Wyniki wyszukiwania - Biblioteka Nauki

1

Color difference ΔE : a survey

100%

Mokrzycki W. S. , Tatol M.

Machine Graphics and Vision

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2011

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tom Vol. 20, No. 4

383-411

EN

Color perception is crucial for human existence. This is why, color spaces have been developed to describe mathematically the color that a person can feel with unaided eye. There was a new need to distinguish colors, define them as similar, identical or completely different. However, a color-matching technique requires a color palette with perceptually linear characteristics. In this article the most popular colors spaces are presented, as both linear and nonlinear due to perceptual abilities, and are briefly discussed and compared to the sample values.

2

Color calibration method providing uniform distribution of color difference throughout the whole vision gamut

80%

Kretkowski M. , Shimodaira Y. , Jabłoński R.

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2009

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tom Vol. 3, No. 4

213-216

EN

Accurate reproduction of colors requires methods of calibrating a digital camera. In case of a camera which employs filters with spectral characteristics deduced from the color matching functions, a set of reference calibration colors must be used to obtain a conversion matrix between raw data from imaging sensor and colorimetric tristimulus values XYZ, from which the output signal is formed. The XYZ camera used for testing of the presented calibration me thod is capable of acquiring colors accurately in the whole vision gamut due to its filters. However, the well-established color references, like the Macbeth Chart or other similar color checkers, are not entirely sufficient for the calibration due to their enclosure in smaller color gamut (HDTV - High Definition Television) than the whole vision gamut. The presented method is based on choosing the calibration colors by their spectral distributions, which are related with the spectral characteristics of the filters. The obtained result was found to be ?E=1.57 for the designed colors.

3

Investigation of color inconstancy and color gamut changes of printed images depending on the standard illuminants

70%

Spiridonov I. , Shopova M. , Boeva-Spiridonova R.

Optica Applicata

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2012

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tom Vol. 42, nr 3

627-641

EN

The main goals of this research are investigation and determination of color balance failure (color inconstancy) of offset printed images expressed by color difference depending on the material used and different standard illuminant conditions. For the experiment, we chose three of the most commonly used in practice illuminants - CIE D50 natural horizon daylight with color temperature 5003 K; CIE F2 cool white fluorescent, 4230 K; CIE A typical Tungsten-filament lighting, 2856 K. A special test form that has been used contains different control strips and measurement components include test chart TC6.02 with about 1000 color patches with different percent combinations of cyan, magenta, yellow and black. The paper, printing inks and printing presses employed in the experiment are some of most commonly used in practice for producing high quality color reproductions. A series of colorimetric and densitometric measurements were performed for different combinations of C, M, Y, K in single, double, triple and quadruple overprint for high tones, middle tones and dark tones. For estimating color balance failure for all the above mentioned measurements there have been calculated the color difference ?E*ab and CMCCON02 depending on standard illuminants CIE D50, F2 and A. For the first time via experimental research in real production conditions (for offset printing method), 3D and 2D presentations and comparison of color gamuts and color gamut volumes for different illuminants were made. According to the results, CIE A has the biggest color gamut volume and CIE F2 - the smallest one. The results obtained are important from scientific and practical points of view. For the first time a methodology is suggested and implemented for examination and estimation of color shifts by studying a big number of color changes in various ink combinations for different illuminants.

4

Obiektywna ocena barwy wyrobów użytkowych

60%

Kazimierska M.

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tom R. 59

44--47

PL

Percepcja i interpretacja barwy jest subiektywna. Każdy obserwator interpretuje barwę bazując na osobistym odniesieniu i inaczej ją nazywa. Obiektywny opis barwy jest idealnym rozwiązaniem w kontaktach handlowych. Obiektywnego pomiaru barwy dokonuje się instrumentalnie w taki sposób aby odpowiadała ocenie wzrokowej, za pomocą spektrofotometrów lub kolorymetrów i definiuje w postaci liczbowej w oparciu o znormalizowany rachunek kolorymetryczny opracowany przez Międzynarodową Komisję Oświetleniową (CIE). Poważnym problemem jest ustalenie granic tolerancji dla różnicy barwy. W artykule omówione są podstawowe zagadnienia mające wpływ na akceptowalność barwy w stosunku do wzorca. Przedstawiony materiał obejmuje tylko niewielki fragment problemów z jakimi spotyka się kolorysta w instrumentalnej ocenie barwy i interpretacji uzyskanych wyników.

EN

The perception and interpretation of color is subjective. Each observer interprets color based on personal respect and determinates it differently. An objective description of color is ideal for business contacts. Objective color measurement is made instrumentally so as to match the inspected visually, using spectrophotometers or colorimeters and defined in numerical form based on the normalized colorimetric bill developed by the International Commission on Illumination (CIE). A major problem is to establish tolerances for color difference. The article discusses the basic problems which affect the acceptability of the color relative to the standard. The material presented covers only a small part of the problems that meets the colorist in instrumental color assessment and interpretation of results.

5

Automation of optical quality control in the example of the furniture industry

51%

Maj M. , Pliszczuk D. , Cieplak T.

Przegląd Elektrotechniczny

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2023

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tom R. 99, nr 1

245--248

EN

A prototype of a quality control system based on optical detection algorithms will be presented here. In its functionality, it will include an exemplary web application used by the customer to place an order - in this case, a wardrobe, based on which an employee will be able to control the quality of the order and, more precisely - to check whether the components of a given order in the warehouse have not undergone the ageing process, e.g. paintwork.

PL

Przedstawiony został prototyp systemu kontroli jakości opartego na algorytmach detekcji optycznej. W swojej funkcjonalności zawiera przykładową aplikację webową, za pomocą której klient może złożyć zamówienie – w tym przypadku szafę, na podstawie której pracownik będzie mógł kontrolować jakość zamówienia, a dokładniej – sprawdzać, czy poszczególne elementy danego zamówienia, jak np. lakier, nie zostały poddane procesowi starzenia się.

6

Badanie różnicy barw CIELAB ΔE*ab oraz CIE DE2000 w procesach reprodukcji poligraficznej

51%

Khadzhynova S.

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2015

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tom R. 71, nr 4

227--230

PL

Celem pracy było obliczenie różnicy barw na podstawie wzorów ΔE*ab i ΔE*00 oraz ustalenie zależności między ΔE*ab a ΔE*00 w zakresie dużych ( ΔE*ab>5) oraz małych (ΔE*ab≤5) różnic barw. Stwierdzono, że we wszystkich zbadanych przypadkach różnica barw ΔE*abjest kilkakrotnie większa od ΔE00. W zakresie dużych różnic barwy (E*ab > 5) zależności między ΔE*ab i ΔE*00 dla barw teoretycznych można przedstawić za pomocą funkcji wielomianowej drugiego stopnia. Natomiast w zakresie małych różnic ( ΔE*ab ≤ 5) zależność ta ma postać funkcji liniowej pierwszego stopnia.

EN

The aim of the investigation was the calculation of color differences on the base of ΔE*ab and ΔE*00 formulas as well as the evaluation of their relationships in the big (ΔE*ab>5) and small (ΔE*ab≤5) colour difference. It was found that in all evaluated cases ΔE*ab is several times greater than ΔE*00. The relationship between these parameters for theoretical colors and big color differences range can be presented as a second-degree polynomial function while for small color differences it is the linear function of the first degree