JP2006053070A - Coloring matter estimation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coloring matter estimation method which performs the estimation of coloring matters such as pigments and dyes coated on a colored member such as a cultural asset when performing digital archiving or the like. <P>SOLUTION: The coloring matter estimation method comprises a data storage process for storing spectral reflectance data obtained by measuring a plurality of coloring matters, a spectral reflectance identification process for scanning the colored member by a photographing means and identifying spectral reflectance for a specific color in the colored member, and a coloring-matter estimation process for estimating a coloring matter used for a specific color in the colored member by comparing the spectral reflectance obtained in the spectral reflectance identification process with the spectral reflectance data stored in the data storage process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pigment estimation method for estimating pigments such as pigments and dyes applied to members to be colored such as cultural properties.

  In recent years, a digital archive business that digitizes and stores precious cultural assets has been implemented. In this digital archive business, for example, a cultural property such as a bran painting, an old document, or a picture is scanned with a large scanner, and the image data is stored (see Non-Patent Document 1 and Non-Patent Document 2).

The cultural assets in this specification are works of art and works of art that are decorated on the surface with a predetermined pigment, and specifically include paintings, pottery, textiles, murals, sculptures, crafts, etc. is there.
June 2, 2004 Kyoto newspaper third page June 2, 2004 The 10th Asahi Shimbun

  Such cultural assets fade over time, or pigments or the like peel off. For this reason, repair work is necessary for such cultural assets. In order to carry out this repair work, it is necessary to estimate pigments such as pigments and dyes used for cultural properties.

  The types of natural pigments and dyes used in Japan for a long time are limited, and it is not impossible to estimate pigments and dyes at the time of repair work. However, it is impossible to estimate the pigment in the image data at the time of digital archiving.

  The present invention has been made in order to solve the above-described problems, and estimates of pigments that can be used to estimate pigments such as pigments and dyes applied to members to be colored such as cultural properties during digital archiving and the like. It aims to provide a method.

  The invention according to claim 1 is a data storage step for storing spectral reflectance data obtained by measuring a plurality of dyes, and a member to be colored is scanned by an imaging unit, and a specific color in the member to be colored is detected. Spectral reflectance identification process for identifying spectral reflectance, spectral reflectance obtained in the spectral reflectance identification process, and spectral reflectance data stored in the data storage step are compared to identify the colorant to be colored. And a pigment estimation step for estimating the pigment used for the color of the color.

  The invention according to claim 2 is the dye invention according to claim 1, wherein in the spectral reflectance specifying step, the light reflected by the surface of the member to be colored is filtered with a plurality of filters having different pass wavelength regions. Then, the spectral reflectance with respect to a specific color in the member to be colored is specified by sequentially entering the imaging unit through the imaging unit.

  According to a third aspect of the present invention, in the pigment invention of the first aspect, the spectral reflectance is specified from the R, G, and B values of the light reflected from the surface of the member to be colored.

  According to a fourth aspect of the invention, in the invention according to any one of the first to third aspects of the invention, in the data storage step, the reflected light from each dye is passed through a plurality of filters having different pass wavelength regions. The spectral reflectance for the dye is specified by sequentially entering the imaging means, and the spectral reflectance data for each dye is stored as first spectral reflectance data. In the dye estimation step, The first spectral reflectance data is used as spectral reflectance data.

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, in the data storage step, spectral reflectance data when a plurality of pigments are mixed is calculated from the first spectral reflectance data. Then, this is stored as second spectral reflectance data, and the first spectral reflectance data and the second spectral reflectance data are used as spectral reflectance data in the dye estimation step.

  The invention according to claim 6 is the invention according to claim 4, wherein in the data storage step, the light reflected by the surface of the mixture obtained by mixing a plurality of dyes is a plurality of light having different pass wavelength regions. By sequentially entering the imaging means through a filter, the spectral reflectance for the mixture obtained by mixing the plurality of pigments is specified, and the spectral reflectance data for the mixture obtained by mixing the plurality of pigments is obtained. The data is stored as second spectral reflectance data, and the first spectral reflectance data and the second spectral reflectance data are used as spectral reflectance data in the dye estimation step.

