Levels Of Ambient Illumination Research Articles

The influence of illumination regimes on the structure of ant (Hymenoptera, Formicidae) community composition in urban habitats

The reliance on visual cues can vary among ant species living in different habitats, and is mostly influenced by the level of ambient illumination and the morphological adaptations of ant species that can determine their period of daily activity. Thus, different illumination regimes might affect ant community composition in habitats with different ambient illumination intensities. Despite this, in the literature, information is scarce about the effects of ambient illumination on ant activity. In the present study, we investigated the effect of ambient illumination intensity on the activity of ant species and their community composition under herbaceous and woody plants in 24 localities from Kyiv and Kyiv region, Ukraine. Our results showed that the ambient illumination properties of the habitat type affect the presence of ant species and the activity of their workers. In open habitats, the maximum ambient illumination had a negative effect, whereas in closed, woody habitats the maximum ambient illumination and tree circumference generally had a positive effect on the number of non-dendrobiotic ant individuals found on individual plants. The dendrobiotic species were less affected by the maximum illumination intensity. Although, in closed habitats, the effect of the previous variables and their interaction had species-specific aspects. Based on the former, we can tell that more structured forest habitats can provide broader illumination intensity ranges, allowing more ant species to coexist. However, similar illumination intensity ranges can lead to overlaps in the activity of ant species under the same illumination conditions, especially in open habitats. The outcomes of these interactions are highly influenced by larger trees that besides lowering illumination intensities, can enhance ant worker activity and promote species coexistence.

Effects of contrast and ambient illumination on visual discomfort of autostereoscopic display

AbstractThe conflict between vergence and accommodation is the main perceptual factors contributing to visual discomfort when viewing autostereoscopic display. The key factors relevant to the accommodation and vergence are the ambient illumination and the contrast. The current study was a 2 × 3 × 3 mixed design comparing VFSI and VIMS symptoms between 2D and 3D video clips with three contrast levels under three ambient illumination levels on the autostereoscopic display. Twenty participants were required to evaluate the degree of discomfort by filing out questionnaires after watching those video clips. According to the result analysis, the 3D viewing participants reported more severe symptoms compared to 2D. The moderate contrast conditions were found to be the optimum for viewing comfort. The difference between VFSI and VIMS symptoms become larger with increasing contrast. The results also suggested the optimum 3D illumination condition should not be too high to effectively relieve visual discomfort. VIMS symptoms were more sensitive to the changes in ambient illumination than VFSI. Moreover, significant interaction between contrast and ambient illumination was found. Participants felt the most comfortable in the combination effect of moderate level of contrast and the high level of ambient illumination.

Histogram Refined Local Ternary Pattern-based Bilateral LPP for Vision Sensor-based Robot Navigation Guidance under Challenging Environments

The present paper proposes a new variant of bilateral locality preserving projection (BLPP), a nonlinear manifold learning technique, for vision sensor-based robot navigation guidance in challenging environments, suffering from both variations in ambient illumination levels and vision sensor noises and uncertainties in image acquisition. In its basic form, the adjacency graph in BLPP is formulated both in feature subspace and spatial subspace, simultaneously. The present work proposes to compute the feature weights using local ternary pattern (LTP), a lesser noise-sensitive feature descriptor, which is also robust against illumination variations. In addition, histogram refinement has been performed on the feature descriptor to encode the local neighborhood structure of the data, proposing a further augmented version of BLPP named histogram refined local ternary pattern-based BLPP (HRLTP-BLPP). Extensive real-life experiments with challenging photometric conditions and sensor noises have been performed to show the usefulness of HRLTP-BLPP over other competing, state-of-the-art approaches, utilized for robot navigation guidance.

Association between Ambient Illumination and Cognitive Impairment: A Population-Based Study of Older.

