Multidimensional Estimation of Spectral Sensitivities

Walowit, Eric; Buhr, H.J.; Wüller, Dietmar

doi:10.2352/issn.2169-2629.2017.25.1

Cited by 5 publications

(3 citation statements)

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“…An accurate and precise measurement of the RGB color sensor's spectral sensitivity functions R(λ), G(λ), and B(λ) is necessary to guarantee an adequate sensor processing for the proper monitoring of the relevant lighting control parameters in mixed lighting conditions as sketched in the Introduction. The literature usually suggests to use a monochromator for this purpose [113][114][115][116][117][118]. An exemplary illustration of the experimental setup is given in Figure 3.…”

Section: Determination Of the Spectral Sensitivity Curves Of An Rgb C...mentioning

confidence: 99%

Processing RGB Color Sensors for Measuring the Circadian Stimulus of Artificial and Daylight Light Sources

et al. 2022

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The three main tasks of modern lighting design are to support the visual performance, satisfy color emotion (color quality), and promote positive non-visual outcomes. In view of large-scale applications, the use of simple and inexpensive RGB color sensors to monitor related visual and non-visual illumination parameters seems to be of great promise for the future development of human-centered lighting control systems. In this context, the present work proposes a new methodology to assess the circadian effectiveness of the prevalent lighting conditions for daylight and artificial light sources in terms of the physiologically relevant circadian stimulus (CS) metric using such color sensors. In the case of daylight, the raw sensor readouts were processed in such a way that the CIE daylight model can be applied as an intermediate step to estimate its spectral composition, from which CS can eventually be calculated straightforwardly. Maximal CS prediction errors of less than 0.0025 were observed when tested on real data. For artificial light sources, on the other hand, the CS approximation method of Truong et al. was applied to estimate its circadian effectiveness from the sensor readouts. In this case, a maximal CS prediction error of 0.028 must be reported, which is considerably larger compared to daylight, but still in an acceptable range for typical indoor lighting applications. The use of RGB color sensors is thus shown to be suitable for estimating the circadian effectiveness of both types of illumination with sufficient accuracy for practical applications.

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Section: Determination Of the Spectral Sensitivity Curves Of An Rgb C...mentioning

confidence: 99%

Processing RGB Color Sensors for Measuring the Circadian Stimulus of Artificial and Daylight Light Sources

et al. 2022

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“…The narrow band emission spectra have very little overlap. Furthermore, the match is not intended for faithful color reproduction [2,38], the analysis of colorants [39], digital color reconstruction [40] or to estimate spectral sensitivities of a capture device [41]. The aim of the factor analysis is only to match light in a way that it causes the same chemical degradation.…”

Section: Prediction Of Fading Of White Light Ledmentioning

confidence: 99%

Spectral Light Fading of Inkjet Prints

Hofmann¹,

Hofmann-Sievert²

2022

Heritage

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(1) Background: The use of light-emitting diode (LED) lighting is increasingly replacing traditional light sources in museums. There is a need to anticipate the damage caused by LED lighting to photographic prints. The aim of this study is to quantitatively predict fading on three inkjet color patches exposed to different white light LED; (2) Method: The novel approach of this work is to measure the wavelength-dependent photochemical efficiency on color patches using a narrow band LED. First, the color patches are exposed to narrow band LED lamps in a proprietary light chamber. Sensitivity curves are obtained by plotting the density changes caused by narrow band exposure as a function of the exposure. In the second step, action spectra are derived from the slopes of the sensitivity curves. The action spectra correspond to the rates of change of a color patch to exposure with different wavelengths of light. In the third step, the narrow band light emissions are fitted to the emission spectra of the white LED of interest. The fitting factors are used to calculate the weighted sum of the density changes; (3) The method predicts the absolute density change of color patches for several white light LED exposures.

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“…Li 11 et al proposed a multispectral imaging system based on a tunable LED light source as an active illumination source. Philipp Urban 12 et al and Eric Walowit 13 et al performed spectral sensitivity estimation using LED light sources, and these methods used multiple LED light sources lit sequentially to provide multiple illumination environments.…”

Section: Introductionmentioning

confidence: 99%

Camera spectral sensitivity estimation based on spectrally tunable LED illumination

2023

Intelligent Photonics (Meta) Technology Symposium (IPTS2023)

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The choice of light source affects the accuracy of the spectral sensitivity estimation. In this paper, we propose to estimate the spectral sensitivity function of digital camera using spectrally tunable LED light sources. The spectral power distribution of the LED light source is determined by a combination of multiple LEDs and their weight coefficients. The method of tuning the weight coefficients of the LEDs includes Monte Carlo method and particle swarm optimization algorithm, so that the LED light source with the smallest estimation error is defined as the optimal light source. Experimental results show that the particle swarm algorithm gives the best estimation results. The relative error of estimation using LED light sources is significantly reduced when compared with the results when using a single light source for estimation (e.g., D65 light source).

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Multidimensional Estimation of Spectral Sensitivities

Cited by 5 publications

References 0 publications

Processing RGB Color Sensors for Measuring the Circadian Stimulus of Artificial and Daylight Light Sources

Processing RGB Color Sensors for Measuring the Circadian Stimulus of Artificial and Daylight Light Sources

Spectral Light Fading of Inkjet Prints

Camera spectral sensitivity estimation based on spectrally tunable LED illumination

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