  According to a seventh aspect of the present invention, in the invention according to any one of the fifth to sixth aspects, the R, G, and R of the light reflected by the surface of the member to be colored by scanning the member to be colored by an imaging unit The B value is measured, and the spectral reflectance in a predetermined wavelength region is calculated from the R, G, and B values, and the spectral reflectance specified in the spectral reflectance specifying step is compared with the calculated spectral reflectance. If the comparison result between the spectral reflectance specified in the spectral reflectance specifying step and the calculated spectral reflectance is within a predetermined value, the spectral reflectance specified in the spectral reflectance specifying step is determined in the dye estimation step. If the comparison result between the spectral reflectance specified in the spectral reflectance specification process and the calculated spectral reflectance is equal to or greater than a predetermined value, the pigment estimation step In the spectral reflectance specification process, Comparing the spectral reflectance second spectral reflectance data.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the data obtained by scanning the member to be colored by the imaging means is classified into a plurality of colors, and the pigment estimation is performed for each classification. Execute the process.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the coloring matter is a pigment or a dye.

  According to a tenth aspect of the present invention, in the invention according to any one of the first to ninth aspects, the member to be colored is a cultural property.

  According to an eleventh aspect, in the invention according to any one of the second, fourth, and sixth aspects, a plurality of single wavelength light sources are used instead of the plurality of filters having different pass wavelength regions.

  According to the first aspect of the present invention, the spectral reflectance obtained in the spectral reflectance identification process is compared with the spectral reflectance data stored in the data storage step, thereby using the specific color in the member to be colored. Since the estimated pigment is estimated, it is possible to automatically estimate the pigment.

  According to the second aspect of the present invention, the spectral reflectance is specified by sequentially entering the light reflected by the surface of the member to be colored into the imaging means through the plurality of bandpass filters. It becomes possible to specify accurately.

  According to the invention described in claim 3, since the spectral reflectance is specified from the R, G, and B values of the light reflected from the surface of the member to be colored, the spectral reflectance can be easily specified. .

  According to the fourth aspect of the present invention, it is possible to accurately obtain spectral reflectance data for each dye and to perform dye estimation.

  According to the fifth and sixth aspects of the invention, it is possible to obtain spectral reflectance data for a mixture obtained by mixing a plurality of dyes and to perform dye estimation.

  According to the invention described in claim 7, a dye obtained by mixing each dye or a plurality of dyes using the R, G, and B values of the light reflected from the surface of the member to be colored Can be estimated.

  According to invention of Claim 8, it becomes possible to perform estimation of a pigment | dye for every color of a to-be-colored member.

  According to the ninth aspect of the present invention, it is possible to perform estimation of pigments or dyes.

  According to the invention described in claim 10, it is possible to perform estimation of the pigment used for the cultural property.

  According to the eleventh aspect of the present invention, it is possible to specify the pigment without exchanging the filter.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an outline of a large scanner used in the present invention. 2 is a side view showing the configuration of the scanning head 23, and FIG. 3 is a plan view thereof.

  This large scanner was used for an image of the surface of the bran 10, for example, by scanning the bran 10 as a member to be colored with a picture drawn on its surface and obtaining its image data and spectral reflectance. It is for estimating pigments such as pigments or dyes. Here, the pigment has relatively large particles, and becomes a paint in a state where the particles are dispersed in the medium. The dye has particles much smaller than the pigment and is colored in a dissolved state in the medium.

  The large scanner includes a frame 22 having a pair of guide members 21, a scanning head 23 that can reciprocate along the pair of guide members 21, an endless belt 24 for driving the scanning head 23, and a motor 25. A drive mechanism.

  As shown in FIGS. 2 and 3, the scanning head 23 includes a pair of linear light sources 31 for illuminating the surface of the bran 10, and an optical system 32 that collects reflected light from the surface of the bran 10. A filter unit 33 on which various band pass filters can be mounted and a CCD line sensor 34 are provided. The light emitted from the linear light source 31 and reflected by the surface of the bran 10 enters the CCD through the optical system 32 and the filter unit 33. Thereby, the image of the surface of the bran 10 can be scanned by the CCD line sensor 34 and the information can be read.

  FIG. 4 is a block diagram showing the main electrical configuration of the large scanner.

  This large scanner has a ROM in which operation programs necessary for controlling the device are stored, a RAM in which data and the like are temporarily stored during control, and a CPU that executes logical operations. The control part 50 to control is provided. The control unit 50 is connected to the CCD line sensor 34 and the motor 25.

  The large scanner also includes first spectral reflectance data composed of spectral reflectance data D1 for a plurality of pigments and second spectral reflectance composed of spectral reflectance data D2 when a plurality of pigments are mixed. A lookup table 52 that stores rate data, and a storage unit 51 that stores spectral reflectances and RGB data for a plurality of colors obtained by scanning the bran 10 with the CCD line sensor 34.

