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Color Image Watermarking by Qingtang Su download in ePub, pdf, iPad

Whether single channel processing or multichannel synthesis, its essence is to treat greyscale image. Semi fragile Watermark Semi fragile watermarking is capable of tolerating some degree of the change to a watermarked image, such as the addition of quantization noise compression attacks. Among the protection techniques, digital watermarking is considered a powerful method, which is a technique that hides the secret information in a host image without affecting its normal usage. Optimally, the values of Y for every pixel corresponding to watermark pixels of a given value would be scaled such that perceived changes in their intensity are the same.

Spread-spectrum techniques are methods in which energy generated at one or more discrete frequencies is deliberately spread or distributed in time. Those skilled in the art will recognize that there are many other ways to represent pixel information. This method hides the watermark in the texture part of the image.

Spreadspectrum techniques are methodsThose skilled in the art will

The computer also includes a number of software modules. The watermarking software applies a watermark to the frontend processed image in accordance with the principles of the present invention, will be described in more detail later.

Embedding Stage The embedding stage is the first stage in which the watermark is embedded in the original image by using the embedding algorithm and the secret key. The wavelet transform decomposes the image into three spatial directions, i. To ensure that the watermark can be detected, the noise is generated by a key, such that the correlation between the numbers of different keys will be very low. One can use a sequence of random numbers or a recognizable binary pattern or an image as a digital watermark. Patchwork imperceptibly inserts a watermark with a particular statistic using a Gaussian distribution.