阅读说明：本技术 一种纺织品自动化色牢度评级方法及装置 (Automatic color fastness rating method and device for textiles ) 是由 瞿顶军 资鑫斌 李文兴 王天晟 邓野强 王玉伟 于振中 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种纺织品自动化色牢度评级方法及装置,所述方法包括：将色牢度评级用测量板置于光源箱中；使用相机采集测量板的图像,分别获取同一等级两个颜色块的色差值和明度差值；根据色差值和明度差值,拟合色牢度转换公式；计算色牢度转换公式中的待拟合系数,得到色牢度公式；获取待测织物的实际变色色牢度等级和实际沾色色牢度等级；所述装置包括：放置模块,用于将色牢度评级用测量板置于光源箱中；获取模块,用于使用相机采集测量板的图像；拟合模块,用于拟合色牢度转换公式；公式获取模块,用于计算待拟合系数；等级获取模块,用于获取色牢度等级；本发明的优点在于：实现自动评级,从而提高纺织品的检测效率。(The invention discloses a method and a device for automatically grading color fastness of textiles, wherein the method comprises the following steps: placing a measuring plate for color fastness rating in a light source box; acquiring an image of a measuring plate by using a camera, and respectively acquiring a color difference value and a brightness difference value of two color blocks at the same level; fitting a color fastness conversion formula according to the color difference value and the lightness difference value; calculating a coefficient to be fitted in a color fastness conversion formula to obtain a color fastness formula; acquiring the actual color-changing color fastness grade and the actual color staining fastness grade of the fabric to be detected; the device comprises: the placing module is used for placing the measuring plate for color fastness rating in the light source box; the acquisition module is used for acquiring the image of the measuring plate by using the camera; the fitting module is used for fitting a color fastness conversion formula; the formula acquisition module is used for calculating a coefficient to be fitted; the grade acquisition module is used for acquiring the color fastness grade; the invention has the advantages that: automatic grading is realized, and therefore the detection efficiency of the textile is improved.)

1. An automated method for rating color fastness of a textile, the method comprising

The method comprises the following steps: placing a measuring plate for color fastness rating in a light source box, wherein a color fastness test recording table, a gray scale sample card for color change, a gray scale sample card for staining, a plurality of fabrics to be tested, a non-staining contrast fabric corresponding to the fabrics to be tested and a non-staining contrast fabric corresponding to the fabrics to be tested are placed on the measuring plate;

step two: acquiring an image of the measuring plate by using a camera, acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray level sample card for changing color, and acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray level sample card for staining color;

step three: fitting a color change color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color change, and fitting a color staining fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color staining;

step four: calculating a coefficient to be fitted in the color changing fastness conversion formula and a coefficient to be fitted in the color staining fastness conversion formula to obtain a color changing fastness formula and a color staining fastness formula;

step five: and acquiring the actual color-changing fastness grade and the actual color staining fastness grade of the fabric to be detected.

2. An automated method for color fastness grading of textiles as claimed in claim 1 wherein in step one said light box is a D65 light box.

3. The method for automatically grading color fastness of textile according to claim 2, wherein in the first step, the plurality of fabrics to be tested and the non-color-changed fabrics are arranged in a matrix on the color fastness test record table.

4. An automated method for rating colour fastness of textiles according to claim 3, characterised in that said first step comprises in particular:

opening a D65 light source box, and preheating for 15-30 min;

placing 1-2.5 levels of the gray sample cards for color change upwards in a first placing groove at the upper left corner of a measuring plate, placing 3-5 levels of the gray sample cards for color change upwards in a second placing groove at the upper right corner of the measuring plate, placing an unpigmented contrast fabric in a third placing groove at the left side of the measuring plate, placing a color fastness test recording table in a fourth placing groove at the middle position on the measuring plate, and placing the gray sample cards for color change in a fifth placing groove at the right side on the measuring plate;

the measurement plate was placed in a D65 light source box.

