noisy.m

对于含有噪声的的数字图像模式“1、2、3、4”

function x = noisy(tab,nv)

%        X = NOISY(X,N) reverses randomly N pixels
%	       		of the patterns X (RxQ)

%	(c) Val Ninov, 1997, [e-mail]

[xx,yy]=size(tab);

% Add noise to the input pattern
%-------------------------------
fprintf('noisy...\n Wait...\n');
for ii=1:xx
    nn=sort(round(yy*rand(1,nv)));
    while nn(1)==0
        nn=sort(round(yy*rand(1,nv)));
    end
    for kk=1:nv
%        fprintf('ii = %u\n',ii);
%        fprintf('kk = %u\n',kk);
%        fprintf('nn(kk) = %u\n=========================\n',nn(kk));
        tab(ii,nn(kk))=-tab(ii,nn(kk));
    end
end
fprintf('noisy Done.\n');
x=tab;
return