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Journal articles on the topic 'Luminance analyser'
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1
Syrkin, Gil, and Moshe Gur. "Colour and Luminance Interact to Improve Pattern Recognition." Perception 26, no. 2 (February 1997): 127–40. http://dx.doi.org/10.1068/p260127.
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The authors have previously hypothesised that colour vision has evolved not only to encode colour per se but also, perhaps principally, to enhance luminance-based visual processing, so that for colour information to be fully effective, luminance as well as chromatic variations should be present in visual targets. Results of previous experiments, testing detection of spatial gratings and detection and perceived brightness of Mach bands support the hypothesis. Further experiments are reported in which the hypothesis was tested by using a higher-level task of pattern recognition. Subjects had to discriminate between luminance (isochromatic), isoluminant (chromatic), or combined colour/luminance ellipses and circles. It was found that the ability to discriminate between a circle and an ellipse was greatly enhanced when both colour and luminance variations were present as compared with the pure luminance or colour presentations. Summation-square analysis shows linear colour-luminance summation which can be modeled by a single-analyser model.
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Bará, Salvador, Martin Aubé, John Barentine, and Jaime Zamorano. "Magnitude to luminance conversions and visual brightness of the night sky." Monthly Notices of the Royal Astronomical Society 493, no. 2 (February 4, 2020): 2429–37. http://dx.doi.org/10.1093/mnras/staa323.
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ABSTRACT The visual brightness of the night sky is not a single-valued function of its brightness in other photometric bands, because the transformations between photometric systems depend on the spectral power distribution of the skyglow. We analyse the transformation between the night sky brightness in the Johnson–Cousins V band (mV, measured in magnitudes per square arcsecond, mpsas) and its visual luminance (L, in SI units cd m−2) for observers with photopic and scotopic adaptation, in terms of the spectral power distribution of the incident light. We calculate the zero-point luminances for a set of skyglow spectra recorded at different places in the world, including strongly light-polluted locations and sites with nearly pristine natural dark skies. The photopic skyglow luminance corresponding to mV=0.00 mpsas is found to vary in the range 1.11–1.34 × 105 cd m−2 if mV is reported in the absolute (AB) magnitude scale, and in the range 1.18–1.43 × 105 cd m−2 if a Vega scale for mV is used instead. The photopic luminance for mV=22.0 mpsas is correspondingly comprised between 176 and 213 μcd m−2 (AB), or 187 and 227 μcd m−2 (Vega). These constants tend to decrease for increasing correlated colour temperature (CCT). The photopic zero-point luminances are generally higher than the ones expected for blackbody radiation of comparable CCT. The scotopic-to-photopic luminance (S/P) ratio for our spectral data set varies from 0.8 to 2.5. Under scotopic adaptation the dependence of the zero-point luminances with the CCT, and their values relative to blackbody radiation, is reversed with respect to photopic ones.
3
Djokic, L., A. Cabarkapa, and A. Djuretic. "Drivers’ impressions under high-pressure sodium and LED street lighting." Lighting Research & Technology 50, no. 8 (October 20, 2017): 1212–24. http://dx.doi.org/10.1177/1477153517727802.
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In order to compare drivers’ subjective impressions when exposed to high-pressure sodium versus LED street lighting, an experiment was conducted on a Belgrade street. All general requirements for an adequate comparison of subjective impressions, equal luminances being the most important, were fulfilled. A survey was conducted using a questionnaire, which the respondents filled out immediately after driving through both zones of the illuminated street. The respondents, who were young drivers (students), aged 20–25 years, were asked to select the more appropriate of the two installations regarding seven lighting parameters as well as giving their overall impression. The two regimes for which the survey was done gave opposite results. In the normal regime, where both installations had the same photopic luminance, the LED installation was evaluated as a better solution by a majority of the respondents for most of the analysed parameters. In the mesopic regime, where both installations had the same mesopic luminance, most of the respondents judged that the high-pressure sodium installation was the better choice.
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Grodon, A., and M. Fahle. "Parallel Processing of Luminance Steps in the Presence of Luminance Gradients." Perception 25, no. 1_suppl (August 1996): 62. http://dx.doi.org/10.1068/v96l0602.
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Some features of complex visual displays are analysed effortlessly and in parallel by the human visual system, without requiring scrutiny. Examples for such features are changes of luminance, colour, orientation, and movement. We measured thresholds as well as reaction times for the detection of abrupt spatial changes in luminance in the presence of luminance gradients, in order to evaluate the ability of the system to ignore such gradients. Stimuli were presented on a 20 inch monitor under control of a Silicon Graphics workstation. Luminance was calibrated by means of a photometer (Minolta). We presented between 4 and 14 rectangles simultaneously on a homogeneous dark background. Rectangles were arranged on an incomplete, imaginary circle around the fixation point and luminance changed stepwise from one rectangle to the next. Five observers had to indicate whether all luminance steps between the rectangles were subjectively equal or whether one luminance step was larger. Detection thresholds were determined for the larger step as a function of the small steps (‘base step size’) by means of an adaptive staircase procedure. The smallest luminance steps were detected when the base step size was zero and when only few rectangles were presented. Thresholds increased slightly with the number of rectangles displayed simultaneously, and to a greater extent (by up to a factor of 2) with increasing base step size. The results of all observers improved significantly through practice, by about a factor of 2. We conclude that the visual system is unable to completely eliminate gradients of luminance and to isolate sharp transitions in luminance.
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Liu, Long, Yun Cui Zhang, and Jun Xiao. "The Influencing Factor Analyses of Narrow Beam LED Luminaire Performance Test." Advanced Materials Research 694-697 (May 2013): 3283–86. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.3283.
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The beam angle of the luminaire is an important factor to influence testing method. This paper mainly discusses the narrow beam luminaire test methods, especially luminaires space photometric, chromaticity characteristic test method. The factors step length and test time which influence spatial distribution photometer are analyzed. An example is introduced which show how to set electrical parameter, photometry parameter test efficiency for a narrow beam LED luminaire.
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Solano Lamphar, HA, and M. Kocifaj. "Urban night-sky luminance due to different cloud types: A numerical experiment." Lighting Research & Technology 48, no. 8 (August 3, 2016): 1017–33. http://dx.doi.org/10.1177/1477153515597732.
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In this paper, we analyse theoretically and numerically the sky glow in urban and suburban areas, focusing on the zenith-normalised luminance of a cloudy sky. The results suggest that the altitude of a cloud imposes important changes in the luminance distribution. Peak values of sky luminance can be observed at a distance [Formula: see text], where R is the city radius, and h is the cloud altitude. Fluctuations of the zenith-normalised luminance over the city are dictated by three effects, specifically (i) extinction and backscatter in the undercloud atmosphere, (ii) the cloud properties and (iii) the radiant intensity function of the dominant ground-based light sources. For high clouds, the aerosol optical property is evident at moderate elevation angles. The light beams emitted from different parts of the city propagate along different inclined trajectories before they contribute to the elevated zenith luminance of low clouds. Then, multiple factors combine together to form the light field at the ground, city-size and city emission pattern being of specific importance.
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Karatsai, Eleni, Piyali Sen, Sarega Gurudas, and Sobha Sivaprasad. "Low Luminance Visual Acuity and Low Luminance Deficit in Proliferative Diabetic Retinopathy." Journal of Clinical Medicine 10, no. 2 (January 19, 2021): 358. http://dx.doi.org/10.3390/jcm10020358.
