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1
Content available Assessment of the visibility of unprotected road users in pedestrian crossing
100%
Różowicz S. , Baran K. , Różowicz A. , Leśko M. , Beňa L.
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tom Vol. 73, nr 1
145--164
EN
The article presents selected results of research on improving pedestrian traffic safety. Based on annually-updated accident statistics made available by the police, as well as the new pedestrian traffic regulations in force, detailed work was undertaken to assess the level of visibility of pedestrians by drivers in pedestrian crossing areas. The research was carried out by analyzing several characteristic cases of pedestrian crossings occurring in Poland, in which there was only dedicated lighting for crossings, only street lighting, and a variant of coexistence of both of the above lighting solutions. Illuminance measurements were made in the horizontal and vertical planes of pedestrian crossings, and the results were confronted with the relevant guidelines. The next step involved a complementary measurement of the luminance distribution of the vertical plane containing the pedestrian and a portion of the sub- and super-horizontal background. Visibility pedestrians was considered in positive and negative contrast variants, and was then related to the obtained results of the illumination distribution. The analysis of the results of the study indicated the possibility of limited visibility of pedestrians at the crossings despite the satisfactory results obtained from measurements of the illuminance distribution within the crossings.
2
Content available remote Analysis of luminance distribution uniformity in CAVE-type virtual reality systems
100%
Mazikowski A.
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tom Vol. 26, No. 2
116--121
EN
In recent years, many scientific and industrial centres in the world developed a virtual reality systems or laboratories. The effect of user “immersion” into virtual reality in such systems is largely dependent on optical properties of the system. In this paper, problems of luminance distribution uniformity in CAVE- type virtual reality systems are analyzed. For better characterization of CAVE luminance nonuniformity corner and edge CAVE nonuniformity were introduced. Based on described CAVE-type virtual reality laboratory, named Immersive 3D Visualization Lab (I3DVL) just opened at the Gdansk University of Technology, luminance nonuniformity of the system is evaluated and discussed. Data collection of luminance distribution allows for software compensation of intensity distribution of individual images projected onto the screen (luminance non-uniformity minimization) in the further research.
3
Content available Advanced modelling and luminance analysis of LED optical systems
100%
Słomiński S.
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tom Vol. 67, nr 6
1107--1116
EN
Designing, optimizing and analyzing optical systems as part of the implementation process into production of modern luminaires require using advanced simulation and computational methods. The progressive miniaturization of LED (light emitting diode) chips and growth in maximum luminance values, achieving up to 108 cd/m2, require constructing very accurate geometries of reflector and lens systems producing complex luminous intensity distributions while reducing discomfort glare levels. Currently, the design process cannot function without advanced simulation methods. Today’s simulation methods in the lighting technology offer very good results as far as relatively large conventional light sources such as halogen lamps, metal halide lamps and high pressure sodium lamps are concerned. Unfortunately, they often fail in the case of chip-on-board LED light sources whose luminous surface dimensions are increasingly often contained inside a cube of the side length below 1mm. With the high sensitivity of such small chips and lenses with dimensions ranging from a just a few to between 10 and 20 mm, which is presented in this paper, modern luminance distribution measurement methods, luminance modelling and ray tracing methods should be used to minimize any errors arising from incorrectly projecting the design in the final physical model. Also, very importantly, focus should be directed towards reducing a chance of making a mistake while collimating the position of the light source inside the optical system. The paper presents a novel simulation calculation method enriched with an analysis of optical system sensitivity to a light source position. The results of simulation calculations are compared with the results of laboratory measurements for corresponding systems.
4
Content available A two-layer neural system for reduced-reference visual quality assessment
86%
Redi J. , Gastaldo P. , Zunino R.
Journal of Artificial Intelligence and Soft Computing Research
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2011
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tom Vol. 1, No. 1
27--41
EN
Real-time assessment of visual quality can be efficiently supported by reduced-refe-rence paradigms, which require a very limited amount of information on the original signal, easily embeddable in the signal itself. In this paper, a reduced-reference system for image quality assessment is proposed, based on a small sized numerical description of images encoding the luminance distribution and its variations due to visual distortions. The assessment paradigm is implemented exploiting machine learning tools and articulates in two phases: first, a Support Vector Machines-based classifier identifies the kind of distortion affecting the image; then, the actual quality level of the distorted image is computed by a specifically trained SVM regressor. The general validity of the approach is supported by experimental validations based on subjective quality data.