It is well-established that light therapy can alleviate cognitive impairment, and ambient illumination (AI) can quantify the amount of exposure to light. However, the relationship between AI and cognitive impairment has been largely understudied. Objectives. We aimed to examine the cross-sectional associations between AI and impaired cognition using data from the National Health and Nutrition Examination Survey (NHANES) (2011-2013) database. Methods. The correlation between AI and cognitive impairment was analyzed using multivariate logistic regression models. Nonlinear correlations were explored using curve fitting. Results. Multivariate logistic regression yielded an OR of 0.872 (95% CI 0.699, 1.088) for the association between AI and cognitive impairment after adjusting for covariates. Smooth curve fitting showed that the correlation was nonlinear, with an inflection point at 1.22. Conclusions. These results suggested that the level of AI may be linked to cognitive impairment. We found a nonlinear relationship of AI with cognitive impairment.

The Influence of Mismatches between Ambient Illumination and Display Colors on Video Viewers’ Subjective Experiences

Mismatches between ambient illumination levels and display luminance can cause poor viewing experiences. This paper explores the influence of chromaticity differences between illumination and display on viewers’ subjective evaluations of color appearance, preference, and visual comfort when watching videos. Results show that when the chromaticity biases of display and illumination are incongruent, viewers like the video less than when the biases are congruent, and find its colors abnormal.

Visual Performance under Varying Illumination Conditions while using an Indigenously Developed Wrist Wearable Computer

Ambient illumination conditions have significant impact on users’ visual performance while carrying out onscreen reading tasks on visual display units, especially smaller screen sizes. Present study assessed the visual performance responses of different ambient illumination levels during onscreen reading on Wrist Wearable Computer (WWC) developed for the command-control-communication between the control room and the soldiers operating in remote locations. Ten (10) Indian Infantry soldiers performed two different types of loud reading tasks on the display of WWC under three different ambient illumination (mean ±SEM) conditions namely, Indoor controlled (450.00±10.00 lx), Outdoor daylight (11818.7±582.91 lx) and Indoor dark (0.12±0.03 lx) environments. While reading, participants wore an eye tracking glass which recorded the eye movement responses. Visualisation techniques were used to predict the association of illumination levelof surrounding with visual performance of the user. Subjective legibility rating was also applied to understand participants’ preferences towards physical attributes of the onscreen information and illumination level. Results indicated that illumination had a significant effect on eye movement parameters like fixation frequency, fixation duration and scanpath length while completing the tasks. Overall, participants performed better under indoor controlled illumination conditions in terms of fixation profile and scanpath length, apart from improved subjective legibility ratings as compared to other two illumination conditions. Future research attempts need to be directed towards the optimum performance of the display across wide range of ambient illumination conditions and to establish how the display of indigenously developed wearable computer performs in comparison to other such displays available across the globe.

Artificial light reduces foraging opportunities in wild least horseshoe bats

Artificial light at night has been proposed as a global threat to biodiversity. Insectivorous bats are strictly nocturnal animals that are vulnerable to disruption from artificial light. Given that many light-sensitive bats tend to avoid night light during roost departure, it is often assumed that nighttime light pollution reduces their foraging opportunities, albeit empirical evidence in support of this hypothesis remains elusive. Here, we used least horseshoe bats, Rhinolophus pusillus, to assess whether white artificial light is detrimental for the opportunities of foraging. We manipulated the levels of ambient illumination and perceived predation risk inside the bat roost. We monitored bats' emergence activity using high-speed video and audio recording systems. DNA-based faecal dietary analysis and insect survey were applied to determine activity time of prey in foraging areas. Following experimentally manipulation of white light-emitting diode (LED) lighting 0–15 min after sunset, bat pass, flight duration, and echolocation pulse emission decreased. The mean emergence time of bats flying out was delayed by 14 min under lit treatment compared with the dark control. Only 10% of bats left for foraging during 40 min of light exposure. Aversive effects of LED light on bat emergence were robust regardless of the presence of a potential predator. Insect prey reached a peak of abundance between 30 and 60 min after sunset. These results demonstrate that white artificial light hinders evening emergence behavior in least horseshoe bats, leading to a mismatch between foraging onset and peak food availability. Our findings highlight that light pollution overrides foraging onset, suggesting the importance of improving artificial lighting scheme near the roosts of light-sensitive bats.

