Visual saliency of urban objects at night: Impact of the density of background light patterns

Davoudian, N

doi:10.1582/leukos.2011.08.02.004

Cited by 19 publications

(14 citation statements)

References 30 publications

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“…Moreover, there seems to be a need for a certain level of illuminance to attract people to walk when it is dark [4,5]. Experimental studies based on simulated environments suggest that different lighting applications, as well as illuminance levels, may fundamentally change people's impressions of public urban outdoor spaces [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Video Analysis of Pedestrian Movement (VAPM) under Different Lighting Conditions—Method Exploration

2020

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When daylight hours are limited, pedestrians are dependent on appropriate outdoor lighting. Although new city lighting applications must consider both energy usage and pedestrian responses, current methods used to capture pedestrian walking behaviour during dark conditions in real settings are limited. This study reports on the development and evaluation of a video-based method that analyses pedestrians’ microscopic movements (VAPM—video analysis of pedestrian movements), including placement and speed, in an artificially lit outdoor environment. In a field study utilising between-subjects design, 62 pedestrians walked along the same path under two different lighting applications. VAPM accurately discriminated pedestrians’ microscopic movements in the two lighting applications. By incorporating methodological triangulation, VAPM successfully complemented observer-based assessments of pedestrians’ perceptions and evaluations of the two lighting applications. It is suggested that in evaluations of pedestrian responses to city lighting applications, observer-based assessments could be successfully combined with an analysis of actual pedestrian movement while walking in the lit environment. However, prior to employing a large-scale application of VAPM, the methodology needs to be further adapted for use with drones and integration into smart city lighting systems.

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Section: Introductionmentioning

confidence: 99%

Video Analysis of Pedestrian Movement (VAPM) under Different Lighting Conditions—Method Exploration

2020

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“…In response to this question, various studies have been conducted. 8,22,23,24 Results indicated that images can be used to avoid spending too much money on real simulation. Today's modeling capabilities allow the researcher to simulate the color and intensity of light accurately and provide a controlled environment for accountability by keeping the illuminance intensity constant through image processing.…”

Section: Introductionmentioning

confidence: 99%

“…An object at night can be seen on a brilliant background, but can be completely neutral on other backgrounds . Previous studies on the relationship between background and object in the night landscape have shown that some factors, such as light density, are associated with the saliency of objects at night . Considering that many buildings are lighting up with the goal of attraction and attention at night, it is essential to use appropriate techniques to reduce energy consumption (less lumens) in a way that does not diminish their visual attractiveness.…”

Section: Introductionmentioning

confidence: 99%

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Viewerphilic nightscape based on correlated color temperature

Pourfathollah

Mahdavinejad

2019

Color Research & Application

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Nowadays, many factors are involved in lighting design to achieve targeted lighting in addition to meeting the user's requirements and security to avoid energy loss. As building indexation at night is one of the main reasons for building lighting, it is necessary to make a decision to reduce energy consumption and increase observer's attention. The present study investigated the relationship between the correlated color temperature of the background and building based on the amount of visual attention and the amount of visual desirability. In this article, using a factor analysis approach, a range that attracts visual attention and visual desirability at the same time was obtained, and it is called viewerphilic perspective. The results presented in the form of a diagram show a relationship between the variables that directly and indirectly influence the formation of a viewerphilic night perspective. The results showed that the elements with a high correlated color temperature in the background and a low correlated color temperature and neutral color were in the viewerphilic range, while the elements with a low color temperature and a background with a high color temperature was in the range of viewer phobic.

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“…[5][6][7] In addition to the contrast, the density and pattern of the light in the background relative to the target can have an effect on how objects stand out. 8 Other factors that affect visibility include the size of the target, the adaptation luminance, the motion of the target and the age of the observer. 5,6 Street lighting design standards such as the International Commission on Illumination (CIE) Publication 115 9 and American National Standards Institute/ Illuminating Engineering Society of North America (ANSI/IESNA) Recommended Practice RP-8-00 10 use vertical illuminance 1.5 m above the ground as a design target.…”

Section: Introductionmentioning

confidence: 99%

Dominant contrast as a metric for the lighting of pedestrians

Saraiji

Oommen

2014

Lighting Research & Technology

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both use vertical illuminance 1.5 m above the ground as a design criterion for the lighting of pedestrians. While vertical illuminance has the advantage of being easy to calculate and measure, visibility is based primarily on target contrast. A central question related to the visibility of pedestrians is whether drivers need to see the whole pedestrian or can they infer the presence of a pedestrian by recognizing any part of the pedestrian's shape. The objective of this work was to first explore various pedestrian contrast profiles that could exist and then to find a simplified approach to characterize pedestrian night-time visibility. The problem was addressed through theoretical analyses and computer simulations. Pedestrian contrast was found to be bipolar and dynamic. From the contrast profiles, we developed the concept of dominant contrast, which is defined as the contrast of any part of the pedestrian that provides the highest visibility. Dominant contrast was examined as a metric for street lighting design and night time visibility for (a) an unlit street with car headlights, (b) a lit street without car headlights and (c) a lit street with car headlights. Dominant contrast was found to be a viable metric for street lighting design and night time visibility studies.

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Visual saliency of urban objects at night: Impact of the density of background light patterns

Cited by 19 publications

References 30 publications

Video Analysis of Pedestrian Movement (VAPM) under Different Lighting Conditions—Method Exploration

Video Analysis of Pedestrian Movement (VAPM) under Different Lighting Conditions—Method Exploration

Viewerphilic nightscape based on correlated color temperature

Dominant contrast as a metric for the lighting of pedestrians

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