Textile deep and light color judgment method based on color photometer

Abstract

The invention discloses a textile deep and light color determination method based on a color photometer, and relates to the field of textile detection and colorimetry, and the method comprises the following steps: based on the color photometer and presetting parameters, obtaining the minimum value of color space distances between a test sample and 18 colors in a 1 / 12 dye dyeing standard depth color card in a CIELAB space, and determining the color space distance between the test sample and the 18 colors in the 1 / 12 dye dyeing standard depth color card; and determining the color division of the test sample in the color card and the color depth value of the test sample under the color, and comparing the color depth value under the color with the color depth value of the test sample so as to judge the color depth of the test sample. According to the invention, the objective judgment of the color of the textile is realized by achieving the purpose of judging the depth value of the color of the target sample, the error of subjective judgment is eliminated, and the judgment accuracy of the color depth of the textile is improved.

Description

Technical Field

[0001] The invention relates to the field of textile detection and colorimetry, and in particular to a method for determining the light and dark colors of textiles based on a colorimeter. Background Art

[0002] The subjective color depth evaluation method generally refers to the evaluator's rapid and accurate evaluation of color depth without the aid of other equipment conditions. However, although this evaluation is rapid, it is somewhat random and requires a certain amount of experience to support it. On the one hand, subjective visual evaluation is affected by human factors. The evaluator's experience, experience, psychology, physiology, age, preferences, emotions, gender, etc. will affect the evaluation results; at the same time, factors such as light source, sample size, background selection, and test environment can also easily affect the measurement results. The subjective evaluation of the color depth of textiles may also be affected by more influencing factors such as fiber properties, yarn status, fabric structure, tightness, etc., which makes this method of subjective evaluation of color depth have a large uncertainty.

[0003] At present, the subjective evaluation of color depth is mainly tested according to the relevant provisions in GB / T 3979 Object Color Measurement Method, GB / T 3978 Standard Illuminant and Illumination Observation Conditions, AATCC Evaluation Procedure 9-2011 Visual Assessment of Color Difference of Textile, and ISO 105-A06-2010 Textile-Tests for colorfastness-Part A01: General principles of testing. Although these standards stipulate objective conditions, which make subjective evaluation more objective, fair, and reasonable to a certain extent, human subjective psychology cannot be stipulated by any standards or specifications. There are inevitable differences between people in different regions or different individuals in the same region. This places high demands on the evaluator and is also the reason for the large deviation in the subjective evaluation of color depth. At the same time, since the subjective evaluation method can only qualitatively characterize the depth of color, it is impossible to give a quantitative description of color depth. Subjective visual evaluation also depends on the referenced standard color depth card. In the 1920s, dye manufacturers in Germany and Switzerland determined a set of auxiliary standards consisting of 18 hues determined by professionals, and studied the method of quickly determining the dark and light colors of textiles based on computer colorimeter. In 1951, ISO recognized and approved the auxiliary standard and developed it to the current six depths of 2 / 1, 1 / 1, 1 / 3, 1 / 6, 1 / 12, and 1 / 25. In 1957, the depth formula proposed by Rabe-Koch under the DIN color system established five standard depths of 2 / 1, 1 / 1, 1 / 3, 1 / 6, and 1 / 25. This is the prototype of DIN54000. This method was adopted by ISO and accepted by the American AATCC in 1972. In 1965, Gall proposed his formula based on the results of visual inspection by human eyes, which was later adopted by Germany's DIN53235. This formula plays an important role in the field of pigments. Unlike other color depth levels, it specifies five depths: 1 / 1ST, 1 / 3ST, 1 / 9ST, 1 / 25ST and 1 / 200ST. After 1971, Japan formulated JIS L0808-1971, 0810, 0812-1973 based on ISO recommendations to test the color fastness of dyes, and emphasized that 1 / 3, 1 / 6 and other depths are not simply converted to 1 / 1 standard depth, but must be readjusted to meet the visual perception of the human eye. Currently, only JIS L0808-2005 has detailed descriptions of the standard depths of 1 / 1 and 1 / 6, and the rest all refer to the standards recommended by ISO.my country has formulated GB / T 4841.1-2006 Dyeing Standard Depth Color Card 1 / 1, GB / T 4841.2-2006 Dyeing Standard Depth Color Card Navy Blue and Black, GB / T 4841.3-2006 Dyeing Standard Depth Color Card 2 / 1, 1 / 3, 1 / 6, 1 / 12, 1 / 25. The instrumental determination of the 1 / 1 standard depth of color in GB / T 16990-1997 Textiles Color Fastness Test is used as a supplementary method for visually evaluating whether the color reaches the 1 / 1 standard depth. When using the standard depth card, the dyed sample and the similar hue in the standard depth card are visually evaluated according to the method specified in GB / T 250-2008 "Gray Sample Card for Assessing Color Change". However, when visually determining the depth, even if it can be compared with the above-mentioned standard depth card, there are often some colors that cannot match the sample card. The observer can only choose similar colors for comparison, which brings difficulties to the observer and makes it difficult to distinguish whether it is a difference in depth or a difference in hue or chroma. Therefore, there is a certain subjective error. At the same time, the 18-22 hues specified in the standard depth are far from meeting the current evaluation of the many color requirements. Summary of the invention