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This study aimed to determine the relation of best corrected visual acuity (BCVA) and low luminance visual acuity (LLVA) in proliferative diabetic retinopathy (PDR) following treatment with either aflibercept or pan-retinal photocoagulation (PRP). The study was conducted as a post-hoc analysis of the CLARITY trial in which naïve and PRP treated PDR patients were randomised to receive either aflibercept or PRP. BCVA and LLVA were assessed at baseline and at week 52. Our analyses showed that the BCVA and LLVA correlate well in treatment naïve PDR with an average low luminance deficit of 11.79 Early Treatment Diabetic Retinopathy Score (ETDRS) letters. However, LLVA at lower levels of BCVA showed more variance. Post aflibercept therapy, the mean change in BCVA and LLVA at 52 weeks after aflibercept was +2.1 (SD 6.05) letters and +0.39 (SD 5.6) letters, respectively. Similarly, after PRP, it was −2.5 (SD 4.9) letters and −1.9 (SD 8.7) letters, respectively. When comparing treatment arms, BCVA change was found to be statistically significant (p < 0.001) whereas LLVA was not (p = 0.11). These findings show that LLVA does not respond as well as BCVA following any treatment for PDR, even though BCVA and LLVA both test foveal function.
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Padmasali, AN, and SG Kini. "A novel measure to analyse the reliability of LED luminaires." Lighting Research & Technology 51, no. 7 (September 11, 2018): 1063–76. http://dx.doi.org/10.1177/1477153518798872.
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LED luminaires are the most promising lighting solutions for general lighting in the current era due to their durability and lower power consumption. Reliability of LED luminaires is dependent on the electrolytic capacitor at the output stage of the LED driver as this is the weakest link failing the luminaire. So, it is required to develop a general measure to understand the effect of capacitance on the drive current and thus on the light output to analyse the reliability of the LED luminaire. To investigate the effect of capacitance and equivalent series resistance (ESR), a capacitor bank setup is developed, with values ranging from 0.017 μF to 860 μF. Six LED luminaires of different ratings and manufacturers are selected and drive current, and lumen output for each is studied. Based on the drive current ripple patterns observed, capacitors are classified into two classes, and also percentage flicker is determined. As driver capacitors decide the amount of ripple in the output current, a generalised measure of capacitance and ESR limit is established for the LED luminaire to work reliably. The work also helps in formulating metrics for determining the service life of an LED luminaire accurately.
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Molino, John A., Kenneth S. Opiela, Carl K. Andersen, and M. Joseph Moyer. "Relative Luminance of Retroreflective Raised Pavement Markers and Pavement Marking Stripes on Simulated Rural Two-Lane Roads." Transportation Research Record: Journal of the Transportation Research Board 1844, no. 1 (January 2003): 45–51. http://dx.doi.org/10.3141/1844-06.
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The FHWA Turner-Fairbank Highway Research Center is undertaking a research program to study the visibility of retroreflective raised pavement markers (RRPMs). The focus of the initial effort is to determine the relative luminance of RRPMs and pavement markings (PMs) needed to produce adequate guidance on rural two-lane roadways at night. A driving simulator was used to test 36 research participants as they drove simulated roadways containing various combinations of RRPMs and PMs. The luminance of the simulated roadway delineation ranged from 0.07 to 4.1 cd/m2. The primary driver performance measure was curve-recognition distance. For the various RRPM and PM luminance conditions, mean curve-recognition distances ranged from 19.0 m (62.3 ft) to 68.4 m (224 ft), with a grand mean of 43.0 m (141 ft). Regression analyses produced predictive equations to estimate the mean curve-recognition distance from the luminance of RRPMs acting alone or of PMs acting alone. Trading ratios were computed for PM luminance with and without RRPMs present on the road. A conservative empirical estimate of 0.52 was computed for such a trading ratio based on the data from the current experiment. This value compared favorably with independent estimates of 0.54 and 0.55 based on an earlier analytical approach. Thus, the current experiment confirmed, with empirical data, earlier estimates that it might be possible to reduce the luminance of PMs on rural two-lane roads by about 45% when appropriate RRPMs are installed.
10
Troscianko, T., C. A. Parraga, G. Brelstaff, D. Carr, and K. Nelson. "Spatio-Chromatic Information Content of Natural Scenes." Perception 25, no. 1_suppl (August 1996): 162. http://dx.doi.org/10.1068/v96l1009.
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A common assumption in the study of the relationship between human vision and the visual environment is that human vision has developed in order to encode the incident information in an optimal manner. Such arguments have been used to support the 1/f dependence of scene content as a function of spatial frequency. In keeping with this assumption, we ask whether there are any important differences between the luminance and (r/g) chrominance Fourier spectra of natural scenes, the simple expectation being that the chrominance spectrum should be relatively richer in low spatial frequencies than the luminance spectrum, to correspond with the different shape of luminance and chrominance contrast sensitivity functions. We analysed a data set of 29 images of natural scenes (predominantly of vegetation at different distances) which were obtained with a hyper-spectral camera (measuring the scene through a set of 31 wavelength bands in the range 400 – 700 nm). The images were transformed to the three Smith — Pokorny cone fundamentals, and further transformed into ‘luminance’ (r+g) and ‘chrominance’ (r-g) images, with various assumptions being made about the relative weighting of the r and g components, and the form of the chrominance response. We then analysed the Fourier spectra of these images using logarithmic intervals in spatial frequency space. This allowed a determination of the total energy within each Fourier band for each of the luminance and chrominance representations. The results strongly indicate that, for the set of scenes studied here, there was no evidence of a predominance of low-spatial-frequency chrominance information. Two classes of explanation are possible: (a) that raw Fourier content may not be the main organising principle determining visual encoding of colour, and/or (b) that our scenes were atypical of what may have driven visual evolution. We present arguments in favour of both of these propositions.
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Scheir, GH, P. Hanselaer, and WR Ryckaert. "Pupillary light reflex, receptive field mechanism and correction for retinal position for the assessment of visual discomfort." Lighting Research & Technology 51, no. 2 (October 20, 2017): 291–303. http://dx.doi.org/10.1177/1477153517737346.
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Light sources causing annoyance or pain produce discomfort glare. Traditional glare metrics fail for non-uniform luminaires. As an alternative, visual discomfort is determined by a model incorporating the centre–surround receptive field mechanism, the pupillary light reflex and a correction for retinal position. The pupil area, controlled by the pupillary light reflex, regulates the retinal illuminance. A centre–surround receptive field, described by a difference of Gaussians, represents the visual signal. A correction according to the Guth position index accounts for the reduction in brightness perception when a light source is moved away from the line of sight. The model is analysed with a forced choice paired comparison experiment involving 17 non-uniform rear projected stimuli with different spatial frequencies and luminance steps. A coefficient of determination of 0.68 between the subjective assessment and the model is obtained. A paired comparison office luminaire experiment and a magnitude estimation experiment involving diffusor luminaires validate the model resulting in a coefficient of determination of 0.86 and 0.81, respectively. By including the pupillary light reflex, receptive field mechanism and a correction for retinal position, the more physiologically justified model is a promising alternative to current, often empirical, glare metrics, especially for non-uniform luminaires.
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Liang, Bo, Guo Bing Pan, Yu Hang Pi, and Wen Yang Li. "Energy-Saving Experimental Study on Reflective Material Auxiliary Tunnel Lighting Based on Visual Effect." Advanced Materials Research 594-597 (November 2012): 1193–96. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1193.
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Applying visual performance method, use reaction time measurement system to measure the small target which randomly appears inside the tunnel and analyse the measured data processing results then obtain the relationship between reaction time and the inner wall material、tunnel light and background luminance. We hold that human eyes on different luminance levels in tunnel lighting and visual characteristics of reflection reflection materials obeys Purkinje phenomenon. According to the visual performance theory, we put forward that reflective material assisting tunnel lighting will achieve good effect in energy saving. The study on reflective materials applied in tunnel lighting energy saving play an important guiding significance.