5. An automated method for color fastness rating of textiles according to claim 1 wherein said second step comprises: acquiring RGB values of a gray level sample card for color change by using a camera, converting the RGB values of the gray level sample card for color change into XYZ tristimulus values, and converting the XYZ tristimulus values into Lxaab values; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for color change according to the L ab value and the color difference formula of CIEDE2000₀₀And lightness difference Δ L₀₀；

Acquiring RGB values of a gray level sample card for staining by using a camera, converting the RGB values of the gray level sample card for staining into XYZ tristimulus values, and converting the XYZ tristimulus values into L ab values; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for staining according to the L ab value and the color difference formula of CIEDE2000₀₁And lightness difference Δ L₀₁。

6. An automated method for color fastness rating of textiles as claimed in claim 5 wherein step three comprises:

using formulasObtaining the index of the color-changing color fastness conversion formula and utilizingFitting a color-changing color fastness conversion formula;

wherein, A, B, C and D are four coefficients to be fitted in a color fastness conversion formula;

using formulas

wherein A is₁,B₁,C₁,D₁The four fitting coefficients in the staining color fastness conversion formula are adopted.

7. The method for automatically grading color fastness of textiles according to claim 6, wherein step four comprises:

using formulasSolving four coefficients to be fitted A, B, C and D in the color-changing color fastness conversion formula, and substituting the four coefficients to be fitted A, B, C and D into the color-changing color fastness conversion formula to obtain a color-changing color fastness formula;

wherein f (A, B, C and D) represents a color-changing color fastness conversion formula, Level is the actual color-changing color fastness grade, n is the measurement times, arg is a function of solving the variable quantity, and min is a function of solving the minimum value;

using formulas

wherein, f (A)₁,B₁,C₁,D₁) Representing the colour-fastness conversion formula, Level₁For the actual color fastness rating, n₁Is the number of measurements.

8. An automated method for color fastness rating of textiles as claimed in claim 7 wherein step five comprises:

obtaining a color difference value and a brightness difference value of the fabric to be detected relative to the non-color-changing contrast fabric, obtaining a predicted color-changing fastness grade of the fabric to be detected according to a color-changing fastness formula, and obtaining an actual color-changing fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade;

and obtaining the color difference value and the brightness difference value of the fabric to be detected relative to the fabric which is not stained and contrasted, obtaining the predicted staining fastness grade of the fabric to be detected according to the staining fastness formula, and obtaining the actual staining fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade.

9. The automatic color fastness grading method of textiles according to claim 1, further comprising an upper computer electrically connected with the light source box for displaying the actual color fastness level and the actual staining fastness level of the fabrics to be tested.

10. An automated textile color fastness rating apparatus, the apparatus comprising:

the device comprises a placing module, a light source box and a color fastness test module, wherein the placing module is used for placing a measuring plate for color fastness rating in the light source box, the measuring plate is provided with a color fastness test recording table, a gray level sample card for color change, a gray level sample card for staining and a non-staining contrast fabric, and the color fastness test recording table is provided with the non-staining contrast fabric and a plurality of fabrics to be tested;

the acquisition module is used for acquiring an image of the measuring plate by using a camera, extracting positioning mark points of four corners of the measuring plate, automatically positioning each area of the measuring plate according to each positioning mark point, then respectively acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray scale sample card for changing color, and acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray scale sample card for staining;

the fitting module is used for fitting a color change color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color change and fitting a color staining fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color staining;

the formula obtaining module is used for calculating a coefficient to be fitted in the color changing color fastness conversion formula and a coefficient to be fitted in the color staining fastness conversion formula to obtain a color changing color fastness formula and a color staining fastness formula;

and the grade acquisition module is used for acquiring the actual color change fastness grade and the actual color staining fastness grade of the fabric to be detected.

Technical Field

The invention relates to the technical field of textile detection, in particular to a method and a device for automatically grading color fastness of textiles.

Background

With the continuous progress of human society, the requirements of clothes quality of people are higher and higher, and the quality detection of textiles which are used as the most main raw materials for manufacturing the clothes is more important. Color fastness is an important indicator in textile testing, and is used to measure the resistance of textile color to various effects during processing and use, and is generally rated according to the discoloration of a sample and the staining of a lining fabric.

At present, color fastness grading is mainly divided into visual grading and instrument grading, wherein the visual grading has the defects of high labor intensity, strong subjectivity and the like, and has higher requirements on the quality of grading personnel; the instrument rating method can eliminate errors caused by human factors, measurement results are stable, common instrument rating methods comprise a spectrophotometry method and a photoelectric integration method, theoretically, the instruments are more accurate in color measurement rating than visual measurement, but the instrument rating results are different from the visual measurement rating results, and the rating results only have reference values. The color fastness rating method based on machine vision has the advantages of non-contact, high measurement precision and the like, for example, a digital color measurement system DigiEye proposed by VeriVide company, but the system has the problems of low automation degree, complicated measurement steps and the like.

