How can I change a pixel image from black and white to red & blue

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Yik lok  Chan
Yik lok Chan on 19 Nov 2021
Commented: yanqi liu on 1 Dec 2021
How can I change a pixel image from black and white to red & blue? The image present a letter 'H' with black and white but I want to change the colour into red & blue. ( testmap is my martix name)
0.2143 0.3395 0.4173 0.3642 0.4025 0.5045
0.4403 1.0000 0.2445 0.2729 1.0000 0.4498
0.4804 1.0000 0.2292 0.2102 1.0000 0.4223
0.3724 1.0000 1.0000 1.0000 1.0000 0.3090
0.4783 1.0000 0.5504 0.3024 0.5916 0.3535
0.5192 1.0000 0.2271 0.3599 1.0000 0.4186
0.3193 0.2616 0.4490 0.2360 0.3270 0.5178
imshow(testmap(:,:,1), 'InitialMagnification' ,2000);

Answers (1)

Robert U
Robert U on 19 Nov 2021
Hi Yik lok Chan,
one way to do so is to utilize colormap()-command:
corn_gray = imread('corn.tif',3);
imshow(corn_gray)
map = [linspace(1,0,256)', zeros(256,1), linspace(0,1,256)'];
figure;
imshow(corn_gray,'Colormap',map)
Kind regards,
Robert
  1 Comment
yanqi liu
yanqi liu on 1 Dec 2021
yes,sir,use Robert U method,can get
clc; clear all; close all;
testmap=[0.2143 0.3395 0.4173 0.3642 0.4025 0.5045
0.4403 1.0000 0.2445 0.2729 1.0000 0.4498
0.4804 1.0000 0.2292 0.2102 1.0000 0.4223
0.3724 1.0000 1.0000 1.0000 1.0000 0.3090
0.4783 1.0000 0.5504 0.3024 0.5916 0.3535
0.5192 1.0000 0.2271 0.3599 1.0000 0.4186
0.3193 0.2616 0.4490 0.2360 0.3270 0.5178];
imagesc(testmap(:,:,1));
% red & blue
map=[linspace(1,0,256)', zeros(256,1), linspace(0,1,256)'];
colormap(map); axis equal; axis off;

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