Discussion on the application of the latest CIE co

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Discussion on the application of CIE's latest color table model (Part 1)

[Abstract] color table model can solve the problem of color reproduction in different media under different observation conditions, different backgrounds and different environments. This paper introduces in detail the latest international color table model ciecam97 and its modified version CIECAM02, in order to be correctly applied in the printing industry in the future

key words: color table model; CIECAM97s; CIECAM02; Yan Duan Xiaoping believes that color space

since CIELab color space and its color difference formula were recommended by the international illumination Association (CIE) in 1976, this formula has been widely used in the quality control of textile printing and dyeing industry. However, due to the visual nonuniformity of its color space in k2016 exhibition, there are some problems in the consistency between the visual results and the calculation results. As an extension of traditional colorimetry, the color table model can be used to predict the color appearance of color stimuli under different observation conditions. It gives parameters related to visual and easy processing sensory attributes, such as lightness, chromaticity and hue, which can maintain the integrity of parts and components and play a good role in digital color reproduction, color rendering evaluation of light sources and other applications

1 CIECAM97S color table model

in order to establish a high-performance color table model, at the first division meeting of CIE in May 1997, tc1-34 (responsible for color table model inspection and evaluation) team jointly proposed a unified simplified version of color table model CIECAM97S (color appearance.ance model 97s), as its first color table model adopted and recommended to be popularized. CIECAM97S is based on the evaluation of various existing color table models and the combination of the advantages of various models. It has better uniformity and consistency between color difference and observation results

1.1 uniformity of color space in the model

when establishing the color space, Professor Luo M.R. of the University of Derby in the UK chose the color description quantities o (red green), B (yellow blue), J (brightness), C (chromaticity), H (color phase angle) in CIECAM97S color table model. Two initial color spaces ja1b1 and ja2b2 are established respectively

in Table 1, the size standard deviation, average oblateness and oblateness standard deviation of ellipse are indicators to measure whether the chromaticity plane is uniform. According to the table, a1-b1. The standard deviation of size and oblateness on the plane is the smallest, A-B: the average oblateness of the ellipse on the plane is the smallest. In addition, all indexes of a1-b1 plane are smaller than those of A-B plane, which indicates that the chromaticity plane of ja1b1 space is more uniform than that of CIELAB

1.2 new color difference formula based on CIECAM97S

ciecam97s color difference formula is as follows:

(to be continued)

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