共查询到16条相似文献,搜索用时 841 毫秒
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针对JPEG图像隐写问题,本文提出一种基于多方向相关性JPEG图像通用检测方法。该检测方法首先对图像进行DCT域变换,提取DCT域块内、块间多方向的DCT系数间的相关性作为统计特征,共形成96维的统计特征。然后利用训练好的支持向量机对几种常见的JPEG图像隐写算法检测,实验结果表明本文提出的算法与其他检测算法相比具有更好的检测结果。 相似文献
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基于JPEG图像压缩技术的研究及其Matlab实现 总被引:1,自引:0,他引:1
JPEG标准主要应用于静止图像的压缩。介绍了JPEG压缩标准,详细分析了JPEG标准下的图像压缩编码和解码原理及实现过程,对基于DCT顺序工作模式的JPEG压缩算法做了分析。仿真实验表明用Matlabl来实现离散余弦的图像压缩,具有方法简单速度快,误差小的优点。 相似文献
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遥感图像自适应分层量化的快速DCT压缩法 总被引:1,自引:0,他引:1
依据遥感图像的频谱特性,提出一种自适应分层量化的快速DCT图像压缩算法,在对原始图像快速DCT之后,根据图像频谱特性自适应修正JPEG量化表,再用新量化表分层量化DCT系数。真实遥感图像压缩实验表明,在同等压缩比下,提出的方法比标准JPEG方法速度快,且峰值信噪比增加1~2dB,并能实现嵌入式码流图像压缩。 相似文献
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提出了一种基于图像DCT域信息熵的盲检测算法。该算法通过分析JPEG图像隐写前后子块DCT系数信息熵的变化,提取JPEG图像子块DCT系数信息熵的64维特征向量,之后用LSSVM分类器对待测图像进行分类,最终达到检测载密图像的目的。实验表明,该算法能有效地针对各种隐写算法下的载密图像进行检测,同时对低嵌入比例下的载密图像也能达到较高的检测率。 相似文献
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A content authentication technique based on JPEG-to-JPEG watermarking is proposed in this paper. In this technique, each 8x8 block in a JPEG compressed image is first processed by entropy decoding, and then the quantized discrete cosine transform (DCT) is applied to generate DCT coefficients: one DC coefficient and 63 AC coefficients in frequency coefficients. The DCT AC coefficients are used to form zero planes in which the watermark is embedded by a chaotic map. In this way, the watermark information is embedded into JPEG compressed domain, and the output watermarked image is still a JPEG format. The proposed method is especially applicable to content authentication of JPEG image since the quantized coefficients are modified for embedding the watermark and the chaotic system possesses an important property with the high sensitivity on initial values. Experimental results show that the tamper regions are localized accurately when the watermarked JPEG image is maliciously tampered. 相似文献
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提出了一种基于离散余弦变换(DCT)系数统计特性的JPEG图像隐写分析算法。该算法在分析JPEG图像DCT系数的统计特性的基础上,提取了8维特征向量,通过最小二乘支持向量机(LS—SVM)分类器对待测图像进行分类,以达到检测载密图像的目的。算法实现简单,计算复杂度低。实验结果表明,该算法检测速度快,具有较高的检测正确率,能够实现针对各类JPEG图像信息隐写算法的有效检测。 相似文献
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HM-JPEG隐写术是一种在DCT系数量化过程中进行隐秘信息嵌入的新型JPEG隐写术,该隐写术通过采用特殊的奇偶量化器方式,最大限度地实现量化取整后DCT系数全局统计特性的保持,但这种全局统计特性保持的代价是破坏局部子块JPEG系数的统计特性.文中通过对块内JPEG系数局部统计特性的研究来实现对HM-JPEG隐写术的检测,试验结果证明了该方案的有效性. 相似文献
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This work proposes a novel protocol of encrypting the JPEG image suitable for image rescaling in the encrypted domain. To protect the privacy of original content, the image owner perturbs the texture and randomizes the structure of the JPEG image by enciphering the quantized Discrete Cosine Transform (DCT) coefficients. After receiving the encrypted JPEG image, the service provider generates a rescaled JPEG image by down-sampling the encrypted DCT coefficients. On the recipient side, the encrypted JPEG image rescaled by the service provider can be decrypted to a plaintext image with a lower resolution with the aid of encryption keys. Experimental results show that the proposed method has a good capability of rescaling the privacy-protected JPEG file. 相似文献
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Modified JPEG Huffman coding 总被引:3,自引:0,他引:3
