Position based watermarking

Abstract

This paper proposes a block based watermarking scheme where the information is associated to watermark blocks positions in a host image. Considering a digital image of size N/spl times/M there are many possibilities (given by the combination expression) as how to combine a given number of watermarks. For each of these possibilities, it can be assigned a bit string, making use of a coding scheme. The detector searches in the image for k positions that present the highest correlation to watermark blocks, determining where in the image these blocks were embedded. The decoding process relates these positions to a bit string. Also evaluate this technique regarding perceptual impact and show that for the same number of inserted bits use less energy if compared with other watermarking methods.