共查询到19条相似文献,搜索用时 156 毫秒
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研究了文本数字水印在追溯涉密纸质文档中的重要意义,介绍了常见的文本数字水印技术,分析了Brassil经典行移编码文本数字水印技术,在算法的标记策略中引入检验编码,文本行分割划段和引入基调行三个方面进行改进,改进后算法具有更大水印信息容量,更强的鲁棒性和可控的计算量. 相似文献
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俞玉莲 《计算机与数字工程》2013,41(8)
论文提出一种新的基于序列假设检验的数字水印双门限检测算法,它能很好地抵抗各种水印攻击,提高了检测概率.实验证明序列检测方法在满足一定检测性能的条件下,比普通检测器的检测速度平均快66%,可用于检测视频水印,搜索大型数字数据库中的水印等. 相似文献
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麦瑞玲 《计算机工程与应用》2006,42(19):167-169
文章把文本的偶数行的移位值作为向量的分量而构成一个数字文本水印的水印向量,给出了水印向量的嵌入与检测方法,讨论了盗版者对水印向量的伪造攻击,最后解决了如何辨识出伪造攻击的问题。 相似文献
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DCT域图像水印方案的可靠性分析 总被引:6,自引:2,他引:4
基于一种全帧DCT域图像水印方案,推导了水印相关检测器的误检测概率公式.理论分析表明:检测器的误检测概率与图像本身无关,只取决于嵌入水印长度和嵌入强度因子.文中的分析显示了哪些因素会影响检测性能,有助于优化水印系统.最后,给出了相应的实验结果. 相似文献
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根据特征编码的思想,首次提出了一种基于文字下划线特征变化的脆弱型文本水印算法.该算法利用字符的内码特征信息生成水印,然后按照特定的顺序插入水印或检测水印.理论分析和实验表明,算法具有良好的不可感知性,能准确地检测各类水印攻击,在大部分情况下能对篡改进行精确定位. 相似文献
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针对小型英文Word文档信息量少的特点,该文提出一种文本水印嵌入方法。以文本中单词内的字符为对象,利用字符特征的变化,将有意义的水印信息置乱后依据单词内容以不同方式嵌入文本中.这样,仅几行文字的小文本亦可嵌入水印信息,该算法具备较好的文本完整性检测性能并兼具一定程度的鲁棒性。 相似文献
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基于内容的英文文本数字水印算法设计与实现 总被引:4,自引:0,他引:4
基于英文字母的文字特征,提出一种用希腊字母替换以嵌入水印的新方法,并将水印编码与差错控制码绑定,实现了对英文文本水印的盲提取、检测和恢复操作,突破了现有水印方法中水印信息无法嵌入文本内容之中的难题。攻击实验数据证明水印的容量得到扩充,鲁棒性有所提高。 相似文献
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一种基于文本行和对角侧面特性的数字水印方法 总被引:5,自引:0,他引:5
针对文本文件的特点,提出一种基于文本的行和对角侧面特性水印方法.该方法利用文本具有行的特征嵌入水印信息,大大增加水印容量,提取水印只需要行对角侧面,可以不用原始文本参照,同时该方法还可以用文本对角侧面特性来检测文本的完整性.实验表明,这种方法对于典型的剪切和噪声干扰具有一定鲁棒性. 相似文献
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Hideaki Goto Hirotomo Aso 《International Journal on Document Analysis and Recognition》1999,2(2-3):111-119
In order to enhance the ability of document analysis systems, we need a text line extraction method which can handle not
only straight text lines but also text lines in various shapes. This paper proposes a new method called Extended Linear Segment
Linking (ELSL for short), which is able to extract text lines in arbitrary orientations and curved text lines. We also consider
the existence of both horizontally and vertically printed text lines on the same page. The new method can produce text line
candidates for multiple orientations. We verify the ability of the method by some experiments as well.