  Next, a method for estimating a dye that scans the bran 10 with the large scanner described above and estimates the dye used therein will be described. FIG. 5 is a flowchart showing the pigment estimation method according to the first embodiment of the present invention.

  When considering the pigment estimation method according to the present invention, first, instead of the bran 10, a sample sheet or plate material coated with a plurality of dyes or pigments (hereinafter referred to as “sample sheet”) Is scanned with a large scanner, and the spectral reflectance of each of the plurality of dyes is measured to obtain spectral reflectance data for each of the dyes (step S11).

  More specifically, the sample sheet is arranged at a position facing the large scanner. Then, in a state where a bandpass filter that passes light having a wavelength of, for example, 400 nm (nanometer) is attached to the filter unit 33 of the large scanner, the sample sheet is scanned, and the intensity of light having that wavelength is measured. Next, a bandpass filter that passes light having a wavelength of 410 nm is attached to the filter unit, and the sample sheet is scanned. Such an operation is repeated a plurality of times, for example, in the range of 400 nm to 800 nm while exchanging the bandpass filter, thereby obtaining spectral reflectance data D1 for each dye. The spectral reflectance data D1 is obtained for each dye.

  Further, spectral reflectance data D2 when a plurality of pigments are mixed is calculated from spectral reflectance data D1 for each pigment. That is, in order to cope with a case where a specific color is expressed by mixing predetermined pigments or dyes, spectral reflectance data D2 when a plurality of pigments are mixed is obtained by combining spectral reflection data D1. calculate.

  FIG. 6 is a graph showing spectral reflectance data for a certain dye as a spectral reflectance curve.

  The spectral reflectance data D1 is stored in the lookup table 52 as first spectral reflectance data, and the spectral reflectance data D2 is stored in the lookup table 52 as second spectral reflectance data (step). S12).

  FIG. 7 is a table showing pigments and dyes as pigments constituting natural paints that have been used in Japan for a long time (from the book “Reviving Japanese Painting: Tradition and Succession / 1000 Wisdom”).

  This table shows 17 pigments and 7 dyes. The spectral reflectance data D1 and D2 described above may be obtained for these 17 types of pigments and 7 types of dyes, for example.

  As an embodiment different from the above-described embodiment, instead of calculating the spectral reflectance data D2 when a plurality of pigments are mixed from the spectral reflectance data D1 for each pigment, a plurality of pigments are used. Prepare a sample sheet that has been mixed and then apply it, and in the same way as in the case of the sample sheet described above, repeat the scanning multiple times while replacing the bandpass filter, so that multiple dyes are mixed. The spectral reflectance data D2 may be obtained.

  The above operation is a step executed as a preparation for pigment estimation.

  It should be noted that step S11 in the present embodiment may be performed in advance independently of the pigment estimation work according to the present invention, and thereafter, spectral reflectance data D1 and D2 stored in advance may be used repeatedly. . Further, as the spectral reflectance data D1 and D2, data obtained by another measuring apparatus may be used, and it is not particularly necessary to obtain the spectral reflectance data D1 and D2.

  If the above operation | movement is completed, the estimation operation | movement of a pigment | dye will be performed about each to-be-colored member.

  That is, the bran 10 as the member to be colored is disposed at a position facing the large scanner and the surface thereof is scanned (step S13).

  More specifically, first, the bran 10 is scanned without attaching a filter to the filter unit 33 of the large scanner, and RGB data of the surface of the bran 10 is obtained. The RGB data is stored in the storage unit 51 shown in FIG.

  Next, as in the case of the sample sheet described above, the sample sheet is scanned with the bandpass filter that allows 400 nm wavelength light to pass through the filter section 33 of the large scanner, and the intensity of the light of that wavelength is measured. taking measurement. Next, a bandpass filter that passes light having a wavelength of 410 nm is attached to the filter unit, and the sample sheet is scanned. By repeating such an operation a plurality of times, for example, in the range of 400 nm to 800 nm while exchanging the bandpass filter, spectral reflectance data for the image drawn on the bran 10 is obtained. The spectral reflectance data is obtained for each dye.

  In the scanning process of the bran 10, when the surface of the bran 10 has a gloss due to the use of a gold foil, the irradiation angle of light from the linear light source 31 or a CCD line sensor is used. It is preferable to perform scanning a plurality of times by changing the reading angle 34.

  Next, the color classification of the image of the bran 10 is executed (step S14). That is, various colors are used for each area of the bran image. For this reason, for example, the colors used in the image of the bran 10 such as a red area, a blue area, and a green area are classified into a plurality of areas according to the RGB data.

