图像相邻像素相关性分析

%图像相邻像素相关性
%随机选取图像A中相邻的N个像素点，分别计算在水平，垂直，正对角和反对角方向上的相关系数
%注意是算密文图像 R G B分量分开算 
function r=ImCoef(A,N)
A=double(A);[m,n]=size(A);r=zeros(1,4);
x1=mod(floor(rand(1,N)*10^10),m-1)+1;
x2=mod(floor(rand(1,N)*10^10),m)+1;
x3=mod(floor(rand(1,N)*10^10),m-1)+2;
y1=mod(floor(rand(1,N)*10^10),n-1)+1;
y2=mod(floor(rand(1,N)*10^10),n)+1;
u1=zeros(1,N);u2=zeros(1,N);u3=zeros(1,N);u4=zeros(1,N);
v1=zeros(1,N);v2=zeros(1,N);v3=zeros(1,N);v4=zeros(1,N);
for i=1:N
    u1(i)=A(x1(i),y2(i));v1(i)=A(x1(i)+1,y2(i));
    u2(i)=A(x2(i),y1(i));v2(i)=A(x2(i),y1(i)+1);
    u3(i)=A(x1(i),y1(i));v3(i)=A(x1(i)+1,y1(i)+1);
    u4(i)=A(x3(i),y1(i));v4(i)=A(x3(i)-1,y1(i)+1);
end
r(1)=mean((u1-mean(u1)).*(v1-mean(v1)))/(std(u1,1)*std(v1,1));
r(2)=mean((u2-mean(u2)).*(v2-mean(v2)))/(std(u2,1)*std(v2,1));
r(3)=mean((u3-mean(u3)).*(v3-mean(v3)))/(std(u3,1)*std(v3,1));
r(4)=mean((u4-mean(u4)).*(v4-mean(v4)))/(std(u4,1)*std(v4,1));

figure;
plot(u1,v1,'b.','linewidth',3,'markersize',3);
axis([0 300 0 300]);
set(gca,'XTick',0:50:300,'YTick',0:50:300,'fontsize',18,'fontname','times new roman');
set(gca,'XTickLabel',{
     '0','50','100','150','200','250','300'});
set(gca,'YTickLabel',{
     '0','50','100','150','200','250','300'});
xlabel('Pixel gray value on location(\itx\rm,\ity\rm)');
ylabel('Pixel gray value on location(\itx\rm+1,\ity\rm)');
% figure(102);
% plot(u2,v2,'b.','linewidth',3,'markersize',3);
% axis([0 250 0 250]);
% set(gca,'XTick',0:50:250,'YTick',0:50:250,'fontsize',22,'fontname','times new roman');
% set(gca,'XTickLabel',{
     '0','50','100','150','200','250'});
% set(gca,'YTickLabel',{
     '0','50','100','150','200','250'});
% % xlabel('Pixel gray value on location(\itx\rm,\ity\rm)');
% % ylabel('Pixel gray value on location(\itx\rm,\ity\rm+1)');
% figure(103);
% plot(u3,v3,'b.','linewidth',3,'markersize',3);
% axis([0 250 0 250]);
% set(gca,'XTick',0:50:250,'YTick',0:50:250,'fontsize',22,'fontname','times new roman');
% set(gca,'XTickLabel',{
     '0','50','100','150','200','250'});
% set(gca,'YTickLabel',{
     '0','50','100','150','200','250'});
% % xlabel('Pixel gray value on location(\itx\rm,\ity\rm)');
% % ylabel('Pixel gray value on location(\itx\rm+1,\ity\rm+1)');
% figure(104);
% plot(u4,v4,'b.','linewidth',3,'markersize',3);
% axis([0 250 0 250]);
% set(gca,'XTick',0:50:250,'YTick',0:50:250,'fontsize',22,'fontname','times new roman');
% set(gca,'XTickLabel',{
     '0','50','100','150','200','250'});
% set(gca,'YTickLabel',{
     '0','50','100','150','200','250'});
% %xlabel('Pixel gray value on location(\itx\rm,\ity\rm)');
% %ylabel('Pixel gray value on location(\itx\rm-1,\ity\rm+1)');
end

简单测试一下

彩色明文图像baboon

• R分量

• G分量
  
• B分量
  

密文图像：

• R分量
  
• G分量
  
• B分量