1

Data Hiding in Binary Image for Authentication and Annotation

Source : IEEE Transactions on Multimedia, Vol. 6, No. 4, August 2004, pp. 528-538 Authors: Min Wu and Bede LiuSpeaker: Shu-Fen Chiou(邱淑芬 )Date: 2004/10/21

2

Outline

Introduction Proposed Method Experimental Results Conclusions Comments

3

Introduction

A new method to embed data in binary images. Scanned text Figures Signature

Flippable pixels.

4

Proposed Method (1/7)

5

Proposed Method (2/7)

Smoothness

1 2 3

4 5 6

7 8 9

Horizontal

Vertical

Diagonal

Anti-diagonal

6

Proposed Method (3/7)

Connectivity

Four way connectivity

7

Proposed Method (4/7)

Compute flippability

Binary image

smoothness

• horizontal

• vertical

• diagonal

• anti-diagonal

connectivity

Score=0.5 – 0.125 + 0.125 – 0.125 = 0.375

Score ≥ T2 : flippable pixel

Before After

5 5

3 3

1 1

3 3

B: 2 B: 3

W: 3 W: 2

Score rules:

• (uniform or isolated)

• (H=0 or V=0 or SB)

• (D=0 or min|Si|<T1)

• (flipping change)

• (connectivity change)

8

Proposed Method (5/7)

Lookup table

9

Proposed Method (6/7)

10

Proposed Method (7/7)

Embed (odd-even mapping)

a 16x16 block in original image after shuffling

(Blk1)

11

Experimental Results (1/3)

Signature in signature

12

Experimental Results (2/3)

Invisible annotation for line drawings

'01/01/2000'

13

Experimental Results (3/3)

Tamper Detection for Binary Document

976-bit embedded, 800 bits form a “PUEE” pattern

14

Conclusions

Manipulates 'flippable pixels' to enforce a specific block-based relationship to embed.

Can detect unauthorized use, detect alterations, and annotate.

The hidden data can be extracted without using the original image.

15

Comments

Partition blocks

Binary patterns

BTC Compute Flippable

Flippable

Embed000100100…