Improved invisible watermarking technique using IWT-DCT

Abstract

Invisible Image Watermarking is secret embedding scheme for hiding of secret image into cover image file and the purpose of invisible watermarking is copyrights protection. Image Watermarking have research challenges for increasing robustness against visual attacks and statistical attacks. Wavelet transformation based Image Watermarking techniques provide better robustness for statistical attacks in comparison to Discrete Cosine Transform domain and Spatial Domain based Image Watermarking. The combined technique of DWT and DCT provides advantages of both techniques. The DWT have disadvantage of fraction loss in embedding which increases mean square error and results decreasing PSNR. Robustness of watermarking technique is proportional to PSNR. The Proposed algorithm presents Hybrid Integer wavelet transform and discrete cosine transform based watermarking technique to obtain increased imperceptibility and robustness compared to DWT+DCT based watermarking technique. The proposed combined IWT+DCT based watermarking technique reduces the fractional loss compared to DWT based watermarking.