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A problem of qualitative determination of the results of colour image capturing by digital devices based on uniform colour systems arises during analysis of colour images. The article describes methods of determining colour difference as recommended by CIE for the CIELAB system, presents mathematical formulation of the system and its modifications, describes the programme developed for calculating colour difference for each described method, and describes testing of this programme using 14 sample colours from the Munsell Book of Colour. Three groups of red, green and blue filters with 7 filters in each were selected as the study object. The filters were selected based on possibility of their further application for determining colour shift by digital devices. Filter colour difference was studied in the groups with different standard sources of light and using three methods of calculation of this difference. Analysis of the obtained results is presented and conclusions are made on possibility to apply each method in different industrial spheres. The article may be useful for colour analysis specialists, quality inspectors and specialists in digital devices and computer vision.

The paper is devoted to digital colorimetry, has a character of review, and deals with the main issues of colorimetric calculations and transformations during digital colour registration. The presented materials are intended to help researchers already at the stage of registration to exclude colour losses and, accordingly, errors of measurements, taking into account the following features: – The connection of colorimetric measurements with digital circuit design is shown, which results in digital colorimetry as a tool for acquiring and processing accurate colour information about the object of study; – Important issues such as: selection criteria for parameters of photodetector arrays, colour separation systems, working colour spaces, formats of colour images, and post-processing methods for colour information of images; – Colour separation systems of photodetector arrays, their advantages and disadvantages, influence on the registration result and prospects of new developments in this field are described; – Working colour spaces of digital recording systems, and also colour systems are considered allowing maximum saving colour parameters of digital impression; – To understand human colour perception, the problem of hardware-independent reproduction of colour and images after image registration is considered; – It is proposed to use such colorimetric systems in the analysis of colour parameters in scientific studies, which give understanding of human image perception in the analysis of image quality. The paper gives a broad overview of the digital colorimetry main aspects and researches on this topic for specialists who use digital colour recorders as a tool in their experimental research. This material can also be useful for specialists with deep knowledge in colorimetry who use digital colour recorders as part of their main tasks in the definite field of science and technology.

The paper presents a spatial-frequency characteristics comparative analysis for obtaining a colour’s image several methods. The modern colour image matrix spatial-frequency characteristics photodetectors spatial-frequency characteristics are presented. Both unique and advanced matrix photodetectors of both multilayer type and standard systems with mosaic filters are being investigated. The author’s matrix photodetector input signal distortion estimation, where two-layer sensors are presented, is carried out. Spatial-frequency characteristics comparative analysis showed that three-matrix colour image systems provide the best spatial resolution and the highest spatial (contrast) sensitivity than mosaic-type photodetectors.