[0004] In view of this problem in practical application, the present invention aims to propose a mathematical model to solve the problem of unstable color zone in determining the shade of textiles, and to form a method for determining the shade of textiles based on a colorimeter to objectively determine the shade of textiles. The specific scheme is as follows:

[0005] A method for determining the shade of textiles based on a colorimeter, the method is based on the colorimeter and preset parameters, and obtains the minimum value of the color space distance between a test sample in the CIELAB space and 18 colors in a 1 / 12 dye standard depth color card, so as to determine the hue division of the test sample in the color card and the color depth value at the hue, and at the same time compares the color depth value at the hue with the color depth value of the test sample, so as to determine the color depth of the test sample.

[0006] The method uses a colorimeter to test textiles of different colors, obtains data changes of the chromaticity parameters of the measured textiles, and thus realizes a method for determining the color depth of the textiles by measuring color with the colorimeter.

[0007] Furthermore, the preset parameters of the colorimeter are geometric conditions d / 8°, observer 10°, light source D 65 , wavelength range is 360~700nm, wavelength interval is 10nm.

[0008] Furthermore, the colorimeter includes a spectrophotometer or a spectrocolorimeter.

[0009] Furthermore, the method for obtaining the minimum color space distance is to obtain the color space coordinates of the test sample in the CIELAB space as a test point, rely on the color space coordinates of 18 colors in the 1 / 12 dye standard depth color card in the CIELAB space as standard points, and obtain the color space distance value between the test point and the 18 standard points based on the color space distance formula, and determine the minimum color space distance between the 18 color space distance values.

[0010] Furthermore, the color space coordinates of the test sample are obtained by converting the color tristimulus values ​​of the test sample surface in the CIE LAB nonlinear transformation space, where:

[0011] The tristimulus values ​​of the test sample are obtained based on the parameters preset by the colorimeter and with the aid of the tristimulus value calculation formula obtained by the CIE standard colorimetry system.

[0012] Specifically, based on the spectral reflectance and the CIE standard colorimetric system, the three stimulus values ​​(X, Y, Z) of the surface color of the object being measured are calculated, as shown in formula (1):

[0013]

[0014] Where:

[0015] ——CIE standard colorimetric system standard colorimetric observer spectrum tristimulus value;

[0016] S(λ)——Relative spectral energy distribution of standard illuminant;

[0017] ρ(λ)——spectral reflectivity of the object;

[0018] k——constant, called adjustment factor.

[0019] Adjust the brightness of various lighting objects to 100 (fixed value), and the k value can be obtained by the following formula:

[0020]

[0021] Next, the color tristimulus values ​​(X, Y, Z) of the surface of the object being measured are converted in the CIE LAB nonlinear transformation space, as shown in formula (2):

[0022]

[0023]

[0024]

[0025]

[0026] In the formula, X, Y, and Z are the three stimulus values ​​of the surface color of the object being measured, X n , Y n , Z n It is the tristimulus value of white stimulus when the CIE standard illuminant is irradiated onto a completely diffuse reflector and then reflected to the observer's eyes through complete diffuse reflection. * represents brightness, a * and b * Represents chromaticity.

