A Study On The Proposed Watermark Technique For Anti-counterfeit Based On Hadamard Transform Implemented By DSP

Nowadays, Internet has walked into many families around the world. And the multimedia technique makes progress with each passing day. They have brought a series of great challenges to the Digital Media Copy Right Protection in an open limitless web. As a result, Digital Watermark came out. Digital Watermark, as a brand new information hiddern technique, is a new research area in the information security field.This paper focuses on the print-scan resilient watermark algorithm. We proposed a watermark technique for anti-counterfeit based on Hadamard transform. And then we employ Ti DSP to implement the watermark retrieving process.Most of the high-end intelligent mobile phones adopt DSP as their kernel. These research fruit bring quite a lot of help to the design of next-generation intelligent mobile phone which could be of great use in the presswork anti-counterfeit applications.First of all, we review the developing route of watermark technique in the last 10 years. And we introduce the recent situation of watermark research in brief. Besides that, we show a great number of watermark applications in the anti-counterfeit and security area.After that, we present different classifications of watermark technique, its classified algorithms and some evaluation standards. Then, we analyze the watermark algorithm based on the Hadamard transform and its C language implementation in detail. The watermark algorithm based on 8*8 block hadamard transform is the kernel of the watermark anti-counterfeit technique adopted in this paper. Further more, we utilize spread spectrum and Arnold technique to advance the watermark algorithm, which improve the rubustness of the algorithm and visibility of the watermark.In order to resist the distortion brought by the print-scan process, a series of preprocess techniques are adopted in this paper, such as image scaling, cutting, rotation rectification, lightness and contrast adjust, .ect. Among them, we use Sobel operator, Radon transform and a new generation fast rotation algorithm in the image rotation rectification procedure.Last but not least, we design a PC terminal platform software to implement the proposed watermark algorithm by Visual C++ NET. And then, we carry out the watermark retrieving and examing procedure on the Spectrum Digital DM642 Evaluation Module. And this process is implemented in the DSP/BIOS realtime OS based on the C64x kernel. Above all, the experiment results demonstrate the ability of the watermark scheme proposed in this article, which shows sactisfacting effect in presswork anti-counterfeit.