A Fragile Watermarking Based on Binomial Transform in Color Images

Abstract

In this paper, a novel Binomial Transform based fragile image watermarking technique has been proposed for color image authentication. The Binomial Transform (BT) is used to convert each 2 × 2 sub-image block of the carrier image into transformed block corresponding to red, green and blue channels in sliding window manner. One/two/three watermark bits are embedded in second/third/fourth transformed components starting from the least significant bit’s position (LSB-0). An adjustment has been incorporated to adjust embedded component closer to the actual value without hampering the fabricated bits. The inverse Binomial transform (IBT) is used to convert the transformed components back into the spatial domain. A delicate re-adjustment method is applied on the first transformed component to remain the pixel components in a valid range. The embedding operation in succession generates the final watermarked image. At the receiving end, whole watermark is extracted based on the reverse procedure and authentication is done through computed message digest and extracted bits. Experimental results conform that the proposed technique produces high payload and Peak Signal to Noise Ratio (PSNR) as compared to existing transformation based techniques[1, 5].