calculate the area percent of non white pixel in the image

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

Answer 1

[Image Analyst]

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

[Sumit Chaudhary]

i have attached the image and will take care not to repeat in the future. By green mean to say that any region in the 5 sub images where we see greensih, brownish, reddish tint.

[Sumit Chaudhary]

gray= rgb2gray(I); [x y] = size( gray); imshow(gray);

now this gray intensities are my region of interest.

[Image Analyst]

Use my hue segmentation tool here: https://www.mathworks.com/matlabcentral/fileexchange/28512-simplecolordetectionbyhue-- to find any green items.

You can also use the Color Thresholder app on the Apps tab of the MATLAB toolribbon to find green things. Use HSV color space.