The Design And Implementation Of Image Digital Watermarking System Based On Android

Digital watermarking technology to solve the problem of copyright protection of multimedia works has always been a hot spot in people's research.At present,there are many watermarking algorithms with better performances,but with the popularization of smart phones and the gradual development tendency of applications from PC to mobile,digital watermarking technology based on Android has gradually become a hot research topic,developing mobile version of the watermarking has become people's needs.The digital watermarking algorithm is improved with color image as the research object in this paper,and the watermarking system is designed and developed which is suitable for Android platform.Based on the DCT domain watermarking algorithm,this paper proposes an algorithm to realize watermark embedding by modifying the middle-low frequency DCT coefficients.The innovation of this method is that there is no need to modify all the DCT coefficients,or the low frequency coefficients,the intermediate frequency coefficients and the high frequency coefficients,making up for these algorithms' shortcoming such as run longer,poor visibility,low robustness.In addition to the local operation of the Android phone,this article also increases the server-side operation mode,through the users' operation at mobile client,the core algorithms are transplanted to the remote server reducing the program running time and improve the efficiency of the implementation furtherly.The DCT domain image digital watermarking system includes the following main functions: carrier image selecting,watermark image preprocess,DCT domain watermark embedding and extraction,the caculation of evaluation index such as MSE,PSNR and NC.In the analysis of experimental results,this paper tests and compares the proposed improved algorithm and contrast algorithms from four aspects: run time,mobile power consumption,invisibility and robustness.The results show that the proposed algorithm has the best effect in the embedding and extraction of image digital watermark,which achieves the balance of the above four evaluation indexes and shows good application prospects.