Project-vector of Spread Transform Dither Modulation Watermarking Algorithm
扩展变换抖动调制水印算法中投影向量的研究

Spread Transform Dither Modulation(STDM) is a watermarking algorithm having good performance.In this algorithm,the Project-vector used for spread transform is an important factor that affects its performance.This paper studies on the project-vector of STDM.Random project vector,uniform project vector,parallel project vector,project vector chosen according frequency and project vector chosen according HVS are introduced,the robustness under different project vectors is compared and analyzed,the way of choosing project-vectors that makes the robustness of STDM best under different attacks is obtained.Further,in order to make full use of the HVS's characteristics,choosing project-vector combined with HVS is introduced,and the experiment results show that by using this method,the visual quality and robustness of the STDM algorithm can be improved further.