Table of Contents
Photometry for Traffic Engineers...
Basic Light Measurement
Taxonomy of Photometric Units
Light Energy
CIE Spectral Luminosity Function
Commission Internationale de l’Eclairage
(CIE) Vl
Radiometric to Photometric Conversion via CIE Vl
and V’l
Luminous Flux (The Lumen)
Luminous Flux
The Lumen
Luminous Flux Equation Revealed
Step-by-Step Calculation of Luminous Flux
Step 1. Measure Radiant Energy across l using
a Spectroradiometer
Sample Data from Spectroradiometer
Step 2. Convert Watts to Lumens
Results of Vl Conversion
Step 3. Integrate Lumens from 380-730 nm
Luminous Flux Equation Revisited
Luminous Intensity (The Candela)
Luminous Intensity
Solid Angles, Surfaces of Spheres and the Steradian
The Candela
Broadband Measurement of Luminous Intensity
Illuminance (Lux)
Illuminance
Inverse-Square Law
Inverse-Square Law Example
Cosine Law
Cosine Law Example
Broadband Photometer (Illumination Meter)
Cosine Diffuser Head
Luminance (Candelas/m2)
Luminance
Luminance as Projected Luminous Intensity
Luminance is an Abstraction
Broadband Luminance Meter
Conservation of Luminance Across Viewing Geometry
Lambertian Surface Diffusion (Another Cosine Law)
Observation Angle
Observation Distance
Special Problems: LED Symbol Heads
Light Emitting Diodes (LED’s) |
Author: Frank Schieber Email: schieber@usd.edu
Home Page: http://www.usd.edu/~schieber/trb2000
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