1. 1 Reversible image hiding scheme using predictive coding and histogram shifting Source: Signal Processing, vol. 89, no. 6, June 2009, pp. 1129-1143. Author: Piyu Tsai, Yu-Chen Hu, and Hsui-Lien Yeh Speaker: Chia-Chun Wu Date: 2009/10/30

2. 2 Outline Introduce histogram-based reversible data hiding scheme The proposed method and how to increase hiding capacity Experiment Conclusion

3. 3 Introduction Histogram-based reversible data hiding 56667 55666 33550 12222 12331 46567 44655 33440 12222 12331 Original image Stego image Peak value=6 Zero value=4, we noted: (6,4) Secret=101100 Only peak value can hide data, If secret value=0,shift peak value closer to zero. Histogram of original image

4. 4 The proposed method (1/4) Step1: Linear prediction 56667 55666 33550 12222 12331 01112 00111 -2 50-5 -4-3 -4-3-2 -4 Original Image Residual Image histogram of residual image Basic pixel

5. 5 The proposed method (2/4) Step2: find peak and zero value, shift residual value Peak value=-3 Zero value=-1 Peak value=1 Zero value=3 01113 00111 50-5 -4-3 -4-3 -4 01112 00111 -2 50-5 -4-3 -4-3-2 -4 Residual imageShifted residual value

6. 6 The proposed method (3/4) Secret bit: 101100 10101, (1,3) (-3,-1) If secret bit=0, shift peak value 01113 00111 50-5 -4-3 -4-3 -4 111 111 -3 Hiding area After hiding secret Stego image Residual image 56768 55677 44560 12323 12441 01213 00122 50-5 -4-3-2-3-2 -4-3 -4

7. 7 The proposed method (4/4) Overlapping scheme for increasing hiding capacity pick two pair: (0,3) (1,4) 1.If secret bit=1, peak value 0 is unchanged If secret bit=0, peak value 0 is modified to 1 2. If secret bit=1, peak value 1 is modified to 2 If secret bit=0, peak value 1 is modified to 3 3. Residual value 2 is modified to 4

8. 8 Experiments (1/2) Original image and histogramStego image and histogram

9. 9 Experiments (2/2)

10. 10 Conclusions The proposed method can provide higher hiding capacity then histogram-based data hiding scheme. Besides, the quality is good.