Geometric system analysis of ILMD-based LID measurement systems using Monte-Carlo simulation

M Katona,C Neumann,K Trampert,U Krüger,C Schwanengel

doi:10.1088/1742-6596/2149/1/012015

M Katona, C Neumann + Show 3 more

Open Access

https://doi.org/10.1088/1742-6596/2149/1/012015

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Abstract

Imaging Luminance Measuring Device (ILMD) based luminous intensity distribution measurement systems are an established method for measuring the luminous intensity distribution (LID) of light sources in the far field. The advantage of this system is the high-resolution acquisition of a large angular range with one image. For the uncertainty budget, the mathematical description of the system can be divided into photometric and geometric contributions. In the following, we will present a Monte-Carlo approach to analyse the geometric contributions which are the uncertainty of measurement direction and measurement distance. Therefore, we set up a geometric system description based on kinematic transformations that describes the connection between detector and light source position. To consider all relevant input quantities we simulate the adjustment and measurement process. Finally, an analysis of the geometric input parameters is shown.

Highlights

The luminous intensity distribution (LID) I(φ, θ) is the luminous flux Φ per solid angle Ω that is emitted in the direction (φ, θ) [1]. dΦ(φ, θ)I(φ, θ) = dΩ(φ, θ). (1) a solid angle is just defined for a point, the necessary assumption of the light source (device under test (DUT)) is a point source
The LID I(φ, θ) is the luminous flux Φ per solid angle Ω that is emitted in the direction (φ, θ) [1]
A solid angle is just defined for a point, the necessary assumption of the light source (device under test (DUT)) is a point source

Summary

Introduction

The LID I(φ, θ) is the luminous flux Φ per solid angle Ω that is emitted in the direction (φ, θ) [1]. A solid angle is just defined for a point, the necessary assumption of the light source (device under test (DUT)) is a point source This indicates that the measurement distance has to be greater than the dimensions of the DUT so that the photometric distance law is satisfied. Common methods to measure the LID are far-field goniophotometers, e.g. an ILMD measurement system [2,3,4] For this method, a DUT is mounted on a goniophotometer and illuminates a lambertian reflecting flat white screen in a large distance (see Figure 1). The geometric adjustment assigns angular directions to camera (or screen) pixels. For this we use an angle standard.

Measurement Model

Detector

21 V-axis rotation V

Results concerning the total measurement system

Conclusion