Chinese patent publication No. CN101100807A, entitled method for rating color fastness and color difference of textiles, discloses copying and transmitting color characteristics of textiles to a computer in a digital manner to obtain metamerism images of RGB color space coordinates in the computer, and then analyzing and measuring the metamerism images to obtain values consistent with or even more accurate than the results of conventional optical measurements, thereby finally achieving the purpose of measuring, analyzing and rating the colors of textiles. The method has the advantages of practicality, reliability, easiness in operation, capability of quick analysis, automatic rating and the like, but the method only shows how to calculate the chromatic aberration and does not analyze the mode for realizing the automatic rating, so that the automatic rating of the production does not have the advantage.

Disclosure of Invention

The invention aims to solve the technical problem of how to improve the automation degree of the color fastness rating of the textile so as to improve the detection efficiency of the textile.

The invention solves the technical problems through the following technical means: an automated method of color fastness rating of a textile, the method comprising

The method comprises the following steps: placing a measuring plate for color fastness rating in a light source box, wherein a color fastness test recording table, a gray scale sample card for color change, a gray scale sample card for staining, a plurality of fabrics to be tested, a non-staining contrast fabric corresponding to the fabrics to be tested and a non-staining contrast fabric corresponding to the fabrics to be tested are placed on the measuring plate;

step two: acquiring an image of the measuring plate by using a camera, extracting positioning mark points of four corners of the measuring plate, automatically positioning each area of the measuring plate according to each positioning mark point, then respectively acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray level sample card for color change, and acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray level sample card for staining;

step three: fitting a color change color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color change, and fitting a color staining fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color staining;

step four: calculating a coefficient to be fitted in the color changing fastness conversion formula and a coefficient to be fitted in the color staining fastness conversion formula to obtain a color changing fastness formula and a color staining fastness formula;

step five: and acquiring the actual color-changing fastness grade and the actual color staining fastness grade of the fabric to be detected.

The method is characterized in that each area of the measuring plate is automatically positioned by each positioning mark point, the color fastness detection process is automated, then the color difference value and the lightness difference value of two color blocks at the same level of the gray level sample card are obtained, the color fastness conversion formula is fitted according to the color difference value and the lightness difference value of the gray level sample card, the to-be-measured fitting parameters in the color fastness conversion formula are calculated, then the color fastness formula is worked out, finally the to-be-measured fabric is subjected to color fastness rating by using the worked-out color fastness formula, the automatic rating of the to-be-measured fabric can be realized as long as the measuring plate provided with the gray level sample card for measurement and used for the to-be-measured fabric is placed in a light source box, the detection efficiency of the textile is improved, the labor intensity of workers is reduced, meanwhile, the color fastness of the to-measured fabric is obtained by the.

Preferably, in the first step, the light source box is a D65 light source box.

Preferably, in the step one, the fabrics to be tested and the uncolored fabrics are arranged on the record table of the color fastness test in a matrix manner. The uncolored fabric is compared with the fabric to be detected, and when the color fastness of the fabric to be detected is calculated, the brightness difference value and the color difference value of the fabric to be detected relative to the uncolored fabric are required.

Preferably, the first step specifically includes:

opening a D65 light source box, and preheating for 15-30 min;

placing 1-2.5 levels of the gray sample cards for color change upwards in a first placing groove at the upper left corner of a measuring plate, placing 3-5 levels of the gray sample cards for color change upwards in a second placing groove at the upper right corner of the measuring plate, placing an unpigmented contrast fabric in a third placing groove at the left side of the measuring plate, placing a color fastness test recording table in a fourth placing groove at the middle position on the measuring plate, and placing the gray sample cards for color change in a fifth placing groove at the right side on the measuring plate;

the measurement plate was placed in a D65 light source box.

