A Novel Comprehensive Watermarking Scheme for Color Images

Algorithm 2

Embedding robust watermark .

(1)  Step 1: select the layer G of the color image and the inscribed circle’s inscribed square of the carrier image I as the watermark embedding area , for the reason that the image information in the inscribed circle S of I will not lose due to the rotation.
(2)  Step 2: apply the one-level shearlet transform on , and obtain a low pass subband .
(3)  Step 3: apply DWT to .
(4)	Step 4: divide the low-frequency area (LL) into nonoverlapping blocks of 4 × 4 sizes, and SVD decomposition is carried out on each block.
(5)  Step 5: get the value of from the singular value matrix. The quantization step size is , set . Embed the watermark by quantifying using the following equations. The following equations are one kind of optimal quantization formulas proved in [19]: .
(6)  Step 6: repeat step 5 until all watermarks are embedded, and then perform a reverse transformation to get the watermarked layer.