| Author(s) | Collection number | Pages | Download abstract | Download full text |
|---|---|---|---|---|
| Терновий І. М., Khamula O. H. | № 2 (69) | 130-139 |
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A mathematical model of raster-converted digital images of light tones has been developed, represented by an analog expression, in which the brightness L is expressed by levels with values [0, 255], over which a normalized raster transformation S = F (Ln,r) has been performed and the coverage of relative areas with paint, described by the amount of paint V, depending on the tinting coefficient, and the tinting of digital images Lv=255V has been determined, which makes it possible to calculate and construct the characteristics of raster conversion, tinting intensity and contrast sensitivity of tinted raster-converted digital images.
A structural diagram of a four-channel simulator model of raster-transformed typical variants of digital images of light tones has been developed in the MATLAB:Simulink package, which simultaneously calculates the characteristics of rasterization, tinting, gradation characteristics of tinted images and their contrast sensitivity, which make it possible to analyze their properties necessary for high-quality preparation of digital images for printing.
The coating of raster elements with paint, a certain amount of paint - tinting of raster-transformed digital images, is described and on its basis the gradation characteristics of typical variants of tinted raster transformation of digital images are constructed. To quantitatively assess the visual perception of tinted raster transformation of digital images, its contrast sensitivity, which corresponds to the sensitivity of images by human vision, is determined.
The results of modeling the characteristics of typical variants of raster-converted digital images, typical gradation characteristics of colored digital images, which are convex curves well located in the tone interval, and contrast sensitivity graphs of colored raster conversion of digital images of light tones are presented. It was established that the thickness of the paint significantly affects the gradation characteristics and causes losses in dark areas, which are 24 - 64 gray levels, and the contrast sensitivity is from -1.0; -1.29; -1.5; -2.0 to -1.0; -0.20; -0.09; -0.02 units.
It was established that the characteristics of colored typical variants of raster conversion of digital images are concave curves evenly located on the plane. The initial curvature of the characteristics depends on the power exponent. The steepest characteristic has a characteristic that corresponds to the power exponent r=2.0. It is proven that the gradation characteristics of typical variants of the colored raster transformation of a digital image have initial values of 255 units and are concave curves with a large steepness, which gradually decreases, the curves approach the final zero value, and the characteristics are compressed in light tones.
The results of the conducted research significantly expand the possibilities of analyzing the preparation of images for rasterization in computer publishing systems
Keywords: make-up, rasterization, digital images, simulator, characteristics, properties, contrast sensitivity.
doi: 10.32403/1998-6912-2024-2-69-120-129
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