How do i scan pixel from an rgb image and then if red value is higher than 200 show red only and if its lower = all 3 colors = 0

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Accepted Answer

David Fletcher
David Fletcher on 22 May 2021
Edited: David Fletcher on 22 May 2021
May not be the best answer - I don't do much image manipulation work
%load and display image
imageData=imread('test.jpeg');
subplot(2,1,1)
imshow(imageData);
%Create mask for red colour data >200
redMask=imageData(:,:,1)>200;
%Apply mask to red channel
red=imageData(:,:,1);
red=red.*cast(redMask,'like',imageData);
%Clear colour data from all channels
imageData=imageData*0;
%Replace red channel with the masked data
imageData(:,:,1)=red;
%Show image with red channel mask mask
subplot(2,1,2)
imshow(imageData);
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More Answers (1)

Image Analyst
Image Analyst on 22 May 2021
Try this:
% Find where red value is more than 200.
mask = rgbImage(:, :, 1) > 200;
% Mask the image using bsxfun() function to multiply the mask by each channel individually.
maskedRgbImage = bsxfun(@times, rgbImage, cast(mask, 'like', rgbImage));
  6 Comments
Image Analyst
Image Analyst on 24 May 2021
Edited: Image Analyst on 24 May 2021
In the future, please "Tag" the post as homework if it's homework (I've done it for you now). That tells us not to post full working code, that, if you turn in as your own, may get you into trouble for plagiarism. We wouldn't want you to get into trouble.

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