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Perception of Visual Targets in
Central and Peripheral Vision

Project Team at Lighting Laboratory
  • Professor, D.Sc. (Tech.) Liisa Halonen
  • Research Scientist, D.Sc. (Tech.) Pasi Orreveteläinen
  • Research Scientist, D.Sc. (Tech.) Marjukka Eloholma
  • Research Scientist, M.Sc. Jaakko Ketomäki
Project Objectives

The aim of the project was to model the spectral sensitivity of the eye at mesopic and low photopic light levels (0.1 cd/m² to 20 cd/m²). The measurements were conducted using a large hemispherical surface and a Goldman perimeter. Two different approaches were applied in the research.

Reaction time measurements were conducted with the large hemispherical surface. It was assumed that if a correct spectral luminous efficiency function is applied for the target contrasts, the reaction time would be the same for all target colours. Reaction time measuremens were conducted at target eccentricities 0° and 10°.

Contrast threshold measurements were made using the large hemispherical surface and the Goldman perimeter. In the contrast threshold measurements it was assumed that the contrasts calculated with the correct spectral luminous efficiency function would yield the same threshold contrast for each target colour. Contrast threshold measurements were conducted at target eccentricity 10° with the Goldman perimeter and at 0°, 10°, 30° and 60° target eccentricities with the large hemisphere.

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