Development of a model of raster power-linear conversion of digital images of light tones

The object of research is the technological process of raster conversion of digital images based on power-linear transformation at the stage of preparation for printing. The problem in the processes of prepress preparation is the lack of functionality in available computer image processing programs to construct the characteristics of the raster conversion, which are the main carrier of information about the image. Accordingly, this limits the capabilities of the reproduction process and leads to a loss of image quality on the print. The work used the method of mathematical modeling, the theory of digital image conversion, and object-oriented programming. To solve the problems set, typical variants of power-linear transformation of digital images of different tonalities were constructed. In the process of the study, algorithms for raster transformation of different lineatures were developed, which are the main carrier of information about the image. Simulators for simulation modeling, analysis, and synthesis of power-linear transformation were built, ensuring high-quality tone reproduction of images of different lineatures. A mathematical model of raster conversion of typical variants of power-linear conversion of digital images for light tones has been developed and new rasterization algorithms have been proposed. Based on them, a structural diagram of a simulator of raster power-linear conversion of images of light tones has been developed in the MATLAB:Simulink package, with which it is possible to calculate and construct gradation characteristics, rasterization characteristics and analyze their properties. The proposed model of algorithms for raster power-linear conversion of digital images eliminates posterization of images in dark areas, which is an advantage of the developed new raster conversion algorithms using power-linear transformation. The results of the conducted studies of raster tone reproduction can be recommended to operators and technologists for use in pre-printing processes at the stage of raster conversion of digital images.