LBP人脸识别（最近邻分类器）

function result = lbp(face, radius, number) image = face ; if size(image,3) > 2 image = rgb2gray(image); end d_image=double(image); r = radius ; num = number; spoints = zeros(num,2); a = 2*pi/num; for i = 1:num spoints(i,1) = -r*sin((i-1)*a); spoints(i,2) = r*cos((i-1)*a); end % Determine the dimensions of the input image. [ysize, xsize] = size(image); miny=min(spoints(:,1)); maxy=max(spoints(:,1)); minx=min(spoints(:,2)); maxx=max(spoints(:,2)); % Block size, each LBP code is computed within a block of size bsizey*bsizex bsizey=ceil(max(maxy,0))-floor(min(miny,0))+1; bsizex=ceil(max(maxx,0))-floor(min(minx,0))+1; % Coordinates of origin (0,0) in the block origy=1-floor(min(miny,0)); origx=1-floor(min(minx,0)); % Minimum allowed size for the input image depends % on the radius of the used LBP operator. if(xsize < bsizex || ysize < bsizey) error('Too small input image. Should be at least (2*radius+1) x (2*radius+1)'); end % Calculate dx and dy; dx = xsize - bsizex; dy = ysize - bsizey; % Fill the center pixel matrix C. C = image(origy:origy+dy,origx:origx+dx); d_C = double(C); % bins = 2^num; % Initialize the result matrix with zeros. result=zeros(dy+1,dx+1); %Compute the LBP code image for i = 1:num y = spoints(i,1)+origy; x = spoints(i,2)+origx; % Calculate floors, ceils and rounds for the x and y. fy = floor(y); cy = ceil(y); ry = round(y); fx = floor(x); cx = ceil(x); rx = round(x); % Check if interpolation is needed. if (abs(x - rx) < 1e-6) && (abs(y - ry) < 1e-6) % Interpolation is not needed, use original datatypes N = image(ry:ry+dy,rx:rx+dx); D = N >= C; else % Interpolation needed, use double type images ty = y - fy; tx = x - fx; % Calculate the interpolation weights. w1 = (1 - tx) * (1 - ty); w2 = tx * (1 - ty); w3 = (1 - tx) * ty ; w4 = tx * ty ; % Compute interpolated pixel values N = w1*d_image(fy:fy+dy,fx:fx+dx) + w2*d_image(fy:fy+dy,cx:cx+dx) + ... w3*d_image(cy:cy+dy,fx:fx+dx) + w4*d_image(cy:cy+dy,cx:cx+dx); D = N >= d_C; end % Update the result matrix. v = 2^(i-1); result = result + v*D; end % figure,imshow(result,[]) mapping = getmapping(num,'u2'); bins = mapping.num; for i = 1:size(result,1) for j = 1:size(result,2) result(i,j) = mapping.table(result(i,j)+1); end end % figure,imshow(result,[]) result=hist(result(:),0:(bins-1)); % result=hist(result(:)); result=result/sum(result); end