texture_extractor.m

function F = texture_extractor(I)
% @param I gray-level image, should be uint8
% @return F feature vector of I
  level = graythresh(I);
  bw = im2bw(I, level);
% bw = bwareaopen(bw, 50);
  glcm = graycomatrix(bw);
  glcm = glcm + glcm';
  glcm = glcm ./ sum(glcm(:));

  % Get row and colum subscripts of GLCM.
  s = size(glcm);
  [c, r] = meshgrid(1:s(1), 1:s(2));
  c = c(:); r = r(:);
  % calculate features
  F = [];
  F(end+1) = calculateHomogeneity(glcm, r, c);
  F(end+1) = calculateEnergy(glcm);
  F(end+1) = calculateEntropy(glcm);
end

function E = calculateEntropy(glcm)
  glcm = glcm(:);
  foo = -log(glcm);
  foo(foo == Inf) = 0;
  E = sum(glcm .* foo);

end

function E = calculateEnergy(glcm)
  bar = glcm.^2;
  E = sum(bar(:));
end

function H = calculateHomogeneity(glcm, r, c)
  term1 = (1 + abs(r-c));
  term = glcm(:) ./ term1;
  H = sum(term);
end
%% thresholding
%% extract graycomatrix
%% ???憭批?嚗??????唬?銝????%% ?嗅??典???????
%%   憒??????渡??箏?嚗?停銝?????
%%   憒??????典之??????撠梯?蝏抒賒??%  ???閬??銋??