify the location and time of the inspection work so that uniform natural light can be obtained, and the inspection efficiency cannot be improved because it is easily affected by the weather. There was a problem. Furthermore, since the test depends on human senses, errors tend to occur, and accurate classification cannot be performed.

On the other hand, JP-A-56-61635, JP-A-61-230778, and JP-A-63-1017
No. 17 discloses a pearl color classification method that does not depend on human judgment. The classification methods disclosed in JP-A-56-61635 and JP-A-61-230778 are based on the pattern of the spectral characteristics of light reflected from pearls, and are disclosed in JP-A-63-101717. The classification method disclosed in the official gazette is a classification method based on three primary colors of RGB (notation of a mixed color system).

However, according to the method of classifying based on the pattern of spectral characteristics, relatively simple shades such as white pearls, pink pearls, and green pearls can be patterned, but the above-mentioned greenishness is strong and It is impossible to pattern a delicate and complicated color tone such as a weak yellowish color, and classification based on human visual sensitivity cannot be performed. In the classification method based on the three primary colors of RGB, since the three primary colors of RGB are data of a mixed color system for displaying psychophysical colors, the same applies to this.
Subtle classifications based on human visual perception of subtle and complex colors cannot be made.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a pearl color classification device capable of performing fine classification in accordance with human visual perception of subtle and complicated colors.

[0009]

According to a first aspect of the present invention, there is provided an illuminating means for illuminating a pearl which is appropriately mounted, and an RGB analog image obtained by imaging the pearl. Imaging means for obtaining data; A / D conversion means for converting the obtained analog image data into digital image data; storage means for storing the converted digital image data; Processing data extracting means for removing the halation portion and extracting the processing data, and converting the obtained processing data into hue data,
HSI data conversion means for converting into HSI data consisting of saturation data and lightness data, histogram calculation means for calculating a hue histogram based on the obtained hue data, and pearl color classification based on the obtained histogram And color classification means.

According to the first aspect of the present invention having the above structure, the pearl is placed at the imaging position, and while the pearl is illuminated by the illumination means, the pearl is imaged by the imaging means and relates to the gradation of each of the RGB components. Obtain analog image data. Next, the obtained analog image data is converted into digital image data by A / D conversion means, and the converted digital image data is stored in the storage means. Then, the processing data extracting unit removes the data relating to the background portion and the halation portion from the digital image data to extract the processing data.
That is, of the digital image data obtained by the A / D conversion means, the data relating to the background part and the part relating to the halation-producing part are the data of the part which does not show the original hue of the pearl. , Data of only the portion showing the original color of the pearl is extracted as processing data.

Then, the obtained processing data is converted into HSI data consisting of hue data, saturation data and lightness data by HSI data conversion means. RGB is a color value of a mixed color system that displays a psychophysical color based on a mixed amount of color light necessary to make a certain color equal to a certain color. Color classification cannot be performed. In other words, it is impossible to express the subtle hue of a pearl with a significant difference using RGB values. On the other hand, the values relating to hue, saturation, and lightness are color values of a developed color system for displaying a perceived color based on the appearance of the standard color of the object, and are color specifications in accordance with human sensitivity and are pearls. It is easy to express the subtle shades of with a significant difference.

The hue data converted by the HSI data conversion means is given as angle data. The histogram calculating means calculates a histogram based on the hue data converted by the HSI data converting means, for each angle divided in a predetermined range, in which the number of pixels belonging to the corresponding section is a frequency.

The color classification means classifies pearl color based on the calculated histogram. That is, for example,
The conventional classifications described above, WN, WG, MN, MG, LN,
In the case of classifying LG, first, the frequency classified into red and the frequency classified into green are compared, and when the frequency of red is large, it is determined that the color is reddish. Is judged to be green. Then, the frequency classified into yellow is classified into three categories of weak yellow, medium, and strong with two thresholds, and classified into a total of six categories.

As described above, according to the first aspect of the present invention, since the hues are classified based on the hue data, pearls having a subtle hue can be surely classified.

According to a second aspect of the present invention, there is provided an illuminating means for illuminating a pearl which is appropriately mounted, and an RG for imaging the pearl.
An imaging unit that obtains analog image data of B; and an A / A that converts the obtained analog image data into digital image data.
D conversion means, storage means for storing the converted digital image data, processing data extraction means for removing a background portion and a halation portion from the stored digital image data to extract processing data, and obtained processing data Data conversion means for converting the hue data, saturation data and lightness data into HSI data, a histogram calculation means for calculating a hue histogram based on the obtained hue data, and a complementary color relationship from the obtained histogram. It is characterized by comprising complementary color frequency ratio calculating means for calculating the frequency ratio between certain hues, and color classification means for classifying pearl colors based on the obtained frequency ratio.

