A digital image watermarking technique using prediction method and Weber ratio

Most violations of digital image copyrights are the cropping of some parts of the image such as human face for applying to other images without permission. Seriously cropped watermarked images which have various shapes, sizes and locations make it difficult to verify the copyright. This paper proposes a digital image watermarking technique in the spatial domain using prediction method and the Weber ratio. Pixels for embedding the watermarks are altered based on the binary watermark image using the Weber ratio to control the strength of the watermark. Our technique does not require the host image to extract the watermarks. An extracted watermark is computed by subtracting the watermarked pixel with its predicted pixel The experimental results showed that our technique yielded high similarity of the watermarks when a watermarked image was attacked by JPEG compression and the cropping attack.