can blkproc function is used in LBP?

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

Answer 1

[Anand]

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

[elfrida]

can you give me the function of @processLLBP ?

[Anand]

Its a nested function thats defined right after the call to nlfilter in the code above.

Answer 2

[Image Analyst]

It takes the standard deviation of a block and replaces every pixel in the block with the standard deviation of that block.