Investigation of the Optimum Display Luminance of an LCD Screen under Different Ambient Illuminances in the Evening

Ambient illuminance and screen luminance have a significant influence on the visual fatigue and visual performance associated with the use of computers. The current study was conducted to investigate optimal screen luminance under different ambient illuminances and fit a curve of the optimum luminance of LCD screens under evening illumination. Thirty-three participants were assigned to rate screen brightness, visual comfort with screen luminance, satisfaction with ambient illuminance and visual fatigue under six screen luminance levels (3.87, 21.47, 42.74, 64.12, 84.77 and 106.7 cd/m2) combined with five ambient illuminance levels (0, 25, 50, 75 and 100 lx) in the evening. The results showed that optimum LCD screen luminance increased with increasing ambient illuminance. Moreover, ambient illuminance and screen luminance levels should be in the range of 13.08–62.16 lx and 20.63–75.15 cd/m2, respectively, to obtain the optimal subjective feelings of visual fatigue and visual comfort during the evening.

Effect of Ambient Illumination, Screen Resolution and Zoom Level on Performance of Typing on Computers

Objective: This work aims to investigate effect of the ambient illumination, screen resolution and Zoom levels on visual-related task performance. The job used in this research is typing on computers. Speed of typing paragraph and typing quality were defined as the task performance.
 Background: In recent years, computers play a remarkable role in nearly everyone’s daily life. We use computers for various purposes and under a wide range of ambient illumination. High illumination level usually results in some problems. Adjusting screen resolution and zoom level are common solutions contra problems for visibility due to unsuitable illuminations.
 Method: Ambient illuminations were examined 114, 230, 340, 420 and 520 lx. Screen resolution scales were diverse to cover all range of regulate ability pliable by characteristics of the offering used; 768*1024, 720*1280 and 768*1366. Zoom levels was tested 50, 100, 150 and 200%.
 Results: Based on this study, can be found that, the more effective illumination level on average typing time was 340 followed by 420 lx. Average typing time decrease with increasing screen resolution, the minimum average typing time observed at 720*1280 and 168*1366 screen resolution. Change the zoom level of text show significant effect on typing time, which the average typing time decreases with increasing zoom level. The minimum typing time observed at 100 and 150% zoom level. Experimental results for all S/N ratio, mean, and standard deviation (real) response values show that, illumination level, screen resolution and zoom scale are the significant parameters among all controllable factors that influence the avearge typing time. Based on S/N Ratio the optimum parameters was 114 lx illumination level and 768*1024 screen Resolution and 50% zoom level. Based on standard deviation the optimum parameters was 114 lx illumination level and 768*1366 screen Resolution and 150% zoom level. Based on the means the optimum parameters was is 230lx illumination level and 768*1366 screen Resolution and 100% zoom level.
 Conclusion: The provision of suitable illumination, screen resolution and zoom levels that feedback to enhancing the performance of typing performance on computers.
 Application: This study can inform in-computer typing offices and policy makers concerned with human factors and work-study.

The Effects of Ambient Illumination, Color Combination, Sign Height, and Observation Angle on the Legibility of Wayfinding Signs in Metro Stations

Well-designed wayfinding signs play an important role in improving the service level of metro stations, ensuring the safety of passengers in evacuation, and promoting the sustainable development of public transport. This study explored the effects of ambient illumination, color combination, sign height, and observation angle on wayfinding signs’ legibility in metro stations. In the experiment, simulated metro-wayfinding signs were made to test legibility. As designed, the legibility was measured based on the following independent variables: two levels of ambient illumination (70 lux and 273 lux), two target/background color combinations (achromatic-white target on black background, chromatic-yellow target on black background), two sign heights (1.5 m and 2 m), and three observation angles (0°, 45°, 70°). The results showed that brighter ambient illumination provided passengers with higher legibility. Achromatic color combination was more legible than chromatic color combination, but not significantly. Different types of signs, set at different height, did not directly affect legibility. Observation angle had significant effects on legibility. Visibility catchment area of wayfinding signs was like an ellipse, with its short axis nearly equal to the legibility distance of the sign at 0 degrees. The findings will facilitate the layout and setting location of wayfinding signs in metro stations and improve the level of wayfinding service.

