An image copyright protection scheme using DCT and a table look-up technique

In this paper, an image copyright protection scheme was proposed which will not involve watermark embedment in the host image. The proposed scheme is suitable for protecting precious image work where the host image should not be altered. Multiple copies of unruly black and white binary images were created by the XORed entwinement with the binary copyright logo (i.e., the watermark) and the binary characteristic extraction of host image's DCT-coefficients. The multiple copies of unruly binary images were then time-stamped with a digital signature and registered with a certified authority for protecting the rightful ownership. A giveup-table was employed to contain possible attacked host image locations and a simple table look-up operation was applied to select better candidates from the multiple copies of unruly binary images for recovering the watermark. Experimental testing will be conducted on attacks such as blurring, rescale, cropping, sharpening, noise, rotation, and JPEG lossy compression. Results showed that the watermark for proof of rightful ownership can be recovered at a high NC > 0.95 and is visually undistorted.