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how to find color pattern?

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ajeet verma
ajeet verma on 14 Aug 2017
Answered: Image Analyst on 14 Aug 2017
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;
  1 Comment
Stephen23
Stephen23 on 14 Aug 2017
@ajeet verma: today I formatted your code correctly for you. In future you can do it yourself: select the code text, then click the {} Code button.

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Accepted Answer

Image Analyst
Image Analyst on 14 Aug 2017
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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