Why the entropy variable stores the same values of all pictures?

Hi all,

I have a code of matlab works on multiple pictures to calculate grey level co-occurrence matrix for each picture , but when i calculated the entropy vlaues , the vlaues are the same for all pictures .I want to know why this problem .

my code is bleow :

folder='C:\Users\Administrator.1-50-185\Desktop\photos';
I=dir(fullfile(folder,'*.jpg'));
for k=1:numel(I)
    filename=fullfile(folder,I(k).name);
    I2{k}=rgb2gray(imread(filename));
end
for r=1:numel(I)
    [px,py]=size(I2{r});
    cr=27;
    x_start=(px-cr)/2;
    x_stop=x_start+cr;
    y_start=(py-cr)/2;
    y_stop=y_start+cr;
    I3{r}= I2{r}(x_start:x_stop,y_start:y_stop,:);
end
for g=1:numel(I)
    
   for m=1:4
       
      switch(m)
        
          case 1
             glcm_matrix{g,m}=graycomatrix(I3{g},'Offset',[0 1]);
             stats{g,m}=graycoprops(glcm_matrix{g,m},{'contrast','homogeneity','energy','correlation'});
             t{g,m}=struct2table(stats{g,m});
             sum1=sum(sum(glcm_matrix{g,m}));
             entropy1=0;
             dissimilarity1=0;
             for i=1:8
                 for j=1:8
                     if(glcm_matrix{g,m}([i],[j])~=0)
                        entropy1=entropy1+(-(glcm_matrix{g,m}([i],[j]).*(log(glcm_matrix{g,m}([i],[j])))));
                        dissimilarity1=dissimilarity1+(abs(i-j).*glcm_matrix{g,m}([i],[j])/sum1);
                     end
                 end
             end
          case 2
             glcm_matrix{g,m}=graycomatrix(I3{g},'Offset',[-1 1]);
             stats{g,m}=graycoprops(glcm_matrix{g,m},{'contrast','homogeneity','energy','correlation'});
             t{g,m}=struct2table(stats{g,m});
             sum2=sum(sum(glcm_matrix{g,m}));
             entropy2=0;
             dissimilarity2=0;
             for a=1:8
                 for b=1:8
                     if(glcm_matrix{g,m}([a],[b])~=0)
                        entropy2=entropy2-(glcm_matrix{g,m}([a],[b]).*(log(glcm_matrix{g,m}([a],[b]))));
                        dissimilarity2=dissimilarity2+(abs(a-b).*glcm_matrix{g,m}([a],[b])/sum2);

                     end
                 end
             end
          case 3
             glcm_matrix{g,m}=graycomatrix(I3{g},'Offset',[-1 0]);
             stats{g,m}=graycoprops(glcm_matrix{g,m},{'contrast','homogeneity','energy','correlation'});
             t{g,m}=struct2table(stats{g,m});
             sum3=sum(sum(glcm_matrix{g,m}));
             entropy3=0;
             dissimilarity3=0;
             for c=1:8
                 for d=1:8
                     if(glcm_matrix{g,m}([c],[d])~=0)
                        entropy3=entropy3-(glcm_matrix{g,m}([c],[d]).*(log(glcm_matrix{g,m}([c],[d]))));  
                        dissimilarity3=dissimilarity3+(abs(c-d).*glcm_matrix{g,m}([c],[d])/sum3);

                     end
                 end
             end
      
          case 4
             glcm_matrix{g,m}=graycomatrix(I3{g},'Offset',[-1 -1]);
             stats{g,m}=graycoprops(glcm_matrix{g,m},{'contrast','homogeneity','energy','correlation'});
             t{g,m}=struct2table(stats{g,m});
             sum4=sum(sum(glcm_matrix{g,m}));
             entropy4=0;
             dissimilarity4=0;
             for e=1:8
                 for f=1:8
                     if(glcm_matrix{g,m}([e],[f])~=0)
                        entropy4=entropy4-(glcm_matrix{g,m}([e],[f]).*(log(glcm_matrix{g,m}([e],[f]))));
                        dissimilarity4=dissimilarity4+(abs(e-f).*glcm_matrix{g,m}([e],[f])/sum4);

                     end
                 end
             end
                          
      end
      
   end
   
end

excelfilename='chall.xlsx';

 
for sheet=1:7366
    
   for s=1:4
       
      switch(s)
        
          case 1
             xlswrite(excelfilename,glcm_matrix{sheet,s},sheet+2649,'A1:H8');
             writetable(t{sheet,s},'chall.xlsx','sheet',sheet+2649,'Range','J1:M2');
             col_header={'entropy'};
             xlswrite(excelfilename,col_header,sheet+2649,'N1');
             xlswrite(excelfilename,entropy1,sheet+2649,'N2');
             col_header={'dissimilarity'};
             xlswrite(excelfilename,col_header,sheet+2649,'O1');
             xlswrite(excelfilename,dissimilarity1,sheet+2649,'O2');

          case 2
             xlswrite(excelfilename,glcm_matrix{sheet,s},sheet+2649,'A10:H17'); 
             writetable(t{sheet,s},'chall.xlsx','sheet',sheet+2649,'Range','J10:M11');
             col_header={'entropy'};
             xlswrite(excelfilename,col_header,sheet+2649,'N10');
             xlswrite(excelfilename,entropy2,sheet+2649,'N11');
             col_header={'dissimilarity'};
             xlswrite(excelfilename,col_header,sheet+2649,'O10');
             xlswrite(excelfilename,dissimilarity2,sheet+2649,'O11');

          case 3
             xlswrite(excelfilename,glcm_matrix{sheet,s},sheet+2649,'A19:H26');
             writetable(t{sheet,s},'chall.xlsx','sheet',sheet+2649,'Range','J19:M20');
             col_header={'entropy'};
             xlswrite(excelfilename,col_header,sheet+2649,'N19');
             xlswrite(excelfilename,entropy3,sheet+2649,'N20');
             col_header={'dissimilarity'};
             xlswrite(excelfilename,col_header,sheet+2649,'O19');
             xlswrite(excelfilename,dissimilarity3,sheet+2649,'O20');


          case 4
             xlswrite(excelfilename,glcm_matrix{sheet,s},sheet+2649,'A28:H35'); 
             writetable(t{sheet,s},'chall.xlsx','sheet',sheet+2649,'Range','J28:M29');
             col_header={'entropy'};
             xlswrite(excelfilename,col_header,sheet+2649,'N28');
             xlswrite(excelfilename,entropy4,sheet+2649,'N29');
             col_header={'dissimilarity'};
             xlswrite(excelfilename,col_header,sheet+2649,'O28');
             xlswrite(excelfilename,dissimilarity4,sheet+2649,'O29');



      end
      
   end
   
end