LED near-field goniophotometer at PTB

López, Marco; Bredemeier, Knut; Rohrbeck, N; Véron, Ch.; Schmidt, Franz; Sperling, Armin

doi:10.1088/0026-1394/49/2/s141

Cited by 22 publications

(17 citation statements)

References 7 publications

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“…All coordinates and directions are transformed from the camera system into the global goniometer system x; y; z; θ; ϕ. As described in [19], for each pixel the discrete part of the luminous flux ΔΦx; y; z; θ; ϕ can be determined and which is then typically summarized by the 6-tuple x; y; z; θ; ϕ; ΔΦ. Collecting all 6-tuples from all pixels at all camera positions yields a set of so-called ray data with typically 10 6 to 10 9 of such tupels, which contain all information about the light-emitting characteristics of the light source.…”

Section: Near-field Goniophotometermentioning

confidence: 99%

Virtual experiment for near-field goniophotometric measurements

et al. 2014

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Near-field goniometric measurements are employed to determine the photometric characteristics of light sources, i.e., the spatial and angular distribution of the emitted light. To this end, a complex measurement system consisting of a goniometer and a CCD-based imaging photometer is employed. In order to gain insight into the measurement system and to enable characterization of the whole measurement setup, we propose to apply a computer model to conduct virtual experiments. Within the computer model, the current state of all parts of the virtual experiment can be easily controlled. The reliability of the computer model is demonstrated by a comparison to actual measurement results. As an example for the application of the virtual experiment, we present an analysis of the impact of axial malpositions of the goniometer and camera.

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Section: Near-field Goniophotometermentioning

confidence: 99%

Virtual experiment for near-field goniophotometric measurements

et al. 2014

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“…As the steady state condition in photometry neglects temporal variations, R is reduced to a 6-dimensional function. Near field goniophotometry [10][11][12] can be used to directly measure a 5-dimensional R(X , Y , Z , φ, ϑ). Only the spectral information is lost due to its integration on an imaging luminance measurement device (ILMD).…”

Section: Introductionmentioning

confidence: 99%

Hyperspectral LED models for optical simulations

et al. 2016

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Precise spectral and colorimetric simulations in commercial ray tracing software require realistic light source models, which provide spectral information as a function of angle and spatial dimension. We describe and validate a general workflow to create hyperspectral LED models as a linear combination of spectral models. The workflow only requires user defined precisions and rayfiles obtained with different optical filters. The rayfiles are transformed into histogram based models, whose precision is evaluated by normalized cross-correlation values of their intensity distributions in the near-, mid-and far field. Additionally, the concept is evaluated with a spatial and spectral well defined test device.

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“…The perfect light source model or rayfile would describe spatially and angular varying luminance and spectra. This information can be created by combining spectral and goniophotometric measurements [1][2][3]. Rykowski [4] proposed different methods to combine goniophotometric measurements and spectral measurements.…”

Section: Introductionmentioning

confidence: 99%

Determination of tailored filter sets to create rayfiles including spatial and angular resolved spectral information

Rotscholl¹,

Trampert²,

Perner³

et al. 2015

Opt. Express

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To simulate and optimize optical designs regarding perceived color and homogeneity in commercial ray tracing software, realistic light source models are needed. Spectral rayfiles provide angular and spatial varying spectral information. We propose a spectral reconstruction method with a minimum of time consuming goniophotometric near field measurements with optical filters for the purpose of creating spectral rayfiles. Our discussion focuses on the selection of the ideal optical filter combination for any arbitrary spectrum out of a given filter set by considering measurement uncertainties with Monte Carlo simulations. We minimize the simulation time by a preselection of all filter combinations, which bases on factorial design.

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LED near-field goniophotometer at PTB

Cited by 22 publications

References 7 publications

Virtual experiment for near-field goniophotometric measurements

Virtual experiment for near-field goniophotometric measurements

Hyperspectral LED models for optical simulations

Determination of tailored filter sets to create rayfiles including spatial and angular resolved spectral information

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