Information steganography algorithm based on wavelet transform is that low - frequency ingredient of watermark is embedded in low - frequency part of host image . the experimental results show that the advantage of it is high efficiency of resisting the current various attack and data hiding , and that recovering image is good 基于小波变换的信息隐写算法是把水印图象的低频成分嵌入到原始宿主图象的低频部分，其抗攻击能力和隐藏能力强，提取的水印图象质量良好。
Simulation results show that the methods we presented have better performance . 2 . data hiding in the digital image combined with hvs ( human visual system ) , we can put secret message in the image without degrading the quality for its redundancy and to secure the information 2数字图象中的信息隐藏由于数字图象中包含了大量的冗余信息，结合人的视觉特性，我们可以把一些重要的秘密信息隐藏于图象中，而不会引起图象的失真，达到了对信息进行秘密传输的目的，在很大程度上保护了秘密传输的消息。
If possible try to recover portions of the image that have been tampered without accessing the original image . in the past , several techniques and concepts based on data hiding or steganography have been introduced as a means for tamper detection in digital images and for image authentication - fragile watermarks , semi - fragile watermarks , and self - embedding watermarks . the research of this thesis mainly includes self - embedding and semi - fragile watermarks 目前用于数字图像完整性验证及自修复的数字水印方案主要有完全脆弱性水印、半脆弱性水印、自嵌入水印等，本文主要研究自嵌入及半脆弱数字水印，分别从空域及变换域角度详细分析当前国内外现有的各种算法，指出其不足之处，并提出了相应的改进算法，实验结果表明本文算法的有效性与实用性。
Give precise criterions and descriptions of some important concepts and disposals of data - hiding technique such as cover , stego - object , hiding information , data embedding , data extraction , stego - key , stego - analysis , insensibility , covert communication , digital watermarking , robustness and etc . then propose a general mathematical model of data hiding which cover most models proposed in other papers and establish the basis for further theory analysis 本论文独立完成的主要成果有： ( 1 )对信息隐藏技术中的一些重要概念和处理给出了准确的规范和描述，主要有隐秘载体、隐秘对象、秘密信息、数据嵌入、数据提取、隐秘密钥、隐秘分析、不可感知性、隐秘通信、数字水印、鲁棒性等。
The necessary content of digital image , which is transported , is also discussed . 3 data hiding for authentication we can divide the information in the network into two kinds : one is that can stand slight tamper , for example , image , video etc . , and we can apply it as long as the tamper does not affect its quality and value . the other kind is the text 3认证数据隐藏技术网络中的传输信息可以分为两类，一类是可以经受篡改的信息，如图象，在篡改后只要不影响大致的内容及其使用价值，我们仍然认为这是可以接受的；另一类是文本信息，如果这些信息是经过加密处理的，经过篡改后所恢复的信息则与原始秘密信息大相径庭。