According to the second aspect of the present invention having the above configuration, first, in the same manner as in the first aspect, pearl digital image data is obtained, and then processing data is obtained from the digital image data. Extract and then use HSI
The histogram is converted into data, and based on the converted hue data, a histogram is calculated in which the number of pixels belonging to the corresponding section is a frequency for each angle divided in a predetermined range.

Then, the complementary color frequency ratio calculating means calculates the frequency ratio between the sections having a complementary color relationship based on the frequency of each section calculated by the histogram calculating means. Then, the pearl color is classified by the color classification means based on the frequency ratio. Generally, when drawing a red apple, 100% of the red paint is used, and 98% of the red paint is used.
% And 2% of green paint,
Is known to be overwhelmingly bright red. Therefore, it is preferable to classify objects such as pearls in which a human feels a subtle hue in consideration of complementary colors so as to match human sensitivity. W, which is a category related to the conventional red, green, and yellow shades described above.
Regarding the case of classifying into six categories of N, WG, MN, MG, LN, and LG, first, a skilled inspector visually inspects a pearl to be a master piece in advance, and complements the same pearl by a series of processes described above. The power ratio for the related red / green and yellow / blue is calculated, and the threshold of the power ratio is determined in consideration of both. And
The frequency ratio of red / green and yellow / blue is calculated for the pearl to be inspected by the above-described series of processes, and is classified according to a predetermined threshold value.

As described above, according to the second aspect of the present invention, since the classification is performed in consideration of the complementary color relationship, it is possible to perform the classification suitable for human visual sensitivity.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment and a second embodiment as specific embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the pearl color is WN, WG, MN,
It shall be classified into six categories of MG, LN, and LG.

A. First embodiment

FIG. 1 is a block diagram showing a pearl color classification apparatus according to a first embodiment. As shown in the figure, this apparatus includes an imaging device 1 for imaging a pearl S, a transport device 2 for transporting the pearl S to an imaging position of the imaging device 1, and an illumination device 3 for illuminating the pearl S at the imaging position. And a processing device 4 for processing image data obtained by the imaging device 1.

The image pickup device 1 comprises, for example, a CCD camera or the like, and receives reflected light from the pearl S at the image pickup position and outputs analog image data relating to the gradation of each of the RGB components. The transport device 2 transports the pearl S to the imaging position of the imaging device 1 as described above, and a belt conveyor or the like can be applied. However, the pearl S is sucked so as not to vibrate during transport. It is preferable to hold and transport the same.

The illuminating device 3 illuminates the pearl S at the image pickup position as described above, and preferably has a spectral characteristic close to that of sunlight. Lamp.
In addition, a xenon lamp or the like can be used.
It is preferable that the illumination direction of the illumination device 3, that is, the angle α (FIG. 1) of the illumination device 3 from the imaging device 1 be in the range of 30 ° to 60 °. As described above, the pearl S is composed of a translucent thin film having a thickness of only about 0.3 μm around the artificial nucleus.
It is provided with a mother-of-pearl layer with more than 00 layers,
Optical phenomena such as surface reflection, multiple reflection, and interference caused by the multilayer film produce a complex color of the pearl S. Therefore, simply illuminating the pearl from above does not make it possible to express the complex color inherent in such a pearl S. As a result of trial and error, the present inventors have found that the above-described illumination direction is most suitable for expressing the complex color of the pearl S.

The processing unit 4 comprises a microcomputer having a CPU, a RAM, a frame memory, a ROM, an I / O port and the like.
It comprises a D conversion unit 5, an image data storage unit 6, a processing data extraction unit 7, an HSI data conversion unit 8, a histogram calculation unit 9, and a color classification unit 10.

The A / D converter 5 spatially samples the RGB analog image data output from the image pickup apparatus 1 and converts it into 8-bit digital image data of RGB. 2
56 digital gradation data are obtained.

The image data storage section 6 is provided with a frame memory, and the A / D
The digital image data converted by the conversion unit 5 is stored.

The processing data extraction unit 7 extracts, from the data stored in the storage unit 6, data that does not show the original hue of the pearl S, that is, data relating to the background portion of the image and the portion where halation occurs. The data is deleted and only the data of the part showing the original color of the pearl S is extracted as the processing data. Specifically, first, the color image data stored in the storage unit 6 is converted into gradation image data by the following equation (1). Here, Y is luminance data, I and Q are color difference data, and R, G, and B are RGB tone values of each pixel. The background portion is dark and the luminance data Y is extremely low, while the halation portion has an extremely high luminance data Y. Therefore, based on the luminance data Y, it is possible to delete the data relating to the part relating to the background and the data relating to the part causing halation. In this example, if the luminance data Y is 0 ≦ Y <50, the luminance data Y is related to the background. If 250 <Y ≦ 255, it is determined that the data is related to a halation portion, and the RGB values of the pixel corresponding to the data are determined.
We decided to delete the data. Then, the processing data extraction unit 7 outputs the RGB data of the remaining pixels to the HSI data conversion unit 8 as processing data.

