binary pictures

[eldjon]

does anyone know how can we hide the information of a binary picture in a normal RGB picture in a way that this changes will not be visuable ?

[RedSon]

Yes this practice is called steganography . It is very difficult to do well but can be one of the most difficult things to detect. There are libraries available for you try this out for yourself. Try a google search and see what you come up with.

[JosAH]

does anyone know how can we hide the information of a binary picture in a normal RGB picture in a way that this changes will not be visuable ?

Use the lowest bits of the R, G or B values for pixels at certain locations only
you know. If you consider all (A, R, G, B) values as one linear aray of size
HxW (Height times Width) and let P > HxW be a prime number than all indexes
i+j*p mod (HxW) are excellent candidates to have the lowest bits of their
(A, R, G, B) values manipulated. Of course those lowest bits are used for the
smaller picture to be hidden.

kind regards,

Jos

[eldjon]

Use the lowest bits of the R, G or B values for pixels at certain locations only
you know. If you consider all (A, R, G, B) values as one linear aray of size
HxW (Height times Width) and let P > HxW be a prime number than all indexes
i+j*p mod (HxW) are excellent candidates to have the lowest bits of their
(A, R, G, B) values manipulated. Of course those lowest bits are used for the
smaller picture to be hidden.

kind regards,

Jos

one more thing
u mean : (i+j*p)mod(H*W)?

[JosAH]

one more thing
u mean : (i+j*p)mod(H*W)?

Yep, that's it. e.g.if a picture is,say, 4x2 pixels (WxH) then just consider it as
4x2 == 8 pixels in total; a next prime number > 8 is 11. So you can fiddle
with the R,G,B values of pixels 0, 3, 6, 1, 4, 7, 2, 5 in that particular order
if you start at pixel #0. Feel free to pick a larger prime number.

kind regards,

Jos