Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC

Abstract In 1924, the CIE published and standardized the photopic luminous efficiency function. Based on the standardized curve, luminous flux in lumens, luminance in cd/m $$^2$$ 2 , and illuminance in lux are determined by an integral of the curve and the incident light spectra in photometers and a...

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Main Authors: Tran Quoc Khanh, Peter Bodrogi, Babak Zandi, Trinh Quang Vinh
Format: Article
Language:English
Published: Nature Portfolio 2023-09-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-023-41084-7
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author Tran Quoc Khanh
Peter Bodrogi
Babak Zandi
Trinh Quang Vinh
author_facet Tran Quoc Khanh
Peter Bodrogi
Babak Zandi
Trinh Quang Vinh
author_sort Tran Quoc Khanh
collection DOAJ
description Abstract In 1924, the CIE published and standardized the photopic luminous efficiency function. Based on the standardized curve, luminous flux in lumens, luminance in cd/m $$^2$$ 2 , and illuminance in lux are determined by an integral of the curve and the incident light spectra in photometers and are considered physical brightness. However, human brightness perception is not only weighted by this simple determination, but is a more complicated combination of all L-cones, M-cones, S-cones, rods and later ipRGCs, which was partly described by the equivalent brightness of Fotios et al. with the correction factor $$(S/V)^{0.24}$$ ( S / V ) 0.24 . Recently, new research has demonstrated the role of ipRGCs in human light perception. However, it is still unclear how these signal components of the human visual system are involved in the overall human brightness perception. In this work, human brightness perception under photopic conditions was investigated by visual experiments with 28 subjects under 25 different light spectra. In this way, the contributions of the signal components can be investigated. An optimization process was then performed on the resulting database. The results show that not only the $$L+M$$ L + M component, but also the S-cones and ipRGC play a role, although it is smaller. Thus, the visually scaled brightness model based on the database optimization was constructed using not only illuminance but also S-cones and ipRGC with $$R^2$$ R 2 of 0.9554 and RMSE of 4.7802. These results are much better than the brightness model after Fotios et al. using only S-cones ( $$R^2$$ R 2 = 0.8161, RMSE = 9.7123) and the traditional model without S-cones and ipRGC ( $$R^2$$ R 2 = 0.8121, RMSE = 9.8171).
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spelling doaj.art-f11e38647a844b5b8bdd2841d7fcc5692023-11-26T13:18:22ZengNature PortfolioScientific Reports2045-23222023-09-0113111210.1038/s41598-023-41084-7Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGCTran Quoc Khanh0Peter Bodrogi1Babak Zandi2Trinh Quang Vinh3Laboratory of Adaptive Lighting Systems and Visual Processing, Department of Electrical Engineering and Information Technology, Technical University of DarmstadtERCO GmbHLaboratory of Adaptive Lighting Systems and Visual Processing, Department of Electrical Engineering and Information Technology, Technical University of DarmstadtLaboratory of Adaptive Lighting Systems and Visual Processing, Department of Electrical Engineering and Information Technology, Technical University of DarmstadtAbstract In 1924, the CIE published and standardized the photopic luminous efficiency function. Based on the standardized curve, luminous flux in lumens, luminance in cd/m $$^2$$ 2 , and illuminance in lux are determined by an integral of the curve and the incident light spectra in photometers and are considered physical brightness. However, human brightness perception is not only weighted by this simple determination, but is a more complicated combination of all L-cones, M-cones, S-cones, rods and later ipRGCs, which was partly described by the equivalent brightness of Fotios et al. with the correction factor $$(S/V)^{0.24}$$ ( S / V ) 0.24 . Recently, new research has demonstrated the role of ipRGCs in human light perception. However, it is still unclear how these signal components of the human visual system are involved in the overall human brightness perception. In this work, human brightness perception under photopic conditions was investigated by visual experiments with 28 subjects under 25 different light spectra. In this way, the contributions of the signal components can be investigated. An optimization process was then performed on the resulting database. The results show that not only the $$L+M$$ L + M component, but also the S-cones and ipRGC play a role, although it is smaller. Thus, the visually scaled brightness model based on the database optimization was constructed using not only illuminance but also S-cones and ipRGC with $$R^2$$ R 2 of 0.9554 and RMSE of 4.7802. These results are much better than the brightness model after Fotios et al. using only S-cones ( $$R^2$$ R 2 = 0.8161, RMSE = 9.7123) and the traditional model without S-cones and ipRGC ( $$R^2$$ R 2 = 0.8121, RMSE = 9.8171).https://doi.org/10.1038/s41598-023-41084-7
spellingShingle Tran Quoc Khanh
Peter Bodrogi
Babak Zandi
Trinh Quang Vinh
Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC
Scientific Reports
title Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC
title_full Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC
title_fullStr Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC
title_full_unstemmed Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC
title_short Brightness perception under photopic conditions: experiments and modeling with contributions of S-cone and ipRGC
title_sort brightness perception under photopic conditions experiments and modeling with contributions of s cone and iprgc
url https://doi.org/10.1038/s41598-023-41084-7
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