Description

The emerging use of Charge Coupled Device (CCD) detectors and frame grabbers in image processing evidently created the challenge to capture all of the available photometric information within a relatively large field of view on the road, but to the same level of spatial resolution as that of a conventional luminance-meter. Most conventional luminance-meters sample only a relatively small area of the environment. Using CCD arrays, large scenes can be captured and converted to digital photometric information. The complexity of such scenes preclude the use of conventional photometric technology since the amount of labour and time involved in obtaining the huge number of measurement data would be prohibitive. CCD based photometers compared to the single cell photodetectors have to cope not only with the spectral matching, uniformity and linearity problem, to mention only the most important ones, but with additional problems, like viewing angle, vignetting, etc.

In the mid 90's the CIE Technical Committee 4-26 "Systems for Measurement of Photometric Quantities of Road Lighting Installations" of the CIE Division 4 "Lighting and Signalling for Transport" dedicated two workshops and intercomparisons to this topic. The material of the workshops, included in these proceedings, gives an overview on the different types of realization of the mobile and static systems for the measurement of photometric quantities of road lighting in different countries. The realized systems gave the possibility to extend the measured photometric quantities beyond luminance and illuminance to determine chromaticity coordinates, to evaluate disability glare or to analyse the theoretical aspects of the moving observer.

The Proceedings contain the text of the papers provided by the speakers. The publication consists of 114 pages.

Description

The Proceedings of the Symposium contains on approximately 100 pages the text (partly only abstracts) of 23 papers read at the symposium. Questions dealt with encompassed items as fundamentals of LED technology, dealing also with problems of OLEDs, spectral and spatial characteristics of LEDs, their use in traffic lights and other applications.

Several papers addressed the problem of colorimetric measurement: not every spectroradiometer is capable of accurately determine the spectral and colorimetric properties of LEDs. Methods of spectral correction, deconvolution of measured spectra have been discussed.

With the continuous increase of LED luminance and radiance the question of eye hazard becomes again acute. Papers discussed the question both from the point of view of coherent and incoherent radiation sources. Among the LED applications the most important one is for the time being the use in traffic lights. This question was thoroughly discussed and both the American and Australian situation delivered. LEDs become applicable also in indoor lighting, and there the colour rendering is an important parameter. A visual experiment has shown that the results of the CIE colour rendering test method do not correlate well with visual observations. In many applications more than one LED has to be used, the testing of such LED clusters is a still unsolved problem, which was also addressed at the symposium.

These Proceedings include the papers provided by the speakers and a transcript of the open discussion. The publication consists 112 pages.