Color Image Copyright Protection On Android Smart Phones

With the rapid development of Internet and communication technologies, it becomes more and more convenient to have access to the Internet on mobile devices. The launch of Android operating system triggers a boom of mobile application development innovation even more, so that a growing number of Internet applications begin to shift their focus of development from the desktop to the mobile device. However, mobile applications are becoming increasingly rich, which highlights the image copyright protection issues on mobile devices. As an important means of copyright protection, digital watermarking has been a hot topic of academic field, however, the digital watermarking solution for mobile devices are rare.In this paper, the research status of digital watermarking at home and abroad is reviewed at first place, and the progress of digital watermarking technologies on Android smart phones and the recent study of copyright protection watermarking in DCT domain are mainly described; Then, the paper gives an overview and the analysis of the basic framework, classification, typical algorithms, attack methods and performance evaluation of digital watermarking, furthermore, it briefly presents the history, system architecture and application components of Android platform.In order to protect the image copyright on Android phones, two blind color image watermarking schemes which combined the advantages of spatial domain and DCT domain were proposed according to the features of mobile devices’ limitation in computing speed, memory size and battery capacity. The proposed schemes conducted the watermarking embedding process which was originally done in the DCT domain in the spatial domain by making use of the characteristics of DCT. By doing so, the process of DCT and inverse DCT could be avoided so that the amount of calculation could be reduced significantly.In addition, the paper makes a brief introduction about the image watermarking Android application based on the proposed schemes and discusses the implementation of the schemes on Android platform in detail. The approach to accelerate the speed of color space conversion via replacing floating-point multiplication with shifting operation and the idea to solve the out of memory problem in image processing on Android platform is described at length. Finally, the experiments on the proposed schemes were conducted on an Android smart phone. Experimental results indicate that the schemes have a good transparency as well as strong resistance to attacks like JPEG compression, adding noise and cropping. Besides, the watermark can be extracted from the watermarked image without the aid of the cover image, which realizes a blind extraction and make those schemes fully applicable to mobile phone environment.