Activity 8: Color Difference

🕑11:10, 14 Oct 2019

For this activity, the values for CIE 1964 standard observer, standard illuminant D65, illuminant D55, and their respective white point tristimulus values were obtained from [2]. The reflectances of the Macbeth patches were obtained from [1]. Interpolation was performed for all the data to ensure that they are all aligned and of the same length. The tristimulus values for each patch under an illuminant were obtained by

where is the spectral power distribution of the illuminant, is the reflectance of a patch, is a standard observer, and is a tristimulus value. From here, conversion to was performed using

where

where are the white point tristimulus values. Conversion to was performed using

The color differences in and are respectively calculated by

The results of applying (4)-(5) on each Macbeth patch is shown in Table 1. Figure 1 shows the reference Macbeth chart.

Table 1: Color difference values for the Macbeth patches under D65 and D55 illumination.

Patch
1	3.14	3.10
2	4.43	4.16
3	2.96	2.67
4	2.40	2.23
5	2.77	2.65
6	3.11	2.92
7	6.10	6.04
8	3.76	2.51
9	5.10	5.04
10	1.80	1.74
11	4.22	3.60
12	6.12	5.82
13	4.38	2.49
14	2.58	2.56
15	5.76	5.73
16	6.29	5.39
17	3.79	3.54
18	4.12	4.08
19	4.18	4.14
20	3.62	4.43
21	3.07	3.92
22	2.54	3.51
23	1.94	1.98
24	1.37	1.38

References

1. M. N. Soriano, Uniform color spaces, color difference, color appearance phenomena (2019).

2. Public.Resource.Org, CIE 15B tables (2004).

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