ABSTRACT
Such as the approach and techniques, based on research of the characteristics of color drawings based on the use CIELab color space, the use of certain methods to achieve watermark embedding work, which uses the DCT coefficients drawings take on this factor ways and means of linear operation, he used several experimental validation repetitive work, concluded: using this algorithm embedded watermark, there is a practical feature is able to tell whether there is piracy from happening, if after a scan is shown to be genuine, and if two scans are detected that piracy has occurred. Haisheng and other presents a watermarking algorithm, in essence also Pictured in color printing works based on the use characteristics CIELab color space to add a watermark to do work on it. Zhang and other research work focused on selecting different areas watermark, they chose the space domain, you can add a watermark in it anti-print scanning, due to the presence of the spatial domain pixel value is unstable, there is a big change characteristics, so to watermark to go through a complicated process. Lin (Lin) conducted a study on the Fourier transform his main research is the Fourier transform of the crop, rotate, zoom and other features, fragile watermarking research in the field, earlier research they conducted, the results of their study is the use of log-polar map, or log-log map the spatial Fourier transform coefficients, where the watermark, this approach can be effective against printing and scanning attacks. Li Gang, etc. Based on the study of binary drawing printed on the drawings, targeted text area made full use of the space, and then watermarked operating on this basis, then make the text area is divided into several blocks, watermark a numerical value determined by the characteristic amount value, which is the area of the 0/1 ratio of the feature quantity. Tada Xi (Tadashi Mizumoto) like the case of print scans were studied
1 INTRODUCTION
Digitized drawings, refers to the traditional paper maps or other materials (analog signal) converted by a certain method of computer input devices and recognizable drawing data (digital signal) process, the purpose is to facilitate further computer for storage and processing of data. Realization of drawing digitization key is accurate, quick and convenient for drawing data the old maps were digitized, standardization of data collection, on the basis of all the data for efficient editing, updating, storage. With CAD (Computer Aided Design) technology digitized drawings, is to complete engineering drawings into a computer store, a better way to edit and output maps tasks, its strong support management, decision support functions are also to be applied in practical work and play.
