Multi watermarking algorithm based on DCT and hash functions for color satellite images

This paper deals with a multi watermarking algorithm which embeds robust ownership watermark and fragile authentication information into satellite images to protect the copyright ownership and integrity of the images. This new watermarking technique is totally blind and does not require the original satellite image for the extraction process of the embedded information. The robust watermark is embedded first in the discrete cosine transform (DCT) and the second hash authentication code is embedded in the spatial domain. The new technique offers high peak signal to noise ratio (PSNR) and similarity structure index measure (SSIM) values. The technique was successfully tested on a variety of satellite images. The fragile watermark is sensitive to any slight tampering and can locate the area of the editing. The robust watermark survived many intentional and non intentional attacks.