5
Rozkład luminancji w samochodowych lampach sygnałowych
86%
Hajduk T.
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2005
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tom nr 10
40-44
PL
Przedstawiono analizę dostępnych na rynku rozwiązań pod kątem rozkładu luminancji na powierzchni lampy sygnałowej w samochodzie.
EN
The paper presents analysis of commercially available designs in respect of luminance distribution on lamp surface in car.
6
Content available remote Identyfikacja problemu pomiarów luminancji wieloźródłowych opraw oświetleniowych LED
72%
Słomiński S.
Przegląd Elektrotechniczny
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2016
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tom R. 92, nr 7
202--205
PL
Prawidłowa rejestracja rozkładu luminancji obiektów zawierających wiele źródeł światła jest zagadnieniem trudnym, nawet przy wykorzystaniu matrycowych mierników luminancji. Wszechobecne reklamy LED oraz oprawy oświetleniowe z wyładowczymi oraz elektroluminescencyjnymi źródłami światła są w miejskim otoczeniu normą. Matrycowe mierniki luminancji są pozornie bardzo proste w obsłudze, co potęguje możliwość nieświadomego popełnienia błędów pomiarowych. W artykule przedstawione zostaną wyniki prac autora, pokazujące z jakimi problemami mamy do czynienia.
EN
Proper registration of the luminance distribution of objects containing multiple light sources is an difficult issue, even using imaging luminance measuring devices (ILMD). Often found LED screens and discharge and LED luminaires in the urban environment are the norm. ILMD are apparently very easy to use, which enhances the possibility of unknowingly committing errors. This paper will present the results of the author's works, showing what problems we face.
7
Jakościowa ocena stanu oświetlenia drogowego na podstawie cyfrowych pomiarów rozkładów luminancji
72%
Słomiński S.
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tom Nr 1-2
26--29
PL
W artykule opisano kwestie pomiarów związanych z weryfikacją i monitorowaniem parametrów oświetleniowych.
EN
Modern measurement methods allow to carry out the accurate measurement of parameters describing the condition of road lighting in a very short time. Parameters that have been previously measured occasionally, such as the luminance distribution on the road surface, can now be measured with high precision in a relatively simple manner. Modern equipment allows to increase measurement accuracy while shortening measurement time and simplifying measurement methods. High repeatability of results favours Imaging Luminance Measuring Device (ILMD). The paper presents measurement requirements in relation to the current standard, taking into account the available hardware and software.
8
Content available remote Visual and photometric consequences of using semi-spherical LEDs in diffuser shades
72%
Żagan W. , Krupiński R.
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tom R. 95, nr 2
150--153
EN
The article presents and analyzes the observed phenomenon of optical deformation of a cylindrical dispersing diffuser as the effect of a classical replacement a light source by LED retrofit. A cylindrical diffuser equipped with such a light source presents a luminance distribution that significantly deviates from the actual view of the unshielded lampshade. This is a feature which disqualifies such an application of these sources for aesthetic reasons, the more so because the accompanying effect is also a noticeable deformation of the cylindrical shape. In the article, apart from the analysis of the phenomenon, the equation of the diffuser profile was presented, which using the discussed type of LED source could realize an even distribution of luminance on the surface.
PL
Artykuł przedstawia i analizuje zaobserwowane zjawisko deformacji optycznej klosza cylindrycznego, rozpraszającego jako efektu zastąpienia klasycznego, źródła światła przez retrofit LED. Cylindryczny klosz rozpraszający wyposażony w takie źródło światła prezentuje rozkład luminancji, który znacząco odbiega od rzeczywistego widoku niezaświeconego klosza. Jest to cecha dyskwalifikująca taką aplikację tych źródeł z powodów estetycznych, tym bardziej, że efektem towarzyszącym jest również zauważalna deformacja kształtu cylindrycznego. W artykule, poza analizą zjawiska przedstawiono równanie profilu klosza, który przy zastosowaniu omawianego rodzaju źródła LED realizował by równomierny rozkład luminancji na powierzchni.
9
Content available Advanced modelling and luminance analysis of LED optical systems
50%
Słomiński S.
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