[0028]

(Equation 1)

The HSI conversion unit 8 receives the RGB gradation data extracted by the processing data extraction unit 7 and converts it into a hue H (Hue) and a saturation S (Saturation).
n), and converts the data into data relating to lightness I (Intensity). As described above, the values relating to the hue H, the saturation S, and the lightness I are colorimetric values of a developed color system that displays a perceived color based on the appearance of the standard color of the object. It is a color that easily expresses the subtle hue of pearls with a significant difference.

Methods for converting to HSI data include "conversion using the HSI 6-pyramid color model", "conversion using the HSI bi-pyramid color model", "conversion based on the definition of Haydn", and "conversion based on the definition of Raines". It is known, but in this example, the conversion is based on "conversion using the HSI bi-hexagonal color model". This is because the “HSI bihexagonal pyramid color model” according to this conversion method is closest to the Munsell color three-dimensional model and belongs to the color specification that most closely matches human sensitivity. The “conversion by the HSI bi-hexagonal pyramid color model” is based on a model in which hexagonal pyramids are vertically stacked as shown in FIG. 2, and the hue value H takes a value of 0 to 2π as shown in FIG. The intensity value S and the brightness value I are 0 to 1.
Take the value of Specifically, the RGB values of each pixel are converted into HSI values by the following equation (2).

[0031]

(Equation 2)

Based on the hue value H of each pixel converted by the HSI data conversion unit 8, the histogram calculation unit 9 calculates a histogram in which the number of pixels belonging to the corresponding section is frequency for each angle divided in a predetermined range. Is calculated. Specifically, in the hue circle shown in FIG. 3, θ is 11π / 6 to π / 6.
Is a red section, a range from π / 6 to π / 2 is a yellow section, a range from ππ to 5π / 6 is a green section, and 5π / 6 to 7π / 6. A range is defined as a blue-green section, and a range from 7π / 6 to 3π / 2 is defined as a blue section.
The range of 3π / 2 to 11π / 6 is set as a purple section, and the frequencies of the pixels belonging to each section are calculated. FIG. 4 shows an example of the calculated histogram.

The color classifying unit 10 includes the histogram calculating unit 9
The corresponding pearl color is W based on the histogram calculated by
This classifies which of N, WG, MN, MG, LN, and LG belongs. Specifically, the following processing is performed.

That is, first, the frequency belonging to the red section of the histogram is compared with the frequency belonging to the green section. If the frequency belonging to the red section is large, the pearl is determined to be WN, M.
Judging that the pearl is classified as either N or LN, and when the frequency belonging to the green category is large, the pearl is WG, MG,
It is determined to be classified into any of LG.

Next, using a threshold value set in advance based on experience, based on the frequency belonging to the yellow category, the yellow is classified into three categories of weak, medium, and strong, and WN, WG, M
N, MG, LN, and LG are classified into a total of six categories.

According to the color classification device having the above configuration,
The pearls S to be inspected are sequentially transported by the transport device 2 toward the imaging position of the imaging device 1, and are imaged by the imaging device 1 at the same imaging position, and the obtained image data is input to the processing device 4. Then, the series of processes described above are performed by the processing device 4, and the color of the pearl S is classified. According to this apparatus, since the obtained color image data is subjected to the HSI conversion and then classified based on the hue value, the pearl having a subtle hue can be surely classified into a desired classification. .

B. Second embodiment

Next, a pearl color classification device according to a second embodiment will be described. FIG. 5 is a block diagram showing a pearl color classification device according to the second embodiment. As shown in the figure, this apparatus is slightly different from the apparatus according to the above-described first embodiment in the configuration of the processing device 4, and includes a complementary color power ratio calculator 11 and a color processing apparatus according to the first embodiment. The classification unit 10 includes a color classification unit 12 having a different function. Therefore, the same components as those of the device according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The complementary color frequency ratio calculating section 11 calculates the frequency ratio between the sections having a complementary color relationship of each section based on the frequency of each section calculated by the histogram calculating section 9. Specifically, the red section and the blue-green section, the yellow section and the blue section, the green section and the purple section are complementary colors to each other,
The frequency ratio is calculated for these, but the classification in this example relates to the shades of red, green, and yellow.
The green section was used instead of the blue-green section, and the frequency ratio between the red section and the green section and the frequency ratio between the yellow section and the blue section were calculated. For example, looking at the histogram shown in FIG. 4, R (frequency of red section) / G (frequency of green section) is R /
G = 1083/1921 = 0.564, and Y (frequency of yellow section) / B (frequency of blue section) is Y / B = 9144.
/1129=8.099.

