1. 多媒體網路安全實驗室 Source: IEICE Trans. Fundamentals, Vol. E90-A, No. 4, April 2007, pp. 771-777. Authors:Hong Lin Jin, Masaaki Fujiyoshi, Hitoshi Kiya Speaker:Cheng Hsu Date:2011/01/19 Lossless Data Hiding in the Spatial Domain for High Quality Images

2. 多媒體網路安全實驗室 Outline 1.Introduction 2.Conventional Methods 3.Proposed Method 4.Experimental Results 5.Conclusions 2

3. 多媒體網路安全實驗室 1. Introduction  This paper proposes a lossless data embedding method that hides only data to be embedded in the spatial domain.  The proposed method embeds and extracts the data by using only one global parameter that is based on the statistics of surrounding pixels of the pixels in which the data are hidden. 3

4. 多媒體網路安全實驗室 2. Conventional Methods Generalized lossless data hiding General diagram of conventional methods embedding the O riginal state information as well as data to be hidden General diagram of conventional methods embedding only data to be hidden 4

5. 多媒體網路安全實驗室 3. Proposed Method (a) Embedding (b) Extracting 5

6. 多媒體網路安全實驗室 97100 99100102 100105 97100 99100102 100105 b = floor((97+100+100+99+102+100+105+105)/8))=101g A pixel 3 × 3 block b. each pixel is k=8 bits Overlapped pixel blocks. 6

7. 多媒體網路安全實驗室 ( 2 k - 2 = 254) 1. Calculating s : s = the minimum of s b 's for all 3 x 3 blocks. 2. Deciding embeddable blocks: block b is embeddable if | △ b | < s. 3. Embedding: (e.g., secret bit w n = 1 --> g b '= 101-2+1 = 100) 7

8. 多媒體網路安全實驗室 8 4. Extracting: in this case, w n = (100-101) mod 2 = 1. 5. Restoration of g b : in this case, g b = (100+101-1)/2 = 100.

9. 多媒體網路安全實驗室 4. Experimental Results Simulation conditions 9

10. 多媒體網路安全實驗室 10 The actual capacity N [bits], the embeddable ratio N/B[%], the image quality of the stego image in terms of the peak signal-to-noise ratio [dB] when the payload is set as its maximum (N [bits]), and parameter s for embedding N bits data.

11. 多媒體網路安全實驗室 11 An example of stego images (Sailboat, PSNR: 36.3 dB)

12. 多媒體網路安全實驗室 12 (a) Capacity versus u.

13. 多媒體網路安全實驗室 13 (b) Image quality versus u.

14. 多媒體網路安全實驗室 5. Conclusions  A lossless embedding method that inserts data in an image in the spatial domain has been proposed.  The proposed method embeds and extracts data by using only one parameter that is based on the statistics of surrounding pixels of stego pixels. 14

15. 多媒體網路安全實驗室