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Stöckl, Anna L., Klara Kihlström, Steven Chandler, and Simon Sponberg. "Comparative system identification of flower tracking performance in three hawkmoth species reveals adaptations for dim light vision." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1717 (April 5, 2017): 20160078. http://dx.doi.org/10.1098/rstb.2016.0078.
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Flight control in insects is heavily dependent on vision. Thus, in dim light, the decreased reliability of visual signal detection also prompts consequences for insect flight. We have an emerging understanding of the neural mechanisms that different species employ to adapt the visual system to low light. However, much less explored are comparative analyses of how low light affects the flight behaviour of insect species, and the corresponding links between physiological adaptations and behaviour. We investigated whether the flower tracking behaviour of three hawkmoth species with different diel activity patterns revealed luminance-dependent adaptations, using a system identification approach. We found clear luminance-dependent differences in flower tracking in all three species, which were explained by a simple luminance-dependent delay model, which generalized across species. We discuss physiological and anatomical explanations for the variance in tracking responses, which could not be explained by such simple models. Differences between species could not be explained by the simple delay model. However, in several cases, they could be explained through the addition on a second model parameter, a simple scaling term, that captures the responsiveness of each species to flower movements. Thus, we demonstrate here that much of the variance in the luminance-dependent flower tracking responses of hawkmoths with different diel activity patterns can be captured by simple models of neural processing. This article is part of the themed issue ‘Vision in dim light’.
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Padmasali, AN, and SG Kini. "A generalised approach for the estimation of junction temperature and its effect on light output." Lighting Research & Technology 52, no. 2 (May 2, 2019): 274–91. http://dx.doi.org/10.1177/1477153519846210.
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LED lighting is the most promising lighting technology of the current era because it is highly reliable and energy efficient. The reliability of an LED luminaire is dependent primarily on its junction temperature in operation. Since LED luminaire design differs across manufacturers, a generalised experimental procedure and simplified model is adapted to estimate the junction temperature of an LED luminaire. The results are analysed, and the model is validated with an experimental study on two different luminaires. Further, to analyse the effect of junction temperature on the light output, a novel model and methodology are adopted such that light output can be estimated for any operating temperature, if the light output at a reference temperature is known. Three models were selected to estimate the light output at different temperatures, and four different LEDs were selected for the experimental study. A linear model for the thermal multiplier is selected as the best model to estimate the light output at a desired temperature and is validated using statistical tools. Thus, this simple model and generalised experimental procedures will help in estimating the effect of junction temperature on the performance of LED luminaires.
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Leccese, Francesco, Davide Lista, Giacomo Salvadori, Marco Beccali, and Marina Bonomolo. "Space Syntax Analysis Applied to Urban Street Lighting: Relations between Spatial Properties and Lighting Levels." Applied Sciences 9, no. 16 (August 14, 2019): 3331. http://dx.doi.org/10.3390/app9163331.
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According to the international technical standards, higher lighting levels (luminance and illuminance levels) are expected in trafficked and central roads (where restrictive minimum lighting requirements are necessary) and lower lighting levels are expected in peripheral and less trafficked roads. Starting from this assumption, in this paper, the authors analyse the correlations between spatial properties (expressed by spatial indicators, for example, the integration index and the choice index) and lighting levels (expressed by lighting parameters, for example luminance and illuminance) upon roads of an urban context. The analysis has been applied to the case study of the medium sized town of Pontedera (central Italy). From the obtained results, it has been possible to observe how the correlations between integration index and luminance and illuminance values are significant in the case of roads equipped with lighting systems able to satisfy the lighting requirements established by the regulations. The presence of the discussed correlations lays the foundation for a change in the lighting design approach on urban scale, being able to set lighting requirements on the basis of space syntax results without the use of traditional methods of road classifications involving traffic volume estimations.
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Hughes, H. C., and J. T. Townsend. "Varieties of Binocular Interaction in Human Vision." Psychological Science 9, no. 1 (January 1998): 53–60. http://dx.doi.org/10.1111/1467-9280.00010.
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Binocular processing was investigated using a quantitative, process-oriented metatheory of response times. The analyses are not confined to particular distributional assumptions or specific models. Upper and lower performance boundaries for probability summation in parallel processing are defined and compared with observed distributions of reaction times using a variety of dichoptic stimuli. Performance that exceeds the upper bound strongly suggests facilitatory convergence between the two eyes (binocular channel summation). Performance below the lower bound suggests that inputs to the two eyes are processed serially. The results indicate that binocular channel summation in subjects with normal stereo vision requires targets of the same luminance polarity (paired increments or decrements) in corresponding retinal locations. When corresponding retinal locations are stimulated with opposing luminance polarities (increment to one eye, decrement to the other), performance is consistent with probability summation, indicating that parallel ON and OFF pathways remain segregated at least to the level of binocular fusion. Further analyses of data from a stereo-blind observer suggest serial processing of binocular inputs.
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Jiang, Yang, C. N. Boehler, Nina Nönnig, Emrah Düzel, Jens-Max Hopf, Hans-Jochen Heinze, and Mircea Ariel Schoenfeld. "Binding 3-D Object Perception in the Human Visual Cortex." Journal of Cognitive Neuroscience 20, no. 4 (April 2008): 553–62. http://dx.doi.org/10.1162/jocn.2008.20050.
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How do visual luminance, shape, motion, and depth bind together in the brain to represent the coherent percept of a 3-D object within hundreds of milliseconds (msec)? We provide evidence from simultaneous magnetoencephalographic (MEG) and electroencephalographic (EEG) data that perception of 3-D objects defined by luminance or motion elicits sequential activity in human visual cortices within 500 msec. Following activation of the primary visual cortex around 100 msec, 3-D objects elicited sequential activity with only little overlap (dynamic 3-D shapes: MT-LO-Temp; stationary 3-D shapes: LO-Temp). A delay of 80 msec, both in MEG/EEG responses and in reaction times (RTs), was found when additional motion information was processed. We also found significant positive correlations between RT, and MEG and EEG responses in the right temporal location. After about 400 msec, long-lasting activity was observed in the parietal cortex and concurrently in previously activated regions. Novel time-frequency analyses indicate that the activity in the lateral occipital (LO) complex is associated with an increase of induced power in the gamma band, a hallmark of binding. The close correspondence of an induced gamma response with concurrent sources located in the LO in both experimental conditions at different points in time (∼200 msec for luminance and ∼300 msec for dynamic cues) strongly suggests that the LO is the key region for the assembly of object features. The assembly is fed forward to achieve coherent perception of a 3-D object within 500 msec.
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Englisch, D., P. Bodrogi, C. Schiller, and TQ Khanh. "Mesopic increment detection sensitivity, Part 2: Modelling mesopic detection sensitivity." Lighting Research & Technology 50, no. 3 (November 3, 2016): 376–89. http://dx.doi.org/10.1177/1477153516667769.
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This paper deals with the modelling of the mesopic detection sensitivity data described in Part 1. The modelling is based on a linear combination of the spectral sensitivity templates of four retinal mechanisms (long + medium wavelength sensitive cones, rods, short wavelength sensitive cones and long - medium wavelength sensitive cones opponency) to describe the experimental data on mesopic detection sensitivity and to provide a practically usable model. Model parameters representing the weighting of these mechanisms are analysed as a function of target eccentricity and background luminance.
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Yamamoto, Nayuta, and Teiji Sota. "Evolutionary fine-tuning of background-matching camouflage among geographical populations in the sandy beach tiger beetle." Proceedings of the Royal Society B: Biological Sciences 287, no. 1941 (December 16, 2020): 20202315. http://dx.doi.org/10.1098/rspb.2020.2315.
