calculate the area percent of non white pixel in the image

Question

Sumit Chaudhary 2018-3-25

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https://ww2.mathworks.cn/matlabcentral/answers/390556-calculate-the-area-percent-of-non-white-pixel-in-the-image

评论： Image Analyst 2018-3-25

In an ongoing project of mine, i have to calculate the area percent of all the pixel having not white coloration. The color is basically green and the shades of green. I have written code for area percentage for green coloration but it dont seem to work. The area percentage it is showing for all the 5 sub images to be 0.33 . Please help me out. I read something related to pure rgb color. Please tell how to check in my image the colors are pure or not.

    I = imread('image.jpg');  
    av = zeros(1,5);
          for i = 1:5 
              imshow(I) ;
              [rgbImage, rect] = imcrop(I);  
              imwrite(rgbImage,strcat(num2str(i),'.jpg')) ;  
              greenChannel = rgbImage(:, :, 2);
              [rows, columns] = size(rgbImage);
              greenCount = sum(greenChannel(:) > 0);
              greenareapercent(i)= greenCount / (rows * columns);
          end

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Answer 1

Image Analyst 2018-3-25

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https://ww2.mathworks.cn/matlabcentral/answers/390556-calculate-the-area-percent-of-non-white-pixel-in-the-image#answer_311869

Unfortunately you haven't read this link, and so haven't included 'image.jpg'.

I don't know what your definition of green is. Is it any pixel in which the green signal is more than the red and blue signal? Is it only pixels with an RGB value of (0, 255, 0)?

About all I can say is to convert your image to HSV with rgb2hav, and threshold on the hue channel to get pixels with a green hue. See color segmentation demos in my File Exchange for demos https://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862&sort=downloads_desc