How can i extract green rectangle area from the rgb image ?

Question

sufian ahmed 2017-9-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/357796-how-can-i-extract-green-rectangle-area-from-the-rgb-image

回答： Image Analyst 2017-9-22

I have two image. one i take in night and another take in daylight. So i only mask the region where green pixels exists. but problem is that for every image i need to change the value. how can i fix it the same value for all images.

Im = imread('4.jpg');
figure,imshow(Im);
lab = rgb2lab(Im);
figure,imshow(Im);
% Im = imresize(Im, [512 512]);
%  figure,imshow(lab(:,:,2));
   I1=lab(:,:,2);
    I2=lab(:,:,3);
    I3=lab(:,:,1);
   mask1=I1>-50 & I1<0 ;
   mask2=I2>30 & I2<50;
   mask =I3 & mask1 & mask2;
%  mask=mask1 ;
   figure,imshow(mask);
     diff_im = im2bw(mask,0.18);
      figure,imshow(diff_im);