Hi Smruti, the below code might help as you want "to extract the part of original image based on pixel values the output will be same image with threshold 200 and other blacken".
img = imread('peppers.png');
[r, c, b] = size(img);
th_img = uint8(zeros(r,c,b));
th = 100; % Put your threshold here
for i = 1:r
for j = 1:c
if img(i, j, :) > th
th_img(i, j, :) = img(i, j, :);
end
end
end
figure, imshowpair(img, th_img, 'montage');
