A study on digital watermark technique based on the phase modulation of sampling lattice and application to still picture

1. 该方法利用原始图像作为标准参考信息对嵌入数据进行解码，提高了算法的抗攻击能力。我们积极利用这一特点，提出了一种新的方法，即用经过数据压缩编码处理的图像代替原始图像作为标准参考信息。我们使用授权的源编码（即JPEG）来检查所提出的方法。结果表明，该方法能较好地改善误码率特性，以《塞尔达传说》为例，在信噪比约为01的情况下，在JPEG压缩比为17的情况下，约有1000个嵌入数据位被正确解码。dB.2。编码和解码信号处理说明从解码错误性能的角度出发，通过比较基于相位调制的数据嵌入方法的鲁棒性，讨论了基于相位调制的数据嵌入方法的编码信号处理。结果表明，与双线性插值相比，带限插值和三次样条插值具有更好的性能。基于对背叛者像素值的算术平均值的使用，研究了最简单的背叛者合谋攻击的效果。结果表明，通过嵌入Walsh函数，新方法可以成功地揭示出被测者的身份。基于纠错码和密码学的数字水印本文提出了一种结合编码理论和密码学的数字图像数据伪造检测新技术。我们证明了以适当的方式将纠错码与密码结合起来是非常重要的。我们还提出了一个使用RSA密码的新技术的例子。

1. The improvement on the attack resistanceOn this method, an original picture is necessary for decoding embedding data as a standard reference information. We positively utilize this feature and propose a new method in which we use a processed picture by data compression coding instead of the original pictures as the standard reference information. We examine the proposed method with the authorized source coding (that is, JPEG). The results show that the new method can exactly improve error rate characteristic such that, for instance, as "Zelda", approximately 1, 000 embedded data bits are decoded correctly with the JPEG compression ration of 17 under the degradation of the signal-to-noise ratio within approximately 01. dB.2. A note on the encoding and decoding signal processingFrom the viewpoint of decoding error performance, we have discussed the encoding signal processing for the phase modulation based data embedding method by comparing the robustness against the degradation due to the JPEG data compression. As a result, we conclude that the band-limited interpolation and cubic spline interpolation give better performance, compared with the bi-linear interpolation.3. The disclosing betrayers in collusion attackThe effect of the simplest collusion attack with this method, based on the use of the arithmetic mean of pixel values by betrayers is examined. The results show that by embedding the Walsh function, the new method can successfully disclose who they are.4. Digital watermark based on error correcting codes and cryptographyWe propose a new technique which can detect the forgery of the digital image data by applying both coding theory and cryptology. We show that it is important to combine error correcting code with cryptogram in an appropriate way. We also present an example of new techniques that use RSA cryptogram.