DIGITAL WATERMARKING SCHEMES FOR AUTHORIZATION AGAINST COPYING OR PIRACY OF COLOR IMAGES

This paper presents digital watermarking methods for authorization against copying or piracy of color images. Watermarking is a very importantfield for copyrights of various electronic documents and media. With images widely available on the Internet, it may sometimes be desirable touse watermarks. Digital watermarking is the processing of combined information into a digital signal. A watermark is a secondary image, whichis overlaid on the host image, and provides a means of protecting the image. This paper presents the survey on digital watermark features, itsclassifications and applications. Various watermarking techniques have been studied in detail in mainly three domains: spatial, frequency andstatistical domain. In spatial domain, Least-Significant Bit (LSB), SSM-Modulation-Based Technique has been developed. For DCT domain, block based approach and for wavelet domain, multi-level wavelet transformation technique and CDMA based approaches has been developed. The Discrete Wavelet Transform (DWT) is currently used in a wide variety of signal processing applications. This paper also presents the various