Preferably, the second step includes: acquiring RGB value of the gray sample card for color change by using a camera, converting the RGB value of the gray sample card for color change into XYZ tristimulus values, and converting the XYZ tristimulus values into the RGB valuesConverting to L ab value; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for color change according to the L ab value and the color difference formula of CIEDE2000₀₀And lightness difference Δ L₀₀；

Acquiring RGB values of a gray level sample card for staining by using a camera, converting the RGB values of the gray level sample card for staining into XYZ tristimulus values, and converting the XYZ tristimulus values into L ab values; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for staining according to the L ab value and the color difference formula of CIEDE2000₀₁And lightness difference Δ L₀₁。

Preferably, step three comprises:

using formulas

Obtaining the index of the color-changing color fastness conversion formula and utilizing

Fitting a color-changing color fastness conversion formula;

wherein, A, B, C and D are four coefficients to be fitted in a color fastness conversion formula;

using formulas

Obtaining the index of the staining color fastness conversion formula and utilizing

Fitting a staining color fastness conversion formula;

wherein A is₁,B₁,C₁,D₁The four fitting coefficients in the staining color fastness conversion formula are adopted.

Preferably, the step four includes:

using formulas

Solving four to-be-fitted coefficients A, B, C and D in the color-changing color fastness conversion formula, and substituting the four solved to-be-fitted coefficients A, B, C and D into the color-changing color fastness conversion formula to obtainColor change color fastness formula;

wherein f (A, B, C and D) represents a color-changing color fastness conversion formula, Level is the actual color-changing color fastness grade, n is the measurement times, arg is a function of solving the variable quantity, and min is a function of solving the minimum value;

using formulasSolving four to-be-fitted coefficients A in staining color fastness conversion formula₁,B₁,C₁,D₁Four to-be-fitted coefficients A to be obtained₁,B₁,C₁,D₁Substituting the formula into a staining color fastness conversion formula to obtain a staining color fastness formula;

wherein, f (A)₁,B₁,C₁,D₁) Representing the colour-fastness conversion formula, Level₁For the actual color fastness rating, n₁Is the number of measurements.

Preferably, step five comprises:

obtaining a color difference value and a brightness difference value of the fabric to be detected relative to the non-color-changing contrast fabric, obtaining a predicted color-changing fastness grade of the fabric to be detected according to a color-changing fastness formula, and obtaining an actual color-changing fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade;

and obtaining the color difference value and the brightness difference value of the fabric to be detected relative to the fabric which is not stained and contrasted, obtaining the predicted staining fastness grade of the fabric to be detected according to the staining fastness formula, and obtaining the actual staining fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade.

Preferably, an upper computer is further used in the method, and the upper computer is electrically connected with the light source box and is used for displaying the actual color change fastness grade and the actual staining fastness grade of the fabric to be tested.

The invention also provides an automatic textile color fastness rating device, comprising:

the device comprises a placing module, a light source box and a color fastness test module, wherein the placing module is used for placing a measuring plate for color fastness rating in the light source box, the measuring plate is provided with a color fastness test recording table, a gray level sample card for color change, a gray level sample card for staining and a non-staining contrast fabric, and the color fastness test recording table is provided with the non-staining contrast fabric and a plurality of fabrics to be tested;

the acquisition module is used for acquiring an image of the measuring plate by using a camera, extracting positioning mark points of four corners of the measuring plate, automatically positioning each area of the measuring plate according to each positioning mark point, then respectively acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray scale sample card for changing color, and acquiring a color difference value and a brightness difference value of two color blocks at the same level of the gray scale sample card for staining;

the fitting module is used for fitting a color change color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color change and fitting a color staining fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color staining;

the formula obtaining module is used for calculating a coefficient to be fitted in the color changing color fastness conversion formula and a coefficient to be fitted in the color staining fastness conversion formula to obtain a color changing color fastness formula and a color staining fastness formula;

and the grade acquisition module is used for acquiring the actual color change fastness grade and the actual color staining fastness grade of the fabric to be detected.

Preferably, the light box is a D65 light box.

Preferably, the plurality of fabrics to be tested and the non-discolored fabric are arranged on the record table of the color fastness test in a matrix manner.

Preferably, the placement module is specifically configured to:

opening a D65 light source box, and preheating for 15-30 min;

placing 1-2.5 levels of the gray sample cards for color change upwards in a first placing groove at the upper left corner of a measuring plate, placing 3-5 levels of the gray sample cards for color change upwards in a second placing groove at the upper right corner of the measuring plate, placing an unpigmented contrast fabric in a third placing groove at the left side of the measuring plate, placing a color fastness test recording table in a fourth placing groove at the middle position on the measuring plate, and placing the gray sample cards for color change in a fifth placing groove at the right side on the measuring plate;

the measurement plate was placed in a D65 light source box.

