Problems and Way out of Zone Models
The right picture is the reversed one of the left picture. This shows that real opponet colors are Red/Cyan and Green/Magenta instead of Red/Green. 

from http://webvision.med.utah.edu/KallColor.html 
From http://www.handprint.com/HP/WCL/color1.html,Thanks. 
Zone Model I: B,G,R result in
White/Black
The problem: G, R cannot be opponent or cannot compose white as indicated by Herring (B,G,R)=(0,0,1) should be typical red color, there should be only output r>0. But The above model also yields y>0. 
Zone Model II: G, R result White/Black, and
Red/Green( actully green here is Cyan; or R is magenta)
Problem: White can be produced without B or S signalnot compatible with YoungHelmholtz's theory and Color optics. The output r should be magenta otherwise r and g are not opponent. (B,G,R)=(1,0,0) should be typical blue color. There should be only output b>0. But The above model also yields r>0. 
How to get Unique Colors? See
decomposition of a color:
(B,G,R)=c1*(0,0,1)+c2*(0,1,1)+....c7(1,1,1) for example: (3,5,9)=3*(1,1,1)+2*(0,1,1)+4*(0,0,1)=3*white+2*yellow+4*red Problem is how to get ci, i=1,2,...,7, which cannot be obtained only by additions and subtractions. 

The way out is: using logical operations to replace arithmetic opertions  
Ven's Diagram to show binary logical
operations:
M=RGVRBVBG RM=RED/Cyan;GN=Green/Magenta; BM=Blue/Yellow 

38 decoding model:
Continously logical operations: M=middle(R,G,B)=max(min(R,G),min(R,B),min(R,B)) RM=RED/Cyan;GM=Green/Magenta; BM=Blue/Yellow กก 

New problem is: there are three
pairs of opponent colors.
My explanation: michanism of color vision is evolving. Green/Magenta and Red/Cyan are not apart to much. So when we test opponent signals, we always confuse them each other. 
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Decoding model can unify YoungHelmholtz's theory and Herring's Theory better, and also explain evolution of color vision better  Opponent color signals change wavelength
Critcal test: The decoding model predicts both above opponent signals' existence. The left one exists because color vision is evolving, some low level processes remain. 
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Chenguang Lu survival@163.net
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