회전 변환에 강인한 주파수 영역 로고 삽입 워터마크 방법

A Rotation Resistant Logo Embedding Watermark on Frequency Domain

In this paper, we propose a rotation resistant robust logo embedding watermarking technique. Geometric manipulations make the detection process very complex and difficult. Watermark embedding in the normalized image directly suffers from smoothing effect due to the interpolation during the image normalization. This can be avoided by estimating the transform parameters using image normalization angle and moments, instead of embedding in the normalized image. Conventional rotation resistant schemes that use full frame transform. In this paper we adopt DCT and calculate masking using a spatio-frequency localization of the $8{\times}8$ block DCT coefficients. Experimental results show that the proposed algorithm is robust against rotation process.