仿真代码之三

部分仿真代码，供参考

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% designedbylilizong
% lilizong[at]gmail


a = imread( ' c:bbb.png ' ); % 读入图像
figure,imshow(a),title( ' 原图像 ' ); % 显示图像
figure,imhist(a);
b = a(:);
[m,n] = size(a);
k = size(b);
% 下述操作可以实现像素的显示
c = linspace( 0 , 0 , 256 );
for i = 1 :k
for j = 1 : 256
if (b(i) == j)
c(j) = c(j) + 1 ;
end
end
end
% 以下步骤简单实现读取整个图像的峰值点

max = c( 1 );
maxi = 0 ;
for i = 1 : 256
if (c(i) > max)
max = c(i);
maxi = i;
end
end
max
maxi




% 下面步骤实现对各个峰值的读取
d = c; % 作为临时操作数组，以不破坏原数组
emax = linspace( 0 , 0 , 256 );
emaxi = linspace( 0 , 0 , 256 );
a = 1 ;
for j = 2 : 256
if (d(j) > d(j - 1 ) & d(j) > d(j + 1 ) & d(j) ~= 8888 )
emax(a) = d(j);
emaxi(a) = j;
d(j) = 8888 ;
a = a + 1 ; % 开始没有想明白，用额外的循环变量
end
end


% 下面的程序读取四个高峰值，并进行显示
fmax = linspace( 0 , 0 , 10 );
fmaxi = linspace( 0 , 0 , 10 );
bnum = 1 ;
for i = 1 : 10
fmax(bnum) = emax( 1 );
for j = 2 : 256
if (emax(j) > fmax(bnum))
fmax(bnum) = emax(j);
fmaxi(bnum) = emaxi(j);
t = j;
end
end
emax(t) = 0 ;
bnum = bnum + 1 ;
end


for i = 1 : 10
fmax(i)
fmaxi(i)
end

% 至此峰值已经提出出来了







% 在第一个峰值嵌入水印
% 首先把小于最大的像素值的都减去2
cc = zeros(m,n);
c = cc(:);

for i = 1 :k
if (b(i) < fmax( 1 ))
c(i) = b(i) - 2 ;
end
end

watermark = imread( ' c:watermark.png ' );
figure,imshow(watermark);
[w1,w2] = size(watermark);
watermark_line = watermark(:);
oo = w1 * w2;

% 开始嵌入水印

% 第一次水印

tt = 1 ; % 让tt加1来遍历整个水印图像
for i = 1 :k
if (c(i) == fmax( 1 ))
if (tt > oo)
tt = 1 ; % 如果超出水印的范围从头开始
if (watermark_line(tt) == 1 )
c(i) = c(i) - 1 ;
end

end
tt = tt + 1 ;
end
end



% 第二次水印
tt = 1 ; % 让tt加1来遍历整个水印图像
for i = 1 :k
if (c(i) == fmax( 2 ))
if (tt > oo)
tt = 1 ; % 如果超出水印的范围从头开始
if (watermark_line(tt) == 1 )
c(i) = c(i) - 2 ;
end
end
tt = tt + 1 ;
elseif(c(i) == fmax( 2 ) + 1 )
if (tt > oo)
tt = 1 ;
if (watermar_line(tt) == 1 )
c(i) = c(i) - 2 ;
end
end
end
end









% 显示嵌入水印的图像


embed = c;
embed = reshape(c,m,n);
figure,imshow(embed,[]),title( ' 嵌入水印的图像 ' );


% 提取水印

% 提取第一层

for i = 1 :k
if (c(i) == fmax( 2 ))
watermark(tt) = 0 ;
% tt = tt + 1 ;
% elseif(c(i) == (fmax( 1 ) + 1 ))
% watermark(tt) = 0 ;
% tt = tt + 1 ;
% elseif(c(i) = fmax( 1 ) - 1 )
% elseif(c(i) = fmax( 1 ) - 1 )
% watermark(tt) = 1 ;
% tt = tt + 1 ;
% elseif(c(i) = fmax( 1 ) - 2 )
% watermark(tt) = 1 ;
% tt = tt + 1 ;
% end
else
if (c(i) == fmax( 2 ) + 1 )
watermark(tt) = 0 ;
else
if (c(i) == fmax( 2 ) - 1 )
watermark(tt) = 1 ;
else
if (c(i) == fmax( 2 ) - 2 )
watermark = 1 ;
end
end
end
tt = tt + 1 ;
end
end


% 提取第二层


for i = 1 :k
if (c(i) == fmax( 1 ))
watermark(tt) = 0 ;
tt = tt + 1 ;
elseif(c(i) == (fmax( 1 ) - 1 ))
watermark(tt) = 1 ;
tt = tt + 1 ;
end
end
for i = 1 :oo
watermark_dect(i) = watermark(i);
end











for i = 1 :oo
watermark_dect(i) = watermark(i);
end
watermark_dect = reshape(watermark_dect,w1,w2);
figure,imshow(watermark_dect,[]),title( ' 提取出来的水印 ' );


% 恢复原图像
dd = embed(:);
for i = 1 :k
if (c(i) == (max - 2 ))
c(i) = c(i) + 2 ;
elseif(c(i) < max - 2 )
c(i) = c(i) + 2 ;
end
end
dd = reshape(c,m,n);
figure,imshow(dd,[]),title( ' 恢复的图像 ' );



a = imread( ' c:bbb.png ' );

x = a;
x1 = embed;
x = double (x);
x1 = double (x1);
for i = 1 : 256 ;
for j = 1 : 256 ;
MYa(i,j) = x(i,j) ^ 2 ; % afterfiltering ' ssingle
MYb(i,j) = x(i,j) - x1(i,j);
end
end
d = 0 ;
e = 0 ;
for i = 1 : 256 ;
for j = 1 : 256 ;
d = d + MYa(i,j);
e = e + MYb(i,j) * MYb(i,j);
end
end
f = log10(d / e);
g = 10 * f