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Background-matching camouflage is a widespread adaptation in animals; however, few studies have thoroughly examined its evolutionary process and consequences. The tiger beetle Chaetodera laetescripta exhibits pronounced variation in elytral colour pattern among sandy habitats of different colour in the Japanese Archipelago. In this study, we performed digital image analysis with avian vision modelling to demonstrate that elytral luminance, which is attributed to proportions of elytral colour components, is fine-tuned to match local backgrounds. Field predation experiments with model beetles showed that better luminance matching resulted in a lower attack rate and corresponding lower mortality. Using restriction site-associated DNA (RAD) sequence data, we analysed the dispersal and evolution of colour pattern across geographical locations. We found that sand colour matching occurred irrespective of genetic and geographical distances between populations, suggesting that locally adapted colour patterns evolved after the colonization of these habitats. Given that beetle elytral colour patterns presumably have a quantitative genetic basis, our findings demonstrate that fine-tuning of background-matching camouflage to local habitat conditions can be attained through selection by visual predators, as predicted by the earliest proponent of natural selection.
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Krupiński, Rafał, Henryk Wachta, Wojciech Maciej Stabryła, and Cedric Büchner. "Selected Issues on Material Properties of Objects in Computer Simulations of Floodlighting." Energies 14, no. 17 (September 1, 2021): 5448. http://dx.doi.org/10.3390/en14175448.
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This paper addresses issues with computer simulation involved in designing illumination for architectural structures. In particular, the reflectance and transmittance of materials were studied with respect to their influence on luminance values, thus directly the power levels for luminaires applied under particular projects. Raster images derived from digitally processed daytime pictures were used to precisely define material properties. Bitmaps were tested with regard to measuring and editing materials with a widely used graphic application. A real architectural object, the Basilica of the Dormition in Jerusalem, served as the test object. A floodlighting design was performed following a complete analysis of all electrical and photometric parameters. Luminance distributions were analysed comprehensively. Hence, the data allowed for an assessment of the lighting design compliance with guidance given by International Commission on Illumination (CIE) for floodlighting objects and its required standards. The floodlighting utilization factor of the lighting solution developed was also verified, as it is the input parameter for evaluating not only the energy efficiency for the installed lighting system, but also the impact it has on the surroundings, in this case, the project that is to be implemented.
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Guliev, Alexander E. "Improvement of Majolica Lighting at the Komsomolskaya – Radial Metro Station." Volume 28, Number 2, 2020, no. 02-2020 (April 2020): 47–53. http://dx.doi.org/10.33383/2018-059.
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The article describes solving of one of the most important problems of perception of architectural decoration of metro stations: removal of veiling reflections on glazed mosaics and majolica caused by lighting devices. A number of lighting methods reducing luminance of the veiling reflections is analysed. Their efficiency is exemplified by lighting of the Mine Laying majolica (based on sketches by Eugene Lancer) at the Komsomolskaya station of Moscow Metro. The content of the article relates not only to metro stations but to any areas with reflective or glazed surfaces.
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Lee, Gyeong Won, Yoonsuk Choi, Heejin Kim, Jongwoo Park, Jong-In Shim, and Dong-Soo Shin. "Analysis of Transient Degradation Behaviors of Organic Light-Emitting Diodes under Electrical Stress." Applied Sciences 11, no. 16 (August 19, 2021): 7627. http://dx.doi.org/10.3390/app11167627.
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Despite the wide application of organic light-emitting diodes (OLEDs), the performance of OLED devices is sometimes limited by their reliabilities. In this paper, we report the transient degradation behaviors of fluorescent blue OLEDs, where both the current and luminance initially increase under electrical stress within a short stress time. We analyze the degradation mechanism in terms of the carrier recombination and transport. From the comprehensive analyses of electrical and optical characteristics, it is suggested that the electron transport is responsible for the initial transient behavior of the device.
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Kim, Jinsheon, Jeungmo Kang, and Woojin Jang. "Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink." Applied Sciences 11, no. 9 (April 29, 2021): 4035. http://dx.doi.org/10.3390/app11094035.
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In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.
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Dong, Wu, Hongxia Bie, Likun Lu, and Yeli Li. "Blind Quality Evaluation for Screen Content Images Based on Regionalized Structural Features." Algorithms 13, no. 10 (October 11, 2020): 257. http://dx.doi.org/10.3390/a13100257.
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Currently, screen content images (SCIs) are widely used in our modern society. However, since SCIs have distinctly different properties compared to natural images, traditional quality assessment methods of natural images cannot precisely evaluate the quality of SCIs. Thus, we propose a blind quality evaluation method for SCIs based on regionalized structural features that are closely relevant to the intrinsic quality of SCIs. Firstly, the features of textual and pictorial regions of SCIs are extracted separately. For textual regions, since they contain noticeable structural information, we propose improved histograms of oriented gradients extracted from multi-order derivatives as structural features. For pictorial regions, since human vision is sensitive to texture information and luminance variation, we adopt texture as the structural feature; meanwhile, luminance is used as the auxiliary feature. The local derivative pattern and the shearlet local binary pattern are used to extract texture in the spatial and shearlet domains, respectively. Secondly, to derive the quality of textual and pictorial regions, two mapping functions are respectively trained from their features to subjective values. Finally, an activity weighting strategy is proposed to combine the quality of textual and pictorial regions. Experimental results show that the proposed method achieves better performance than the state-of-the-art methods.
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Hao, R., A. Ge, X. Tao, Y. Liu, B. Zhao, and E. Yang. "Optical design of a high-mast luminaire based on four COB LED light source modules." Lighting Research & Technology 51, no. 3 (May 14, 2018): 447–56. http://dx.doi.org/10.1177/1477153518764774.
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Light-emitting diodes (LEDs) have been widely used in road lighting. This study investigates the optical design of a high-mast luminaire based on four chips-on-board LED light source modules and applies it to road lighting. The model of the high-mast luminaire is built with Solidworks, and then the optical simulations are analysed by Tracepro and Dialux. We also make a physical prototype of the high-mast luminaire to test its performance in practice. The illuminance distribution of the test area is nearly rectangular. The interior of the rectangle forms a smaller highlighted rectangular illumination area with uniform illumination. The outer edges of the rectangular illumination area will overlap the outer edges of the illumination area of other high-mast luminaires. The desired illuminance distribution and the uniform illumination can be obtained. Both the simulations and the experimental results meet the requirements of road lighting standards and the high-mast lamp can even achieve a better optical performance.
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Englisch, D., C. Schiller, P. Bodrogi, and TQ Khanh. "Mesopic increment detection sensitivity, Part I: Phenomenological analysis." Lighting Research & Technology 50, no. 3 (September 10, 2016): 360–75. http://dx.doi.org/10.1177/1477153516667768.
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Mesopic threshold detection sensitivity was investigated by projecting quasi-monochromatic incremental targets with 22 centroid wavelengths between 422 nm and 652 nm onto different backgrounds. Every detection target was observed by at least nine subjects under eight different viewing conditions: two mesopic luminance levels (0.1 cd/m2; 1 cd/m2) and four eccentricities of target appearance off the visual axis (0°, 2.65°, 10° and 20°). Results were expressed in terms of absolute detection sensitivity values, i.e. inverse increment radiance values for each target at the detection threshold in sr·m2·W−1 units. In this part, the experimental method is described, and the dataset is analysed in terms of retinal mechanisms.
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Viana, Nayara I., Sabrina T. Reis, Nelson G. Dip, Denis R. Morais, Caio M. Moura, Iran A. Silva, Betina Katz, Miguel Srougi, Katia R. M. Leite, and Alberto A. Antunes. "MicroRNAs 143 and 145 May be Involved in Benign Prostatic Hyperplasia Pathogenesis through Regulation of Target Genes and Proteins." International Journal of Biological Markers 29, no. 3 (July 2014): 246–52. http://dx.doi.org/10.5301/jbm.5000069.
