计算机与现代化
計算機與現代化
계산궤여현대화
COMPUTER AND MODERNIZATION
2014年
2期
197-200
,共4页
灰度水印图像%离散余弦变换%离散小波变换%Arnold置乱%位平面%盲提取
灰度水印圖像%離散餘絃變換%離散小波變換%Arnold置亂%位平麵%盲提取
회도수인도상%리산여현변환%리산소파변환%Arnold치란%위평면%맹제취
gray watermark image%discrete cosine transform%discrete wavelet transform%Arnold scrambling%bit planes%blind extraction
图像中嵌入的多为二值水印，容量有限且抗攻击能力有待提高。为了增加嵌入水印的容量以及增强算法的鲁棒性，提出基于DWT与DCT的灰度水印图像嵌入算法。首先对灰度水印进行Arnold置乱预处理，其次对所选取的载体图像进行二级小波变换，选择第二层的逼近子带LL2与细节子带LH2、HL2、HH2依次嵌入灰度水印的高四位位平面。嵌入水印时对4个子带分别进行8×8分块DCT变换，然后采用一种改进的交换中频系数的方法将置乱后水印的高四位位平面分别嵌入所选取的4个子带，为增强算法的鲁棒性，在不同的子带由实验选择不同的水印嵌入因子。仿真实验表明，本算法抵抗图像裁剪、图像加噪、直方图均衡化、常用滤波处理、JPEG压缩等攻击的效果较好。
圖像中嵌入的多為二值水印，容量有限且抗攻擊能力有待提高。為瞭增加嵌入水印的容量以及增彊算法的魯棒性，提齣基于DWT與DCT的灰度水印圖像嵌入算法。首先對灰度水印進行Arnold置亂預處理，其次對所選取的載體圖像進行二級小波變換，選擇第二層的逼近子帶LL2與細節子帶LH2、HL2、HH2依次嵌入灰度水印的高四位位平麵。嵌入水印時對4箇子帶分彆進行8×8分塊DCT變換，然後採用一種改進的交換中頻繫數的方法將置亂後水印的高四位位平麵分彆嵌入所選取的4箇子帶，為增彊算法的魯棒性，在不同的子帶由實驗選擇不同的水印嵌入因子。倣真實驗錶明，本算法牴抗圖像裁剪、圖像加譟、直方圖均衡化、常用濾波處理、JPEG壓縮等攻擊的效果較好。
도상중감입적다위이치수인，용량유한차항공격능력유대제고。위료증가감입수인적용량이급증강산법적로봉성，제출기우DWT여DCT적회도수인도상감입산법。수선대회도수인진행Arnold치란예처리，기차대소선취적재체도상진행이급소파변환，선택제이층적핍근자대LL2여세절자대LH2、HL2、HH2의차감입회도수인적고사위위평면。감입수인시대4개자대분별진행8×8분괴DCT변환，연후채용일충개진적교환중빈계수적방법장치란후수인적고사위위평면분별감입소선취적4개자대，위증강산법적로봉성，재불동적자대유실험선택불동적수인감입인자。방진실험표명，본산법저항도상재전、도상가조、직방도균형화、상용려파처리、JPEG압축등공격적효과교호。
For embedding in the cover image are mostly binary watermarks , capacity is limited and needs to be improved anti-at-tack capability .In order to increase the capacity and enhance watermarking robustness of the algorithm , this paper proposes an embedded algorithm for gray watermarking image based on DWT and DCT .Firstly, the gray watermark image is preprocessed by Arnold scrambling.Secondly, after decomposing the selected cover image into the secondary layer , LL2, HL2, LH2 and HH2 of the secondary layer are selected to embed watermark .We apply 8 ×8 block DCT to each band and adopt an improved approach to embed high four bit planes of the gray watermark by switching two middle frequency coefficients .In order to enhance the robust-ness, the embedding intensity varies with different subbands .Finally, the simulation experiments show that the method is of strong robustness to cutting, image adding noise, histogram equalization, filtering, JPEG compression, and other attacks.
