MATLAB: Can blkproc function is used in LBP

digital image processingImage Processing Toolboxlbp

can you explain me fun function in blkproc below:
I = imread('liftingbody.png');
fun = @(x) std2(x)*ones(size(x));
I2 = blkproc(I,[32 32],fun);
figure, imshow(I), figure, imshow(I2,[])
what the function of 'fun' if I use LBP?
thx before

Best Answer

You can use the nlfilter function to implement this. It will be slow, though. Here's a mocked up implementation that you could try:
function out = computeLLBP(im,kernel_width)
%COMPUTELLBP - Compute Local Line Binary Pattern of an image.
validateattributes(im,{'numeric'},{'2d'},mfilename,'im',1);
validateattributes(kernel_width,{'numeric'},{'odd','numel',2},mfilename,'kernel_width',2);
out = nlfilter(im,kernel_width,@processLLBP);
      function c = processLLBP(block)
          sz     = size(block);
          center = (sz+1)/2;
          vertical   = block(:        ,center(2))>block(center(1),center(2));
          horizontal = block(center(1),:        )>block(center(1),center(2));
          llbpv = bin2dec(       (int2str(vertical(1          :center(2)-1)))') +...
                  bin2dec(fliplr((int2str(vertical(center(2)+1:end        )))'));
          llbph = bin2dec(       int2str(horizontal(1          :center(1)-1))) +...
                  bin2dec(fliplr(int2str(horizontal(center(1)+1:end        ))));    
          c = hypot(llbpv,llbph);  
      end
  end
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