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Objectives The aim of this study was to analyze the roles of miR-143 and miR-145, as well as the gene and protein expression of their targets ( KRAS, ERK5, MAP3K3, and MAP4K4) in the pathogenesis of benign prostatic hyperplasia (BPH). Methods We analyzed the specimens of 44 patients diagnosed with BPH who underwent surgical treatment. The control group consisted of prostate samples from 2 young patients who were organ donors. miRNAs and their target genes were assessed using real-time polymerase chain reaction (qRT-PCR), and protein levels were assessed by Western blotting. Results miR-143 and miR-145 were overexpressed in, respectively, 62.5% and 73.8% of the cases. The ERK5 and MAP4K4 genes were underexpressed respectively in 59.4% and 100% of the BPH samples, whereas KRAS and MAP3K3 were overexpressed respectively in 79.4% and 61.5% of the samples. Increased protein expression was found for both KRAS (4,312.2 luminance/area) and MAP3K3 (7,461.7 luminance/area), while the ERK5 protein was more abundant in the samples from patients with prostate larger than 60 grams (p=0.019). Conclusions The overexpression of miR-143 and miR-145 in BPH samples suggests an association with the pathogenesis of the disease; additionally, the latter miRNA may act through the inhibition of MAP4K4. KRAS and MAP3K3 overexpression may also be associated with BPH pathogenesis. Further analyses are necessary to confirm these results.
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Doi, Eizaburo, Toshio Inui, Te-Won Lee, Thomas Wachtler, and Terrence J. Sejnowski. "Spatiochromatic Receptive Field Properties Derived from Information-Theoretic Analyses of Cone Mosaic Responses to Natural Scenes." Neural Computation 15, no. 2 (February 1, 2003): 397–417. http://dx.doi.org/10.1162/089976603762552960.
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Neurons in the early stages of processing in the primate visual system efficiently encode natural scenes. In previous studies of the chromatic properties of natural images, the inputs were sampled on a regular array, with complete color information at every location. However, in the retina cone photoreceptors with different spectral sensitivities are arranged in a mosaic. We used an unsupervised neural network model to analyze the statistical structure of retinal cone mosaic responses to calibrated color natural images. The second-order statistical dependencies derived from the covariance matrix of the sensory signals were removed in the first stage of processing. These decorrelating filters were similar to type I receptive fields in parvo- or konio-cellular LGN in both spatial and chromatic characteristics. In the subsequent stage, the decorrelated signals were linearly transformed to make the output as statistically independent as possible, using independent component analysis. The independent component filters showed luminance selectivity with simple-cell-like receptive fields, or had strong color selectivity with large, often double-opponent, receptive fields, both of which were found in the primary visual cortex (V1). These results show that the “form” and “color” channels of the early visual system can be derived from the statistics of sensory signals.
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Cengiz, Mehmet Sait, and Seda Yetkin. "Thermal Analysis In Fixed, Flowed And Airless Environment For Cooling In Led Luminaires." Volume 28, Number 6, 2020, no. 03-2020 (December 2020): 28–35. http://dx.doi.org/10.33383/2020-030.
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In this study, a simulation study was conducted for the loss of efficiency caused by the heat emitted by the LED chips. The temperature change of LED luminaire was analysed for three different scenarios using finite element method. Due to the increase in the internal temperature of the luminaire and due to the air effect inside the LED luminaires, failure of the LEDs has been tried to be prevented. For this purpose, a passive cooling method was proposed in the simulation environment. So, in high power LED luminaires, the high heat emitted by the LED chips is reduced to low heat by an air flow method. In this way, efficiency in LED outputs has been achieved.
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Kambezidis, HD, ThI Oikonomou, and D. Zevgolis. "Daylight climatology in the Athens urban environment: guidance for building designers." Lighting Research & Technology 34, no. 4 (December 2002): 297–309. http://dx.doi.org/10.1191/1365782802li037oa.
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Global and diffuse horizontal illuminance data are analysed for Athens, Greece, for the period 1992-1997. It is shown in a graphical manner that horizontal illuminance (global and diffuse) is dependent upon the time of the day and the month of the year. The diagrams are categorized according to Perraudeau’s nebulosity index, which reflects the sky cover and the climate at a given area. The cumulative frequency distribution of the parameters under all-sky types are estimated and discussed. Some examples of sky-luminance distributions using appropriate software are given. The conclusions are of potential value to local architectural practice, installations of lighting, and in developing an energy-saving policy for the Athens region.
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Tural, Elif, and Mehmedalp Tural. "Luminance contrast analyses for low vision in a senior living facility: A proposal for an HDR image-based analysis tool." Building and Environment 81 (November 2014): 20–28. http://dx.doi.org/10.1016/j.buildenv.2014.06.005.
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Sato, Keiko, and Takaaki Inoue. "Perception of color emotions for single colors in red-green defective observers." PeerJ 4 (December 8, 2016): e2751. http://dx.doi.org/10.7717/peerj.2751.
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It is estimated that inherited red-green color deficiency, which involves both the protan and deutan deficiency types, is common in men. For red-green defective observers, some reddish colors appear desaturated and brownish, unlike colors seen by normal observers. Despite its prevalence, few studies have investigated the effects that red-green color deficiency has on the psychological properties of colors (color emotions). The current study investigated the influence of red-green color deficiency on the following six color emotions: cleanliness, freshness, hardness, preference, warmth, and weight. Specifically, this study aimed to: (1) reveal differences between normal and red-green defective observers in rating patterns of six color emotions; (2) examine differences in color emotions related to the three cardinal channels in human color vision; and (3) explore relationships between color emotions and color naming behavior. Thirteen men and 10 women with normal vision and 13 men who were red-green defective performed both a color naming task and an emotion rating task with 32 colors from the Berkeley Color Project (BCP). Results revealed noticeable differences in the cleanliness and hardness ratings between the normal vision observers, particularly in women, and red-green defective observers, which appeared mainly for colors in the orange to cyan range, and in the preference and warmth ratings for colors with cyan and purple hues. Similarly, naming errors also mainly occurred in the cyan colors. A regression analysis that included the three cone-contrasts (i.e., red-green, blue-yellow, and luminance) as predictors significantly accounted for variability in color emotion ratings for the red-green defective observers as much as the normal individuals. Expressly, for warmth ratings, the weight of the red-green opponent channel was significantly lower in color defective observers than in normal participants. In addition, the analyses for individual warmth ratings in the red-green defective group revealed that luminance cone-contrast was a significant predictor in most red-green-defective individuals. Together, these results suggest that red-green defective observers tend to rely on the blue-yellow channel and luminance to compensate for the weak sensitivity of long- and medium-wavelength (L-M) cone-contrasts, when rating color warmth.
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Słomiński, Sebastian, and Magdalena Sobaszek. "Intelligent Object Shape and Position Identification for Needs of Dynamic Luminance Shaping in Object Floodlighting and Projection Mapping." Energies 13, no. 23 (December 5, 2020): 6442. http://dx.doi.org/10.3390/en13236442.
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Innovative lighting and dynamic sound systems as well as adaptive object mapping solutions constitute a rapidly developing branch of lighting technology and multimedia technology. In order to make it possible to adjust the content to specific objects in the scene, it is necessary to correctly identify them and place them in the accepted frame of reference. Dynamic identification and tracking of objects can be carried out based on two particular types of input data: data from markers installed on objects and data from digital recording systems, founding the operation on infrared (IR), visible light (RGB) and the most advanced RGB-D (RGB and depth) analysis. Most systems used today are those that use various types of markers. This paper presents the advantages and disadvantages of such solutions as well as a target system for dynamic identification and mapping of objects and the human body based on the analysis of data from digital RGB-D cameras. Analyses of identification times, implementation of perspective transformations and 3D-to-2D transformations have been carried out in relation to a planar and cuboidal moving surface. Time analyses have been performed in relation to the resolution of registered and processed images.
