Abstract

Complexity of integrating color control systems into a workflow for obtaining digital half-tone images results in appearance of color rendering imperfections in photographic images as exposure conditions constantly vary in power and spectral composition of radiation. A wide range of corrective means in graphic editors does not ensure full elimination of color rendering imperfections in photographic images because of imperfect technical approaches to realization of the corrective effect. The process of correcting color rendering imperfections is complicated by the lack of methods for objective quantitative assessment of qualitative characteristics of digital color halftone images. The developed method of quantitative assessment of color characteristics of digital images by conversion of actinicity in values of effective densities provides optimal and comprehensive analysis of color rendering accuracy. The procedure consists in representation of color separation characteristics in a form of dependence of effective densities of the photographic image on grey-equivalent densities of the recorded object. It becomes possible to numerically evaluate imperfections of color rendering in a digital color photographic image. The developed assessment procedure has become the basis for implementation of a new method for correcting color rendering imperfections with the help of compensatory corrective images ensuring elimination of the imperfection of insufficient color. The correction effect is provided by the physical content of compensatory images which contain effective densities for the separated colors which are absent in digital photographic images because of non-isoactinism of isochrome colors. The new technology for correcting color rendering is implemented in the developed Image Redactor specialized software. Effectiveness of the described method was proved on the basis of analysis of images processed in the created software product according to the method of graphical representation of color separation characteristics described in the paper. Color separation matrices indicate a significant increase in useful contrasts of separated colors in comparison with similar characteristics of color rendering in images before their processing. This provides for the possibility of applying the developed method of correcting color rendering imperfections in the digital work flow of processing photographic images.

Highlights

  • Digital photography today has confidently occupied position as an only means of obtaining half-tone images in the current working flow of recording optical information

  • Photographic post-processing is complicated by the absence of a standard procedure for objective assessment of digital photography quality and the list and maximum permissible values of quality indicators is not regulated by any normative document

  • The study objective was to improve the technology of correction of color separation imperfections in photographic images taking into consideration physical content of causes of occurrence to reduce errors of rendering pure and binary colors

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Summary

Introduction

Digital photography today has confidently occupied position as an only means of obtaining half-tone images in the current working flow of recording optical information. The resulting photographs mostly require significant improvement of their quality characteristics in graphic editors and other software products. Information technology editors are based on the principles of tone correction without taking into consideration the origin of color separation imperfections. Within the set) which will inevitably result in recording light fluxes of some individual radiation wavelengths behind two or even three light filters. This causes inaccuracy in recording color information and subsequent inaccuracy of color rendering of the photographed object in a digital image

Literature review and problem statement
The aim and objectives of the study
Create a compensatory image for the green-channel image
Creation of a compensatory image for the red-channel image
Conclusions
Full Text
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