White appearance and chromatic adaptation on a display under different ambient lighting conditions

2021 ◽  
Author(s):  
Rui Peng ◽  
Mingkai Cao ◽  
Qiyan Zhai ◽  
Ming Ronnier Luo
Keyword(s):  
Chromatic Adaptation ◽  
Lighting Conditions ◽  
Ambient Lighting

Modelling incomplete chromatic adaptation on a display under different ambient illuminations

2019 ◽  
Vol 2019 (1) ◽  
pp. 231-236
Author(s):  
Rui Peng ◽  
Ming Ronnier Luo ◽  
Mingkai Cao
Keyword(s):  
Lower Degree ◽  
Chromatic Adaptation ◽  
White Background ◽  
Color Stimulus ◽  
Lighting Condition ◽  
Lighting Conditions ◽  
Ambient Lighting ◽  
Illuminance Level ◽  
Adaptation Factor

The purposes of this study was to investigate the chromatic adaptation and adaptive whites on a display under various ambient lighting conditions with different chromaticity and illuminance. An image including black text and white background was rendered by means of the CAT02 chromatic adaptation transform, into 42 different white stimuli varying at 6 CCTs and 7 Duv levels. Twenty observers assessed the neutral white evaluations of each color stimulus via psychophysical experiments. The optimization based on the neutral white stimulus under each ambient lighting condition suggested a lower degree of chromatic adaptation under the conditions with a lower CCT and a lower illuminance level. The results were used to model the adaptive display white and the incomplete adaptation factor (D) for CAT02 under different ambient illumiantions.

scholarly journals Preferred skin tones reproduction of three ethnic groups under different ambient lighting conditions

2020 ◽  
Vol 2020 (28) ◽  
pp. 94-99
Author(s):  
Mingkai Cao ◽  
Ming Ronnier Luo ◽  
Guoxiang Liu
Keyword(s):  
Ethnic Groups ◽  
Large Scale ◽  
Skin Tone ◽  
Chromatic Adaptation ◽  
Lighting Conditions ◽  
Ambient Lighting ◽  
Predicted Probability ◽  
Hue Angle ◽  
Scale Experiment ◽  
Facial Images

A large-scale experiment was conducted to investigate facial image quality on mobile phones. There were 8 original facial images from 4 skin tone types, each included a male and a female image. Each image was captured at 6500K and they were rendered to have 5 CCT (correlated colour temperature) and 5 Duv (the shifts away from the Blackbody locus) levels via CAT02 chromatic adaptation transform to simulate the effect of the images captured under 25 different lighting conditions. Each image was assessed under 9 ambient lighting conditions( including one dark condition) by 90 observers from 3 ethnic groups (Caucasian, Chinese and South Asian), each 30 observers. Preferred facial skin tone ellipse was established by maximizing the correlation coefficient between the model predicted probability and the preference percentage from the visual results. Four types of preferred skin tones had small differences in hue angle and chroma, but concentrated into a small colour region, about [24.7, 46.1°] for Cab* and hab values respectively. All ethnic group preferred images taken under illuminants having high CCT (6500-8000 K). It was also found that the chroma of the preferred skin tones will slightly increase as the ambient lighting CCT decrease.

Flight By Periscope: Making Takeoffs and Landings; The Influence of Image Magnification, Practice, and Various Conditions of Flight

1966 ◽  
Vol 8 (1) ◽  
pp. 13-40 ◽  
Author(s):  
Stanley N. Roscoe ◽  
Scott G. Hasler ◽  
Dora J. Dougherty
Keyword(s):  
Image Magnification ◽  
Flight Experience ◽  
Lighting Conditions ◽  
Ambient Lighting ◽  
Experience Effects ◽  
Detailed Determination ◽  
Accuracy Speed

The proficiency with which pilots can make takeoffs and landings using a periscope as the only source of outside visibility was studied under various conditions of flight. A detailed determination was made of the effects of variations in image magnification upon landing accuracy. Speed of transition to flight by periscope was related to flight experience. Effects of various weather, runway surface, and ambient lighting conditions upon flight by periscope were investigated.

A Practical Tool for Ambient Illumination Comparisons at Dusk/Dawn

2016 ◽  
Vol 60 (1) ◽  
pp. 470-474 ◽  
Author(s):  
Hilary Lam ◽  
Sayf Gani ◽  
Randy Mawson ◽  
Jason Young ◽  
Erin Potma
Keyword(s):  
Human Perception ◽  
Time Lapse ◽  
Time Of Day ◽  
Ambient Illumination ◽  
Adjustment Factor ◽  
Lighting Conditions ◽  
Accurate Knowledge ◽  
Ambient Lighting ◽  
Practical Tool ◽  
Sky Conditions

Nighttime visibility is an important consideration in collision reconstruction and personal injury investigation. Decreased contrast in low ambient lighting conditions can greatly affect human perception and response. Because ambient lighting levels change rapidly at dawn and dusk, forensic investigators must have an accurate knowledge of the time of day and the cloud conditions at the time of the incident before initiating a nighttime visibility assessment. Previously, human factors experts attempting re-enactments at dawn or dusk have had to wait for sky conditions that match those at the time of the incident, making the investigation of those cases extremely difficult, if not unfeasible. In this study, an ambient illumination equivalency tool has been developed based on a database of time-lapse light meter readings collected by the authors. This new tool can be used to facilitate nighttime visibility assessments on any day by providing a time adjustment factor to account for the changes in ambient illuminance due to differences in the cloud conditions between the day of the incident and the day of the re-enactment.

