TITLE:
Enhanced Contrast of Reconstructed Image for Image Secret Sharing Scheme Using Mathematical Morphology
AUTHORS:
Yogesh K. Meghrajani, Himanshu S. Mazumdar
KEYWORDS:
Contrast, Mathematical Morphological Operator, Image Secret Sharing, Visual Secret Sharing
JOURNAL NAME:
Journal of Information Security,
Vol.6 No.4,
September
25,
2015
ABSTRACT: Visual secret sharing
(VSS) is one of the cryptographic techniques of Image secret sharing scheme
(ISSS) that performs encoding of secret message image (text or picture) into
noise like black and white images, which are called as shares. Shares are
stacked together and secret message image is decoded using human visual system.
One of the major drawbacks of this scheme is its poor contrast of the recovered
image, which improves if computational device is available while decoding. In
this paper, we propose to improve poor contrast of classical VSS schemes for
text or alphanumeric secret messages and low entropy images. Initially, stacked
image is binarized using dynamic threshold value. A mathematical morphological
operation is applied on the stacked image to enhance contrast of the
reconstructed image. Moreover, a method is proposed that allows the size of the
structuring element to change according to the contrast and the size of a
stacked image. We perform experiments for different types of VSS schemes,
different share patterns, different share types (rectangle and circle), and low
entropy images. Experimental results demonstrate the efficacy of the proposed
scheme.