This paper proposes an improved watermarking algorithm for high fidelity of image. While the watermark is embedded in the third level subband of wavelet domain according to neighboring symbol’s mean value and odd-even adjugement rule

the watermark embedding strength of the third level subband can be increased or decreased according to frequency characteristics of the second level subband. This is a blind watermarking which can confirm the copyright without the original image. Experimental results and attack analyses show that the watermark algorithm can produce the watermarked image which has high fidelity and is robust against some image processing operations

such as JPEG lossy compression

filtering and additive noise attacks.