Anti-counterfeiting company introduces two common anti-counterfeiting methods_Anti-counterfeiting company-Shanghai Nuobiao Anti-counterfeiting Technology Development Co., Ltd.
With the development of digital information, the protection of digital images is becoming more and more important. As an important method of protecting digital images, digital watermarking technology adopts embedded hidden information into digital images. After transmission, compression and some malicious attacks, the hidden information can be extracted, so as to distinguish the authenticity of the image. . In the process of digital printing, the digital image must go through the halftone process in order to become a printed image. Anti-counterfeiting companies introduce two common anti-counterfeiting methods. 1. Halftone digital watermarking technology In the process of digital screening, continuous digital images are screened to generate halftone images, which greatly affects or even destroys the hidden watermark information. The predecessors have done a lot of research on halftone digital watermarking technology, and put forward many algorithms of halftone digital watermarking technology. According to the different watermark embedding methods, it can be divided into two categories: spatial domain watermarking and transform domain watermarking. At present, the spatial halftone watermarking technology is roughly divided into two categories. One is to scan the watermarked image and use the corresponding algorithm to extract the watermark. Information method, this kind of technology is called halftone digital watermarking technology of scanning and extracting watermark; another kind of method is to hide the watermark information in two or more halftone images, and then superimpose these images to directly observe the hidden information, which is This method is called the halftone digital watermarking technique of superimposed extraction watermarking. At the same time, there are microstructure screening anti-counterfeiting technology. 2. Anti-counterfeiting technology of halftone image For these problems of halftone watermarking technology, there are two main research directions: one is anti-print scanning digital watermarking technology, and the other is digital watermarking technology of direct detection. Anti-print scanning digital watermarking technology is to prevent the watermarked image from being affected by color separation and digital screening in the printing process. The main achievement of the print-resistant scanning digital watermarking algorithm is the anti-counterfeiting of 2D and 3D barcodes, which anti-counterfeiting companies say have been widely used, such as commodity information and train tickets. The digital watermarking technology of direct detection does not extract the watermark by scanning, but directly detects the image through some common or special equipment, so as to determine the authenticity of the printed matter. This anti-counterfeiting technology is generally processed in the spatial domain, such as microstructure screening anti-counterfeiting and moire anti-counterfeiting. Anti-counterfeiting companies say that microstructure screening anti-counterfeiting technology is to embed extremely tiny dots that are invisible to the human eye, or various special dot shapes or patterns to replace conventional dots during the prepress process, and then directly use a magnifying glass at a known position. Observe the watermark. Halftone watermarking technology has developed rapidly, and halftone anti-counterfeiting technology of raster extraction watermark is a direct detection anti-counterfeiting technology, so as to reduce the influence of scanning on watermarked images.