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Fröhner, Klaus-Dieter, and Ze Li. "STABILITY AND INSTABILITY OF AN OUTDOOR ILLUMINATION INSTALLATION." JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 12, no. 4 (December 31, 2004): 115–19. http://dx.doi.org/10.3846/16486897.2004.9636831.
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Stability and instability are very important for the layout of real world processes concerning safety and health esp. when planned by scientists. The long‐term investigation of stability was carried out for the last ten years on the basis of the installation and the evaluation of an ergonomically designed outdoor illumination. In the depicted dynamic situation the lighting design influences directly visual discomfort and human performance and in the end stability and instability. The improvement of the adaptation of luminance and its influence on the visual tasks after the rearrangement are presented and discussed. The effective factors on the visual capability and performance of workers, work efficiency and potential accidents in the night shift, and furthermore the accelerators and barriers for the stability of the project are analysed and discussed.
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Coves-Campos, Andrés, Luis Bañón, José Coves-García, and Salvador Ivorra. "In Situ Study of Road Marking Durability Using Glass Microbeads and Antiskid Aggregates as Drop-On Materials." Coatings 8, no. 10 (October 21, 2018): 371. http://dx.doi.org/10.3390/coatings8100371.
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Road markings play an important role in road safety because they provide significant information to drivers about the road. For that reason, they must be replaced when they are not correctly perceived by road users. To analyse which are the main factors that affect road marking perception over time, a test section was designed in a two-lane rural highway, running actual traffic over 18 different types of markings fabricated with different combinations of drop-on materials. Chromatic coordinates, luminance, and retroreflectivity of each sample were measured during 18 months in order to study their evolution over time. The results obtained show different behaviours depending on the aggregates and application method used. An increment of the durability has been observed with the use of different layers and mixtures of glass microbeads with different sizes.
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Balasubramanian, Siva, Akihito Uji, Jianqin Lei, Swetha Velaga, Muneeswar Nittala, and SriniVas Sadda. "Interdevice comparison of retinal sensitivity assessments in a healthy population: the CenterVue MAIA and the Nidek MP-3 microperimeters." British Journal of Ophthalmology 102, no. 1 (May 11, 2017): 109–13. http://dx.doi.org/10.1136/bjophthalmol-2017-310258.
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BackgroundTo compare and correlate the retinal sensitivity measurements obtained with Nidek Microperimetry-3 (MP-3) and the CenterVue Macular Integrity Assessment (MAIA) microperimeters among healthy subjects.MethodsIn this prospective comparative study, 31 eyes of 23 subjects underwent complete ophthalmological examination including retinal sensitivity assessments using two microperimeters, the MP-3 (Nidek Technologies) and the MAIA (CenterVue). The mean retinal sensitivity (dB) and its corresponding luminance (asb) and contrast (log units) were analysed between the two instruments. The interdevice reproducibility and level of agreement between the sensitivity values of the devices were assessed.ResultsThe mean retinal sensitivity (dB) measured by the MP-3 (25.02±1.06 dB, range: 20.90–26.70) was significantly (p<0.0001) lower compared with the MAIA (30.68±0.74 dB, range: 28–31.84). The luminosity levels were significantly (p<0.0001) higher with the MP3 (7.75±1.31 asb, range: 6.44–9.06) compared with the MAIA (0.92±0.14 asb, range: 0.78–1.06). The contrast sensitivity was significantly higher for the MP-3 (0.94±0.33 log units, range: 0.61–1.27) compared with the MAIA (0.23±0.03 log units, range: 0.20–0.26). Despite these absolute differences, the intraclass coefficient was 0.85 (95% CI 0.70 to 0.92) between the two devices after applying a standard correction factor to each data point (MAIA sensitivity=MP-3 sensitivity+5.65) with a mean difference between MAIA and MP-3 of 0.01.ConclusionRetinal sensitivity measures higher, but luminance and contrast sensitivity measure lower for MAIA-generated values compared with the MP-3. The relationships, however, appeared fairly consistent, and application of a standard correction factor allowed the data to be inter-related, at least for normal eyes.
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Ali, Azlan Shah, Shirley Jin Lin Chua, and Melissa Ee-Ling Lim. "The effect of physical environment comfort on employees’ performance in office buildings." Structural Survey 33, no. 4/5 (November 9, 2015): 294–308. http://dx.doi.org/10.1108/ss-02-2015-0012.
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Purpose – Maintaining a comfortable physical environment in the workplace is claimed to be vital as it will create a “healthier” building with optimum environmental conditions, which enable employees to be healthier and have a lower absenteeism rate, and hence be more productive. Thus, the purpose of this paper is to deal with the importance of physical environment comfort in the office workplace. Evaluation was made of the office workers’ performance that is mainly affected by levels of comfort in the office. Design/methodology/approach – Three selected case studies were evaluated based on aspects of employees’ comfort, perceived health and absenteeism rate, by considering the elements of physical comfort that consist of room temperature, relative humidity and luminance level. The selected case studies were the Department of Development and Estate Maintenance of three research universities in Malaysia. Field studies were carried out using hygrometers and lux meters in measuring the said elements as well as post-occupancy evaluation, which involved 30 respondents for each case (total 90 respondents), to determine their perception of comfort and its effect on their health and absenteeism rate. Data collected were analysed using Statistical Package for the Social Sciences. Findings – The results suggest that employees did not find luminance level uncomfortable, when compared with room temperature, thus proving that employees are more sensitive to room temperature comfort. Furthermore, when the room temperature comfort was low, significant correlations were found with health-related issues such as feeling “stuffy”, being easily tired and having difficulty concentrating. Originality/value – This paper investigates the relationship between employee performance and a comfortable workplace environment. It could be concluded that an uncomfortable environment in an office workplace leads to health-related issues as well as increasing the absenteeism rate. High levels of employee absenteeism lead to decreased employee productivity, therefore affecting their work performance.
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Mather, George. "Aesthetic Image Statistics Vary with Artistic Genre." Vision 4, no. 1 (February 1, 2020): 10. http://dx.doi.org/10.3390/vision4010010.
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Research to date has not found strong evidence for a universal link between any single low-level image statistic, such as fractal dimension or Fourier spectral slope, and aesthetic ratings of images in general. This study assessed whether different image statistics are important for artistic images containing different subjects and used partial least squares regression (PLSR) to identify the statistics that correlated most reliably with ratings. Fourier spectral slope, fractal dimension and Shannon entropy were estimated separately for paintings containing landscapes, people, still life, portraits, nudes, animals, buildings and abstracts. Separate analyses were performed on the luminance and colour information in the images. PLSR fits showed shared variance of up to 75% between image statistics and aesthetic ratings. The most important statistics and image planes varied across genres. Variation in statistics may reflect characteristic properties of the different neural sub-systems that process different types of image.
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Upchurch, Jonathan E., and Jeffrey T. Bordin. "A Human Factors Evaluation of Freeway Guide Sign Lighting Systems." Proceedings of the Human Factors Society Annual Meeting 33, no. 10 (October 1989): 615–19. http://dx.doi.org/10.1177/154193128903301015.
