运用CS-LBP提取裂纹的梯度特征

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        目前对CS-LBP 的理解是CS-LBP只能描述电池片裂纹的梯度特征:CS-LBP值的大小代表的是方向,每一个值出现的频率代表的大小。CS-LBP作为一种特征描述的方法,所提取的特征向量维数小,并且对锑度变化响应明显,这也就是为什莫选用它作为裂纹特征提取主要原因。而缺点只能描述梯度特征,一旦噪声干扰与裂纹有相似的锑度变化,CS-LBP就不能很好的分辨出到底是背景还是裂纹。这是目前针对裂纹这缺陷效果低的主要原因。现在对研究的最新理解是,创新之处一定是针对所要解决的问题。所要解决的问题也要明确,像CS-LBP对于锑度变化相似的裂纹和背景区分度就不高,这就是要解决的核心问题,并非是非均匀纹理背景下的缺陷分类,非均匀纹理背景还是太大。

        解决方案目前想到了两种,一种是用采用减少类间距,增加类间间距的方法。另一种是提取裂纹的专有特征,即有针对性的提取特征。

CS-LBP 的简单理解及实现:CS-LBP利用关于中心像素对称位置的像素大小关系进行二进制编码,再将这个二进制数映射成十进制数,属于将像素信息映射到了空间域。这种方法利用了图像的中心对称差分信息,也就是梯度信息,对梯度响应明显。

源码是我在LBP基础上改的(matlab写的):CSDN为啥插入的图片不能显示,真他妈气人。

% % function result = cslbp(image,radius,neighbors)
% clc 
% clear 
% close all
% image = imread('E:\裂纹\25乘25测试\194.jpg');
% figure;
% imshow(image)
% image = rgb2gray(image);
% image = mat2gray(image);
% radius = 1;
% neighbors = 8;
% d_image = double(image);
% 
% % [m,n] = size(I);
% % dst = zeros(m-2*radius,n-2*radius);
% % for i = radius+1:(m-radius)
% %     for j = radius+1:(n-radius)
% %     lbpcircle = [];
% %     center = I(i,j);
% %     lbpvalue = 0;
% %         for k = 1:neighbors
% %             x = i+radius*cos(2*pi*k/neighbors);
% %             y = j-radius*sin(2*pi*k/neighbors);
% %             x1 = floor(x);
% %             y1 = floor(y);
% %             x2 = ceil(x);
% %             y2 = ceil(y);
% %             rx = round(x);
% %             ry = round(y);
% %             if abs(x-rx)<1e-6 && abs(y-ry)<1e-6
% %                 lbpcircle(k) = I(rx,ry);
% %             else
% %                 tx = x-x1;
% %                 ty = y-y1;
% %                 w1 = roundn((1-tx)*(1-ty),-6);
% %                 w2 = roundn(tx*(1-ty),-6);
% %                 w3 = roundn((1-tx)*ty,-6);
% %                 w4 = roundn(tx*ty,-6);
% %                 lbpcircle(k) = I(x1,y1)*w1 + I(x1,y2)*w2 + I(x2,y1)*w3 + I(x2,y2)*w4;
% %             end
% %         end
% %                 lbpvalue = (lbpcircle(1)>=lbpcircle(5))*2^0 + (lbpcircle(2)>=lbpcircle(6))*2^1 +(lbpcircle(3)>=lbpcircle(7))*2^2 +...
% %             (lbpcircle(4)>=lbpcircle(8))*2^3;
% %             I(i,j) =lbpvalue;
% %     end
% % end
% % I
% 
%     spoints=zeros(neighbors,2);
% 
%     % Angle step.
%     a = 2*pi/neighbors;
%     
%     for i = 1:neighbors
%         spoints(i,1) = -radius*sin((i-1)*a);
%         spoints(i,2) = radius*cos((i-1)*a);
%     end
%     [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; %3
% bsizex=ceil(max(maxx,0))-floor(min(minx,0))+1; %3
% 
% % Coordinates of origin (0,0) in the block
% origy=1-floor(min(miny,0)); %2
% origx=1-floor(min(minx,0)); %2
% dx = xsize - bsizex; %22
% dy = ysize - bsizey; %22
% 
% % Fill the center pixel matrix C.
% C = image(origy+dy,origx+dx); %2:24,2:24
% d_C = double(C); 
% 
% bins = 2^neighbors;  %256
% 
% % Initialize the result matrix with zeros.
% result=zeros(dy+1,dx+1); %23*23
% 
% %Compute the LBP code image
% 
%         
%         for i = 1:neighbors
%               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,rx);
%                         D = N >= C; 
%                   else
%                         % Interpolation needed, use double type images 
%                         ty = y - fy;
%                         tx = x - fx;
% 
%                         % Calculate the interpolation weights.
%                         w1 = roundn((1 - tx) * (1 - ty),-6);
%                         w2 = roundn(tx * (1 - ty),-6);
%                         w3 = roundn((1 - tx) * ty,-6) ;
%                         % w4 = roundn(tx * ty,-6) ;
%                         w4 = roundn(1 - w1 - w2 - w3, -6);
% 
%                         % Compute interpolated pixel values
%                         N = w1*d_image(fy,fx) + w2*d_image(fy,cx) + ...
%                     w3*d_image(cy,fx) + w4*d_image(cy,cx);
%                         N = roundn(N,-4);
%                         D = N >= d_C; 
%             end
%           v = 2^(i-1);
%           result = result + v*D;
%         end
%     end
% end
%LBP returns the local binary pattern image or LBP histogram of an image.
%  J = LBP(I,R,N,MAPPING,MODE) returns either a local binary pattern
%  coded image or the local binary pattern histogram of an intensity
%  image I. The LBP codes are computed using N sampling points on a 
%  circle of radius R and using mapping table defined by MAPPING. 
%  See the getmapping function for different mappings and use 0 for
%  no mapping. Possible values for MODE are
%       'h' or 'hist'  to get a histogram of LBP codes
%       'nh'           to get a normalized histogram
%  Otherwise an LBP code image is returned.
%
%  J = LBP(I) returns the original (basic) LBP histogram of image I
%
%  J = LBP(I,SP,MAPPING,MODE) computes the LBP codes using n sampling
%  points defined in (n * 2) matrix SP. The sampling points should be
%  defined around the origin (coordinates (0,0)).
%
%  Examples
%  --------
%       I=imread('rice.png');
%       mapping=getmapping(8,'u2'); 
%       H1=LBP(I,1,8,mapping,'h'); %LBP histogram in (8,1) neighborhood
%                                  %using uniform patterns
%       subplot(2,1,1),stem(H1);
% 
%       H2=LBP(I);
%       subplot(2,1,2),stem(H2);
% 
%       SP=[-1 -1; -1 0; -1 1; 0 -1; -0 1; 1 -1; 1 0; 1 1];
%       I2=LBP(I,SP,0,'i'); %LBP code image using sampling points in SP
%                           %and no mapping. Now H2 is equal to histogram
%                           %of I2.

