
8 Image Processing for Cinema
L =
740
X
i=380
l(λ
i
)E(λ
i
)
M =
740
X
i=380
m(λ
i
)E(λ
i
)
S =
740
X
i=380
s(λ
i
)E(λ
i
), (1.3)
which, arranged into matrix form, becomes:
L
M
S
= SE, (1.4)
where S is a 3×361 matrix whose rows are the (discrete) cone sensitivities,
and E is the radiance spectrum expressed as a column vector. Equation 1.4 is
a (very) undetermined system of equations, with only three equations for the
361 unknowns of the radiance vector, and therefore for every light E
1
there
will be many lights E
2
producing the same tristimulus (L, M, S), i.e. many
metamers.
From Equation 1.4 we can also derive the property of trichromacy, which
is a fundamental property of human ...