Finding Normalized 3 bins Histogram code

 histogram(dgri_foto,3);
 title(' 3 bins histogram');
[h_variable,h]=hist(dgri_foto,3); 
 [width, height]=size(dgri_foto);
 total_pixel=height*width;
 disp(['Total Number of Pixels:' num2str(total_pixel)]);
Total Number of Pixels:307200
normalized_hist=(h_variable/sum(h_variable))*total_pixel;
 display(normalized_hist);
normalized_hist =
   1.0e+05 *
    2.7662
    0.1508
    0.1550 
 figure;
 bar(h,h_variable,'hist');
subplot(1,2,2);
imshow(dgri_foto);
title('grayscale image');
subplot(1,2,1);
bar(h,h_variable,'hist');
title('normalized 3 bins');
darker1=0;
darker2=0.3;
medium1=0.44;
medium2=0.62;
lighter1=0.77;
lighter2=0.95;

darkerint= dgri_foto >= darker1 & dgri_foto <= darker2;
mediumint= dgri_foto >= medium1 & dgri_foto <= medium2;
lightint= dgri_foto >= lighter1 & dgri_foto <= lighter2;


numof_dark= nnz(darkerint);
numof_med= nnz(mediumint);
numof_light= nnz(lightint);

tot_pixelnum= numel(dgri_foto);
perc_of_dark=(numof_dark/tot_pixelnum)*100;
perc_of_med=(numof_med/tot_pixelnum)*100;
perc_of_light=(numof_light/tot_pixelnum)*100;

>> display(perc_of_dark);

perc_of_dark =

   89.4391

>> display(perc_of_med);

perc_of_med =

    2.5924

>> display(perc_of_light);

perc_of_light =

    2.6406