Measurement of Circadian Effectiveness in Lighting for Office Applications

Babilon, Sebastian; Beck, Sebastian; Kunkel, Julian; Klabes, Julian Marcel; Myland, Paul; Benkner, Simon; Khanh, Tran Quoc

doi:10.3390/app11156936

Cited by 12 publications

(13 citation statements)

References 93 publications

(80 reference statements)

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“…Our measurements show a significant reduction of up to 60% for illuminance and MEDI when considering the FOV (at horizontal view and realistic settings, see Figure 3 and Figure 4 ). These results are consistent with the still sparse literature on this topic [ 5 , 46 ] and have a high relevance towards study design and replicability.…”

Section: Discussionsupporting

confidence: 90%

“…The CIE recommends this approach in Annex A.6 of the standard CIE S 026:2018 [ 3 ]. Methods to achieve this include using an occlusion or radiance hood to limit the detection areas of photometers and spectroradiometers, or applying imaging measurements, e.g., from a luminance camera, followed by FOV-selective postprocessing [ 4 , 5 , 6 ]. However, these methods are not commonly used in current projects and studies, leading to potential inconsistencies and lack of standardization for non-image-forming effects of light (NIF).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of the Human Field of View on Visual and Non-Visual Quantities in Indoor Environments

Zauner,

Broszio,

Bieske

2023

Clocks & Sleep

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The visual and non-visual effectiveness of light is often determined by measuring the spectrally weighed irradiance on the corneal plane. This is typically achieved using spectral irradiance or illuminance measurements, captured in a hemispheric (2π) geometry with a diffuser. However, the human binocular field of view (FOV) is not a perfect hemisphere, as it is occluded both upward and downward. Previous research on FOV-restricted measurements is limited, leaving the error from using hemispheric measurements for non-visual quantities undefined. In our study, we tackled this issue by designing and 3D printing FOV occlusions as attachments to spectral measurement devices. We took measurements with and without the occlusion in various laboratory (light from different directions) and real-world lighting situations (light typically from above). Our findings reveal a reduction of visual and melanopic values due to the FOV occlusion. These ranged from negligible to more than 60% in realistic scenarios. Interestingly, the reduction was consistent for both visual and melanopic parameters, as the distribution of light in the FOV was generally spectrally homogeneous. An exception occurred in a specific artificial laboratory situation, where the melanopic daylight (D65) efficacy ratio changed by more than a factor of 2 solely because of the FOV occlusion. Additionally, we observed that head orientation had a marked effect on all quantities measured. In conclusion, our results highlight the potential for substantial errors when solely relying on vertical, hemispheric measurements in experiments and non-visual lighting design projects. We encourage the (additional) use of FOV occlusion in eye-level measurements for typical viewing directions, and we are providing open-source 3D-print files to facilitate this practice.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Influence of the Human Field of View on Visual and Non-Visual Quantities in Indoor Environments

Zauner,

Broszio,

Bieske

2023

Clocks & Sleep

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show abstract

“…Our measurements show a significant reduction of up to 60% for illuminance and MEDI when considering the FOV (at horizontal view and realistic settings, see Figures 3 and 4). These results are consistent with the still sparse literature on this topic [5,46] and have a high relevance towards study design and replicability.…”

Section: Further Discussion and Outlooksupporting

confidence: 89%

Influence of the Human Field of View on Visual and Non-visual Quantities in Indoor Environments

Zauner¹,

Broszio²,

Bieske³

2023

Preprint

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Spectrally weighed irradiance on the corneal plane is often used to determine the visual and non-visual potency of light. Spectral irradiance or illuminance is measured with a diffuser in the so-called 2π geometry (i.e., a hemispheric measurement). Due to anatomical conditions, the human binocular field of view (FOV) does not correspond to a hemisphere but is occluded upwards and downwards. FOV-restricted measurements are scarce, however, and thus the error when using hemispheric measurements is yet to be determined. For our study, we designed and 3D printed FOV occlusions as attachments to spectral measurement devices. Measurements with and without the occlusion were taken in different lighting situations in the laboratory (light from different directions) and in real-world conditions (light typically from above). Our measurements show a reduction of visual and melanopic values due to the FOV occlusion ranging from negligible to over 60% for realistic scenarios. Further, the reduction was comparable for visual and melanopic parameters, as the distribution of light in the FOV was generally spectrally homogeneous. In the case of an exemplary and artificial laboratory situation, however, the melanopic daylight (D65) efficacy ratio changed by more than a factor of 2 only due to the FOV occlusion. Finally, head orientation showed a marked impact on all quantities. Our results reveal the potential for considerable error when just evaluating and comparing vertical, hemispheric measurements in experiments and non-visual lighting design projects. We thus encourage the (additional) use of a FOV occlusion for eye-level measurements in typical viewing directions and provide open-source 3D-print files.

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“…Many groups have worked on standardizing HCL evaluation criteria by considering the melanopic effects of ocular light in human-centric lighting [10][11][12][13]. Numerous attempts have been made to develop light-emitting diode (LED) spectral power distributions (SPDs) for human users in the HCL framework [14,15]. For LED office lighting, Islam et al [16] and Dangol et al [17] showed that color perception is related to the degree of acceptance by users, which can be assessed on scales of acceptable-unacceptable or like-dislike.…”

Section: Introductionmentioning

confidence: 99%

A Randomized Controlled Trail for Comparing LED Color Temperature and Color Rendering Attributes in Different Illuminance Environments for Human-Centric Office Lighting

Lee

Yoon

2021

Applied Sciences

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In this study, two experiments were conducted to investigate the effects of the color rendering index (CRI) and correlated color temperature (CCT) of light-emitting diode (LED) lighting on office user acceptance and to explore the proper color attributes for human-centric office lighting. Experiment 1 had four LED lights, with two levels for the CRI (CRI < 80: 79, 76; or CRI ≥ 80: 83, 84) and CCT (3000 K or 6500 K) at 300 lux. In experiment 2, there were four LED lights, with several levels for the CRI (CRI < 80: 78; or CRI ≥ 80: 87, 83) and CCT (3000 K or 6500 K) at 500 lux. Ninety-six participants in experiment 1 and ninety-four participants in experiment 2 performed a reading task. The results in experiment 1 and experiment 2 showed that LEDs with lower CRI values at warm color temperatures were rated as more acceptable than LEDs with higher CRI values at warm color temperatures. However, the positive effect extended to LEDs with higher CRI values at cool temperatures but not to LEDs with lower CRI values at cool temperatures. Therefore, the findings are that LEDs with lower CRI values at warm color temperatures and LEDs with higher CRI values at cool temperatures provide the right level of color attributes for office lighting.

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Measurement of Circadian Effectiveness in Lighting for Office Applications

Cited by 12 publications

References 93 publications

Influence of the Human Field of View on Visual and Non-Visual Quantities in Indoor Environments

Influence of the Human Field of View on Visual and Non-Visual Quantities in Indoor Environments

Influence of the Human Field of View on Visual and Non-visual Quantities in Indoor Environments

A Randomized Controlled Trail for Comparing LED Color Temperature and Color Rendering Attributes in Different Illuminance Environments for Human-Centric Office Lighting

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