Bitmap-based Digital Watermarking Technology And Its Applied Research

Along with the application of the digital media(include digital image, digital video, digitalaudio and so on) get more abroad, protect copyright become more important. Although theconventional encrypt system can protect data in the process of transfer, it will lose action oncereceived data being unfurl, So it is limited.Digital watermarking can work as a efficiency and availability way to resolve copyrightprotection. It can authenticate the possession of originality data that have embedded a secretinformation-watermarks. Watermark mostly apply in: 1)examination of illegality mediadata; 2)cognizance of media ownership; 3)prevention of media data copy; 4)distinguish theoriginal edition By digital image, watermarking can be sorted into invisible and visible, thispaper mostly discusses the invisible image watermarking.The disposal of watermarking mostly has two ways: Spatial domain and frequency domain.This paper works on the watermarking in this ways. It separately discuss the principium,embedding,inspecting,example and comment of the algorithmic. This paper disposes ways ingray and color images, and also work in this two methods. In the last of this paper, there isanalysis of many attack of image watermarking.Using Spatial domain to dispose watermarking, there is two way in this paper: direct-endow-byte and linearity-adding After analyzing, this two arithmetic have remarkable bug andthe watermarking will be destroyed easily by many attack methods. So these can't get apply inpractice.Using frequency domain to dispose watermarking is keystone of this paper. Because thisarithmetic has much advantage relative to Spatial domain. There are many arithmetic infrequency domain. This paper mostly discusses two methods: Discrete Fourier Transform (DFT)and Discrete Cosine Transform (DCT) to dispose watermarking, and separately analysis thedisadvantage.Two sOrtS of Mod in Discrete Fourier TranSform tO dispose watwng and theywt differnt attack ways. One is c ircu mvol vo MwW ng allth odi c. Another isshift-ci rcu mvo lverobustwatennarking edthmei c. There al so twO Patul ous ways in the fi rstedthIneic, tha is ziWembedding and areaembeddng.There are also tWo Mc in DisCrete Cosine TranSform this PaPer they are adjustingWNding and base on HVS (Human Msion System block classification arithedc.Above arithodic is just disposed gray iInages. But some arithmetic also can be used indisposing color bitInaP. consider the advantag this Paper only discusses the arithotic in DCTto dispose wedng.The attack analyes in the last of this mp Inainly discuss many ldnd of attack mode anddefense methods.