2 : (Jaeyoung Kim et al.: A Statistical Approach for Improving the Embedding Capacity of Block Matching based Image Steganography) (Regular Paper) 22

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1 (Regular Paper) 22 5, (JBE Vol. 22, No. 5, September 2017) ISSN (Online) ISSN (Print) a), a), b) A Statistical Approach for Improving the Embedding Capacity of Block Matching based Image Steganography Jaeyoung Kim a), Hanhoon Park a), and Jong-Il Park b), 3.,..,, k-. PSNR. Abstract Steganography is one of information hiding technologies and discriminated from cryptography in that it focuses on avoiding the existence the hidden information from being detected by third parties, rather than protecting it from being decoded. In this paper, as an image steganography method which uses images as media, we propose a new block matching method that embeds information into the discrete wavelet transform (DWT) domain. The proposed method, based on a statistical analysis, reduces loss of embedding capacity due to inequable use of candidate blocks. It works in such a way that computes the variance of each candidate block, preserves candidate blocks with high frequency components while reducing candidate blocks with low frequency components by compressing them exploiting the k-means clustering algorithm. Compared with the previous block matching method, the proposed method can reconstruct secret images with similar PSNRs while embedding higher-capacity information. Keyword : Image steganography, block matching, discrete wavelet transform, high capacity, block variance, statistical analysis Copyright 2017 Korean Institute of Broadcast and Media Engineers. All rights reserved. This is an Open-Access article distributed under the terms of the Creative Commons BY-NC-ND ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited and not altered.

2 (JBE Vol. 22, No. 5, September 2017).., [2,3]. (steganography) [1]... LSB(least significant bits) [4]. PVD [5], PVD PVD [6]. Fresnel [7], DCT [8], DWT [9-11]. a) (Department of Electronic Engineering, Pukyong National University) b) (Department of Computer and Software, Hanyang University) Corresponding Author : (Hanhoon Park) hanhoon_park@pknu.ac.kr Tel: ORCID: Manuscript received July 11, 2017; Revised August 28, 2017; Accepted August 28, DWT [12]. PSNR.. 2 [12] - [13], 3. 4, 5.. DWT [12] DWT(discrete wavelet transform) DWT. 2 2D-DWT. 1D-DWT 1 (b) (b) 1D-DWT 2D-DWT 1 (c) 4

3 (a) (b) (c) 1. (a), 1D-DWT (b), 2D-DWT (c) Fig. 1. The origin image (a), 1D-DWT image (b) and 2D-DWT image (c) LL, LH, HL, HH. LL LH, HL, HH,,. 1, 2. DWT,. 2. DWT. 100% /. DWT [12]. step 1 : 2D-DWT LL, LH, HL, HH. step 2 : LL. step 3 :. step 4 : LL ( ). step 5 : ( ) step log LSB LH, HL, HH

4 (JBE Vol. 22, No. 5, September 2017) ( 1 ). [12] , DWT LL 1. Table 1. Ratio of unused blocks Previous block matching method [12] cover secret baboon boat lena goldhill einstein average baboon boat lena goldhill einstein Fig. 2. Pixel and deviation values of low frequency blocks with a size of

5 .. LL.,, 6.,. LL LL ( ) LL - k. k. LL. 7. log log 1, 8, LL. LH, HL, HH LSB. 2. DWT LL. LH, HL, HH.. 5 log + 9 log [12], -. bpp(bits per a pixel)( 8 ). bpp. PSNR(peak signal to noise ratio) 9. / log log

6 648 방송공학회논문지 제22권 제5호, 2017년 9월 (JBE Vol. 22, No. 5, September 2017), (9) log. 1. 기존 블록 매칭 방법과 제안된 방법의 PSNR과 bpp비교 기존 볼록 매칭 방법 과 제안된 방법의 삽입 용량, 스테 [12] 고 영상의 은닉성 복원률을 비교하기 위해서 크 기의 8비트, 1채널 영상 5개(baboon.bmp, boat.bmp, lena.bmp, goldhill.bmp, einstein.bmp)를 커버와 비밀 영상으 로 사용한다(그림 3 참조). 실험은 크기로 영상을 분할하여 삽입을 하였고 군 집화 알고리즘의 =16, 삽입의 대체 비트 수는 2비트 로 하였다. 표 2의 결과는 제안된 방법과 기존 블록 매칭 방법의 복원된 비밀 영상의 PSNR에 대해서 보여준다. 제 안된 방법의 경우 PSNR이 1dB정도 적지만 일반적으로 3. 실험에 사용된 영상 Fig. 3. The images used for the experiment 그림 2. 복원된 비밀 영상의 PSNR 비교 Table 2. Comparison of PSNRs of the reconstructed secret images 표 =16 Proposed method Previous block matching method[12] (a) cover secret baboon boat lena goldhill einstein baboon boat lena goldhill einstein baboon (b) boat lena goldhill (c) 4. 커버 영상 (a), 비밀 영상 (b), 스테고 영상 (c), 복원 영상 (d) Fig. 4. a cover image (a), a secret image (b), a stego image (c) and a restored image (d) 그림 einstein avg PSNR (d)

