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Research of the possibility of sharpening image information intended for electronic publications

The article is devoted to the possibility of sharpening images intended for electronic publications through the use of mathematical filtering algorithms. It is believed that the processing of images with special filters can increase their sharpness, but in conditions of visual perception from the screen of an electronic device, the use of some filters does not always give a significant increase in sharpness. This is due to the physiological features of the structure of the human visual system, which works as a low-pass filter. If the degree of filter impacts is insufficient or the mathematical algorithm underlying the filter itself will show low efficiency under visual perception conditions, the sharpening results of image details can be completely lost. On the other hand, for the final consumer it is important to reproduce precisely those image details that relate to informative areas, which are perceived by the human eye and which determine the plot content of visual information. Thus, the effectiveness of application sharpening filters is determined by the effectiveness of their impact on the informative areas of the image. For reaching the purposes of this article, evaluation of the effectiveness of sharpening filters in terms of visual perception of final images by the consumer is carried out by the method of spectral analysis. A comparative analysis of the spectra obtained for images processed using various sharpening algorithms allows us to judge the real change in sharpness, as well as the effectiveness of the implementation of these algorithms in terms of visual perception of the image. The results of the study can be used to develop recommendations for choosing the necessary sharpening algorithm, depending on the nature of theimagesd. Read more...

Evaluation of the fluctuation properties of the interaction of halftone screens of various lineatures when reproducing full-color images

The article is devoted to the study of the fluctuation properties of the interaction of halftone screens with different lineatures in the process of full-color printing and the development of a method for assessing the visual perception of these interactions. One of the main tasks solved in the process of printing reproduction of graphic information is to maintain uniformity of tone of large background areas in a print. Violation of the uniformity of the tone of these areas leads to fl - disturbances in the reproduction stability of halft screen structures used in the reproduction process, which become noticeable during the visual perception of the finished images. This issue is especially relevant in the manufacture of full-color images, where there is an interaction of several halftone screens produced for four copies of the image, corresponding to the colors of printing synthesis in the process of color separation. A significant influence on the level of fluctuations is exerted not only by the choice of angles of mutual arrangement of these halftone screens, which is regulated by technological standards, but also by the choice of halftone screening lineature. At the same time, compliance with technological standards does not always guarantee a high-quality result. The purpose of the study is to provide the opportuni-ty to choose the optimal lineature of regular halft screening, which, with a combination of these screens, will minimize the level of noticeability of fluctuations (noise) and, as a result, improve the quality of full-color printed materials. To achieve this goal, in the framework of this work, a method for evaluation of the fl properties of the interaction of raster structures based on the calculation of the standard deviation characterizing the histogram of a particular halftone field and, as a result, the level of fluctuations is developed. The developed method allows choosing the optimal halftone screening lineature, which can be used with a double or triple combination of halftone screens. Read more...

Investigation of color differences in the reproduction of memorable colors on visualization devices

This work is devoted to the study of changes in color coordinates on various visualization devices during color reproduction, in particular smartphones, as one of the most commonly used devices in the modern world, which is associated with the hardware dependence of the color reproduction system. The purpose of the work is to select visualization tools, determine their technical characteristics, determine test colors for visualization on various devices, determine the tolerances in reproduction of each color when using various viewing devices. To achieve the goal, such tasks were set as the selection of images containing memorable colors. These colors are fundamental in determining the tolerances in color reproduction, since information about them is inherent in each person on the basis of his life experience and knowledge, and a change in the reproduction of memorable colors, a violation in color rendering, is the most visually noticeable. Memorable colors are converted into samples – test objects, which are used to determine coordinates in a device-independent color space. Determination of tolerances is made when changing color reproduction through the use of selective (color) correction. When solving the problem, it was noted that there are colors in which, with small changes in color coordinates, the visual component changes to a sufficiently strong degree, while other colors, with a numerically identical change, do not visually change. For the selected colors on various visualization tools, the difference in color reproduction is calculated and the calculations of color differences for different models of viewing devices with a visual difference in perception are given. Read more...