CAJ | 학술논문

提出一种基于不变矩的DCT域图像拷贝检测方法，选取图像亮度分量的整体DCT变换后的中低频系数的符号作为其DCT域特征，分别计算原始图像及其角度规范化后图像的DCT域特征，计算并比较查询图像与图像库中图像的两类特征的相关性，取较大的相关值来判断图像是否存在拷贝。图像的整体DCT中低频系数已被验证对于信号处理攻击鲁棒性高，且随着图像缩放攻击呈规律性变化，因而利用图像的整体DCT中低频系数构建的DCT域特征对于信号处理和图像缩放攻击鲁棒性高；利用图像的缩放不变矩估算出图像特征角度，再依据特征角度对图像进行角度规范化可消除旋转失真的影响，因而利用角度规范化后的图像的DCT域特征能抵抗旋转、以及旋转和等比例缩放的混合攻击。实验结果证明在抗旋转和包含旋转的混合攻击方面，该算法的检测效果明显优于已有算法。
제출일충기우불변구적DCT역도상고패검측방법，선취도상량도분량적정체DCT변환후적중저빈계수적부호작위기DCT역특정，분별계산원시도상급기각도규범화후도상적DCT역특정，계산병비교사순도상여도상고중도상적량류특정적상관성，취교대적상관치래판단도상시부존재고패。도상적정체DCT중저빈계수이피험증대우신호처리공격로봉성고，차수착도상축방공격정규률성변화，인이이용도상적정체DCT중저빈계수구건적DCT역특정대우신호처리화도상축방공격로봉성고；이용도상적축방불변구고산출도상특정각도，재의거특정각도대도상진행각도규범화가소제선전실진적영향，인이이용각도규범화후적도상적DCT역특정능저항선전、이급선전화등비례축방적혼합공격。실험결과증명재항선전화포함선전적혼합공격방면，해산법적검측효과명현우우이유산법。
In this paper, an invariant moment based robust image copy detection algorithm in discrete cosine transformation (DCT) domain is proposed. Low and middle frequency coefficients which are calculated from full DCT transformation on luminance component of image are used as the image eigenvector in DCT domain. The query image and its angle normalized image eigenvector in DCT domain are computed, then correlation values of two eigenvectors of the query image and those of test image are respectively computed and the larger one is used to judge whether the query image is a copy or not. Full DCT coefficients are verified to have high robustness against common signal attacks and regularly vary with scaling attacks, thus the DCT eigenvector constructed by middle and low frequency full DCT coefficients can resist signal attacks and scaling distortion. The characteristic angle estimated by the image scale invariant moment is used to normalize the image to counteract the rotation distortion, so the angle normalized image can resist rotation distortion. The experimental results show that the algorithm is superior to Ling’s methods in terms of rotation distortion.