Visual Cryptography and Secret Image Sharing

13

Steganography in Halftone Images

Oscar C. Au, Yuanfang Guo and John S. Ho

Hong Kong University of Science and Technology, China

CONTENTS

13.1 Introduction

13.2 A Review of Error Diffusion

13.3 Data Hiding by Stochastic Error Diffusion (DHSED)

13.4 Data Hiding by Conjugate Error Diffusion (DHCED)

13.5 Performance Analysis

13.6 Summary

Bibliography

13.1 Introduction

While gray-scale images can be readily displayed in computer monitors and other light-emitting displays, they also need to be displayed routinely in other reflective media such as newspaper, magazines, books, and other printed documents. However, in reflective media, the application of ink on the reflective media implies that only 1-bit images (with two tones: black and ...