[0027] Furthermore, based on the color space distance formula, the color space distance value is introduced into the determination model as a basis for determining the hue division. The color space distance formula is:

[0028] Zi=[(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2 ] 1 / 2 (4)

[0029] in

[0030]

[0031] Where Zi is the color space distance value, L* is the lightness value in CIELAB space, a* and b* are chromaticity coordinates, and △L*, △a* and △b* are the differences between the three scales in CIELAB space;

[0032] The method mainly relies on the color space coordinates of 18 main colors in the 1 / 12 dye standard depth color card in CIELAB space, namely L, a, b, and these 18 points are used as standard points. During the test, the color space coordinates of the test sample in CIELAB space are obtained, and the distance value from the 18 standard points is obtained. and minimum value The division of hue is determined by the minimum value of color space distance;

[0033] After determining the minimum color space distance between the 18 colors of the test sample in the color card, the division of the hue of the test sample in the color card and the color depth value D under the hue are i Obtained by dyeing the standard depth color chart with 1 / 12 dye.

[0034] Furthermore, the color depth value of the test sample is calculated by substituting the color space coordinates of the test sample in the CIELAB space into the color depth formula.

[0035] The color depth formula is used, and the color depth value is used as a reference value for color depth determination in the determination model. The color depth formula is:

[0036]

[0037] Where: D ab * is the color depth value;

[0038] L* is the lightness value in CIELAB space;

[0039] a* is the value of the red and green coordinate axes of the CIELAB space;

[0040] b* is the value of the yellow-blue coordinate axis of the CIELAB space.

[0041] Based on the color depth formula and the spatial distance formula as the characterization method and evaluation basis for determining the color depth, the color depth value D is determined as the main color determination parameter, and the distance method is used as an auxiliary determination color interval, that is, by calculating the minimum distance from 18 points to find the corresponding color card, and then compare the size of the test sample and the corresponding color card D value, so as to achieve the purpose of determining the depth value of the target sample.

[0042] Finally, the difference ΔD between the test sample and the corresponding color card D value is used as the basis for determining the color depth value, that is,

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The method for determining the color depth of textiles provided by the present invention uses a colorimeter to test textiles of different colors, obtains the colorimetric parameters of the measured textiles, determines the color depth value as the determination parameter, and determines the color depth value of the target sample by comparing the color depth difference between the target sample and the corresponding color card in the 1 / 12 dye standard depth color card, thereby achieving objective determination of the color of the textile, eliminating the error of subjective determination, and improving the accuracy of color depth determination. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with specific embodiment.It should be understood that the present embodiment is only used to illustrate the present invention and is not intended to limit the scope of the present invention.In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0046] In this embodiment, the method for determining the shade of textiles is to use a colorimeter, obtain the color space coordinates of the test sample in the CIELAB space as the test point, rely on the color space coordinates of 18 colors in the 1 / 12 dye standard depth color card in the CIELAB space as the standard point, obtain the color space distance value between the test point and the 18 standard points based on the color space distance formula, and determine the division of the hue of the test sample in the color card in the form of the minimum color space distance by taking the minimum color space distance value among the 18 color space distance values; based on the determined hue, obtain the color depth value under the hue, and simultaneously obtain the color depth value of the test sample, and determine the color depth of the test sample by comparing the color depth value of the test sample with the color depth value under the obtained hue.

[0047] The determination method specifically includes the following steps:

[0048] Step 1) Cut a test sample of a certain size and make it flat;

[0049] Step 2) calibrating the colorimeter and adjusting the parameters according to the preset colorimetric conditions;

[0050] Step 3) obtaining the color space coordinates L, a, and b values ​​of the test sample;

[0051] Step 4) Calculate the color space distance values ​​Zi between the test sample at the color space coordinates obtained in step 3) and 18 corresponding color cards in the knitted product standard depth sample card (1 / 12) according to the color space distance formula and record them;

[0052] Step 5) Get the minimum color space distance value Zi min , and find the corresponding color card name in the color card min ;

[0053] Step 6) The color card name obtained in step 5) min , check the color depth value Di of the corresponding color card in the color card min ;

[0054] Step 7) calculating the color depth value D of the test sample based on the color space coordinates and the color depth formula;

[0055] Step 8) D and Di min For comparison, if D>Di min , the test sample is judged as deep, otherwise it is judged as shallow.

