Hybrid Method For Image Watermarking Using 2 Level LWT-Walsh Transform-SVD in YCbCr Color Space

Abstract

Due to tremendous development in technology in recent time and availability of abundant tool, it is very easy for an unauthorized person to imitate crucial information which is present on internet. Therefore to shield valuable information present on internet there are various advanced techniques for example watermarking technique, cryptography technique, steganography and many more. With pace of time analog techniques replaced by digital techniques due to various advantages and in current scenario every country moving towards digitalization. Digital watermarking is a technique through which digital information is embedded into an image and secret digital data can be extracted at receiver side with authentication otherwise impossible to fetch. Spatial domain and frequency are the two techniques through which secret digital information can be embedded. In this paper two level lifting wavelet transform (LWT), Walsh Hadamard transform and singular value decomposition (SVD) technique has been proposed in YCbCr color space. First of all cover image and watermark image converted into YCbCr color space from RGB color space after that one of channel is selected for embedded purpose. Now perform first level LWT on the Y channel of cover and watermark image so that image split into four groups. Now apply second level LWT on any one of four bands. Further Walsh hadamard transform technique applied with singular value decomposition (SVD) technique to get enhanced output. In base paper DWT-DFT-SVD used but in this paper DWT-DFT replaced by LWT-WHT due to various advantages. One disadvantage of DWT is that the use of larger DWT basis functions or wavelet filters produces blurring and also ringing noise near edges in images. This disadvantage of DWT is overcome in LWT. Other advantages of LWT are that it significantly reduces the computation time and speed up the computation process. This method provides better results in terms of enhanced PSNR values and is able to withstand a variety of image processing attacks and besides this processing time also reduced.