A neural response-based model to predict discomfort glare from luminance image

2016 ◽  
Vol 50 (3) ◽  
pp. 416-428 ◽  
Author(s):  
M Safdar ◽  
M Ronnier Luo ◽  
M Farhan Mughal ◽  
S Kuai ◽  
Y Yang ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Current Method ◽  
Neural Response ◽  
Human Vision ◽  
Visual Discomfort ◽  
Similar Performance ◽  
Discomfort Glare ◽  
Symmetric Patterns

It is well known that one of the problems of the current method for discomfort glare evaluation, called the unified glare rating, is the non-uniform luminance of the glare source. This paper addresses this issue by considering the spatial contrast of luminance as a measure of non-uniformity. An image-based metric is proposed to evaluate discomfort glare by modeling the neural response of human vision. The model takes an absolute luminance image as input and predicts visual discomfort based on the spatial distribution of the luminance of the stimulus and the background. The developed model was tested to predict subjective glare ratings based on an experiment conducted using non-uniform LED sources with symmetric and asymmetric patterns of LEDs, and its performance was compared with the unified glare rating. As expected, the unified glare rating predictions correlated well with the subjective glare evaluations of luminaires with symmetric patterns of LEDs (as they appear less non-uniform) but not for those with asymmetric patterns. Results showed that the developed model, named the Neural Response-based Glare Model, gave similar performance to unified glare rating for symmetric patterns but outperformed UGR for asymmetric patterns of LEDs.

Is there a difference in how people from different socio-environmental contexts perceive discomfort due to glare from daylight?

2021 ◽  
pp. 147715352098353
Author(s):  
C Pierson ◽  
B Piderit ◽  
T Iwata ◽  
M Bodart ◽  
J Wienold
Keyword(s):  
Environmental Context ◽  
Office Buildings ◽  
Visual Discomfort ◽  
Physical Measurements ◽  
Subjective Assessments ◽  
Discomfort Glare

Exposure to daylight has much to offer and should be optimised to maximise its potential. In order to harvest its benefits, any visual discomfort from daylight should be anticipated and minimised. Hence, there is the need to predict discomfort from daylight glare. While more than 20 models for predicting discomfort from daylight glare have been developed, none accurately predict it. The inclusion of additional factors in the models may improve the predictions. One such factor is the socio-environmental context of the observer. This study compares the evaluations of discomfort glare from daylight for office buildings in four socio-environmental contexts: Chile, Belgium, Japan and Switzerland. The evaluations of discomfort glare, each consisting of subjective assessments and physical measurements of a view condition, were collected at the office desks of 401 participants, although only 211 responses were used in the analyses due to exclusion rules. The results do not suggest evidence of an influence of socio-environmental context on discomfort from daylight glare. In other words, the participants in this study perceived discomfort glare similarly, regardless of their socio-environmental context.

scholarly journals Visual discomfort and the spatial distribution of Fourier energy

2015 ◽  
Vol 108 ◽  
pp. 1-7 ◽  
Author(s):  
Olivier Penacchio ◽  
Arnold J. Wilkins
Keyword(s):  
Spatial Distribution ◽  
Visual Discomfort

scholarly journals Verification of the accommodative responses in viewing an on-axis analog reflection hologram

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 119-126
Author(s):  
Seunghyun Lee ◽  
Philippe Gentet ◽  
Jungho Kim ◽  
Sungjae Ha ◽  
Soonchul Kwon
Keyword(s):  
Experimental Results ◽  
Human Vision ◽  
3D Image ◽  
Perceptual Distortion ◽  
Visual Discomfort ◽  
Reflection Hologram

Abstract Vergence and accommodation responses of human vision are very important factors when a 3D image is observed, and a vergence-accommodation conflict (VAC) causes perceptual distortion, visual discomfort, and fatigue for an observer. Theoretically, a hologram is expected to provide a 3D image without such a conflict. In this article, natural focusing was verified by human accommodation response (A-R) measurement during on-axis analog reflection Denisyuk hologram observation. The A-R of a group of participants were measured for a real marker and its Denisyuk hologram at various visualization distances using an Nvision K5001 autorefractor. The experimental results statistically confirmed the equivalence of the responses to the Denisyuk hologram and its real counterpart, as well as the absence of a VAC.

