信息隐藏技术 第四章 数字图像水印教学幻灯片.ppt

第四章数字图像水印
信息隐藏研究范畴
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Fabien博士(1999)
信息隐藏
鲁棒水印
隐写术
数字水印
可视分存
阈下信道
脆弱水印
隐写
隐写分析
普通水印
数字指纹
隐秘通道
数字水印定义
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Digital watermarking is the process of embedding information into a digital signal. The signal may be audio, pictures or video, for example. If the signal is copied, then the information is also carried in the copy.
数字水印是永久镶嵌在其他数据(宿主数据)中具有可鉴别性的的数字信号或模式,而且并不影响宿主数据的可用性。
Steganography and watermarking
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Steganography
In steganography, the object munication is the hidden message. This message may have nothing to do with the carrier. A goal of steganography is to keep the message (or munication of) from being detected.
Watermarking
Watermarks, on the other hand can be considered more of attributes of the carriers. They convey some information about the carrier, author, or owner. The existence of an embedded watermark may be known or unknown. The idea here has less to do with secrecy than to do with survivability.
数字指纹Digital fingerprinting
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数字指纹利用数字作品中普遍存在的冗余数据和随机性,向被分发的每一份图像、视频等数据拷贝中嵌入不同的信息,这些信息被称作“指纹”,使得该拷贝是唯一的,从而可以在该拷贝被非法分发时,根据其唯一性特征跟踪有盗版行为的用户。
数字水印系统
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Basic design of a system
Original
work
Message
(regarding
work)
Watermark
embedder
Watermarked
work
(looks like
original)
Watermark
detector
Detected
message
数字水印的属性
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Embedding effectiveness 嵌入的有效性
Fidelity 保真性
Data payload 数据容量
Blind vs. informed detection 盲检测或含辅助信息检测
False positive rate 虚警率或错误肯定率
Robustness 鲁棒性
Security 安全性
数字水印的分类
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水印载体 Carrier
嵌入域 Embedding domain
鲁棒性 Robustness
可见性(可察觉性) Visibility
检测方式 Detection
可逆性 Reversibility