[0056] Example 1

[0057] (1) Take a red knitted solid color textile with a size of 15 cm*15 cm and make it flat for use;

[0058] (2) Calibrate the colorimetric spectrometer and adjust the colorimetric conditions according to the following table:

[0059] Color measurement conditions

[0060]

[0061] (3) The sample was tested and its L value was 53.84, a value was 48.50, and b value was 28.41

[0062] (4) According to the color space distance formula, calculate the color space distance value Zi between this point and the 18 corresponding color cards in the knitted product standard depth sample card (1 / 12) and record them, and you can get Z 土红 =31.15; Z 砖红 =24.10; Z 仁红 =25.47; Z 橘黄 =34.75; Z 咖啡 =51.62; Z 芥黄 =60.16; Z 驼黄 =54.52; Z 豆绿 =59.00; Z 黄绿 =61.15; Z 灰绿 =67.40; Z 艳绿 =84.52; Z 湖绿 =82.90; Z 中灰 =65.67; Z 湖蓝 =82.90; Z 灰蓝 =73.78; Z 蓝紫 =62.37; Z 紫色 =55.03; Z 紫红 =47.99;

[0063] (5) The minimum value Z can be obtained imin Z 砖红 =24.10, where i min It is brick red, that is, the color judgment interval of the sample is brick red;

[0064] (6) Due to i min It is brick red. By checking Appendix 1, we can get D imin =D 砖红 =55.26;

[0065] (7) Test sample according to the formula: So D = 72.73;

[0066] (8) D and Di min In contrast, due to D>Di min , the test sample is judged to be deep.

[0067] Example 2

[0068] (1) Take a green knitted solid color textile with a size of 15 cm*15 cm and make it flat for use;

[0069] (2) Calibrate the colorimetric spectrometer and adjust the colorimetric conditions according to the following table:

[0070] Color measurement conditions

[0071]

[0072] (3) The sample was tested and its L value was 82.02, a value was -31.58, and b value was -3.03

[0073] (4) According to the color space distance formula, calculate the color space distance value Zi between this point and the 18 corresponding color cards in the knitted product standard depth sample card (1 / 12) and record them, and you can get Z 土红 =69.45; Z 砖红 =76.29; Z 仁红 =71.21; Z 橘黄 =65.72; Z 咖啡 =42.37; Z 芥黄 =46.95; Z 驼黄 =39.30; Z 豆绿 =35.53; Z 黄绿 =36.14; Z 灰绿 =31.38; Z 艳绿 =15.70; Z 湖绿 =19.03; Z 中灰 =33.29; Z 湖蓝 =39.08; Z 灰蓝 =37.85; Z 蓝紫 =51.35; Z 紫色 =56.64; Z 紫红 =65.61;

[0074] (5) The minimum value Z can be obtained imin Z 艳绿 =15.70, where i min It is brilliant green, that is, the color judgment interval of the sample is brilliant green;

[0075] (6) Due to i min It is bright green, and by checking Appendix 1, we can get that D imin =D 艳绿 =42.97;

[0076] (7) Test sample according to the formula: So D = 36.47;

[0077] (8) D and Dimin In contrast, due to D <Di min , the test sample is judged to be shallow.

[0078] Example 3

[0079] (1) Take a blue knitted solid color textile with a size of 15 cm*15 cm and make it flat for use;

[0080] (2) Calibrate the colorimetric spectrometer and adjust the colorimetric conditions according to the following table:

[0081] Color measurement conditions

[0082]

[0083]

[0084] (3) The sample was tested and its L value was 57.32, a value was -21.85, and b value was -39.03;

[0085] (4) According to the color space distance formula, calculate the color space distance value Zi between this point and the 18 corresponding color cards in the knitted product standard depth sample card (1 / 12) and record them, and you can get Z 土红 =70.90; Z 砖红 =79.49; Z 仁红 =80.74; Z 橘黄 =86.67; Z 咖啡 =55.72; Z 芥黄 =80.12; Z 驼黄 =58.15; Z 豆绿 =58.90; Z 黄绿 =63.18; Z 灰绿 =44.64; Z 艳绿 =45.99; Z 湖绿 =37.60; Z 中灰 =39.07; Z 湖蓝 =19.20; Z 灰蓝 =27.19; Z 蓝紫 =38.35; Z 紫色 =47.32; Z 紫红 =58.18;

[0086] (5) The minimum value Z can be obtained imin Z 湖蓝 =19.20, where i min It is lake blue, that is, the color judgment interval of the sample is lake blue;

[0087] (6) Due to i min It is lake blue, which can be obtained by checking Appendix 1. imin=D 湖蓝 =51.97;

[0088] (7) Test sample according to the formula: So D = 61.83;

[0089] (8) D and Di min In contrast, due to D>Di min , the test sample is judged to be deep.

