Visual Cryptography and Secret Image Sharing

7

Visual Cryptography and Random Grids

Shyong Jian Shyu

Ming Chuan University, Taiwan

CONTENTS

7.1 Introduction

7.2 Random Grids

7.2.1 Random Pixel, Random Grid, and Average Light Transmission

7.2.2 Superimposition of Random Grids

7.3 Visual Cryptograms of Random Grids

7.3.1 Definition of VCRG

7.3.2 (2, 2)-VCRG Algorithms for Binary Images

7.3.3 Experiments for (2, 2 VCRG

7.3.4 Definition of Light Contrast and Performance Evaluation

7.3.5 Algorithms of (n, n)-VCRG for Binary Images

7.3.6 Algorithms of (n, n)-VCRG for Gray-Level and Color Images

7.3.7 Experiments for (n, n)-VCRG

7.4 Concluding Remarks

Bibliography

7.1 Introduction

A random grid was defined by Kafri and Keren in 1987 [7] as a transparency comprising a two-dimensional ...