Question

Previously, i wrote a code for Local Binary Pattern(LBP) and Obtained a LBP image and histogram. Now i would like to divide the image into 6×6 matrixes and obtain the LBP image and histogram for each 6×6 matrix. I written the code below. But it doesnt work that well.

    I2=imread('CropF.jpg');
    m=size(I2,1);
    n=size(I2,2);
    counter = 1; 
    for i=2:6:m-1
        for j=2:6:n-1
            for k=i:i+6
               for l=j:j+6
                 J0=I2(k,l);
                 I3(k-1,l-1)=I2(k-1,l-1)>J0;
                 I3(k-1,l)=I2(k-1,l)>J0;
                 I3(k-1,l+1)=I2(k-1,l+1)>J0; 
                 I3(k,l+1)=I2(k,l+1)>J0;
                 I3(k+1,l+1)=I2(k+1,l+1)>J0; 
                 I3(k+1,l)=I2(k+1,l)>J0; 
                 I3(k+1,l-1)=I2(k+1,l-1)>J0; 
                 I3(k,l-1)=I2(k,l-1)>J0;
                 LBP(k,l)=I3(k-1,l-1)*2^7+I3(k-1,l)*2^6+I3(k-1,l+1)*2^5+I3(k,l+1)*2^4+I3(k+1,l+1)*2^3+I3(k+1,l)*2^2+I3(k+1,l-1)*2^1+I3(k,l-1)*2^0;
               end
            end
            LBP=uint8(LBP);
            LBPv=reshape(LBP,1,size(LBP,1)*size(LBP,2));
            Hist=hist(LBPv,0:255);
            Hist1(counter,:)= Hist;
            fname = sprintf('HistInf%03d.mat', counter);      
            save(fullfile(BASE_DIR,fname), 'Hist');     
            counter = counter + 1; 
        end
    end
    save('C:\Users\Lakshmen\Documents\MATLAB\HistInfMain','Hist1');

I have an error like this : ??? Index exceeds matrix dimensions.

Morever, the value for m and n I get is 394 and 330. Hence the value i should get for counter is 55 which is what i get but I get the error said above.

Answer 1

I guess you are still working on the problem from your previous questions.

I am assuming that m and n denote the size of the I2 matrix. If that is the case, then the issue here is with the two inner loops for the k and l variables. They go from the current values of i and j and go up to i+6 and j+6. But i and j themselves can reach m-1 and n-1 respectively thus you get “out of bound” errors.

If I am correct, you need to change the upper bounds of the i,j for-loops:

counter = 1;
Hist1 = [];               %# you can probably pre-allocate a fixed size here
for i=2:6:m-1-6
    for j=2:6:n-1-6
        for k=i:i+6
            for l=j:j+6
                %#...
            end
        end
        %# ...
    end
end
%# ...