How do I correct my colors in my indexed image displayed with image() function?
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For this problem I needed to code an image that contains five different colors placed in different places in a 40 x 40. My code gets the image to print, but the colors are wrong. There are different colors, but they are all variations of purple. I am not sure what I am doing wrong and what I need to do to fix it. I tried retyping the code and redoing the figure, but it didn't help. I also tried to look up several solutions and nothing I came across helped. I tried with variable names, numbers, colormap, no colormap, and I am not sure how to fix it. Help would be greatly appreciated. Thank you in advance!
Guidelines:
My Figure:
My Code:
teal = [0.08,0.25,0.3];
black = [0,0,0];
red = [1,0,0];
darkred = [0.24,0.008,0.008];
% 1 == teal;
% 2 == black;
% 3 == red;
% 4 == darkred;
% myColors = [teal; black; red; darkred];
%
% colormap(myColors)
pixelPicture = ones(40,40);
pixelPicture(1:10,1:5) = 1;
pixelPicture(11:20,1:5) = 4;
pixelPicture(21:40,1:5) = 1;
pixelPicture(1:5,6:10) = 4;
pixelPicture(6:40,6:10) = 1;
pixelPicture(1:5,11:15) = 1;
pixelPicture(6:10,11:15) = 4;
pixelPicture(11:15,11:15) = 1;
pixelPicture(16:20,11:15) = 3;
pixelPicture(21:25,11:15) = 4;
pixelPicture(26:30,11:15) = 1;
pixelPicture(31:40,11:15) = 2;
pixelPicture(1:15,16:20) = 1;
pixelPicture(16:25,16:20) = 3;
pixelPicture(26:40,16:20) = 1;
pixelPicture(1:15,21:25) = 1;
pixelPicture(16:20,21:25) = 3;
pixelPicture(21:25,21:25) = 4;
pixelPicture(26:40,21:25) = 1;
pixelPicture(1:5,26:30) = 1;
pixelPicture(6:10,26:30) = 4;
pixelPicture(11:15,26:30) = 1;
pixelPicture(16:25,26:30) = 4;
pixelPicture(26:30,26:30) = 1;
pixelPicture(31:40,26:30) = 2;
pixelPicture(1:5,31:35) = 4;
pixelPicture(6:40,31:35) = 1;
pixelPicture(1:10,36:40) = 1;
pixelPicture(11:15,36:40) = 3;
pixelPicture(16:20,36:40) = 4;
pixelPicture(21:40,36:40) = 1;
figure(2);
image(pixelPicture)
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Accepted Answer
Image Analyst
on 18 Nov 2022
You aren't calling colormap function - it's commented out and was appearing before you displayed anything. This works fine:
teal = [0.08,0.25,0.3];
black = [0,0,0];
red = [1,0,0];
darkred = [0.24,0.008,0.008];
% 1 == teal;
% 2 == black;
% 3 == red;
% 4 == darkred;
pixelPicture = ones(40,40);
pixelPicture(1:10,1:5) = 1;
pixelPicture(11:20,1:5) = 4;
pixelPicture(21:40,1:5) = 1;
pixelPicture(1:5,6:10) = 4;
pixelPicture(6:40,6:10) = 1;
pixelPicture(1:5,11:15) = 1;
pixelPicture(6:10,11:15) = 4;
pixelPicture(11:15,11:15) = 1;
pixelPicture(16:20,11:15) = 3;
pixelPicture(21:25,11:15) = 4;
pixelPicture(26:30,11:15) = 1;
pixelPicture(31:40,11:15) = 2;
pixelPicture(1:15,16:20) = 1;
pixelPicture(16:25,16:20) = 3;
pixelPicture(26:40,16:20) = 1;
pixelPicture(1:15,21:25) = 1;
pixelPicture(16:20,21:25) = 3;
pixelPicture(21:25,21:25) = 4;
pixelPicture(26:40,21:25) = 1;
pixelPicture(1:5,26:30) = 1;
pixelPicture(6:10,26:30) = 4;
pixelPicture(11:15,26:30) = 1;
pixelPicture(16:25,26:30) = 4;
pixelPicture(26:30,26:30) = 1;
pixelPicture(31:40,26:30) = 2;
pixelPicture(1:5,31:35) = 4;
pixelPicture(6:40,31:35) = 1;
pixelPicture(1:10,36:40) = 1;
pixelPicture(11:15,36:40) = 3;
pixelPicture(16:20,36:40) = 4;
pixelPicture(21:40,36:40) = 1;
figure(2);
image(pixelPicture)
impixelinfo
myColors = [teal; black; red; darkred];
colormap(myColors)
colorbar
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