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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Moe Makki 2021-5-22

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https://ww2.mathworks.cn/matlabcentral/answers/836838-how-do-i-scan-pixel-from-an-rgb-image-and-then-if-red-value-is-higher-than-200-show-red-only-and-if

评论： Moe Makki 2021-5-24

采纳的回答： David Fletcher

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David Fletcher 2021-5-22

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https://ww2.mathworks.cn/matlabcentral/answers/836838-how-do-i-scan-pixel-from-an-rgb-image-and-then-if-red-value-is-higher-than-200-show-red-only-and-if#answer_705998

编辑：David Fletcher 2021-5-22

在 MATLAB Online 中打开

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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Moe Makki 2021-5-23

oops my bad there was an error with imshow i replaced it with the same picture

Moe Makki 2021-5-23

Thanks for your help appreciated.

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Image Analyst 2021-5-22

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https://ww2.mathworks.cn/matlabcentral/answers/836838-how-do-i-scan-pixel-from-an-rgb-image-and-then-if-red-value-is-higher-than-200-show-red-only-and-if#answer_706028

在 MATLAB Online 中打开

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));

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Image Analyst 2021-5-24

编辑：Image Analyst 2021-5-24

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.

Moe Makki 2021-5-24