Effects of high ambient illuminations on image quality in mobile displays

Images displayed on mobile terminals are influenced by high ambient illumination. This work sets out to investigate the effects of ambient illumination on image quality (IQ). In this study, 20 test images, which were displayed on a mobile phone with six levels of screen backlight luminance, were visually evaluated under six levels of ambient illumination up to 20,000 lx. In the visual experiment, several perceptual attributes including brightness, contrast, and overall IQ were evaluated via the categorical judgment method. The experimental results suggest that IQ declined with increasing ambient highlight incident upon the screen. Moreover, the IQ and ambient contrast ratio (ACR) could be expressed by a logarithmic relation. Finally, a model was proposed to reveal the effects of the high ambient illumination on IQ based on the ACR.

Perceptual Image Quality Assessment for Various Viewing Conditions and Display Systems

From complete darkness to direct sunlight, real-world displays operate in various viewing conditions often resulting in a non-optimal viewing experience. Most existing Image Quality Assessment (IQA) methods, however, assume ideal environments and displays, and thus cannot be used when viewing conditions differ from the standard. In this paper, we investigate the influence of ambient illumination level and display luminance on human perception of image quality. We conduct a psychophysical study to collect a novel dataset of over 10000 image quality preference judgments performed in illumination conditions ranging from 0 lux to 20000 lux. We also propose a perceptual IQA framework that allows most existing image quality metrics (IQM) to accurately predict image quality for a wide range of illumination conditions and display parameters. Our analysis demonstrates strong correlation between human IQA and the predictions of our proposed framework combined with multiple prominent IQMs and across a wide range of luminance values.

Eyelid squinting during food pecking in pigeons.

The visual control of pecking by pigeons (Columba livia) has latterly been thought to be restricted to the fixation stops interrupting their downward head movements because these stops prevent interference by motion blur. Pigeons were also assumed to close their eyes during the final head thrust of the peck. Here, we re-examined their pecking motions using high-speed video recordings and supplementary provisions that permitted a three-dimensional spatial analysis of the movement, including measurement of pupil diameter and eyelid slit width. The results confirm that pigeons do not close their eyes completely during the presumed optically ballistic phase of pecking. Instead, their eyelids are narrowed to a slit. The width of this slit is sensitive to both the ambient illumination level and the visual background against which seed targets have to be detected and grasped. There is also evidence of some interaction between pupil diameter and eyelid slit width. We surmise that besides being an eye-protecting reflex, the partial covering of the pupil with the eyelids may increase the depth of focus, enabling pigeons to obtain sharp retinal images of peck target items at very close range and during the beak-gape 'handling' of food items and occasional grit particles.

Assessing Feasibility of Secure Quantum Communications Involving Underwater Assets

In this paper, we apply a mathematical model of the quantum bit error rate to assess the viability of quantum key distribution (QKD) protocols for secure and covert underwater communications. We consider scenarios that may include passive sensor arrays, coordinated underwater vehicles, and surface and aerial assets. This analysis suggests that single-photon QKD can potentially be used effectively at depths between 60 and 110 m in clear waters, with the precise depth depending in part on ambient illumination levels. We discuss how diurnal variations in background illumination can be exploited in some applications to achieve improved communications rate and/or reliability when using QKD or other secure optical protocol.

