MATLAB: How to find color pattern

image processingImage Processing Toolboxmatrix manipulationsignal processing

i am coding trapezoidal fringe pattern and i need color pattern but something being wrong, please help my code is here:
%%trapezoidal color fringes (vertical)
clc;
clear all;
f1=10;                              % No. of vertical fringes
f2=0;                               % No. of horizontal fringes
m=1000;
n=1000;
a1 = zeros(m,n) ;
a2 = zeros(m,n) ;
a3 = zeros(m,n) ;
% trapezoidal fringe
imx=8;
imn=2;
T = 20;
s1= @(x) (imx+imn).*((0<=x & x<=T/6)|(x>=5*T/6 & x<=T))...
                +(imx+imn*(2-6*x/T)).*(T/6<=x & x<=T/3)...
                +(imx).*(T/3<=x & x<=2*T/3)...
                +(imx+imn*(6*x/T-4)).*(2*T/3<=x & x<=5*T/6);
s2= @(x) (imx+imn*(6*x/T)).*(0<=x & x<=T/6)...
                +(imx+imn).*(T/6<=x & x<=T/2)...
                +(imx+imn*(4-6*x/T)).*(T/2<=x & x<=2*T/3)...
                +(imx).*(2*T/3<=x & x<=T);
s3= @(x) (imx).*(0<=x & x<=T/3)...
                +(imx+imn*(6*x/T-2)).*(T/3<=x & x<=T/2)...
                +(imx+imn).*(T/2<=x & x<=5*T/6)...
                +(imx+imn*(6-6*x/T)).*(5*T/6<=x & x<=T);
x = linspace(0,20,50);            
X = repmat(x, 1000, 20);
I1 = s1(X);
I2 = s2(X);
I3 = s3(X);
% figure(1)
% subplot(131),imshow(I1,[])
% subplot(132),imshow(I2,[])
% subplot(133),imshow(I3,[])
a1=exp(1i*I1);
a2=exp(1i*I2);
a3=exp(1i*I3);
subplot(131),imshow(a1,[]),impixelinfo;
subplot(132),imshow(a2,[]),impixelinfo;
subplot(133),imshow(a3,[]),impixelinfo;
Color=zeros(m,n,3);
Color(:,:,1)=a1;
Color(:,:,2)=a2;
Color(:,:,3)=a3;
figure(2)
imshow(Color),title('vertical fringes'),impixelinfo;

Best Answer

Your values are negative so they show up as black because imshow() expects floating point color images to be the in the range 0-1 and anything below 0 is black and anything above 1 is white. Here's a workaround to scale your data using mat2gray():
realColor = mat2gray(real(Color));
imagColor = mat2gray(imag(Color));
figure(2)
imshow(realColor);
figure(3)
imshow(imagColor);
title('vertical fringes'),impixelinfo;
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