Улучшенный алгоритм встраивания информации в область ДКП цифровых изображений на основе метода QIM с переменным шагом квантования
Steganographic concealment of information in digital images frequency domain involves such problems as loss of embedded information and distortion of the natural model of digital images. Previously, the authors of this study proposed an approach to solving the first problem, consisting in iterative correction of embedding errors, and obtained an algorithm based on the QIM method and ensuring the error-free extracting of embedded information through the proposed approach. In this paper, we propose an approach to minimizing the distortions of the natural digital image model in the DCT domain, based on changing the quantization step depending on the image local characteristics in the frequency domain. The result of the work is an improved algorithm for embedding information in the DCT domain of digital images, combining the two proposed approaches. The results of the experiments show that the developed algorithm along with ensuring the error-free extraction makes it possible to reduce the distortions introduced into the DCT coefficients and to ensure the statistical indistinguishability of the cover images and stego images in 75% of cases.