Dissertation in the field of Illumination Engineering, Can Cengiz
The title of thesis is Visual Performance Under Mesopic Conditions: Towards Determination of Adaptation Luminance
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International Commission on Illumination (CIE) published a system for visual performance-based mesopic photometry in 2010. It is valid between the lumi-nances 0.005 cd/m2 and 5 cd/m2. In night-time driving conditions, the luminances in the visual scene are in the mesopic range; thus, mesopic photometry should be adopted when assessing lighting in outdoor areas and other night-time traffic environments. In order to implement the CIE mesopic photometry, the back-ground photopic luminance, i.e. adaptation luminance, is required as an input value.
The aim of the study is to develop methods for estimating the field of view of which the luminance is to be used as the adaptation luminance in implementing the CIE 191 system for mesopic photometry. This is realised by applying methods such as combining eye-tracking data with corresponding luminance data and analysing peripheral target detection under uniform and non-uniform luminous backgrounds.
In the study of combining eye-tracking measurements with luminance data, the visual scene areas with the highest density of gaze distributions were determined. Experiments in laboratory conditions were conducted in order to obtain the effect of background and target location and its luminance on visual performance. Re-action time and contrast threshold measurements were made to analyse periph-eral target detection in uniform and non-uniform backgrounds. Under non-uniform background luminances, peripheral target detection depends on the local luminance of the target and the luminance uniformity of the surrounding area of the target. The results verify that each part of the retina adjusts its sensitivity inde-pendently, which refers to local adaptation. However, the complexity of the visual field also has an effect on visual sensitivity in peripheral vision.
Opponent: Prof. Frangiskos Topalis, National Technical University of Athens, Greece
Supervisor: Professor Liisa Halonen, Aalto University School of Electrical Engineering, Department of Electrical Engineering and Automation
Contact information:
Can Cengiz
tel +358 40 9324 450
can.cengiz@aalto.fi