Study On Digital Watermark Coding System In Pdm

The watermark technology is an effective technology for digital product copyright production. It overcomes the problem that the encrypted data is no longer safe after deciphering in traditional cryptograph technology. PDM (Product Data Management) technology is used to manage information of a whole life cycle of product, large quantities of engineering drawings can be saved by use of this technology. Only one code is designed for the product data in PDM system to suit to computer management. Popularization and development of net provide convenience for illegal embezzlement and tamper, bringing potential threats to the data copyright protection in PDM system. As a result, integrate the digital watermark technology with PDM data code to solve the problem of intellectual property of engineering drawing and safety protection.This paper expounds the digital watermark technology system, describes the characteristics, classification and application of digital watermark. It also discusses the universal model for image watermark algorithm, analyzes the same points and differences between the graphics and image of the computer graphics, describes the format of AutoCAD graphics data base, puts forward the code standards for parts and components of PDM system, as a result, the coding and watermark technology are closely integrated. The paper introduces the method of embedding the watermark of product code information into he engineering drawing, the details are as follows: according to the amount of secret information and carrier image to be hidden, hide information by randomly selecting pixel points in the image by means of random function, scatter the secret information bit in the whole carrier randomly to reach the purpose of information hiding.