Color image watermarking using local quaternion Fourier spectral analysis

Color image watermarking based on quaternion Fourier transform and improved uniform log-polar mapping

“…The advantage of this scheme is that the watermark is evenly spread into the luminance and chrominance components of the host image. Ma et al [12] introduced a color image watermarking scheme that takes advantage of an invariant feature transform and utilizing a geometric correction strategy to enhance the robustness of the watermark against geometric attacks. A watermark bit is embedded in QDFT coefficients of blocks centered on each of the invariant feature points.…”

“…q Reviews processed and recommended for publication to the Editor-in-Chief by Associate Editor Dr. Eduardo Cabal-Yepez. [1][2][3], discrete Fourier transform (DFT) [4], discrete wavelet transform (DWT) [5][6][7][8][9], and quaternion discrete Fourier transform (QDFT) [10][11][12][13][14][15][16]. Barni and Piva et al [1] proposed to embed the watermark in a subset of DCT coefficients for each color channel while exploiting the characteristics of the human visual system (HVS) and the correlation between RGB channels in order to achieve a good trade-off between robustness and imperceptibility.…”

Full 4-D quaternion discrete Fourier transform based watermarking for color images

“…Quaternions, which have been more and more used in color imagep rocessing in the past two decades, offer an interesting solution to achieve this goal. They represent an image by encoding its three color channels on the imaginary parts of quaternion numbers [4][5][6][7][8][9][10][11][12][13][14][15][16]. The main advantage of such a representation is that a color image can be processed holistically as a vector field [5][6][7].S o does color image watermarking [8][9][10][11][12][13][14][15][16], which mainly makes use of the quaternion discrete Fourier transform (QDFT).…”

“…In fact, they modulate a color watermark pattern added to blocks of QDFT coefficients. On their side, Ma et al [12] propose a semiblind color watermarking scheme based on local QDFT. They first utilize an invariant feature transform so as to get some significant points or features of interest, and embed a binary watermark into QDFT coefficients of blocks centered on each of these points.…”

Quaternion Zernike moments and their invariants for color image analysis and object recognition

“…Sangwine [24] then applied them to color image. Since then, the QFTs have been successfully employed in color image registration [25], [26], watermarking [27], [28], motion estimation [29] and texture analysis [30]. Recently, the use of quaternion-based moment functions to color image has been investigated [31], [32].…”