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In the last article we showed how a digital camera’s captured raw data is related to Color Science. In my next trick I will show that CIE 2012 2 deg XYZ Color Matching Functions $\bar{x}$ , $\bar{y}$ , $\bar{z}$ displayed in Figure 1 are an exact linear transform of Stockman & Sharpe (2000) 2 deg Cone Fundamentals $\bar{\rho}$ , $\bar{\gamma}$ , $\bar{\beta}$ displayed in Figure 2

(1) $\begin{equation*} \left[ \begin{array}{c} \bar{x}} \\ \bar{y} \\ \bar{z} \end{array} \right] = M_{lx} * \left[ \begin{array} {c}\bar{\rho} \\ \bar{\gamma} \\ \bar{\beta} \end{array} \right] \end{equation*}$

with CMFs and CFs in 3xN format, $M_{lx}$ a 3×3 matrix and $*$ matrix multiplication. Et voilà:^[1]

Figure 1. Solid lines: CIE (2012) 2° XYZ “physiologically-relevant” Colour Matching Functions and photopic Luminous Efficiency Function (V) from cvrl.org, the Colour & Vision Research Laboratory at UCL. Dotted lines: The Cone Fundamentals in Figure 2 after linear transformation by 3×3 matrix Mlx below. Source: cvrl.org.

Continue reading Cone Fundamentals & the LMS Color Space →

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