In case of image watermarking if we use lsb technique ,then its not robust when attacks perform,how to recover that data which is lost. CRC only detect the error but can not recover it, can any one help me with any technique to recover lost data.

how to recover lost data when attacks perform on the images. CRC only detect dnt recover. help me with this.

Answer 1

[Image Analyst]

I don't think you can. For example, if the attach was a crop, and all you have is the cropped image, and not the original, how could you possibly know what was in the scene that was cropped away?

[jaishree bansal]

ok. yes its true we cant recover croping attack, but what about other attacks like noise attack or embedding other information on image. can it be recover by check sum or other technique......?

Answer 2

[Walter Roberson]

Use an Error Correcting Code

Note: if you restrict your changes to the LSB then you are helpless if the person just zeros the last bit, thus reducing from 256 shades to 128 shades (but most people would not notice.)