scholarly journals A neural correlate of visual discomfort from flicker

2020 ◽  
Author(s):  
Carlyn Patterson Gentile ◽  
Geoffrey K. Aguirre
Keyword(s):  
Visual Cortex ◽  
Neural Response ◽  
Cortical Activation ◽  
Uniform Field ◽  
Visual Aura ◽  
Visual Discomfort ◽  
Flickering Light ◽  
General Acceptance ◽  
Visual Stress ◽  
Visual Cortical

AbstractThe theory of “visual stress” holds that visual discomfort results from overactivation of the visual cortex. Despite general acceptance, there is a paucity of empirical data that confirm this relationship, particularly for discomfort from visual flicker. We examined the association between neural response and visual discomfort using flickering light of different temporal frequencies that separately targeted the magnocellular, parvocellular, and koniocellular post-receptoral pathways. Given prior work that has shown larger cortical responses to flickering light in people with migraine, we examined 10 headache free people and 10 migraineurs with visual aura. The stimulus was a uniform field, 50 degrees in diameter, that modulated with high-contrast flicker between 1.625 and 30 Hz. We asked subjects to rate their visual discomfort while we recorded steady state visually evoked potentials (ssVEP) from primary visual cortex. The peak temporal sensitivity ssVEP amplitude varied by post-receptoral pathway, and was consistent with the known properties of these visual channels. Notably, there was a direct, linear relationship between the amplitude of neural response to a stimulus and the degree of visual discomfort it evoked. No substantive differences between the migraine and control groups was found. These data link increased visual cortical activation with the experience of visual discomfort.

Assessing glare, Part 4: Generic models predicting discomfort glare of light-emitting diodes

2017 ◽  
Vol 50 (5) ◽  
pp. 739-756 ◽  
Author(s):  
Y Yang ◽  
MR Luo ◽  
WJ Huang
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Human Vision ◽  
Appearance Model ◽  
Generic Model ◽  
Light Emitting ◽  
Generic Models ◽  
Discomfort Glare ◽  
Colour Appearance

Two generic models to predict the influence of the luminance uniformity and spectral power distribution of light-emitting diode luminaires on discomfort glare were developed. One model was an extension of the empirical Unified Glare Rating, the other was based on a colour appearance model for unrelated colours. A new experiment was carried out to verify the performance of the generic models. There were twelve glare sources, having three types of luminance uniformity and four spectral power distributions. The results showed both generic models outperformed Unified Glare Rating but gave similar performance to each other. The generic model based on the colour appearance model bridges the gap between glare perception and human vision theory.

Testing a procedure to determine spatial proximity in semi-free-ranging macaque groups

2021 ◽  
Vol 22 (1) ◽  
pp. 24-54
Author(s):  
Laura Mármol ◽  
Hélène Meunier ◽  
Ruth Dolado ◽  
Francesc S. Beltran
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Social Factors ◽  
Current Method ◽  
Distribution Patterns ◽  
Spatial Position ◽  
Spatial Proximity ◽  
Viable Option ◽  
Spatial Variables ◽  
Free Ranging

Abstract Individuals’ spatial position is affected by social factors. The majority of studies correlating spatial position and social factors have used methods with drawbacks. A more complete method was developed by Dolado & Beltran (2011) in captive animals. The present study aimed to apply a modified version of this method in two semi-free-ranging macaque groups. The proposed method divides group’s surroundings into different subareas, selecting different points in each subarea and calculating the coordinates of these points. We filmed each group and analyzed the videos using an activated time transition recording to determine the individuals’ coordinates. With these data, we calculated spatial variables, allowing us to obtain groups’ spatial patterns. The current method improves on previous procedures and could be applied to larger study areas and groups than the method of Dolado & Beltran (2011), thus representing a viable option for studying spatial distribution patterns in semi-free-ranging macaque groups.

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

Ultrastructural analysis of the spatial distribution of MRNA

1992 ◽  
Vol 50 (1) ◽  
pp. 552-553
Author(s):  
Gary Bassell ◽  
Robert H. Singer
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
In Situ Hybridization ◽  
High Resolution ◽  
Nucleic Acids ◽  
Colloidal Gold ◽  
Dna Probe ◽  
Nucleotide Analogs ◽  
Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

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