scholarly journals Software package for testing three-dimensional shape measurement methods using structured lighting

2021 ◽  
Vol 2057 (1) ◽  
pp. 012087
Author(s):  
S V Dvoynishnikov ◽  
V O Zuev ◽  
I K Kabardin ◽  
D V Kulikov ◽  
V V Rahmanov
Keyword(s):  
Software Package ◽  
Three Dimensional ◽  
Measurement Methods ◽  
Shape Measurement ◽  
Structured Lighting ◽  
Lighting Conditions ◽  
Ambient Lighting ◽  
Dimensional Shape ◽  
Shadow Maps ◽  
Three Dimensional Shape

Abstract This work aims at creating a universal software package for the development and testing of triangulation methods using structured lighting for measuring the three-dimensional geometry of objects in difficult ambient lighting conditions. As a result, a software package meeting the stated requirements is created. Lighting is based on the Fong model. A method for preloading objects is implemented to optimize the operation of the software package. An accelerated method for creating shadow maps is proposed and implemented. The developed software package is shown to successfully perform all required functions.

scholarly journals The impact of transition type on chromatic adaptation under dual lighting conditions

2020 ◽  
Vol 2020 (28) ◽  
pp. 36-41
Author(s):  
Shining Ma ◽  
Peter Hanselaer ◽  
Kees Teunissen ◽  
Kevin A.G. Smet
Keyword(s):  
Chromatic Adaptation ◽  
Spatial Complexity ◽  
Lighting Conditions ◽  
Adaptation State ◽  
Cat Model ◽  
The Impact ◽  
Transition Type

Over the years, many CATs (chromatic adaptation transform), typically based on the von Kries coefficient rule, have been developed to predict the corresponding colors under different illuminants. However, these CATs were derived for uniform stimuli surrounded by a uniform adapting field. To investigate the adaptation state under spatially complex illumination, an achromatic matching experiment was conducted under dual lighting conditions with three color pairs and two transition types. It has been found that the transition type has an impact on both the equivalent chromaticity and degree of adaptation. These results can help build a comprehensive von Kries based CAT model, with considering the spatial complexity of illumination.

Clinical Study of the Influence of Ambient Lighting Conditions on the Mesh Quality of an Intraoral Scanner

2020 ◽  
Vol 29 (8) ◽  
pp. 651-655 ◽  
Author(s):  
Marta Revilla‐León ◽  
Sai Ganesh Subramanian ◽  
Mutlu Özcan ◽  
Vinayak Raman Krishnamurthy
Keyword(s):  
Clinical Study ◽  
Mesh Quality ◽  
Intraoral Scanner ◽  
Lighting Conditions ◽  
Ambient Lighting

The relationship between ambient lighting conditions, absolute dark-adapted thresholds, and rhodopsin in black and hypopigmented mice

2004 ◽  
Vol 21 (6) ◽  
pp. 925-934 ◽  
Author(s):  
GERARD H. DALY ◽  
JESSICA M. DILEONARDO ◽  
NATALIE R. BALKEMA ◽  
GRANT W. BALKEMA
Keyword(s):  
Bright Light ◽  
Visual Sensitivity ◽  
Segment Length ◽  
Single Strain ◽  
Photoreceptor Layer ◽  
Lighting Conditions ◽  
Ambient Lighting ◽  
Dim Light ◽  
Albino Mice ◽  
The Relationship

Significant variation in absolute dark-adapted thresholds is observed both within and between strains of mice with differing ocular pigmentation levels. Differences in threshold within a single strain are related to the Williams' photostasis effect, that is, photoreceptor rhodopsin levels are dependent upon ambient lighting conditions. To examine threshold differences among strains, we equalized rhodopsin levels by maintaining albino mice (c2J/c2J) at 2 × 10−4 cd/m2 (dim light) and black mice at 2 × 102 cd/m2 (bright light). This resulted in ocular rhodopsin levels for albino mice (albino—dim) of 494 ± 11 pmoles/eye and rhodopsin levels for black mice (black—bright) of 506 ± 25 pmoles/eye. For comparison, rhodopsin levels in black mice maintained in dim light are 586 ± 46 pmoles/eye and 217 ± 46 pmoles/eye in albino mice maintained in bright light. We found similar dark-adapted thresholds (6.38 log cd/m2vs. 6.47 log cd/m2)) in albino and black mice with equivalent rhodopsin determined with a water maze test. This suggests that dark-adapted thresholds are directly related to rhodopsin levels regardless of the level of ocular melanin. The number of photoreceptors, photoreceptor layer thickness, and outer segment length did not differ significantly between albino (dark) and black mice (bright). These results demonstrate that the visual sensitivity defect found in hypopigmented animals is secondary to abnormal rhodopsin regulation and that hypopigmented animals have either an improper input to the photostasis mechanism or that the photostasis mechanism is defective.

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