Protecting the Content Integrity of Digital Imagery with Fidelity Preservation

摘要

Fragile watermarking is applied to protect the content integrity of digital images. The main concerns related to watermarking include retaining the quality of the watermarked image and retaining the ability to detect whether any manipulation has occurred. Because recent watermarking techniques seriously distort the quality of the protected image after embedding the authentication code into the image content, attention has been drawn to how to satisfy both the need for image fidelity and detection ability. To account for the influence from both essentials, a novel algorithm is proposed in this article. The new scheme utilizes a weighted-sum function to embed (n+1) authentication bits into a block with 2~n pixels by modifying only one original pixel with (±1). With fewer authentication codes, the new process can protect the content of the image. The experimental results demonstrate that the approach can guarantee the fidelity of the watermarked image while retaining tamper-proof functionality.