It is a well observed characteristic that when a DCT block is traversed in the zigzag order, the AC coefficients generally decrease in size and the run-length of zero coefficients increase in number. This article presents a minor modification to the Huffman coding of the JPEG baseline compression algorithm to exploit this redundancy. For this purpose, DCT blocks are divided into bands so that each band can be coded using a separate code table. Three implementations are presented, which all move the end-of-block marker up in the middle of DCT block and use it to indicate the band boundaries. Experimental results are presented to compare reduction in the code size obtained by our methods with the JPEG sequential-mode Huffman coding and arithmetic coding methods. The average code reduction to the total image code size of one of our methods is 4%. Our methods can also be used for progressive image transmission and hence, experimental results are also given to compare them with two-, three-, and four-band implementations of the JPEG spectral selection method. 相似文献
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A content authentication technique based on JPEG-to-JPEG watermarking is proposed in this paper. In this technique, each 88 block in a JPEG compressed image is first processed by entropy decoding, and then the quantized discrete cosine transform (DCT) is applied to generate DCT coefficients: one DC coefficient and 63 AC coefficients in frequency coefficients. The DCT AC coefficients are used to form zero planes in which the watermark is embedded by a chaotic map. In this way, the watermark information is embedded into JPEG compressed domain, and the output watermarked image is still a JPEG format. The proposed method is especially applicable to content authentication of JPEG image since the quantized coefficients are modified for embedding the watermark and the chaotic system possesses an important property with the high sensitivity on initial values. Experimental results show that the tamper regions are localized accurately when the watermarked JPEG image is maliciously tampered. 相似文献
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基于双混沌系统的抗JPEG压缩的图像认证水印算法 总被引:1,自引:0,他引:1
提出了一种新的兼具水印高安全性和高定位精度的抗JPEG压缩的图像认证水印算法.根据JPEG图像压缩过程中DCT系数的不变特性,将预先量化的DCT低频系数和水印密钥合成为混沌系统的初值.再将图像块的编号映射为混沌系统的迭代次数,经过logistic混沌迭代生成图像块水印.在水印嵌入过程中,利用另一混沌系统猫映射构造循环结构,建立图像块之间一一对应的循环关系,并将块水印嵌入到对应图像块的DCT中频系数中.实验结果表明,该算法对JPEG有损压缩具有良好的鲁棒性,同时可对图像内容的恶意篡改进行精确的检测与定位. 相似文献
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Yu Chen Vrizlynn L.L. Thing 《Journal of Visual Communication and Image Representation》2013,24(7):857-866
In this paper, we propose a sector-wise JPEG fragment classification approach to classify normal and erroneous JPEG data fragments with the minimum size of 512 bytes per fragment. Our method is based on processing each read-in sector of 512 bytes with using the DCT coefficient analysis methods for extracting the features of visual inconsistencies. The classification is conducted before the inverse DCT and can be performed simultaneously with JPEG decoding. The contributions of this work are two-folds: (1) a sector-wise JPEG erroneous fragment classification approach is proposed (2) new DCT coefficient analysis methods are introduced for image content analysis. Testing results on a variety of erroneous fragmented and normal JPEG files prove the strength of this operator for the purpose of forensics analysis, data recovery and abnormal fragment inconsistencies classification and detection. Furthermore, the results also show that the proposed DCT coefficient analysis methods are efficient and practical in terms of classification accuracy. In our experiment, the proposed approach yields a false positive rate of 0.32% and a true positive rate of 96.1% in terms of erroneous JPEG fragment classification. 相似文献