Preferably, the obtaining module is specifically configured to: acquiring RGB values of a gray level sample card for color change by using a camera, converting the RGB values of the gray level sample card for color change into XYZ tristimulus values, and converting the XYZ tristimulus values into Lxaab values; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for color change according to the L ab value and the color difference formula of CIEDE2000₀₀And lightness difference Δ L₀₀；

Acquiring RGB values of a gray level sample card for staining by using a camera, converting the RGB values of the gray level sample card for staining into XYZ tristimulus values, and converting the XYZ tristimulus values into L ab values; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for staining according to the L ab value and the color difference formula of CIEDE2000₀₁And lightness difference Δ L₀₁。

Preferably, the fitting module is specifically configured to:

using formulas

Obtaining the index of the color-changing color fastness conversion formula and utilizing

Fitting a color-changing color fastness conversion formula;

wherein, A, B, C and D are four coefficients to be fitted in a color fastness conversion formula;

using formulas

Obtaining the index of the staining color fastness conversion formula and utilizing

Fitting a staining color fastness conversion formula;

wherein A is₁,B₁,C₁,D₁The four fitting coefficients in the staining color fastness conversion formula are adopted.

Preferably, the formula obtaining module is specifically configured to:

using formulas

Solving four coefficients to be fitted A, B, C and D in the color-changing color fastness conversion formula, and substituting the four coefficients to be fitted A, B, C and D into the color-changing color fastness conversion formula to obtain a color-changing color fastness formula;

wherein f (A, B, C and D) represents a color-changing color fastness conversion formula, Level is the actual color-changing color fastness grade, n is the measurement times, arg is a function of solving the variable quantity, and min is a function of solving the minimum value;

using formulas

Solving four to-be-fitted coefficients A in staining color fastness conversion formula₁,B₁,C₁,D₁Four to-be-fitted coefficients A to be obtained₁,B₁,C₁,D₁Substituting the formula into a staining color fastness conversion formula to obtain a staining color fastness formula;

wherein, f (A)₁,B₁,C₁,D₁) Representing the colour-fastness conversion formula, Level₁For the actual color fastness rating, n₁Is the number of measurements.

Preferably, the level obtaining module is specifically configured to:

obtaining a color difference value and a brightness difference value of the fabric to be detected relative to the non-color-changing contrast fabric, obtaining a predicted color-changing fastness grade of the fabric to be detected according to a color-changing fastness formula, and obtaining an actual color-changing fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade;

and obtaining the color difference value and the brightness difference value of the fabric to be detected relative to the fabric which is not stained and contrasted, obtaining the predicted staining fastness grade of the fabric to be detected according to the staining fastness formula, and obtaining the actual staining fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade.

Preferably, the device still includes the host computer, the host computer is connected with the light source box electricity for show the fabric that awaits measuring actual colour fastness grade and the actual colour fastness grade of staining.

The invention has the advantages that:

(1) the method comprises the steps of automatically positioning each area of a measuring plate through each positioning mark point, then obtaining the color difference value and the lightness difference value of two color blocks at the same level of a gray level sample card, fitting a color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card, calculating to-be-measured fitting parameters in the color fastness conversion formula, then obtaining the color fastness formula, finally carrying out color fastness grading on the to-be-measured fabric by using the obtained color fastness formula, and only placing the measuring plate, provided with the to-be-measured fabric and the gray level sample card for measurement, in a light source box, realizing automatic grading of the to-be-measured fabric, improving the detection efficiency of the textile and reducing the labor intensity of workers.

(2) The color fastness to change formula and the color staining fastness formula are obtained under the same environment as the experimental environment of the fabric to be detected, so that the color fastness of the fabric to be detected under the current environment can be represented more accurately, and the color fastness accuracy and consistency of the finally obtained fabric to be detected are higher.