7 3. PSNR Table 3. Comparison of PSNRs of the stego images =16 cover secret baboon boat lena goldhill einstein avg PSNR baboon Proposed method Previous block matching method [12] boat lena goldhill einstein baboon boat lena goldhill einstein bpp Table 4. Comparison of bpp and insertion bits =16 cover secret baboon boat lena goldhill einstein Proposed method Previous block matching method [12] baboon boat lena goldhill einstein all images avg bpp avg insertion bits PSNR 30dB (human visual system). baboon PSNR 25dB baboon PSNR ( 2 ). ( 4 ). 1dB PSNR ( 3 ). bpp. bpp bpp bpp 77%. baboon PSNR bpp 0.1 ( 4 ). 2. k PSNR bpp PSNR bpp. 5 ( )

8 (JBE Vol. 22, No. 5, September 2017) 5. PSNR, bpp, Table 5. Average PSNR, bpp and insertion bits of the proposed method according to the number of clusters restored images average PSNR stego images average PSNR average bpp average insertion bits PSNR bpp PSNR bpp. baboon 4 PSNR 30dB PSNR bpp PSNR...,. PSNR PSNR PSNR. k-. baboon.. (References) [1] J. Zollner, H. Federrath, H. Klimant, A. Pfitzmann, R Piotraschke, A. Westfeld, G. Wicke, and G. Wolf, Modeling the Security of Steganographic Systems, Proc. of Workshop on Information Hiding, pp , [2] H. Kim, Theoretical Background and Detection Technique of Steganography, Journal of the Korea Information Security, Vol. 12, No. 1, pp , [3] K. Jung, J. Lee, and K. Yoo, Steganography on Android Smart Devices, Journal of the Institute of Electronics and Information Engineers, Vol. 52, No. 4, pp , [4] D. C. Wu and W. H. T, A Steganographic Method for Images by Pixel-Value Differencing, Pattern Recognition Letters, Vol. 24, pp , [5] J. Kim, H. Park, and J-I. Park, PVD Image Steganography with Locally-fixed Number of Embedding Bits, Journal of Broadcast Engineering, Vol. 22, No. 3, pp , [6] S. Ji, A Study of Optimal Image Steganography Based on LSB

9 Techniques, Journal of the Korea Industrial Information Systems Research, Vol. 20, No. 3, pp , [7] Y. Lee, Y. Seo, and D. Kim, Hologram Watermarking using Fresnel Diffraction Model, Proc. of the Korea Society of Broadcast Engineers Conference, Vol. 19, No. 5, pp , [8] W. Sohn and L. N. T. dung, A Blind Watermarking Scheme using Singular Vector Based on DWT/RDWT/SVD, Journal of Broadcast Engineering, Vol. 21, No. 2, pp , [9] Y. Lee, Y. Seo, and D. Kim, A Robust Blind Watermarking for Digital Image using DWT According to Its Resolution, Journal of Broadcast Engineering, Vol. 20, No. 6, pp , [10] S. Youssef, A. A. elfarag, and R. Raouf, A Robust Steganography Model using Wavelet-based Block-partition Modification, International Journal of Computer Science & Information Technology, Vol. 3, No. 4, pp , [11] S. Singh and T. J. Siddiqui, A Security Enhanced Robust Steganography Algorithm for Data Hiding, International Journal of Computer Science Issues, Vol. 9, No. 1, pp , [12] J. Kim, H. Park, and J-I. Park, Image Steganography Based on Block Matching in DWT Domain, Proc. of BMSB, Cagliary, Italy, [13] T. Kanungo, D. Mount, N. Netanyahu, C. Piako, R. Silverman, and A. Wu, An Efficient -means Clustering Algorithm: Analysis and Implementation, IEEE Trans. Pattern Anal. Mach. Intell., Vol. 24, No. 7, pp , : ~ : - ORCID : - : : : : ~ 2011 : NHK ~ : - ORCID : - :,, 3 / : : : ~ 1994 : NHK ~ 1996 : ~ 1999 : ATR ~ : - ORCID : - :,, 3,