Hybrid DWT-DCT-Hash function based digital image watermarking for copyright protection and content authentication of DubaiSat-2 images

Abstract

This paper presents a new technique for copyright protection and content authentication of satellite images. The novelty in the presented approach consists in designing a hybrid Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT) and hash function based digital image watermarking. In this study, two watermarks are embedded in the cover image called robust copyright watermark and fragile authentication watermark. The robust watermark is embedded in hybrid frequency and wavelet domain by applying DWT and DCT respectively. Such two steps embedding allows the proposed approach to provide better imperceptibility in harmony with the human visual system and offers higher robustness against signal processing attacks. Subsequently, the fragile watermark is embedded in a spatial domain using the hash function approach. The proposed hybrid watermarking technique has been tested on DubaiSat-2 images with 1 meter resolution. The experimental results show that the proposed method is robust against JPEG compression, rotation and resizing attacks. In addition, the multi-watermarked image has a good transparency and the fragile watermark is sensitive to any tampering.

A Computational Model of Watermark Algorithmic Robustness Capable of Resisting Image Cropping for Remote Sensing Images

“…Evaluating a watermarking algorithm is commonly performed from several perspectives, e.g., peak signal-to-noise ratio ( PSNR ) is used to measure the degradation of image fidelity [ 13 , 36 ], false negative probability (missed detection) or false positive probability (false alarms) are used to evaluate the authority and authentication of watermarking algorithms [ 15 , 37 ]. Regarding robustness, it is common to use NC [ 10 , 17 , 23 ] or BER [ 17 , 24 ] to compare the similarity between the extracted watermark sequence with the embedded one in a quantitative method. For further evaluation, taking BER as an example, assume wm is the original watermark sequence and is the extracted, BER is calculated as: where NOR is the operation of exclusive OR .…”

“…From the perspective of computational complexity, the experimental methods can be divided into three types: robustness verification, algorithm comparisons, and criteria systems. The robustness verification experiments are mainly conducted after the watermarking algorithms have been proposed by performing some attacks [ 8 , 10 , 11 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Normalized correlation ( NC ) [ 10 , 17 , 23 ] and bit error rate ( BER ) [ 17 , 24 ] have been used as the evaluation indexes, which are calculated by comparing the extracted copyright information with the original.…”