Binary Image Watermarking with Tampering Localization in Binary Wavelet Transform Domain

We propose a watermarking scheme for the authentication of binary images. We transform the image using the binary wavelet transform and partition the resulting coefficients into treestructured blocks. The size of each block is decided by the number of flippable coefficients in the block. The flippable coefficients are found in the frequency domain by investigating high frequency coefficients. A random bit sequence generated by the block identifying key is embedded in the flippable coefficients in each block. Block-wise localization of tampered regions is accomplished with imperceptible visual degradations. Counter-measures against the vector quantization attack to which most existing watermarking schemes are vulnerable may also be implemented in our scheme