Drawings

FIG. 1 is a flow chart of an automated method for color fastness rating of textiles as disclosed in example 1 of the present invention;

FIG. 2 is a schematic structural diagram of a measuring board in an automated color fastness rating method for textiles according to embodiment 1 of the present invention;

FIG. 3 is a schematic view of a gray scale sample card for color change in an automated method for color fastness rating of textiles according to example 1 of the present invention at a scale of 1-2.5;

FIG. 4 is a schematic diagram of gray scale sample cards for color change in an automated method for color fastness rating of textiles according to example 1 of the present invention at 3-5 levels;

fig. 5 is a schematic diagram of a gray scale sample card for staining in the method for automatically rating color fastness of textile according to embodiment 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, a method for automated color fastness rating of textiles, the method comprising

Step S1: opening a light source box, wherein the light source box is a D65 light source box, and preheating for 15-30 min; as shown in fig. 2, 1-2.5 levels of the gray sample cards for color change are upwards placed in a first placing groove 3 at the upper left corner of the measuring plate 1, as shown in fig. 3, a schematic diagram of 1-2.5 levels of the gray sample cards for color change is shown, wherein the number indicates the chroma level, 2-3 indicates that the chroma level is in the range of 2-3, and 2.5 is taken in the invention; placing 3-5 levels of the gray sample cards for color change upwards in a second placing groove 4 at the upper right corner of the measuring plate 1, as shown in fig. 4, wherein the number represents the chromaticity level of the gray sample cards for color change in a schematic diagram of 3-5 levels; the non-staining contrast fabric is placed in a third placing groove 5 on the left side of the measuring plate 1, the dye fastness test recording table is placed in a fourth placing groove 6 located in the middle of the measuring plate 1, and the staining gray scale sample card is placed in a fifth placing groove 7 on the right side of the measuring plate 1, as shown in fig. 5, the staining gray scale sample card is a schematic diagram; the measurement plate 1 was placed in a D65 light source box.

It should be noted that the same level of the color-changing gray sample card and the staining gray sample card in fig. 3-5 includes two color blocks, for example, two color blocks with a level of 1 in fig. 3 are placed side by side and used for calculating the color difference value and the brightness difference value of the two color blocks at the same level.

The dyeing fastness test record table is provided with an uncolored contrast fabric and a plurality of fabrics to be tested, wherein the uncolored contrast fabric comprises wool, nitrile, polyester, polyamide, cotton and diacetate, and the fabrics to be tested corresponding to the uncolored contrast fabric also comprises wool, nitrile, polyester, polyamide, cotton and diacetate;

and the fabrics to be detected and the uncolored fabrics are arranged on the dye fastness test record table in a matrix manner. The uncolored fabric is compared with the fabric to be detected, and when the color fastness of the fabric to be detected is calculated, the brightness difference value and the color difference value of the fabric to be detected relative to the uncolored fabric are required.

Step S2: the image of the measuring board 1 is collected by a camera, and the positioning mark points 2 of the four corners of the measuring board 1 are extracted, wherein the positioning mark points 2 are red or blue points generally used for positioning the position of the measuring board 1 for color fastness rating. Since the relative positions of the respective grooves on the measurement plate 1 for color fastness rating and the positioning mark points 2 are fixed, the positions of the respective grooves can be determined from the positioning mark points 2, and the positions of the articles placed in the respective grooves can be determined.

Automatically positioning each area of the measuring plate 1 according to each positioning mark point 2, wherein each area is a dye fastness test recording list, a gray scale sample card for color change and an area where a non-colored contrast fabric is located, acquiring an RGB value of the gray scale sample card for color change by using a camera, converting the RGB value of the gray scale sample card for color change into a tristimulus value of XYZ, and converting the tristimulus value of XYZ into an L & ab value; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for color change according to the L ab value and the color difference formula of CIEDE2000₀₀And lightness difference Δ L₀₀；

Acquiring RGB values of a gray level sample card for staining by using a camera, converting the RGB values of the gray level sample card for staining into XYZ tristimulus values, and converting the XYZ tristimulus values into L ab values; calculating the color difference value delta E of two color blocks at the same level of the gray scale sample card for staining according to the L ab value and the color difference formula of CIEDE2000₀₁And lightness difference Δ L₀₁。

The conversion formula for converting RGB into XYZ is as follows:

the conversion formula of XYZ to L AB is:

wherein Xn, Yn and Zn are response values of coordinates xyz under a D65 light source box, Xn is 0.950456, Yn is 1.0, and Zn is 1.088754;

the color difference formula for the L ab values and CIEDE2000 is:

t is the color difference value or the brightness difference value in the above,

the calculation process of the color difference value or the brightness difference value belongs to the prior art, and is not described herein again.

