Algorithm 1: Algorithm for codebook construction

C ← ϕ

for t= 1 → N do

xt = (R, G, B), $I\leftarrow \sqrt{R^2+G^2+B^2}$

Find the codeword, cm, in C matching to xt based on two conditions:

(a) colordist(xt, vm) ≤ ϵ1

(b) brightness (I, 〈 $I_{\mathit{\text{min}}}^m$, $I_{\mathit{\text{max}}}^m$〉) = true

if C = ϕ or there is no match then

{Create new codeword and add it to C}

else

{Update matched codeword}

end if

end for