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The objective of the study was to identify a lighting system for freeway guide signs which is more economical and which adequately satisfies motorist's needs in terms of legibility, illumination, color rendition, and other factors. Through the use of technical data and specification review, photometric tests, and computer analyses, ten lighting systems were selected for field testing (10–14 months). Luminance levels, power consumption, maintenance requirements, and lamp life were noted. A human factors study determined legibility distance and rated viewing comfort, lighting uniformity, and color rendition. Senior citizens and young adults were used to detect possible age-related differences. None were noted other than seniors placed more importance on color rendition. It was determined that the differences between the best human factors performing lighting systems and the best regarding economics was only marginal concerning human factors. The most economical system was thus recommended.
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Yang, Lan, Yun Ye, Tai Liang Guo, and Xiao Jin Huang. "Surfacial Metallization of Carbon Fibers by Copper Coating and Field Emission Properties." Materials Science Forum 663-665 (November 2010): 183–86. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.183.
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Carbon fibers (CNFs) were surfacial metallized by electroless deposited with copper, and their field emission properties were investigated by diode test. The results indicated that the field emission properties of CNFs were affected by the thicknesses of copper. After CNFs were surfacial metallized, the volume resistivity of CNFs was decreased and field emission property was increased, respectively; increase the thin-film thickness, there appeared an optimal film thickness value for properties of field electron emission. It was found that CNFs owned the best field emission properties after electroless depositing for 15 min, with copper metal thickness as 2.1 µm and the volume resistivity down to 2.3510-4 Ω•cm. The field emission tests showed when applied voltage was 562 V, CNFs appeared bright dots, and the high luminance achieved 1388 cd/m2 under applied voltage 1013 V. Further more theoretical analyses, copper coating on CNFs surface is attributed to good electric conductivity, the low work function and the lower attenuation of electron scattering in thin-film.
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Wan, Hongliang, Zhigang Du, Qixiang Yan, and Xiaohong Chen. "EVALUATING THE EFFECTIVENESS OF SPEED REDUCTION MARKINGS IN HIGHWAY TUNNELS." Transport 33, no. 3 (July 10, 2018): 647–56. http://dx.doi.org/10.3846/transport.2018.1574.
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As typical weak visual reference systems, highway tunnels have low illumination, monotonous environment and few references, which may cause severe visual illusion and reduce drivers’ speed perception ability. Thus, drivers tend to underestimate their driving speed, which may induce speeding behaviours that result in rear-end collisions. The cost-effective pavement markings installed on both sides of the lane or shoulder may make drivers overestimate their speed. This perception can help ensure safe driving and regulate driving behaviour effectively. This study analyses the effects of sidewall markings in typical low luminance highway tunnels, specifically observing how their angles and lengths affect the driver’s speed perception. A three-dimensional model of highway tunnels was built in a driving simulator. Psychophysical tests of speed perception were carried out by the method of limits. The simulation tests studied the Stimulus of Subjectively Equal Speed (SSES) and reaction time in relation to sidewall markings with different angles. Furthermore, based on the optimal angle, the effects of sidewall marking with different lengths on speed perception were also analysed. The test results reveal that the angle and length of sidewall markings have a significant impact on the driver’s SSES and reaction time. Moreover, the level of speed overestimation decreases with the increase of angle or length of sidewall marking. As the angle of sidewall marking gradually increases, the maximum reaction time first increases and then decreases. Within the angle of sidewall marking of 15°, the subjects have the highest speed overestimation and an easy speed judgment. This may due to Zöllner illusion, the driver’s perception of lane width shrinks may induce deceleration behaviour.
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Kim, Gyung-Dong, Hyuk Jin Kang, Sung-Hoon Ahn, Chul Ki Song, Chang Back, and Caroline S. Lee. "Laser-marking process for liquid-crystal display light guide panel." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 219, no. 7 (July 1, 2005): 565–69. http://dx.doi.org/10.1243/095440505x32337.
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A light guide panel is an element of the liquid-crystal display backlight unit, which is extensively used for display devices. In this study, a laser-marking process is applied to the fabrication of light guide panels, and the new fabrication process may replace existing manufacturing methods such as silk screen printing, stamping, or V-cutting methods. The objective of this research is to evaluate the feasibility of the laser patterning system. A series of light guide patterns were made with a 50 W CO2 laser (continuous wave) to understand the effects of laser power and scanning speed on the geometry of groove patterns. The width and depth of the fabricated grooves increased with increasing laser power and decreasing scanning speed. In order to analyse surface geometry, scanning electron microscopy (SEM) photography was used and, for luminance measurement, a Topcon-BM7 was used. As a result, the marking conditions of the laser patterning, 5W and 0.4m/s, were suggested.
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Huemer, Karl-Heinz, Gerhard Garhöfer, Claudia Zawinka, Elisabeth Golestani, Brigitte Litschauer, Leopold Schmetterer, and Guido T. Dorner. "Effects of dopamine on human retinal vessel diameter and its modulation during flicker stimulation." American Journal of Physiology-Heart and Circulatory Physiology 284, no. 1 (January 1, 2003): H358—H363. http://dx.doi.org/10.1152/ajpheart.00642.2002.
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We performed a randomized, subject-blinded, placebo and time-controlled, two-way crossover study in 12 healthy male subjects. Placebo or dopamine was administered on two separate study days. After saline infusion, dopamine hydrochloride was infused in three consecutive doses (5, 10, and 15 μg · kg−1 · min−1). Plasma levels of dopamine were determined at each perfusion step. Arterial and venous retinal vessel diameters were measured with the use of a Zeiss retinal vessel analyzer. Diffuse luminance flicker stimuli of 8 Hz were applied for 60 s. Blood pressure and pulse rate were monitored continuously. Flicker stimulation (8 Hz) increased retinal vessel diameters under basal conditions. The response to 8-Hz flicker light was significantly reduced by dopamine administration. In addition, dopamine slightly but significantly increased retinal vessel diameters. Dopamine hydrochloride significantly increased systolic but not diastolic or mean arterial pressure. The present study indicates that dopamine has a distinct effect on retinal vessel diameters also attenuating the flicker-induced response reactivity of retinal vessels. This implies a role of dopamine in retinal blood flow hemodynamics.
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Aw, Y. K., Robyn Owens, and John Ross. "An analysis of local energy and phase congruency models in visual feature detection." Journal of the Australian Mathematical Society. Series B. Applied Mathematics 40, no. 1 (July 1998): 97–122. http://dx.doi.org/10.1017/s0334270000012406.
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AbstractA variety of approaches have been developed for the detection of features such as edges, lines, and corners in images. Many techniques presuppose the feature type, such as a step edge, and use the differential properties of the luminance function to detect the location of such features. The local energy model provides an alternative approach, detecting a variety of feature types in a single pass by analysing order in the phase components of the Fourier transform of the image. The local energy model is usually implemented by calculating the envelope of the analytic signal associated with the image function. Here we analyse the accuracy of such an implementation, and show that in certain cases the feature location is only approximately given by the local energy model. Orientation selectivity is another aspect of the local energy model, and we show that a feature is only correctly located at a peak of the local energy function when local energy has a zero gradient in two orthogonal directions at the peak point.
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Kööts, Liisi, Anu Realo, and Jüri Allik. "The Influence of the Weather on Affective Experience." Journal of Individual Differences 32, no. 2 (January 2011): 74–84. http://dx.doi.org/10.1027/1614-0001/a000037.