Received December 21, 1998 / Revised version September 2, 1999 相似文献
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论文从水印检测过程中可能发生的两类错误入手,讨论了降低检测虚警概率和漏报概率的一般方法。在此基础上,论文构造了一种水印信息预处理方法,即首先通过本原线性移存器(LFSR)产生的m序列将水印信息扩展,然后用加密的扩展信息进行嵌入。在检测时充分考虑到嵌入信息遭受破坏的情况,利用Walsh谱的仿射逼近理论,提出了一种水印的容错性提取技术,使水印可以在大量误码条件下得以恢复,为水印的可靠性检验开辟了一条新的思维途径。 相似文献
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一种可抗二值化攻击的文本图像可见水印算法 总被引:1,自引:0,他引:1
一些在文本图像中嵌入可见水印标识的方法会在二值化攻击下完全失效,因此提出一种基于灰度均匀分布的文本图像可见水印算法。该算法通过对二值水印图像的黑色像素进行概率筛选来控制水印的嵌入强度,然后将二值文本图像和筛选后的水印图像映射到相同的灰度分布范围,以得到含可见水印标识的文本水印作品。仿真实验表明,该算法生成的文本图像可见水印作品灰度均匀分布,能够抵抗二值化攻击,具有良好的鲁棒性。 相似文献
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This paper presents a morphology-based text line extraction algorithm for extracting text regions from cluttered images. First
of all, the method defines a novel set of morphological operations for extracting important contrast regions as possible text
line candidates. The contrast feature is robust to lighting changes and invariant against different image transformations
like image scaling, translation, and skewing. In order to detect skewed text lines, a moment-based method is then used for
estimating their orientations. According to the orientation, an x-projection technique can be applied to extract various text geometries from the text-analogue segments for text verification.
However, due to noise, a text line region is often fragmented to different pieces of segments. Therefore, after the projection,
a novel recovery algorithm is then proposed for recovering a complete text line from its pieces of segments. After that, a
verification scheme is then proposed for verifying all extracted potential text lines according to their text geometries.
Experimental results show that the proposed method improves the state-of-the-art work in terms of effectiveness and robustness
for text line detection. 相似文献
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A parallel-line detection algorithm based on HMM decoding 总被引:1,自引:0,他引:1
Zheng Y Li H Doermann D 《IEEE transactions on pattern analysis and machine intelligence》2005,27(5):777-792
The detection of groups of parallel lines is important in applications such as form processing and text (handwriting) extraction from rule lined paper. These tasks can be very challenging in degraded documents where the lines are severely broken. In this paper, we propose a novel model-based method which incorporates high-level context to detect these lines. After preprocessing (such as skew correction and text filtering), we use trained hidden Markov models (HMM) to locate the optimal positions of all lines simultaneously on the horizontal or vertical projection profiles, based on the Viterbi decoding. The algorithm is trainable so it can be easily adapted to different application scenarios. The experiments conducted on known form processing and rule line detection show our method is robust, and achieves better results than other widely used line detection methods. 相似文献
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为了使矢量地图水印检测算法具有鲁棒性和运算简单,首先分析了矢量地图归一化相关检测算法的可行性:鉴于矢量地图图形的可嵌入水印长度较短,而且其DFT系数的幅度不能较好地满足高斯分布等原因,对不同图形的水印,采用归一化相关检测方法无法确定检测阈值,因此是不可行的,同时还分析了图形简化对水印检测的影响。为使水印算法抗简化,对几何失真鲁棒及减小运算量,提出了以图形的特征点的DFT系数幅度和相位作为水印嵌人域的方法,并提出了一种以提取水印与原始水印的相关系数作为检测值的实用的检测算法。实验结果表明,该算法是鲁棒的和可行的。 相似文献
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G. Louloudis Author Vitae B. Gatos Author Vitae I. Pratikakis Author Vitae 《Pattern recognition》2008,41(12):3758-3772
In this paper, we present a new text line detection method for handwritten documents. The proposed technique is based on a strategy that consists of three distinct steps. The first step includes image binarization and enhancement, connected component extraction, partitioning of the connected component domain into three spatial sub-domains and average character height estimation. In the second step, a block-based Hough transform is used for the detection of potential text lines while a third step is used to correct possible splitting, to detect text lines that the previous step did not reveal and, finally, to separate vertically connected characters and assign them to text lines. The performance evaluation of the proposed approach is based on a consistent and concrete evaluation methodology. 相似文献