swapcities.m

matlabf非常好基于Contourlet变换的水印算法.与小波变换不同的是Contourlet变换采用类似于线段（contoursegment的基得到一种多分辨、局部化、方向性的图像表示。水印信号

function s = swapcities(inputcities,n)
% SWAPCITIES
% s = SWAPCITIES(inputcities,n) returns a set of m cities where n cities
% are randomly swaped. 
s = inputcities;

for i = 1 : n
    city_1 = round(length(inputcities)*rand(1));
    if city_1 < 1 
        city_1 = 1;
    end
    city_2 = round(length(inputcities)*rand(1));
    if city_2 < 1
        city_2 = 1;
    end
    temp = s(:,city_1);
    s(:,city_1) = s(:,city_2);
    s(:,city_2) = temp;
end