The Case for Further Advancing the Performance of Displays

Timo Kunkel Robert Wanat If there is one word to describe the difference between displays today and at the turn of the last century, it’s ubiquity. Modern consumers are surrounded by displays in their everyday lives, from the mobile devices we use when on the move to the TVs we enjoy at home for entertainment to the cinema screens we watch while socializing. It has become difficult to spend a day without once looking at a display. At the same time, expectations regarding the performance of these screens have steadily increased. This motivates display manufacturers to improve the capabilities of their devices and increasingly accommodate the challenges that changing viewing environments impose. Despite those complex challenges, amazing progress has been made in the last few decades in understanding how human visual perception works and how to use that information to create displays with improved image rendering consistency, accuracy, and overall capability. Though there is still a ways to go, the viewer experience today is more compelling than it has ever been. In this edition of Information Display, we pay close attention to high-performance displays, particularly in the Frontline Technology section. The articles there are centered around high dynamic range (HDR) imaging, which is currently one of the most prominent technological subfields. We believe that the lessons about the development of HDR pipelines that are explored in this issue will also benefit other high-performance display trends, such as AR/;VR, folding displays, 8K (see page 17 for an in-depth look at this trend), and very high framerate displays. The articles also focus on cutting-edge display technologies for home entertainment and automotive applications. Both of these contexts present different and sometimes unique challenges that have to be approached with a focus on how the visual system performs within the framework of the specific environment. One example discussed in the pages ahead is the effect of screen reflections and surround light, which are major challenges for image display and therefore need to be addressed as such. We can be even more specific with this illustration: Rendering accurate colors at very low ambient luminance levels is not as important for a TV display that is observed at high peak ambient illuminance levels–for example, a living room during the daytime—as colors rendered at very low luminance levels are likely less perceivable under this condition. Rather, in this case, the benefit from ambient compensation approaches that retarget those colors to improve their visibility exceeds that of having chromatic accuracy in the low luminances. However, accurate color rendering in low luminance levels becomes crucial in dark ambient environments, such as a living room at night or in a cinema. For automotive displays, accurate low-luminance appearance becomes even more important as there is a safety factor: Information must be communicated to drivers without distracting them while they’re in traffic. Many more concepts and examples are discussed in further detail. Ultimately, each article tells a part of the story and showcases how our industry is actively working on not only improving the status quo but also seamlessly rendering more accurate image quality, regardless of how consumers want to view their content. Timo Kunkel is a senior color and imaging researcher in the CTO office of Dolby Laboratories, Inc. His main areas of interest are advanced display and imaging technologies and exploring how we can continue to bring them closer to human perception. Kunkel can be reached at Timo.Kunkel@dolby.com. Robert Wanat is a senior color scientist for Dolby Laboratories, Inc. His work revolves around creating models of the human visual system that simulate visual perception and how it is affected by changing viewing conditions. Wanat can be reached at Robert.Wanat@dolby.com.

Modeling the effect of electric vehicle adoption on pedestrian traffic safety: An agent-based approach

When operated at low speeds, electric and hybrid vehicles have created pedestrian safety concerns in congested areas of various city centers, because these vehicles have relatively silent engines compared to those of internal combustion engine vehicles, resulting in safety issues for pedestrians and cyclists due to the lack of engine noise to warn them of an oncoming electric or hybrid vehicle. However, the driver behavior characteristics have also been considered in many studies, and the high end-prices of electric vehicles indicate that electric vehicle drivers tend to have a higher prosperity index and are more likely to receive a better education, making them more alert while driving and more likely to obey traffic rules. In this paper, the positive and negative factors associated with electric vehicle adoption and the subsequent effects on pedestrian traffic safety are investigated using an agent-based modeling approach, in which a traffic micro-simulation of a real intersection is simulated in 3D using AnyLogic software. First, the interacting agents and dynamic parameters are defined in the agent-based model. Next, a 3D intersection environment is created to integrate the agent-based model into a visual simulation, where the simulation records the number of near-crashes occurring in certain pedestrian crossings throughout the virtual time duration of a year. A sensitivity analysis is also carried out with 9000 subsequent simulations performed in a supercomputer to account for the variation in dynamic parameters (ambient sound level, vehicle sound level, and ambient illumination). According to the analysis, electric vehicles have a 30% higher pedestrian traffic safety risk than internal combustion engine vehicles under high ambient sound levels. At low ambient sound levels, however, electric vehicles have only a 10% higher safety risk for pedestrians. Low levels of ambient illumination also increase the number of pedestrians involved in near-crashes for both electric vehicles and combustion engine vehicles.

