Lossless robust image watermarking by using polar harmonic transform

Abstract

Abstract In this paper, we propose a lossless robust watermarking method by using the polar harmonic transform with reversible and robust watermarking techniques. Firstly, a new quantization watermarking strategy is designed to embed bits into the polar harmonic transform moments. Secondly, the compensation information for recovery of the original image is computed by using the quantized error, the watermarked error and the rounded error to represent the difference between the original image and the robust watermarked image. Finally, the final watermarked image is achieved by reversibly inserting the compensation information into the the robust watermarked image. The proposed method is able to recover the original image lossless in case of no attacks. In case of attacks, the watermark can be directly extracted for copyright authentication. Experimental results show that the proposed method is reversible and provides strong robustness to those content-preserving manipulations. Compared with previous state of the art methods, the proposed one not only provides stronger robustness to those noise-like image processing operations (e.g., JPEG compression with quality factor 10), but has an ability to resist geometric deformations like rotation and scaling.