how to change pixels value of a color image according to thresholding?

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kristie bell 2015-3-23

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https://ww2.mathworks.cn/matlabcentral/answers/184536-how-to-change-pixels-value-of-a-color-image-according-to-thresholding

编辑： kristie bell 2015-3-23

Hi guys,

I needed some help with my current code. What i wanted to do is to read in a colour image, change it to grayscale and enhance the color using thresholding (like pixel values of 4 i want it to be enhanced to 10 etc). Then i wanted to map back to the color image.

I understand that i am currently using 0-255 threshold values on a grayscale level, but if i were to manipulate the values on pixels(:,:,1), how can i use something that is equivalent?

I could not get back the color image.

May i know how could this be done? Any help will be appreciated! Thanks!

below is my code:

%color image pixels = imread('new_matched_area.jpg');

% allocate space for image %image_2 = zeros(size(pixels)); image_1 = zeros(size(pixels));

image_thresholded = pixels(:,:,1);

image_2 = rgb2gray(pixels);

tic % perform thresholding by logical indexing %image_thresholded = image_2; image_thresholded(image_2>250) = 256; image_thresholded(image_2>=100 & image_2<=110) = 155; image_thresholded(image_2>=10 & image_2<11) = 130; image_thresholded(image_2>=9 & image_2<10) = 120; image_thresholded(image_2>=8 & image_2<9) = 110; image_thresholded(image_2>=7 & image_2<8) = 100; image_thresholded(image_2>=6 & image_2<7) = 70; image_thresholded(image_2>=5 & image_2<6) = 60; image_thresholded(image_2>=4 & image_2<5) = 40; image_thresholded(image_2>=3 & image_2<4) = 10; image_thresholded(image_2<2) = 5; image_thresholded = image_1; %image_thresholded(image_2<0.5) = 0; image_2 = cat (3, pixels(:,:,1) +pixels(:,:,2) +pixels(:,:,3));

toc % display result figure(1), imshow(image_1) figure(2),imshow(pixels) figure(3),imshow(image_2) title('thresholded image')