DIGITAL WATER MARKING:
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.
