Joint Bi-Watermarking and Halftoning Technique Capability for Both Tampered Areas Localization and Recovery of Still Image
This paper presents a method to localize and to recover the tampered areas in the watermarked image simultaneously. First, the proposed watermarking algorithm aims to embed a bi-watermark, which is the binary halftone of the downscaled host image, into the host image. While the watermarked image is tampered unauthorizedly, the extracted bi-watermark can be exploited to localize the tampered areas automatically without initial bi-watermark. Subsequently, Gaussian lowpass filter and quadratic programming are used to restore the bi-watermark to gray-scale image for inverse halftoning procedure. Eventually, the restored gray-scale image is used to recover the tampered areas.