The difference and application of ordinary watermark and digital watermark

Digital watermarks are very different from ordinary watermarks, but they all play a significant role in anti-counterfeiting, copyright certification and protection.

An ordinary watermark

Ordinary watermarks are also known as traditional watermarks, which were produced during the papermaking process. When the paper is copied, when the paper sheet is just formed by interweaving with water, a part of the wet paper sheet is displaced by means of a special pattern character to adjust the thickness of the paper layer. The pattern of text, wait until the paper is dry, you can see the watermark of these pattern text to see the light. Watermark is divided into black watermark, white watermark and so on. The most common is a black watermark, which is relatively simple. A watermark device with text and graphics is added to the paper machine. The graphics are concave in the net. When the paper is formed, more pulp is attached than the other parts of the paper to make the paper. The watermark text portion is thicker than the rest of the paper. The white watermark is opposite to the black watermark. The picture and text is convex. When the paper sheet is formed, the watermark graphic part is less than the pulp attached to other parts of the paper, and the thickness is small.

Ordinary watermarks have been formed during the papermaking process, and the production of watermarked papers is strictly controlled in various countries. Therefore, it can be said that it is difficult to imitate watermarked papers. In today’s era of advanced science and technology, ordinary watermarks are still recognized as an effective anti-counterfeiting technology by security experts around the world. They continue to be adopted and developed by various countries, and are used by most countries’ banknotes, various bills, and certificates. Paper, with its own different watermark images and text.

Second, digital watermarking

Digital watermarking is based on information hiding technology. It uses tag information with specific significance. It uses digital information processing methods. It is processed by computer processing and hidden in digitized digital files such as images, sounds, documents, and videos. It passes digital files. Detection and analysis to extract hidden watermark information, use the watermark information to prove the author's ownership of his works, and to identify the authenticity of the product and prosecute evidence of illegal infringement, so that the digital watermark becomes intellectual property protection and digital multimedia anti-counterfeiting Effective means. The digital watermarking technology has the following features:

1, invisibility. When an ordinary person uses a carrier data containing a watermark, it is difficult to determine the location where the watermark is hidden. The change in carrier data caused by the embedding of the watermark information is a change in the carrier data caused by the observer's visual or auditory system. Not easily to find out.

2. Provability. The hidden watermark information should provide reliable evidence of the ownership of the product to be protected. A good watermarking algorithm should be able to embed the necessary information (such as product logos or meaningful words, etc.) into the protected object and extract it when needed, as an uncontroversial evidence to the product. Identification.

3, reliability. Reliability means that the watermark should be able to withstand a certain amount of physical and geometrical distortions, including intentional (such as malicious attacks) or unintentional (such as image compression, denoising, printing, scanning and copying, size conversion, etc.). After these operations, the robust watermarking algorithm should still be able to extract the embedded watermark or prove the existence of the watermark from the watermark carrier. If the watermark is forcibly removed, the carrier data must undergo large changes and the quality degradation is more serious. Cannot be used consistently.

Digital watermarking technology hides a certain amount of information through special embedded software into the carrier data. For testing and identification, as long as the carrier data is input into a computer, and special extraction software is used for detection and extraction, these two processes do not require special equipment and no additional cost is added, taking into account the current technology used in print anti-counterfeiting. With the increase in cost, people began to study the use of digital watermarks in anti-counterfeiting of printed materials, hoping to achieve a reliable anti-counterfeit effect without increasing costs, and to study the surface. This method is feasible. The following digital watermarks are used in prints. The anti-counterfeiting application in the specific introduction is as follows.

When the image is used as a carrier, when the image to be printed is prepared, the watermark is embedded to hide the certain watermark information as seen in the image. The original image and the watermark embedded in the watermark are visually indistinguishable. It is almost exactly the same, and then the image is output, processed, printed, and printed. During the inspection, the image in the printed matter is scanned into the computer to obtain a digitized image. The digital image is first corrected and denoised, and then the watermark information is detected by the extraction software, and the printed matter is discriminated according to the situation of the watermarking information. Pseudo. For counterfeiters, this method is difficult to counterfeit because the hidden information is invisible. They neither know the method used for watermark embedding nor what information is embedded in the watermark, so they cannot hide the hidden information. Only copy the text and images of the prints that can be seen by the cats and tigers. In this case, the fake prints do not contain watermark information, and the watermarks cannot be extracted during the test, so that authenticity can be determined.

Digital watermarking has its own technical advantages compared to other print anti-counterfeiting technologies, which are mainly reflected in the following aspects:

(1) The cost of anti-counterfeiting is low, and there is no need to add special materials, change the original printing production process, keep printing costs constant, and do not need to invest large amounts of funds at one time, and can easily realize high-tech anti-counterfeiting agent copyright protection.

(2) Forgery is difficult, digital watermarking has a high technological content, and it is a relatively new technology in the field of anti-counterfeiting. The watermark information has a great degree of concealment, and it can also use encryption technology, which is very fake.

(3) The technology upgrade is fast. According to the product features, a set of special software is designed and manufactured for each product. The anti-counterfeiting information is updated and upgraded very quickly.

(4) It is easy to implement, and watermark embedding and detection and extraction can be realized through scanners or special detectors and supporting software.

(5) Good compatibility, non-interference with other anti-counterfeiting measures and copyright protection, mutual compatibility, and further improvement of anti-counterfeit effect.

In short, ordinary watermarks are added to paper during the papermaking process. Such watermarks are usually used to make important documents and documents. In order to ensure the excellent performance of paper, the requirements for raw materials used in papermaking are high, which results in watermarked paper. The price is higher, and ordinary watermarks can be seen with the naked eye and may be counterfeited by various means. However, due to the state's better control of watermarked paper, ordinary watermarking is still a widely used method of anti-counterfeiting for paper prints. Compared with ordinary watermarks, digital watermarking technology has the technical advantages of safety, reliability, low cost, difficult to counterfeit, and strong adaptability. It is gradually gaining importance in the security of printed materials. If common watermarks and digital watermarks are used together in the anti-counterfeiting of printed materials, letting the two together exert their own anti-counterfeiting effects, it will certainly make it harder for the printed materials to be forged. It is believed that with the continuous improvement of the research level and the continuous development of the anti-counterfeiting market for print products, Both will play an increasingly important role in the field of anti-counterfeiting.

Source: China Ink Technology Network