Faculty Publications
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Item Contrast enhancement of Progressive Visual Secret Sharing (PVSS) scheme for gray-scale and color images using super-resolution(Elsevier B.V., 2019) Mhala, N.C.; Pais, A.R.Traditional Visual Secret Sharing (VSS) scheme encrypts the secret image into multiple shares. It recovers the secret image based on the “all or nothing” methodology (i.e. all shares must be stacked together to recover the secret image else nothing will be revealed). The modern VSS schemes differ from traditional VSS by progressively recovering the secret image by stacking number of shares. These are also referred as Progressive VSS (PVSS). PVSS schemes generate two types of shares namely 1) meaningful (are the shares which have a meaningful image embedded as the cover image on top of the shares) and 2) noise-like (shares have a random noise-like appearance). In the previous work, we have proposed PVSS based Randomized VSS (RVSS) scheme to recover the secret image by hiding random data into the shares. RVSS achieves the maximum contrast of 70–80% and 70–90% for meaningful and noise-like shares respectively. In this paper, we propose a novel PVSS based super-resolution technique to improve the contrast of RVSS scheme. The experimental results showed that the proposed scheme achieves the contrast of 70–80% for meaningful shares and 99% for noise-like shares. Also, proposed scheme recovers the secret image free from blocking artifacts, for noise-like shares. © 2019 Elsevier B.V.Item A secure visual secret sharing (VSS) scheme with CNN-based image enhancement for underwater images(Springer Science and Business Media Deutschland GmbH, 2021) Mhala, N.C.; Pais, A.R.Nowadays, underwater images are being used to identify various important resources like objects, minerals, and valuable metals. Due to the wide availability of the Internet, we can transmit underwater images over a network. As underwater images contain important information, there is a need to transmit them securely over a network. Visual secret sharing (VSS) scheme is a cryptographic technique, which is used to transmit visual information over insecure networks. Recently proposed randomized VSS (RVSS) scheme recovers secret image (SI) with a self-similarity index (SSIM) of 60–80%. But, RVSS is suitable for general images, whereas underwater images are more complex than general images. In this paper, we propose a VSS scheme using super-resolution for sharing underwater images. Additionally, we have removed blocking artifacts from the reconstructed SI using convolution neural network (CNN)-based architecture. The proposed CNN-based architecture uses a residue image as a cue to improve the visual quality of the SI. The experimental results show that the proposed VSS scheme can reconstruct SI with almost 86–99% SSIM. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.