OPTIMIZATION THE METHOD OF APPLYING DIGITAL MARKERS TO THE IMAGE BY USING WAVELET TRANSFORMS
[1. Information systems and technologies]
Author: Polovynko I.I., Electronics and Computer Technologies Department, Ivan Franko National University of Lviv, Lviv
With the rapid development of the Internet, the amount of information, which includes various types of documents, high-quality multimedia audio and high-quality video products, as well as the transmission of paper newspapers via computers and communication services, has increased significantly. At the same time, methods of digital image processing are being intensively developed [1-3].
All these opportunities lead to the intensification of trade in multimedia products in the computer market by e-commerce. In parallel with trade, technologies for copyright protection and legal distribution of multimedia products are being developed.
Therefore, there is a need to develop methods for applying to the documents of multimedia identification marks of the owner, in the form of a visible or invisible image. In general, data encryption, securities application, data decoding, securities verification, as well as hardware and software, which are the basis of system security, are used as security criteria for digital data trading.
Currently, many scientific papers are devoted to the application of markers (digital signatures, watermarks) on the image [4, 5]. Also number of works are deal with wavelet transformations. However, many issues still require study. In particular, this applies to the application of markers on color images. Therefore, the presented work is devoted to the improvement of the technique of applying markers to color images by using wavelet transformations.
All methods of protection image seek to meet two main requirements: the invisibility of the markers and its stability during image modification while maintaining its desired quality.
The technology of applying the markers depends on the type of means and methods of data conversion. It involves hiding information in visual data, such as images and videos, and is divided into visible and invisible markers application.
Studies have shown that image, labeling in the wavelet area provides reliable protection of images from external influences and can be used to transmit large amounts of information in a short period of time. Figure shows a diagram of the device that will provide such transmission of marked information. The circuit consists of two parts - a provider and a receiver of digital information which are connected by a communication line. In the information provider, the image enters the computer's input, where it is decomposed by wavelet functions into four levels. This is where the decomposed black-and-white image of the marker arrives, which is additively superimposed on the details of the high-level subbands of the decomposed image.
Fig.. The structure of the application and selection of the marker in the wavelet region.
The resulting tagged image, as well as the marker image, is sent to the receiver via a communication line. It should be noted that there is no need to transmit the original image to the information receiver, because it is not used for further processing. Due to the fact that the transmission line can introduce certain distortions into the signal, the receiver uses a correlator. In this case, the marked image is converted using the inverse discrete wavelet transform. The correlations between the marker and the detailed frequency components of the image at the first and second levels are then calculated. The final correlation response is chosen as the maximum value for all subbands.
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