DWT and TSVQ-based Semi-fragile Watermarking Scheme for Tampering Detection in Remote Sensing Images

A semi fragile watermarking scheme for remote sensing images is presented. The suggested scheme uses the signature of the multispectral or hyper spectral image to embed the mark and detects a forgery of the marked image, e.g. a tampered region. The original image is segmented in three-dimensional blocks and, for each block, a discrete Wavelet transform (DWT) and a tree structured vector quantizer is built. These trees are manipulated using an iterative algorithm until the resulting image satisfies some selected conditions. Each tree is partially modified accordingly to a secret key in order to avoid tampering attacks. This key determines the internal structure of the tree and, also, the resulting distortion. In order to make the marked image robust against near-loss less compression, the trees are built using only the LL sub-band of the DWT. The results show that the method works correctly with remote sensing images and detects copy-and-replace attacks from segments of the same image, whilst allowing for JPEG2000 compression.