Three-Dimensional Control of Color Management Systems - Control of Color Imaging Systems: Analysis and Design - page 335

W 1
W 2
W 3
W 4
W 5
W 6
W 7
W 8
W 9
W 10
W 11
W 12
W 13
W 14
W 15
W 16

Cyan dot growth
function

c

C

m

Magenta dot growth
function

M

Mixing equations Neugebauer

equation

R (λ)

y

Yellow dot growth
function

Y

Black dot growth
function

k

K

FIGURE 7.19 Block diagram of the Neugebauer model for a color printer.

K

Y

M

C

FIGURE 7.20 Dot-on-dot halftone screen example.

The ideal dot-on-dot mixing model does not consider noise and misregistration
effects. Therefore, a combination of dot-on-dot and random mixing model is pro-
posed [31] to improve the model accuracy by giving relative weights to the re

ect-
ance predicted by the dot-on-dot model and the random mixing model. The predicted
spectral re ectance in the combined model is given by

R (l) ¼ ( 1 a) R d (l) þ a R r (l) ( 7 : 56 )

where
R d (

l

) is the spectral re ectance that is predicted by the dot-on-dot model using

Equation 7.55
R r (

l ) is the spectral re ectance predicted by the random mixing model using

Equation 7.54

a is a weighting parameter between 0 and 1 that is used to relatively weight the

two models

The interested reader may refer to the original work on this subject in Ref. [31].
While the basic form of the mixing equations is similar to Equation 7.51, the
weights W i are modeled differently based on the way the dots are positioned. In order
to use the Neugebauer model to model the printer accurately, we need to estimate the