Improvement of line image reproduction in the system of prepress engineer work

Abstract

In order to optimise the process of prepress engineer work, it is necessary to provide a high-quality display of the line image, which ensures the most accurate transfer of the geometric dimensions of individual elements. The purpose of the article was to determine the degree of influence of the binarization threshold on the resolution value of raster line images. The experiments were based on the use of general scientific methods of analysis, generalisation, classification, deduction. To assess the quality of line image reproduction in this paper, photoforms were employed using a line test object which was designed as an accurate photograph with the use of an optical density distribution profile. The paper examines the influence of various parameters of raster structures on the playback quality of reproductions. The specifics of using a photo output device as the main link, which ensures the reproduction quality of image details, have been determined. The geometry of the raster structure when using rotation angles with rational tangents has been analysed. Features of the Accurate Screening technology have been systematised. The difference between “rational” and “irrational” rasterization methods has been considered. The main aspects of the use of line details in the reproduction process have been considered. The proposed method for assessing the quality of a line image reproduction with an uneven edge has been called the “signal-to-noise ratio” method, and it has been concluded that the scanning stage affects the quality of image reproduction to a greater extent than the photo output. The practical result of the work is the development of recommendations that can find practical application in reproduction processes. The developed binarization algorithms allow processing of images with significant zonal brightness unevenness, with monotonous brightness areas, and highly noisy images.