How do I change image background to red

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I have an image with black background, which I got from imfreehand function. I want to change that black background to red. Following is link for image.

Accepted Answer

Image Analyst
Image Analyst on 18 Feb 2014
background = grayImage == 0; % Find black pixels.
redChannel = grayImage;
redChannel(background) = 255; % Set black pixels to max value.
% Create true color image.
rgbImage = cat(3, redChannel, grayImage, grayImage);
imshow(rgbImage); % Display it.
Kirti on 21 Feb 2014
I got gray scale Image with red background as per your code. In next step of Image processing I want to binarize only region of Interest keeping red background as it is. but when I apply im2bw all image convert into black and white, even red background. So what is the solution for keeping red background as it is and convert gray image into binary

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More Answers (2)

Ravi Shekhar
Ravi Shekhar on 29 Mar 2018
Hi, you can use following MATLAB code to change the color scheme of a gray image.
gray_image = imread('cameraman.tif');
map = colormap('autumn');
rgb_image = ind2rgb(gray_image,map);
You can get different color schemes under 'colormap' function in MATLAB.

hf fh
hf fh on 19 Sep 2018
Please help me I have an image and I want to make the background color white I used the previous method but did not good out with me
Image Analyst
Image Analyst on 20 Sep 2018
Making the surround white does not make sure there is no noise in the image. And you didn't finish the second part of the sentence about making sure the edges.....are what?

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