[0090] It should be noted that the chromaticity parameters of the 18 main 1 / 12 color cards involved in the above embodiment are shown in Appendix 1:

[0091] Schedule 1

[0092]

[0093]

[0094] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for determining the shade of a textile based on a colorimeter, characterized in that: The method is based on a colorimeter and preset parameters to obtain the minimum color space distance between the test sample and 18 colors in a 1 / 12 dye standard depth color card in the CIELAB space, so as to determine the hue division of the test sample in the color card and the color depth value at the hue, and at the same time compare the color depth value at the hue with the color depth value of the test sample, so as to determine the color depth of the test sample.

2. The method for determining the shade of a textile based on a colorimeter according to claim 1, characterized in that: The preset parameters of the colorimeter are geometric conditions d / 8°, observer 10°, light source D 65 , wavelength range is 360~700nm, wavelength interval is 10nm.

3. The method for determining the shade of a textile based on a colorimeter according to claim 2, characterized in that: The method for obtaining the minimum color space distance is to obtain the color space coordinates of the test sample in the CIELAB space as a test point, rely on the color space coordinates of 18 colors in the 1 / 12 dye standard depth color card in the CIELAB space as standard points, obtain the color space distance value between the test point and the 18 standard points based on the color space distance formula, and determine the minimum color space distance value among the 18 color space distance values.

4. The method for determining the shade of a textile based on a colorimeter according to claim 3, characterized in that: The color space coordinates of the test sample are obtained by converting the color tristimulus values ​​of the test sample surface in the CIE LAB nonlinear transformation space, where: The tristimulus values ​​of the test sample are obtained based on the parameters preset by the colorimeter and with the aid of the tristimulus value calculation formula obtained by the CIE standard colorimetry system.

5. The method for determining the shade of textiles based on a colorimeter according to claim 3, characterized in that: The color space distance formula is: Zi=[(ΔL * ) 2 +(D a * ) 2 +(Δb * ) 2 ] 1 / 2 in: Where Zi is the color space distance value, L* is the lightness value in the CIELAB space, a* and b* are the chromaticity coordinates, and △L*, △a* and △b* are the differences between the three scales in the CIELAB space.

6. The method for determining the shade of a textile based on a colorimeter according to claim 1, characterized in that: After determining the minimum color space distance between the 18 colors of the test sample in the color card, the hue division of the test sample in the color card and the color depth value at the hue are obtained through a 1 / 12 dye-dyed standard depth color card.

7. The method for determining the shade of a textile based on a colorimeter according to claim 3, characterized in that: The color depth value of the test sample is calculated by substituting the color space coordinates of the test sample in the CIELAB space into the color depth formula.

8. The method for determining the shade of textiles based on a colorimeter according to claim 7, characterized in that: The color depth formula is: Where: D ab * is the color depth value; L* is the lightness value in CIELAB space; a* is the value of the red and green coordinate axes of the CIELAB space; b* is the value of the yellow-blue coordinate axis of the CIELAB space.

9. The method for determining the shade of a textile based on a colorimeter according to any one of claims 1 to 8, characterized in that: The method specifically comprises the following steps: Step 1) Cut a test sample of a certain size and make it flat; Step 2) calibrating the colorimeter and adjusting the parameters according to the preset colorimetric conditions; Step 3) obtaining the color space coordinates L, a, and b values ​​of the test sample; Step 4) Calculate the color space distance values ​​Zi between the test sample at the color space coordinates obtained in step 3) and 18 corresponding color cards in the knitted product standard depth sample card (1 / 12) according to the color space distance formula and record them; Step 5) Get the minimum color space distance value Zi min , and find the corresponding color card name i in the color card min ; Step 6) The color card name obtained in step 5) min , find the color depth value Di of the corresponding color card in the color card min ; Step 7) calculating the color depth value D of the test sample based on the color space coordinates and the color depth formula; Step 8) D and Di min For comparison, if D>Di min , the test sample is judged as deep, otherwise it is judged as shallow.

10. The method for determining the shade of a textile based on a colorimeter according to claim 1, characterized in that: The colorimeter includes a spectrophotometer or a spectrocolorimeter.

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