function Arnold1(Image,Frequency,crypt)
%图像数值矩阵Arnold转换函数
%输入参数
% Image: 待加密(待解密)图像文件名(注意写格式后缀),只能为二维
% Frequency: 图像需要变换迭的次数
% crypt 0~加密;1~解密
%输出参数
% M: 转换后图像数据矩阵
% 输出由M对应的图像文件
if nargin<3
disp('请按程序的输入参数格式输入参数!!!');
return;
end
if crypt~=0 && crypt~=1
disp('encrypt 必须为0或1!');
end
%将Q赋值给M,计算Q的大小
Q=imread(Image);
M = Q ;
Size_Q = size(Q);
%如果不是二维或三维数组,则不处理,返回
if (length(Size_Q) == 2)
if Size_Q(1) ~= Size_Q(2)
disp('不是方阵,不能Arnold转换');
return
end
else
disp('不是二维数组,不进行Arnold变换');
return
end
%---------------------------------------
%Arnold转换
n = 0;
K = Size_Q(1);
M1_t = Q;
M2_t = Q;
if crypt==1 %解密
Frequency=ArnoldPeriod( Size_Q(1) )-Frequency;
end
for s = 1:Frequency
n = n + 1;
if mod(n,2) == 0
for i = 1:K
for j = 1:K
c = M2_t(i,j);
M1_t(mod(i+j-2,K)+1,mod(i+2*j-3,K)+1) = c;
end
end
else
for i = 1:K
for j = 1:K
c = M1_t(i,j);
M2_t(mod(i+j-2,K)+1,mod(i+2*j-3,K)+1) = c;
end
end
end
end
if mod(Frequency,2) == 0
M = M1_t;
else
M = M2_t;
end
%----------------------------------------
%imwrite( double(M)/255,strcat( 'Arnold_',num2str(Frequency),'_',Image ),'bmp' );
imshow(M);