The dissertation is devoted to the solution of the current scientific and applied task of developing models of the information system of analysis and synthesis of tone reproduction of images for offset printing, methods of synthesis and correction to increase technological and functional capabilities, in relation to the printing of high-quality book and magazine products. Models of the intensity of the visual perception of the optical density of a halftone image for a given range of density change in the offset [0≤D≤3.0] were developed, which correspond to the Weber-Fechner law, which makes it possible to establish the correspondence of the perception of optical density images and properties of the human visual system. Simulators of visual perception of optical density were developed, characteristics of visual perception were constructed for different maximum values of optical density and for different paper densities, which quantitatively evaluate the visual perception of images. By means of simulation modeling, the characteristics of visual perception of optical density were calculated, constructed and analyzed.
Developed models of typical variants of gradation of editorial raster transformation characteristics based on the adjustment of the relative area of raster elements implemented by the Menten function, which provides the necessary gradation characteristic of the raster density, which is determined by the Yule-Nielsen derastering formula. A simulator of variants of raster editorial tone reproduction has been developed, which calculates and builds variants of corrected rasterization characteristics and typical variants of gradation characteristics of raster optical density of editorial tone reproduction. The results of simulation modeling of variants of gradation characteristics of editorial raster tone reproduction are presented. On the basis of the constructed characteristics of visual perception for various variants of synthesized gradation characteristics of editorial raster tone reproduction, it was established that they correspond to the human visual system.
An information technology for the synthesis of raster tone reproduction for elements of different shapes has been developed, which takes into account the informational content of the image, on the basis of which an editorial tone reproduction option is selected, and a synthesis algorithm has been developed that includes the following basic components: editorial tone reproduction models, rasterization models, the Michaelis-Menten function, the Yule derastering formula Nielsen.
Similarly to the previous one, a tone reproduction synthesis simulator for round raster elements has been developed to implement the synthesis and correction of tone reproduction. It differs from the previous one in that the scheme of synthesis models includes a raster transformation for round elements. In the interactive mode of the simulator, the parameters of the corrective links were determined. The presented synthesis results in the form of adjusted rastering characteristics and gradation characteristics are expressed by raster density, and it is established that they are close to the specified tone transfer options. Similarly, a tone reproduction synthesis simulator was developed for elements of a rhombic shape. The presented results of simulation modeling of corrected tone reproduction expressed by raster density for elements of different shapes confirm the reliability of the developed method of synthesis and correction of editorial tone reproduction, ensure the deviation of corrected tone reproduction from the given one, which meets the regulatory requirements for quality assessment of book, magazine and advertising products. The presented parameters of the correction links for raster elements of different shapes can be used at the stage of tonal correction of the image.
Key words: editorial tone reproduction, image, rasterization, information technology, synthesis, correction, models, simulators, quality.
