Magnetic ink printing digital watermarking (Part 2)
digital watermarking is anti-counterfeit and its charging time is less than 8 minutes
with the development of digitalization and network, the infringement, piracy and arbitrary tampering of digital products are becoming more and more serious. A technology that helps protect copyright was born, that is digital watermarking
what is a digital watermark
the so-called digital watermarking is to add some digital information to multimedia data (image, sound, video signal, etc.) to achieve the functions of file authenticity identification, copyright protection, etc
the process of digital watermarking is to add some information that can prove the ownership of copyright or track the infringing content to the protected digital objects (such as still images, video, audio, etc.), which can be the author's serial number, company logo, meaningful text, etc. It can be used to identify the source, version, original author, owner, publisher and legal user of documents, images or music products. They are hidden in the original image as invisible data, so as to protect all copyrights and not damage the subjective quality and integrity of the image. Watermarked images can maintain the image format and other information of the original image, and do not affect the copy and processing of normal information
in terms of subjective quality, the difference between the two images is very small and cannot be detected with the naked eye. Only through a specific decoder can hidden information be extracted
how to protect the copyright of digital products
digital watermarking can protect the ownership of digital images, videos, sounds, etc. When using photoshop7.0 images, you can protect your works by using the digital watermark filter. Generally, the filter used is digimarc
The digimarc filter consists of two components, namely embedded watermark (embedded digital watermark component) and read watermark (horizontal leveling component for reading the plane of digital watermark concrete foundation). Their main function is to add copyright information to Photoshop format images. When users use such images processed with filters, they will be reminded that the image is protected by a digital watermarkthe digital watermark is added to the image in the form of speckle, which will not affect the characteristics of the image, but it can shield a variety of image operations, such as color correction, filter effect, printing, etc
using the embedded digital watermark filter
using the embedded watermark filter can add copyright information to the image. When other users use the image, they will remind the user that the image has been embedded with digital watermark using digimarc picture Marc technology, that is, the copyright has been protected. This watermark effect is added in the form of miscellaneous lines, which is not easy to detect with the eyes. It can be permanently saved in computers or printed publications. Embed watermark filter can only be used for CMYK, RGB, lab or grayscale images
based on the protection of copyright, the watermark effect cannot be cancelled. In other words, images that have been watermarked by digimarc cannot be watermarked, otherwise there will be no copyright. Therefore, before embedding the watermark, it is best to copy it as a copy backup. In addition, before embedding watermark in image, the following contents must be considered: image color change, image pixel number, workflow, etc. The embedded watermark filter is generally used in the final image. Because many operations will be limited after embedding the watermark, it is necessary to complete the operation of all images before using the filter
digimarc filters use figures provided by digimarc. To embed a digital watermark in an image, you must first register with digimarc to get a creator ID, and then insert this ID number into the image along with the copyright information (such as the year and time of creation)
first execute the filter | digimarc | embedded watermark filter, first click the personalize button to open the embedded creator ID dialog box, and then click the register button to find the page of digimarc web through the Internet and apply for a user specific license number (ID number). The returned page will provide a pin code (two digits) and an ID number. You should keep the pin code yourself. The ID number is public, and it is your number that others read. At the same time, this ID number is also your password to enter personal information maintenance. Then enter the ID number in the creator ID text box, Then click the "OK" button to return to the embed watermark dialog box. If the user has created an ID number, the "personalize" button in the embed watermark dialog box will become a change button, allowing the user to enter a new creator ID. after obtaining the ID, you can click the copyright year (s) in the copyright information option group In the text box of the image, type the year mark created by the image, so that it can be embedded in the image as a watermark
of course, to truly reflect the copyright protection effect of digital watermarking, we need to set the following attributes of the image according to our own needs in the image attributes option group:
1.restricted use (restricted): other users can be restricted from using the image, that is, the copyright has been owned
2.do not copy (D. regularly check whether the connecting line on the rear panel of the controller is in good contact and allow copying): after selection, it is not allowed to copy the image file
3.adult content: after selection, the watermark will indicate that it contains restricted content to restrict minors from viewing restricted content
4. Target output (output standard): the target output option determines the type of watermark written into this image. Print is used for printing, which has the strongest watermark effect and the greatest impact on the image. After printing the photo, re import it into the computer by scanning, reverse shooting and other imaging means, and also use digimarc to read out the watermark
5.watermark durability: set value. The larger this value is, the greater the impact on the quality of the image is, but the less likely it is to be damaged. Level can be used for high-quality printing output, while level is mostly used for multimedia and publishing. Although it affects the image quality greatly, it is not easy to see the difference on the screen
after completing the above procedures, click the "OK" button to end the operation of embedding the digital watermark effect
use the read watermark filter
read watermark filter is mainly used to read the digital watermark content in the image. When an image contains a digital watermark effect, a symbol of (c) will be displayed on the title bar and status bar of the image window
to use this filter, just execute the filter|digimarc| command when the stress reaches point B. Photoshop will analyze the image content and find out the embedded digital watermark data. If you find the ID and related data, you can connect to the website of digimarc company and find the author's contact information and the rental fee (that is, renting the image with copyright) according to the ID code
at first, the technology of digital watermarking was only used to recognize digital images. Now it has developed to include other forms of digital media, especially sound and video. Recently, sound files have attracted wide attention due to the desire of the music industry to implement MP3 digital watermarking scheme. A typical example of this application is DVD anti copy system, which adds watermark information to DVD data, so that DVD players can judge its legitimacy and copyability by detecting the watermark information in DVD data, so as to protect the commercial interests of manufacturers
digital watermarking has opened up a new way of information security. Its imperceptible concealment and the ability to resist various attacks can realize the integrity protection and tamper identification of digital products, and can also be used in digital anti-counterfeiting. Digital watermarking will become one of the core technical measures of copyright protection and authenticity authentication of digital works, and play an irreplaceable role in e-commerce transactions
source: printed in Guangzhou
LINK
Copyright © 2011 JIN SHI