Abstract
Multi-channel LED luminaires offer a powerful tool to vary retinal receptor signals while keeping visual parameters such as color or brightness perception constant. This technology could provide new fields of application in indoor lighting since the spectrum can be enhanced individually to the users’ favor or task. One possible application would be to optimize a light spectrum by using the pupil diameter as a parameter to increase the visual acuity. A spectral- and time-dependent pupil model is the key requirement for this aim. We benchmarked in our work selected L- and M-cone based pupil models to find the estimation error in predicting the pupil diameter for chromatic and polychromatic spectra at 100 cd/m2. We report an increased estimation error up to 1.21 mm for 450 nm at 60–300 s exposure time. At short exposure times, the pupil diameter was approximately independent of the used spectrum, allowing to use the luminance for a pupil model. Polychromatic spectra along the Planckian locus showed at 60–300 s exposure time, a prediction error within a tolerance range of ± 0.5 mm. The time dependency seems to be more essential than the spectral dependency when using polychromatic spectra.
Highlights
The pupil aperture is an essential factor in photometric and visual investigations because of its direct influence on both retinal illumination and the retinal image q uality[1]
We found that there are statistically significant differences in both, chromatic and polychromatic spectra at one second exposure time, an approximately constant averaged pupil diameter can be assumed for different spectra
When evaluating the models from Crawford, De Groot and Gebhard and Watson and Yellot, we found that the largest miscalculation of the pupil diameter lies in this time range
Summary
The pupil aperture is an essential factor in photometric and visual investigations because of its direct influence on both retinal illumination and the retinal image q uality[1]. The first step to actively optimize the pupil aperture through illumination without influencing other image-forming vision parameters such as brightness or color perception is the construction of an accurate model which predicts the spectral and time-dependent pupil diameter. Such a model can be used in a heuristic or gradient-based optimization procedure as an objective or constraint function to design the desired light spectrum for visual tasks. We have used a custom build accurate temperature-controlled multi-channel LED luminaire to investigate how high the prediction errors in L- and M-cone based models can be and to what extent this is influenced by the temporal and spectral dependence of the pupil control path. We collected pupil data from an inter- and intrapersonal study to ensure a general statement and to guarantee repeatability of the Scientific Reports | (2020) 10:10988 |
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