Embedded In The Image Dual Watermarking Algorithm,

With the development of modern computer's computation capability,popularization of computers and the quick development of Internet, the security of personal information is being threatened. Traditional data encryption can partly prevent invalid distribution of data, but with the development of decryption technology, almost all the encrypted data are facing the danger of being cracked.Many hackers cannot help trying to crack the encrypted data while finding them,which makes the encrypted data are as dangerous as the unencrypted. In addition to that, when it comes to the validation and ownership check of data in use, traditional encryption cannot help anymore.Early research of digital watermarking dwelled on space field of images, but it proved not robust. It is proved that human vision has different sensitivity towards different part of images. In order to improve the robustility of digital watermarking,the watermark should be embedded into the important visual parts of the images,such as low frequency part. It leads to the development of transformation field watermarking. Present researches mostly concentrate on transformation field watermarking.The theory of Wavelet Transformation is a new math branch which emerged in recent years. It is a landmark since Fourier put forward Fourier Transformation in 1822, and can solve many problems which are hard for Fourier Transformation. The general idea of the use of Wavelet transformation in image processing is to perform multi-resolution decomposition with the target image, and then processing the coefficients of the sub-images in different space and frequency. The core is the processing of the coefficients, such as image compress and coding. According to the tower decomposition put forward by S. Mallat, the target image can be divided into 4 frequency bands: horizontal, vertical,diagonal and the low frequency part, and the low frequency part can still be further divided. Images generated by wavelet decomposition have different attributes to the original image. The power of the original image concentrates on the low frequency part, which is the most important part to human vision, which there's much less power in the detail parts of the image. The high frequency parts present the horizontal, vertical and diagonal edge information of the original image.This article also take use of the Wavelet Transformation to embed watermarks into the image.This article first introduces the fundamentals of digital watermarking, and makes some necessary statement on wavelet theory, and then put forward a new transformation field watermarking scheme based on human vision attributes. First,The RGB color image was changed into YIQ color image,Then,dual watermark was embedded in proper place in the light component of color image.The proposed algorithm allows to extract watermark without the help of original image.In the experimental phase, image with watermark has been attacked in several ways, such as image compression (JPEG), Gaussian filtering, median filtering,Gaussian noise, pepper and salt noise and resizing.The results show that the new watermarking scheme is fairly robust.