function [result,lbpimage] = cslbp(varargin) % image,radius,neighbors,mapping,mode)
% Version 0.3.3
% Authors: Marko Heikkil?and Timo Ahonen

% Changelog
% Version 0.3.2: A bug fix to enable using mappings together with a
% predefined spoints array
% Version 0.3.1: Changed MAPPING input to be a struct containing the mapping
% table and the number of bins to make the function run faster with high number
% of sampling points. Lauge Sorensen is acknowledged for spotting this problem.


% Check number of input arguments.
error(nargchk(1,5,nargin));

image=varargin{1};
d_image=double(image);

if nargin==1
    spoints=[-1 -1; -1 0; -1 1; 0 -1; 0 1; 1 -1; 1 0; 1 1];
    neighbors=8;
    mapping=0;
    mode='h';
end

if (nargin == 2) && (length(varargin{2}) == 1)
    error('Input arguments');
end

if (nargin > 2) && (length(varargin{2}) == 1)
    radius=varargin{2};
    neighbors=varargin{3};
    
    spoints=zeros(neighbors,2);

    % Angle step.
    a = 2*pi/neighbors;
    
    for i = 1:neighbors
        spoints(i,1) = -radius*sin((i-1)*a);
        spoints(i,2) = radius*cos((i-1)*a);
    end
    
    if(nargin >= 4)
        mapping=varargin{4};
        if(isstruct(mapping) && mapping.samples ~= neighbors)
            error('Incompatible mapping');
        end
    else
        mapping=0;
    end
    
    if(nargin >= 5)
        mode=varargin{5};
    else
        mode='h';
    end
end

if (nargin > 1) && (length(varargin{2}) > 1)
    spoints=varargin{2};
    neighbors=size(spoints,1);
    
    if(nargin >= 3)
        mapping=varargin{3};
        if(isstruct(mapping) && mapping.samples ~= neighbors)
            error('Incompatible mapping');
        end
    else
        mapping=0;
    end
    
    if(nargin >= 4)
        mode=varargin{4};
    else
        mode='h';
    end   
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; %3
bsizex=ceil(max(maxx,0))-floor(min(minx,0))+1; %3

% Coordinates of origin (0,0) in the block
origy=1-floor(min(miny,0)); %2
origx=1-floor(min(minx,0)); %2

% 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; %22
dy = ysize - bsizey; %22