The color classification unit 12 uses the threshold value set in advance to determine the pearl color from WN, WG, MN, MG, LN,
It is classified into six categories of LG. The threshold value is empirically determined, and the R / G value and the Y / B value are calculated by the above-described series of processes using pearls belonging to the above-described six sections classified by a skilled inspector as master pieces. FIG. 6 shows an example of the result calculated in this way. As shown in the figure, the R / G value is on the vertical axis, and the Y / B value is on the horizontal axis.
When the values of the pearls belonging to each section are plotted, the pearls belonging to each section are distributed in a certain range. In this example, based on this, 0 ≦ R / G <1 and 0
If ≦ Y / B <1, it is classified as WG, and 0 ≦ R / G
If <1 and 1 ≦ Y / B <2.5, it is classified as MG. If 0 ≦ R / G <1 and 2.5 ≦ Y / B, it is classified as MG. ≦ R / G and 0 ≦
If Y / B <0.6, it is classified as WN and 1 ≦ R /
G if G and 0.6 ≦ Y / B <1.8
And when 1 ≦ R / G and 1.8 ≦ Y / B, it is classified as LN.

According to the color classification device having the above configuration,
By performing a series of processes in the complementary color frequency ratio calculation unit 11 and the color classification unit based on the histogram calculated by the histogram calculation unit 9, the pearl color can be classified into the above-described six categories. Thus, according to this device, since the color classification is performed in consideration of the complementary color relationship of the hue, it is possible to perform the classification according to the human visual sensitivity.

[0042]

As described in detail above, claim 1 of the present invention
According to the invention, since the color image data is converted into the HSI data, the histogram regarding the hue is calculated, and the pearl color is classified based on the obtained histogram.
Pearls with subtle shades can be reliably and clearly classified.

According to the second aspect of the present invention, after calculating the histogram relating to the hues, the frequency ratio between the hues having a complementary color relationship is calculated, and the pearl color is classified based on the frequency ratio. Therefore, it is possible to perform color classification in accordance with human visual sensibility that can feel a subtle hue.

According to the first and second aspects of the present invention, since the pearl color classification can be automatically performed without human involvement, the classification can be performed accurately.
Further, there is an effect that the inspection efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a pearl color classification device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an “HSI bi-hexagonal pyramid color model” related to HSI conversion.

FIG. 3 is an explanatory diagram showing a hue circle relating to “conversion using an HSI bi-six-pyramid color model”.

FIG. 4 is a graph showing a histogram related to hue.

FIG. 5 is a block diagram showing a pearl color classification device according to a second embodiment of the present invention.

FIG. 6 is a distribution diagram relating to a complementary color power ratio of a master pearl.

FIG. 7 is an explanatory diagram showing a conventional classification of pearls.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 imaging device 2 transport device 3 illumination device 4 processing device 5 A / D conversion unit 6 image data storage unit 7 processing data extraction unit 8 HSI data conversion unit 9 histogram calculation unit 10 color classification unit 11 complementary color frequency ratio calculation unit 12 color classification Department

Claims (2)

[Claims] 1. An illuminating means for illuminating a pearl appropriately mounted, an imaging means for imaging the pearl to obtain RGB analog image data, and an A / A for converting the obtained analog image data into digital image data. D conversion means, storage means for storing the converted digital image data, processing data extraction means for removing background and halation portions from the stored digital image data to extract processing data, and obtained processing data Data conversion means for converting the hue data, saturation data and lightness data into HSI data, histogram calculation means for calculating a hue histogram based on the obtained hue data, and pearls based on the obtained histogram A pearl color classification device, comprising: a color classification means for classifying colors. 2. An illuminating means for illuminating a pearl appropriately placed, an imaging means for imaging the pearl to obtain RGB analog image data, and an A / A for converting the obtained analog image data into digital image data. D conversion means, storage means for storing the converted digital image data, processing data extraction means for removing background and halation portions from the stored digital image data to extract processing data, and obtained processing data HSI data conversion means for converting the hue data, saturation data and lightness data into HSI data; histogram calculation means for calculating a hue histogram based on the obtained hue data; Complementary color frequency ratio calculating means for calculating the frequency ratio between certain hues, and pearl color based on the obtained frequency ratio Pearl color classification system which is characterized by being configured of the classification color classification means.