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This study examined the relationship between affective experiences and weather variables using an experience-sampling method. The moderating effects of personality and age on the relationship were also investigated. Two age groups of participants (students and elderly people) recorded their moods when signalled during 14 consecutive days on 7 randomly determined occasions per day. Hourly weather data (temperature, relative humidity, barometric pressure, and luminance) for the same period were obtained from the local weather station. Previously participants had completed the Estonian versions of the Revised NEO Personality Inventory ( Kallasmaa, Allik, Realo, & McCrae, 2000 ) and the Positive and Negative Affect Schedule ( Allik & Realo, 1997 ). Multilevel random coefficient modeling analyses showed that momentary ratings of positive and negative affect were weakly related to temperature, positive affect was also related to sunlight. However, momentary ratings of fatigue showed a distinct tendency for greater incidence of sleepiness in the cold and dark. Age group was one of the most important moderators of the weather-emotion models. The influence of weather on emotions interacted with being outdoors. Personality traits also explained a small portion of variance in the influence of weather on affective states.
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Ezpeleta, Silvia, Elvira Orduna-Hospital, Justiniano Aporta, María José Luesma, Isabel Pinilla, and Ana Sánchez-Cano. "Evaluation of Visual and Nonvisual Levels of Daylight from Spectral Power Distributions Considering Orientation and Seasonality." Applied Sciences 11, no. 13 (June 28, 2021): 5996. http://dx.doi.org/10.3390/app11135996.
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The evaluation of both visual and nonvisual effects from the spectral power distribution (SPD) of outdoor light is critical in lighting design. The dome-light SPD characteristically changes continuously depending on the seasonality, orientation, altitude of the sun or hour of the day. Traditional photopic parameters, such as the illuminance, luminance or correlated colour temperature (CCT), have been widely studied, but presently, there is no melanopic measurement or evaluation method. This article discusses the processes involved in establishing a simple method to determine the SPD of daylight and solar radiation over the skydome in a location to accurately account for the effects of both photopic and circadian levels around a location. Once per month for one year, natural daylight was spectrally measured in the city of Zaragoza (Spain); radiometric and photometric characteristics were analysed by season; and circadian effects were calculated in terms of standard parameters described by the Commission International de l’Eclairage (CIE), factors recommended by normative and scientific backgrounds. Finally, we suggest that the best parameter is the melanopic versus photopic irradiance ratio, which achieves reliable results at simplifying and correlating calculations.
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Solomon, Samuel G., Chris Tailby, Soon K. Cheong, and Aaron J. Camp. "Linear and Nonlinear Contributions to the Visual Sensitivity of Neurons in Primate Lateral Geniculate Nucleus." Journal of Neurophysiology 104, no. 4 (October 2010): 1884–98. http://dx.doi.org/10.1152/jn.01118.2009.
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Several parallel pathways convey retinal signals to the visual cortex of primates. The signals of the parvocellular (P) and magnocellular (M) pathways are well characterized; the properties of other rarely encountered cell types are distinctive in many ways, but it is not clear that they can provide signals with the same fidelity. Here we study this by characterizing the temporal receptive field of neurons in the lateral geniculate nucleus of anesthetized marmosets. For each neuron, we measured the response to a flickering uniform field, and, from this, estimated the linear and nonlinear receptive fields using spike-triggered average (STA) and spike-triggered covariance (STC) analyses. As expected the response of most P-cells was dominated by the STA, but the response of most M-cells required additional nonlinear components, and these usually acted to suppress cell responses. The STC analysis showed stronger suppressive axes in suppressed-by-contrast cells, and both suppressive and excitatory axes in on-off cells. Together, the STA and the STC analyses form a model of the temporal response to a large uniform field: under this model, the information that was provided by suppressed-by-contrast cells or on-off cells approached that provided by the P- and M-cells. However, whereas P- and M-cells provided more information about luminance, the nonlinear cells provided more information about the contrast energy. This suggests that the nonlinear cells provide complimentary signals to those of P- and M-cells, with reasonably high fidelity, and may play an important role in normal visual processing.
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Nijhawan, Romi. "Visual prediction: Psychophysics and neurophysiology of compensation for time delays." Behavioral and Brain Sciences 31, no. 2 (April 2008): 179–98. http://dx.doi.org/10.1017/s0140525x08003804.
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AbstractA necessary consequence of the nature of neural transmission systems is that as change in the physical state of a time-varying event takes place, delays produce error between the instantaneous registered state and the external state. Another source of delay is the transmission of internal motor commands to muscles and the inertia of the musculoskeletal system. How does the central nervous system compensate for these pervasive delays? Although it has been argued that delay compensation occurs late in the motor planning stages, even the earliest visual processes, such as phototransduction, contribute significantly to delays. I argue that compensation is not an exclusive property of the motor system, but rather, is a pervasive feature of the central nervous system (CNS) organization. Although the motor planning system may contain a highly flexible compensation mechanism, accounting not just for delays but also variability in delays (e.g., those resulting from variations in luminance contrast, internal body temperature, muscle fatigue, etc.), visual mechanisms also contribute to compensation. Previous suggestions of this notion of “visual prediction” led to a lively debate producing re-examination of previous arguments, new analyses, and review of the experiments presented here. Understanding visual prediction will inform our theories of sensory processes and visual perception, and will impact our notion of visual awareness.
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Kim, Bu-Yo, and Joo Wan Cha. "Cloud Observation and Cloud Cover Calculation at Nighttime Using the Automatic Cloud Observation System (ACOS) Package." Remote Sensing 12, no. 14 (July 18, 2020): 2314. http://dx.doi.org/10.3390/rs12142314.
Full textAbstract:
An Automatic Cloud Observation System (ACOS) and cloud cover calculation algorithm were developed to calculate the cloud cover at night, and the calculation results were compared with the cloud cover data of a manned observatory (Daejeon Regional Office of Meteorology, DROM) that records human observations. Annual and seasonal analyses were conducted using the 1900–0600 local standard time (LST) hourly data from January to December 2019. Prior to calculating the cloud cover of ACOS, pre-processing was performed by removing surrounding obstacles and correcting the distortion caused by the fish-eye lens. In addition, the red–blue ratio (RBR) threshold was determined, according to the image characteristics (RBR and luminance) using the red, green, and blue (RGB) brightness value of the area in which the solar zenith angle (SZA) was less than 80°, to calculate the cloud cover. The calculated cloud cover exhibited a bias of −0.28 tenths, root mean square error (RMSE) of 1.78 tenths, and a correlation coefficient of 0.91 for DROM across all cases. The frequency of the cases that exhibited differences less than 1 tenth between the observed and calculated cloud cover was 46.82%, while the frequency of cases that exhibited differences less than 2 tenths was 87.79%.
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Akkaynak, Derya, Liese A. Siemann, Alexandra Barbosa, and Lydia M. Mäthger. "Changeable camouflage: how well can flounder resemble the colour and spatial scale of substrates in their natural habitats?" Royal Society Open Science 4, no. 3 (March 2017): 160824. http://dx.doi.org/10.1098/rsos.160824.
Full textAbstract:
Flounder change colour and pattern for camouflage. We used a spectrometer to measure reflectance spectra and a digital camera to capture body patterns of two flounder species camouflaged on four natural backgrounds of different spatial scale (sand, small gravel, large gravel and rocks). We quantified the degree of spectral match between flounder and background relative to the situation of perfect camouflage in which flounder and background were assumed to have identical spectral distribution. Computations were carried out for three biologically relevant observers: monochromatic squid, dichromatic crab and trichromatic guitarfish. Our computations present a new approach to analysing datasets with multiple spectra that have large variance. Furthermore, to investigate the spatial match between flounder and background, images of flounder patterns were analysed using a custom program originally developed to study cuttlefish camouflage. Our results show that all flounder and background spectra fall within the same colour gamut and that, in terms of different observer visual systems, flounder matched most substrates in luminance and colour contrast. Flounder matched the spatial scales of all substrates except for rocks. We discuss findings in terms of flounder biology; furthermore, we discuss our methodology in light of hyperspectral technologies that combine high-resolution spectral and spatial imaging.