CN-121978034-A - Anti-chromatic aberration interference fabric metamerism evaluation method

Abstract

The invention belongs to the technical fields of color science and textile printing and dyeing, and relates to an anti-chromatic aberration interference fabric metamerism evaluation method, which comprises the steps of firstly obtaining reflectance spectrum curves of standard color samples and batch color samples, and recording the reflectance spectrum curves as And , for Standardized pretreatment is carried out to obtain a standardized reflectivity spectrum curve Then calculate And And calculating to obtain a metamerism index M Y based on the spectrum slope angles of the wavelength points, and judging the metamerism degree according to the value M Y . The method is simple and easy to implement, has strong anti-chromatic aberration interference performance, and obviously improves the judgment accuracy compared with the conventional special metameric index M t evaluation method.

Inventors

• JI BAILIN
• LI YAWEI
• XU ZHONGZHE
• MAO ZHIPING
• ZHONG YI
• WU WEI
• XU HONG
• ZHANG LINPING

Assignees

• 东华大学
• 云鹏(上海)色彩科技有限公司

Dates

Publication Date

20260505

Application Date

20260409

Claims (7)

1. 1. A fabric metamerism evaluation method for resisting chromatic aberration interference is characterized by comprising the following steps: (1) Under the same measurement condition, respectively obtaining reflectance spectrum curves of the standard color sample and the batch color sample, and marking as And Wherein λ represents a wavelength; (2) For a pair of Standardized pretreatment is carried out to obtain a standardized reflectivity spectrum curve ; (3) The interval between any two adjacent wavelength points is controlled to be equal and not more than 10 nm, and the calculation is respectively carried out And (3) with Spectral slope angles at each wavelength point λ i , noted as θ 1 (λ i ) and θ 2 (λ i ); (4) Based on θ 1 (λ i ) and θ 2 (λ i ), the calculation formula of the metameric index M Y ,M Y is calculated as follows: ; the summation sigma is carried out on all the wavelength points lambda i participating in the slope calculation, wherein n is the total number of the wavelength points actually participating in the slope calculation; (5) Comparing the M Y value with a preset judging threshold T to judge whether the metamerism exists between the standard color sample and the batch color sample; if M Y is more than or equal to T, judging that the metamerism exists between the standard color sample and the batch color sample; If M Y < T, judging that the standard color sample and the batch color sample have no metamerism.
2. 2. The method for evaluating fabric metamerism with color difference interference resistance according to claim 1, wherein the measurement condition in the step (1) is that the wavelength range is 400-700 nm, and the wavelength interval is 10 nm.
3. 3. The method for evaluating fabric metamerism with color difference interference resistance according to claim 2, wherein the ordinate of the reflectance spectrum curve in the step (1) is a percentage value of reflectance, and the value is 0-100.
4. 4. The method for evaluating fabric metamerism with color difference interference resistance according to claim 3, wherein the standardized pretreatment in the step (2) is realized by adopting a scaling method, specifically by the following formula: ; wherein the summation Σ is performed for all measurement wavelengths.
5. 5. The method for evaluating fabric metamerism with color difference interference resistance according to claim 4, wherein the calculation formulas of θ 1 (λ i ) and θ 2 (λ i ) in the step (3) are as follows: ; ; wherein R 1 (λ i ) and R 1 (λ i+1 ) are each Spectral reflectivity at wavelength lambda i and the next sampling wavelength lambda i+1 , And Respectively is Spectral reflectivity at wavelength lambda i and the next sampling wavelength lambda i+1 , delta lambda being the sampling wavelength interval.
6. 6. The method for evaluating fabric metamerism with color difference interference according to claim 5, wherein the value of the determination threshold T in step (5) is related to the wavelength range and the sampling wavelength interval used in measurement.
7. 7. The method for evaluating fabric metamerism with color difference interference resistance according to claim 6, wherein the determination threshold T is 0.5 when the measurement wavelength range is 400-700 nm and the sampling wavelength interval Δλ is 10 nm.

Description

Anti-chromatic aberration interference fabric metamerism evaluation method Technical Field The invention belongs to the technical fields of color science and textile printing and dyeing, and relates to a fabric metamerism evaluation method for resisting chromatic aberration interference. Background Color is critical in the fields of textile, printing, packaging, leather and the like, and the accuracy of color reproduction directly influences the quality of products and market performance. However, in actual production, metamerism may lead to color matching of the product under a particular light source, but when the lighting conditions change, the colors no longer match. In the color matching processing process of textiles such as polyester, dyes are often replaced due to the fact that the original formula of a standard sample is difficult to obtain or the raw material supply, cost control, environmental protection regulations and other factors are limited, and the phenomenon of metamerism of different batches of products can be caused. The resulting off-grade product will cause economic losses to the manufacturer and a challenge to the manufacturing enterprise. Currently, the international commission on illumination (CIE) recommends a method of evaluating a specific metamerism index (M t) for a method of evaluating fabric metamerism (see GB/T7771-2008, determination of specific metamerism index changes illuminant). The method evaluates the metamerism degree by calculating the color difference change of the color sample under different light sources. However, this method relies on a test light source and the evaluation is disturbed by the color difference of the color sample under the reference light source. Specifically, when the batch color sample and the standard color sample are not completely same color (i.e., there is a small color difference such as a brightness difference Δl *, a chroma difference Δc *, or a hue angle difference Δh) under a reference light source (e.g., D65), the index is easy to misjudge, and in the actual production process, the two fabric color samples are often difficult to realize accurate color matching under the reference light source due to factors such as fabric colorant formulation, fabric material batch and process fluctuation, and further the tristimulus value needs to be corrected. The existing correction method can only be effective in a small range of chromatic aberration under a reference light source, and cannot effectively resist chromatic aberration interference generated in the production process of the fabric, so that the accuracy of the evaluation result of metamerism is reduced. Subsequent researchers have proposed a series of general metamerism indices that are independent of the light source. For example, document 1 (spectral fuzzy matching evaluation of degree of metamerism [ J ]. Donghua university journal (natural science edition): 2006, 32 (1): 73-75) proposes an evaluation method based on differences in spectral visual response based on the Poplar-Helmholtz contrast theory. Literature 2（Study on metamerism degree evaluation based on wavelength sensitive cone weighting algorithm[J]. Color Research and Application. 2019; 44(6): 894-909） builds a wavelength sensitive cone weight algorithm model based on long wave, medium wave and short wave cones (LMS), and shows good visual consistency in simulation experiments. However, most of the existing methods are based on limited samples or analog data, and the anti-interference performance of the existing methods on chromatic aberration under a light source is not verified yet. On the other hand, if the color difference of the color sample is controlled in a smaller range before the metamerism judgment, a large number of dyeing experiments are required, which is time-consuming and labor-consuming and is difficult to adapt to the requirements of rapid and efficient quality control of industrial production. Therefore, the fabric metamerism evaluation method which is strong in anti-chromatic aberration interference, accurate in judgment and simple is researched, so that the problems existing in the prior art are solved, and the method has very important significance. Disclosure of Invention The invention aims to solve the problems in the prior art and provides an anti-chromatic aberration interference fabric metamerism evaluation method. In order to achieve the above purpose, the invention adopts the following technical scheme: A fabric metamerism evaluation method for resisting chromatic aberration interference comprises the following steps: (1) Under the same measurement condition, respectively obtaining reflectance spectrum curves of the standard color sample and the batch color sample, and marking as AndWherein λ represents a wavelength; (2) For a pair of Standardized pretreatment is carried out to obtain a standardized reflectivity spectrum curveTo eliminate the overall reflected intensity differences due to sam