Improved Watermarking Scheme Using Discrete Cosine Transform and Schur Decomposition

TL;DR

This paper introduces a robust watermarking method combining Discrete Cosine Transform and Schur decomposition, allowing secure embedding of marks in images with improved resistance to various attacks.

Contribution

The paper presents a novel watermarking technique that integrates Schur decomposition with DCT, enabling the host image and mark to be the same size and enhancing robustness.

Findings

Robust against JPEG compression and noise addition

Effective under image cropping and filtering

Maintains watermark integrity under various attacks

Abstract

Watermarking is a technique which consists in introducing a brand, the name or the logo of the author, in an image in order to protect it against illegal copy. The capacity of the existing watermark channel is often limited. We propose in this paper a new robust method which consists in adding the triangular matrix of the mark obtained after the Schur decomposition to the DCT transform of the host image. The unitary matrix acts as secret key for the extraction of the mark. Unlike most watermarking algorithms, the host image and the mark have the same size. The results show that our method is robust against attack techniques as : JPEG compression, colors reducing, adding noise, filtering, cropping, low rotations, and histogram spreading.