% Fill the center pixel matrix C.
C = image(origy:origy+dy,origx:origx+dx); %2:24,2:24
d_C = double(C); 

bins = 2^4;  %256

% Initialize the result matrix with zeros.
result=zeros(dy+1,dx+1); %23*23

%Compute the LBP code image

for i = 1:neighbors
  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(1:dy+1,1:dx+1,i) = image(ry:ry+dy,rx:rx+dx);
    D = N(1:dy+1,1:dx+1,i) >= C; 
  else
    % Interpolation needed, use double type images 
    ty = y - fy;
    tx = x - fx;

    % Calculate the interpolation weights.
    w1 = roundn((1 - tx) * (1 - ty),-6);
    w2 = roundn(tx * (1 - ty),-6);
    w3 = roundn((1 - tx) * ty,-6) ;
    % w4 = roundn(tx * ty,-6) ;
    w4 = roundn(1 - w1 - w2 - w3, -6);
            
    % Compute interpolated pixel values
    N(1:dy+1,1:dx+1,i) = 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);
    N(1:dy+1,1:dx+1,i) = roundn(N(1:dy+1,1:dx+1,i),-4);
%     D = N >= d_C; 
  end  
  % Update the result matrix.
%   v = 2^(i-1);
%   result = result + v*D;
end
%   result = result + ((N(1:dy+1,1:dx+1,1)+N(1:dy+1,1:dx+1,5))/2<d_C)*2^0+((N(1:dy+1,1:dx+1,2)+N(1:dy+1,1:dx+1,6))/2<d_C)*2^1+...
%       ((N(1:dy+1,1:dx+1,3)+N(1:dy+1,1:dx+1,7))/2<d_C)*2^2+((N(1:dy+1,1:dx+1,4)+N(1:dy+1,1:dx+1,8))/2<d_C)*2^3;
%     resultaverge = (N(1:dy+1,1:dx+1,1)+N(1:dy+1,1:dx+1,2)+N(1:dy+1,1:dx+1,3)+N(1:dy+1,1:dx+1,4)+N(1:dy+1,1:dx+1,5)+...
%         N(1:dy+1,1:dx+1,6)+N(1:dy+1,1:dx+1,7)+N(1:dy+1,1:dx+1,8))/8;
%         image_o = d_image(fy:fy+dy,fx:fx+dx);
%     result = result + (resultaverge(1:dy+1,1:dx+1)>image_o(1:dy+1,1:dx+1))*2^0+(N(1:dy+1,1:dx+1,1)>N(1:dy+1,1:dx+1,5))*2^1+(N(1:dy+1,1:dx+1,2)>N(1:dy+1,1:dx+1,6))*2^2+...
%       (N(1:dy+1,1:dx+1,3)>N(1:dy+1,1:dx+1,7))*2^3+(N(1:dy+1,1:dx+1,4)>N(1:dy+1,1:dx+1,8))*2^4;
     result = result + (N(1:dy+1,1:dx+1,1)>=N(1:dy+1,1:dx+1,5))*2^0+(N(1:dy+1,1:dx+1,2)>=N(1:dy+1,1:dx+1,6))*2^1+...
       (N(1:dy+1,1:dx+1,3)>=N(1:dy+1,1:dx+1,7))*2^2+(N(1:dy+1,1:dx+1,4)>=N(1:dy+1,1:dx+1,8))*2^3;

  lbpimage = result; %126*126原图(128*128)
%Apply mapping if it is defined
if isstruct(mapping)
    bins = mapping.num;
    for i = 1:size(result,1) %23
        for j = 1:size(result,2) %23
            result(i,j) = mapping.table(result(i,j)+1);  %mapping之后的结果
        end
    end
end

if (strcmp(mode,'h') || strcmp(mode,'hist') || strcmp(mode,'nh'))
    % Return with LBP histogram if mode equals 'hist'.
    result=hist(result(:),0:(bins-1));
    if (strcmp(mode,'nh'))
        result=result/sum(result);
    end
else
    %Otherwise return a matrix of unsigned integers
    if ((bins-1)<=intmax('uint8'))
        result=uint8(result);
    elseif ((bins-1)<=intmax('uint16'))
        result=uint16(result);
    else
        result=uint32(result);
    end
end

end

function x = roundn(x, n)

error(nargchk(2, 2, nargin, 'struct'))
validateattributes(x, {'single', 'double'}, {}, 'ROUNDN', 'X')
validateattributes(n, ...
    {'numeric'}, {'scalar', 'real', 'integer'}, 'ROUNDN', 'N')

if n < 0
    p = 10 ^ -n;
    x = round(p * x) / p;
elseif n > 0
    p = 10 ^ n;
    x = p * round(x / p);
else
    x = round(x);
end

end



 

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