Applying the Twilight Envelope to the Forensic Analysis of Pedestrian and Bicyclist Conspicuity in the Dark

The large majority of traffic crashes involving vulnerable road users such as pedestrians and bicyclists occur when ambient illumination levels are reduced. The difficulty drivers face in recognizing the presence of these road users in the darkness can be attributed to the selective degradation of foveal visual functions, which support a driver’s ability to detect and identify the presence of potential hazards and other objects in the environment. Clothing worn by pedestrians and bicyclists can contribute to their conspicuity to oncoming drivers; extensive research has demonstrated that dark-clothing-clad pedestrians are often recognized at dangerously short distances. Vehicle headlamps serve to illuminate the path ahead for drivers, particularly in the absence of artificial illumination along the roadway, in order to improve driver visibility in the dark. The twilight envelope is a means of determining the visibility distance afforded by headlamps. This approach to describing illumination was applied to the analysis of a traffic crash involving a vulnerable road user, providing insight into the driver’s visibility. Future research should address the relationship between the twilight envelope of vehicle headlamps and the distance at which drivers are able to recognize potential hazards such as pedestrians and bicyclists using those headlamps.

Improving color reproduction accuracy of an OLED‐based mobile display

AbstractFor improving color reproduction accuracy of mobile displays, we recently developed a generic model for device‐specific display characterization model that also accounts for the influence of illuminance from ambient light. In the present article, this MDCIM model (Mobile Display Characterization and Illumination Model) is applied to a Samsung Galaxy S4 display, representing OLED displays. The performance of the model was tested by determining the values of all model parameters using publicly available technical data only. We organized visual tests under various ambient illuminance levels from 600 to 3000 lux. Seven observers compared the color of displayed images with the color of physical samples. With the MDCIM method, the quality of the color match was shown to improve considerably as compared to using only device‐independent encoding color space. On a five‐point scale to quantify color reproduction accuracy, the MDCIM resulted in more than 1 unit improvement at 1000 lux illuminance. At lower and higher illuminance, the improvement was even larger. Color reproduction accuracy was found to be at least reasonable, according to the subjective assessment of visual observers, for more than 75% of the samples when using the MDCIM method, but only 20% or less when using the common device‐independent encoding color space.

Effects of varying light conditions and refractive error on pupil size

Purpose: To investigate the effects of small scale illumination levels and refractive error type on the pupil size measured with Visante Optical Coherence Tomography in healthy eyes. Findings: Pupil size increased with illumination decrements. Mean pupil size was 3.5 mm at 550 lux, 4.2 mm at 350 lux, 5.2 mm at 150 lux, 5.03 mm at 40 lux, and 5.4 mm at 2 lux. In multi-pairwise comparison of the five illumination levels, there were significant differences (p < 0.05) down to 150 lux. Comparisons among 150, 40 and 2 lux show no differences (p > 0.05). Refractive error ranged from spherical equivalent of +0.50 to –7.75D. Group of myopes had larger mean pupil size than emmetropes at all light levels but was not significant (p < 0.05). Both refractive groups had some amount of increase in pupil size with illumination decrements. There were no hyperopes and presbyopes in the study. This study has demonstrated that ambient illumination levels from high to low cause increase in pupil size and refractive error does not appear to have an extra influence. At or below 150 lux, pupil was maximally dilated at about 5.2 mm. These findings may assist in further understanding pupillary light reflex.

Improving color reproduction accuracy of a mobile liquid crystal display.

The default method for color representation on displays involves sRGB as device-independent encoding color space. For improving color reproduction accuracy, we develop a device-specific display characterization model for the Apple iPad Air 2. In separate articles, we will evaluate the same method for other devices and for other display technologies. This model is combined with an easy-to-implement new method to account for the influence of illuminance from ambient light. The combination is called the mobile display characterization and illumination model (MDCIM) for the iPad Air 2, representing modern liquid crystal displays. Seven observers performed psychophysical tests at ambient illuminance levels from 600 to 3000 lx. They visually compared colors of calculated images with those of physical samples. The MDCIM model achieves similar color reproduction accuracy as when using the default method involving sRGB encoding at 1000 lx, while considerably improving color accuracy at other illuminance levels. At 600 lx, 98% of the observers prefer images directly generated with the MDCIM model over those created using the default method. The average color reproduction accuracy improves by two categories on a five-point scale. At 3000 lx, the percentage of colors that is represented at least reasonably well, according to the subjective assessment of visual observers, increased from 0% to 60%.