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ABSTRACT:
A robust, computationally efficient and blind digital image watermarking in spatial domain has been discussed in this paper. Embedded watermark is meaningful and recognizable and recovery process needs only one secret image. Watermark insertion process exploits average brightness of the homogeneity regions of the cover image. Spatial mask of suitable size is used to hide data with less visual impairments. Experimental results show resiliency of the proposed scheme against large blurring attack like mean and Gaussian filtering, non linear filtering like median, image rescaling, symmetric image cropping, lower order bit manipulation of gray values and loss data compression like JPEG with high compression ratio and low PSNR values. Almost as discreetly as the technology itself, digital watermarking has recently made its debut on the geo-imaging stage.
This innovative technology is proving to be a cost-effective means of deterring copyright theft of mapping data and of ensuring the authenticity and integrity of asterisked image data. First developed around six years ago, digital watermarking is a sophisticated modern incarnation of steganography-the science of concealing information within other information. In the field of e-commerce, digital watermarking has already established itself as an effective deterrent against copyright theft of photographs and illustrations. Now digital watermarking software is finding uses within national mapping agencies and others working with asterisked images or map data. Current applications range from protecting valuable map data against copyright theft to securing photographic survey or reconnaissance images against tampering.
1. INTRODUCTION:
In the recent time, the rapid and extensive growth in Internet technology is creating a pressing need to develop several newer techniques to protect copyright, ownership and content integrity of digital media. This necessity arises because the digital representation of media possesses inherent advantages of portability, efficiency and accuracy of information content in one hand, but on the other hand, this representation also puts a serious threat of easy, accurate and illegal perfect copies of unlimited number. Unfortunately the currently available formats for image, audio and video in digital form do not allow any type of copyright protection. A potential solution to this kind of problem is an electronic stamp or digital watermarking which is intended to complement cryptographic process [1].
The technology:
Digital watermarking, an extension of steganography, is a promising solution for content copyright protection in the global network. It imposes extra robustness on embedded information. To put into words, digital watermarking is the art and science of embedding copyright information in the original files. The information embedded is called ‘watermarks’.
Digital watermarks don’t leave a noticeable mark on the content and don’t affect its appearance. These are imperceptible and can be detected only by proper authorities. Digital watermarks are difficult to remove without noticeably degrading the content and are a covert means in situations where cryptography fails to provide robustness.
The content is watermarked by converting copyright information into random digital noise using a special algorithm that is perceptible only to the content creator. Digital watermarks can be read only by using the appropriate reading software. These are resistant to filtering and stay with the content as long as Originally purposely degraded.
Digital watermarks don’t leave a noticeable mark on the content and don’t affect it’s appearance. These are imperceptible and can be detected only by proper authorities. Digital watermarks are difficult to remove without noticeably degrading the content and are a covert means in situations where cryptography fails to provide robustness.
The content is watermarked by converting copyright information into random digital noise using a special algorithm that is perceptible only to the content creator. Digital watermarks can be read only by using the appropriate reading software. These are resistant to filtering and stay with the content as long as Originally purposely degraded.