  Then, the spectral reflectance data for the image drawn on the bran 10 obtained previously is stored in the storage unit 51 shown in FIG. 4 for each classified color. In this embodiment, the spectral reflectance data C1 to C8 are classified into eight color classifications.

  Next, the spectral reflectance in each color classification is calculated from the previously measured RGB data (step S15). This calculation is performed using a known arithmetic expression. The following steps are repeated 8 times for each color classification.

  Then, spectral reflectance data to be used in the next step is selected by comparing the spectral reflectance obtained by the calculation with the spectral reflectance obtained in step S13 (step S16). That is, when the difference between the two is within a preset allowable range, it can be determined that the color is expressed by a single dye. Therefore, the spectral reflectance data used in the next step is the spectral reflectance described above. The first spectral reflectance data comprising the rate data D1 is used. On the other hand, when the difference between the two exceeds a preset allowable range, it can be determined that the color is expressed by a plurality of pigments. Therefore, the spectral reflectance data used in the next step is the spectral reflectance described above. Second spectral reflectance data comprising the rate data D2 is used.

  Thereafter, the spectral reflectance of each pigment constituting the selected spectral reflectance data is compared with the spectral reflectance of the image of bran 10 obtained in step S13 (step S17).

  Then, the spectral reflectance of the pigment that is closest to the spectral reflectance of the image of the bran 10 is selected, and it is estimated that the pigment having the spectral reflectance is the pigment used to draw the image of the bran 10 (step S18).

  As a method for determining the closest spectral reflectance, for example, the spectral reflectance of the image of the bran 10 is compared with the spectral reflectance of the dye stored in advance, and the error of the spectral reflectance for each predetermined wavelength is compared. A curve fitting method or the like can be used for determining when the sum of the values becomes the smallest (least square error).

  By executing the above operation for each classified color classification, all the pigments used to draw the image of the bran 10 are estimated, and the operation is completed.

  Next, a second embodiment of the present invention will be described. FIG. 8 is a flowchart showing a pigment estimation method according to the second embodiment of the present invention.

  In the first embodiment described above, after the color classification is performed, the spectral reflectance calculated from the RGB data is compared with the spectral reflectance obtained in step S13 to thereby use the spectral reflectance used in the next step. Data is selected. In contrast, in the second embodiment, in the spectral reflectance comparison step S25, the spectral reflectance first obtained in step S23 is compared with the first spectral reflectance data composed of spectral reflectance data D1. Then, the spectral reflectance of the pigment that is closest to the spectral reflectance of the image of the bran 10 is selected, and it is estimated that the pigment having the spectral reflectance is the pigment that was used to draw the image of the bran 10. (Step S26).

  On the other hand, in step S25, if the first spectral reflectance data composed of the spectral reflectance data D1 cannot be found that is close to the spectral reflectance obtained in step S23, first, it is obtained in step S23. The spectral reflectance and the second spectral reflectance data composed of the spectral reflectance data D2 are compared, and the spectral reflectance of the pigment that is closest to the spectral reflectance of the image of the bran 10 is selected, and the spectral reflectance is selected. It is presumed that the pigment having the rate is the pigment used to draw the image of the bran 10 (step S26). Other steps are the same as those in the first embodiment described above.

  In each of the above-described embodiments, the spectral reflectance obtained by sequentially entering the light reflected from the surface of the bran 10 into the CCD line sensor via a plurality of bandpass filters is obtained in advance. The spectral reflectance data of the dyes are compared. However, for easy scanning, the spectral reflectance calculated from the R, G, and B values of the light reflected from the surface of the bran 10 is compared with the spectral reflectance data of the dye obtained in advance. May be.

  In the embodiment described above, the spectral reflectance is measured while changing the bandpass filter. Instead, the spectral reflectance may be measured while switching a plurality of single wavelength light sources. Good.

  Further, in the above-described embodiment, the entire surface of the bran 10 as the member to be colored is scanned, but only the region where the estimation of the pigment is necessary may be scanned for the purpose of repair work or the like.

  Furthermore, in the above-described embodiment, the pigment is estimated for the image of the planar bran 10 as the member to be colored, but the three-dimensional member is the same as the planar member such as the bran 10. The present invention can be applied to.