Step S3: fitting a color change color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color change, and fitting a color staining fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card for color staining; the specific process is as follows:

using formulasObtaining the index of the color-changing color fastness conversion formula and utilizingFitting a color-changing color fastness conversion formula;

wherein, A, B, C and D are four coefficients to be fitted in a color fastness conversion formula;

using formulas

Obtaining the index of the staining color fastness conversion formula and utilizing

Color fastness of fitting stainingChanging a formula;

wherein A is₁,B₁,C₁,D₁The four fitting coefficients in the staining color fastness conversion formula are adopted.

And solving the primary color difference value and the lightness difference value for each grade of the gray scale sample card for color change to obtain nine groups of color change fastness conversion formulas containing A, B, C, D, and similarly solving the primary color difference value and the lightness difference value for each grade of the gray scale sample card for color change to obtain nine groups of color change fastness conversion formulas containing A, B, C, D.

Step S4: calculating a coefficient to be fitted in the color changing fastness conversion formula and a coefficient to be fitted in the color staining fastness conversion formula to obtain a color changing fastness formula and a color staining fastness formula; the specific process is detailed as follows:

using formulasSolving four coefficients to be fitted A, B, C and D in the color-changing color fastness conversion formula, and substituting the four coefficients to be fitted A, B, C and D into the color-changing color fastness conversion formula to obtain a color-changing color fastness formula;

wherein f (A, B, C and D) represents a color-changing color fastness conversion formula, Level is the actual color-changing color fastness grade, n is the measurement times, arg is a function of solving the variable quantity, and min is a function of solving the minimum value; nine sets of color-changing color fastness conversion formulas obtained in step three and containing A, B, C, D, namely nine sets of f (A, B, C and D) are substituted into the formulaIn the method, nine groups of A, B, C, D values are solved by using the least square method, and the nine groups of A, B, C, D values are replaced by the formula

The value of A, B, C, D when the residual error is minimum is the optimal solution, i.e. the coefficients to be fitted A, B, C, D obtained by the final solution of the invention. Wherein, the minimum residual error means that the value of Level-f (A, B, C, D) is minimum.

Using formulas

Solving four to-be-fitted coefficients A in staining color fastness conversion formula₁,B₁,C₁,D₁Four to-be-fitted coefficients A to be obtained₁,B₁,C₁,D₁Substituting the formula into a staining color fastness conversion formula to obtain a staining color fastness formula;

wherein, f (A)₁,B₁,C₁,D₁) Representing the colour-fastness conversion formula, Level₁For the actual color fastness rating, n₁Is the number of measurements. Fitting coefficient A₁,B₁,C₁,D₁The solving method of (3) is the same as the solving method of the coefficients to be fitted A, B, C and D, and is not described herein again.

Step S5: acquiring the actual color change fastness grade and the actual color staining fastness grade of the fabric to be detected, and detailing the specific process of the step S5 as follows:

obtaining a color difference value and a brightness difference value of the fabric to be detected relative to the non-color-changing contrast fabric, obtaining a predicted color-changing fastness grade of the fabric to be detected according to a color-changing fastness formula, and obtaining an actual color-changing fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade;

and obtaining the color difference value and the brightness difference value of the fabric to be detected relative to the fabric which is not stained and contrasted, obtaining the predicted staining fastness grade of the fabric to be detected according to the staining fastness formula, and obtaining the actual staining fastness grade of the fabric to be detected according to a relation table between the predicted grade and the actual grade. The calculation method of the color difference value and the brightness difference value is the same as the above method, and is not described herein again.

As a further improvement scheme of the invention, the method also uses an upper computer which is electrically connected with the light source box and is used for displaying the actual color-changing fastness grade and the actual color staining fastness grade of the fabric to be tested.

The working process and principle of the invention are as follows: the method comprises the steps of automatically positioning each area of a measuring plate 1 through each positioning mark point 2, then obtaining the color difference value and the lightness difference value of two color blocks at the same level of a gray level sample card, fitting a color fastness conversion formula according to the color difference value and the lightness difference value of the gray level sample card, calculating to-be-measured fitting parameters in the color fastness conversion formula, then obtaining the color fastness formula, finally utilizing the obtained color fastness formula to grade the to-be-measured fabric, placing the measuring plate 1 with the gray level sample card for measurement placed on the to-be-measured fabric and placed in a light source box, achieving automatic grading of the to-be-measured fabric, improving the detection efficiency of textiles and reducing the labor intensity, and meanwhile, the color fastness of the to-be-measured fabric is obtained through the color fastness formula calculated under the same experimental condition, and the accuracy and the consistency are high.