Novel multiple spatial watermarking technique in color images

This paper proposes novel robust multiple watermarking technique for color images in spatial domain. The host image is divided into four different regions. Each region consists of four 128*128 blocks in order to hide a watermark. The watermark is a binary image, encrypted and embedded into different regions of the blue component of the host image by altering intensity values of the selected region. Five watermarks can be extracted by comparing the intensities of the selected region of the original image with the corresponding region of the watermarked image. The extracted watermark bits can be determined by calculating the probability of detecting '0' or '1'. Only one watermark will be selected or built from the five extracted watermarks according to the highest value of the normalized cross correlation (NCC). The proposed watermarking technique is shown to be robust fora wide range of attacks, including JPEG2000, JPEG compression, rotation, cropping, scaling, self-similarity, rotation-scaling, rotation-cropping and filtering.