It is a perspective view which shows the outline | summary of the large sized scanner used for this invention. 4 is a side view showing the configuration of the scanning head 23. FIG. 4 is a plan view showing a configuration of a scanning head 23. FIG. It is a block diagram which shows the main electrical structures of this large sized scanner. It is a flowchart which shows the estimation method of the pigment | dye which concerns on 1st Embodiment of this invention. It is a graph which shows the spectral reflectance data about a certain pigment | dye as a spectral reflectance curve. It is a table | surface which shows the pigment and dye as a pigment | dye which comprise the natural paint used for a long time in Japan It is a flowchart which shows the estimation method of the pigment | dye which concerns on 2nd Embodiment of this invention.

Explanation of symbols

10 bran 21 guide member 22 frame 23 scanning head 24 endless belt 25 motor 31 linear light source 32 optical system 33 filter unit 34 CCD line sensor 50 control unit 51 storage unit 52 lookup table

Claims (11)

A data storage step for storing spectral reflectance data obtained by measuring a plurality of dyes;
Spectral reflectance specifying step of scanning the colored member by the imaging means and specifying the spectral reflectance for a specific color in the colored member;
A pigment estimation step for estimating a pigment used for a specific color in the member to be colored by comparing the spectral reflectance obtained in the spectral reflectance identification step with the spectral reflectance data stored in the data storage step. When,
A method for estimating a pigment characterized by comprising: In the estimation method of the pigment | dye of Claim 1,
In the spectral reflectance specifying step, the light reflected by the surface of the member to be colored is sequentially incident on the image pickup unit through a plurality of filters having different transmission wavelength regions, so that a specific color in the member to be colored is obtained. Method for estimating a pigment that specifies the spectral reflectance with respect to. In the estimation method of the pigment | dye of Claim 1,
The spectral reflectance is an estimation method of a pigment specified from R, G, and B values of light reflected from the surface of a member to be colored. In the estimation method of the pigment | dye in any one of Claim 1 thru | or 3,
In the data storage step, the reflected light from each dye is sequentially incident on the imaging means through a plurality of filters having different pass wavelength regions, thereby specifying the spectral reflectance for the dye, and for each dye. Storing spectral reflectance data as first spectral reflectance data;
In the pigment estimation step, a pigment estimation method using the first spectral reflectance data as spectral reflectance data. In the estimation method of the pigment | dye of Claim 4,
In the data storage step, spectral reflectance data when a plurality of pigments are mixed is calculated from the first spectral reflectance data, and this is stored as second spectral reflectance data.
In the pigment estimation step, a pigment estimation method that uses the first spectral reflectance data and the second spectral reflectance data as spectral reflectance data. In the estimation method of the pigment | dye of Claim 4,
In the data storage step, light reflected by the surface of a mixture obtained by mixing a plurality of dyes is sequentially incident on the imaging means through a plurality of filters having different pass wavelength regions, thereby the plurality of dyes. And the spectral reflectance data for the mixture obtained by mixing the plurality of pigments is stored as the second spectral reflectance data,
In the pigment estimation step, a pigment estimation method that uses the first spectral reflectance data and the second spectral reflectance data as spectral reflectance data. In the estimation method of the pigment | dye in any one of Claim 5 thru | or 6,
The coloring member is scanned by an imaging means, R, G, and B values of light reflected from the surface of the coloring member are measured, and a spectral reflectance in a predetermined wavelength region is calculated from the R, G, and B values. And comparing the spectral reflectance specified in the spectral reflectance specifying step and the spectral reflectance after the calculation,
If the comparison result between the spectral reflectance specified in the spectral reflectance specification process and the calculated spectral reflectance is within a predetermined value, the spectral reflectance specified in the spectral reflectance specification process in the dye estimation step. And the first spectral reflectance data,
If the comparison result between the spectral reflectance specified in the spectral reflectance specification step and the calculated spectral reflectance is a predetermined value or more, the spectral reflectance specified in the spectral reflectance specification step in the dye estimation step. And the second spectral reflectance data. In the estimation method of the pigment | dye in any one of Claim 1 thru | or 7,
A pigment estimation method in which data obtained by scanning a member to be colored by an imaging unit is classified into a plurality of colors, and the pigment estimation step is executed for each classification. In the estimation method of the pigment | dye in any one of Claim 1 thru | or 8,
The method for estimating a pigment, wherein the pigment is a pigment or a dye. In the pigment estimation method according to any one of claims 1 to 9,
The coloring material is a method for estimating a coloring matter, wherein the member to be colored is a cultural property. In the estimation method of the pigment | dye in any one of Claim 2, 4, 6,
A method for estimating a dye using a plurality of single wavelength light sources instead of a plurality of filters having different pass wavelength regions.

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