Robust Watermarking Technique using Hybrid Wavelet Transform Generated from Kekre Transform and Discrete Cosine Transform

This paper presents a novel image watermarking technique using Kekre’s algorithm to generate hybrid wavelet transform DKT_DCT from Kekre transform and Discrete Cosine Transform. In the proposed technique, 256x256 hybrid transform is generated using 16x16 Kekre transform and 16x16 DCT whereas, 128x128 hybrid wavelet transform is generated using 32x32 Kekre transform and 4x4 DCT matrix. Generated DKT_DCT transform is applied to host and watermark in three different ways: column wise, row wise and full transform. Performances of these three ways of applying transform are compared against various image processing attacks namely image cropping, image compression, adding noise and image resizing attacks. Column DKT_DCT transform is most robust for compression and resizing attack whereas row DKT_DCT wavelet transform is most robust for cropping, JPEG compression attack and binary distributed run length noise attack for increased run length. Column and row DKT_DCT transform show exceptionally better performance than full DKT_DCT wavelet transform. Also column DKT_DCT transform is observed to be better than column DCT wavelet transform for above mentioned attacks and row DKT_DCT wavelet is better than row DCT wavelet for binary distributed run length noise attack showing the strength of hybrid wavelet transform over wavelet transform generated from same component orthogonal transform matrices.