permutation of a watermark image

i have taken a watermark image and assign -1 value to black and 1 to white to whole watermark now i want permutation of this image. whats would b the efficient method for permuation process of this image.. if anyone have matlab code for this send me  and please help me...

regards siyab

[umar siyab]

the watermark image only contain black and white colour

Answer 1

[Walter Roberson]

reshape(Image(randperm(numel(Image))),size(Image))

[umar siyab]

i didn't get it clear can u explain rhe code to me...... kindly if u hve time to explain

[Walter Roberson]

See http://www.mathworks.com/help/techdoc/ref/randperm.html

along with linear indexing, http://www.mathworks.com/help/techdoc/math/f1-85462.html#f1-85511

and reshape, http://www.mathworks.com/help/techdoc/ref/reshape.html

[umar siyab]

thanks for your kind reply i will work on it...... thanks once again

[Sanghamitra Tripathy]

How to reshape the Image again to the Original Image?

[arwa allubani]

How to reshape the Image again to the Original Image?

[Walter Roberson]

You cannot get back to the original image by reshaping the result of the above. The order of the pixels has been randomized. You would need to know (or be able to recreate) the random order that was used.