Improving Quality of Multiple Secret Shares Using GSNL Filter in Visual Cryptography

In this paper, (Embedded Extended Visual Cryptography Scheme (EEVCS) is utilized to hide multiple secret images into two or more meaningful cover images which are called share images with no pixel expansion. The manifold secret images are concatenated and embed in the respective number of cover images. People who congregate the multiple share images can acquire either the separated secret images or the concatenated secret images by stacking them without any complex computation. The visual quality of the stacked share is improved using general sliding neighborhood filter (GSNL FILTER) that exploits the functionalities of sliding window protocol, pixel padding, sorting and filtering. Visual quality factors like PSNR (Peak Signal-to-Noise Ratio), UQI (Universal Quality Index), EME (Enhancement Measure of Entropy), SSIM (Structural Similarity of Image Measure), and Mean SSIM are determined and compared with the existing values to appraise the enhanced factors.