Methods and apparatus are provided for subjecting an original, pixel
domain image to an Integer Wavelet Transform (IWT) to obtain a matrix of
wavelet coefficients; selecting at least one bit plane between a least
significant bit plane and a most significant bit plane of the matrix of
wavelet coefficients; compressing the at least one selected bit plane to
produce free space in the at least one selected bit plane; embedding
hidden data in the free space of the at least one compressed bit plane;
and subjecting the at least one embedded bit plane to an Inverse IWT to
produce a marked pixel domain image. Methods and apparatus are also
provided for reversing this process.